Lithium battery for a ball machine

Topspin_80 · Jan 23, 2013

I had my ball machine for 2 and a half years now , I am going through the second battery and ready to get a new one .

The first battery , the original one , was an 18 AH lead acid , within 5 months playing time was half of what I was getting at the beginning , so I decided to get a new one with more capacity , I bought a Panasonic 22 AH also lead acid .

With the new battery I was getting 5 and a half hrs without any spin nor oscillation and with the standard speed of 60 mph , since I play with plenty spin and with two line or any of the pre-programmed drills , a little over 4 hrs was all I used to get .

Now after 2 years , playing time has dropped dramatically to about 90' , this is not enough for me , therefore I am buying a new one .

I can not buy a bigger size because it wouldn't fit inside the machine so I can only go for bigger capacity .

I was going to buy a silicone lead greensaver 24AH , but then I saw a lithium battery twice as expensive as the green saver , I started doing some research , and apparently , I say apparently because I am not an expert on batteries and I can get lost with the specifications , it can give you much more running time .

Does anyone have experience with Lithium Iron Phosphate batteries ???

Any input would be much appreciated

IdrinkYourMilkshake · Jan 23, 2013

I'm looking for the same solution. Currently I'm using a 35ah lead acid that sits externally behind the machine. I put a plug in the back. The best solution I could find was this, its not cheap, but if the user does get 5x the life then it more than pays. 50% less weight is nice. I thought about building my own pack from LiFePO4 cells, but they don't naturally add up to 12v, which is why the 12v batteries have circuitry to bring it down. Also they need to be protected from overcharge and discharge. So a specific 12v battery is the best solution, there just aren't many different ones available. A123 Systems is the top of the line cell, but I can't find any12v from them.

BoingTennis · Jan 23, 2013

Very interesting idea! I'm having the same battery life problem with normal SLA battery. My 2year old Lobster only last max 2hrs now.

With good SLA at around 40-50 bucks, I'd be willing to try this lithium batt if it at least doubles the lifetime of the old SLA. I'm not looking for a batt that would last for more than 4hours each session, but more concerned about capacity maintenance over the lifetime of the battery.

Do we need to swab the batt charger as well? My Lobster premium charger is made by Soneil. I believe it has pulse mode charging to remove sulphation which the lithium iron batt is not compatible with.

Chas Tennis · Jan 23, 2013

Topspin_80 said:
I had my ball machine for 2 and a half years now , I am going through the second battery and ready to get a new one .

The first battery , the original one , was an 18 AH lead acid , within 5 months playing time was half of what I was getting at the beginning , so I decided to get a new one with more capacity , I bought a Panasonic 22 AH also lead acid .

With the new battery I was getting 5 and a half hrs without any spin nor oscillation and with the standard speed of 60 mph , since I play with plenty spin and with two line or any of the pre-programmed drills , a little over 4 hrs was all I used to get .

Now after 2 years , playing time has dropped dramatically to about 90' , this is not enough for me , therefore I am buying a new one .

I can not buy a bigger size because it wouldn't fit inside the machine so I can only go for bigger capacity .

I was going to buy a silicone lead greensaver 24AH , but then I saw a lithium battery twice as expensive as the green saver , I started doing some research , and apparently , I say apparently because I am not an expert on batteries and I can get lost with the specifications , it can give you much more running time .

Does anyone have experience with Lithium Iron Phosphate batteries ???

Any input would be much appreciated

A friend of mine had a Tennis Tudor with a lead acid battery. He replaced the battery with two white plastic battery holder tubes that had 3 or 4 rechargeable D cells in each tube. I assume that they were Lithium batteries. They were very reasonable in cost.

I burrowed the machine. Although I did not do long hitting secessions I found the performance to be very satisfactory for running the machine. They are much lighter than a lead acid battery. I guess that you could analyze running time using amp-hours.

The machine manufacturers should research using them instead of lead acid.

I posted the details in this forum I believe but did not find searching so far.

Topspin_80 · Jan 23, 2013

BoingTennis said:
Very interesting idea! I'm having the same battery life problem with normal SLA battery. My 2year old Lobster only last max 2hrs now.

With good SLA at around 40-50 bucks, I'd be willing to try this lithium batt if it at least doubles the lifetime of the old SLA. I'm not looking for a batt that would last for more than 4hours each session, but more concerned about capacity maintenance over the lifetime of the battery.

Do we need to swab the batt charger as well? My Lobster premium charger is made by Soneil. I believe it has pulse mode charging to remove sulphation which the lithium iron batt is not compatible with.

I have also myself a lobster , I have the original 1amp fast charger , but I ended up buying the 3 amp premiun charger , because the 1 amp fast charger would take for ever . When the original 18 AH battery was fully discharged with the fast charger it would take 22hr 30' to recharge , so if I had to go back to back days to the park at the same time , I had to take it not completely recharged .

Premium charger solved this problem . Specially since I had already bought the Panasonic 22 AH and since it has more capacity it would take 30 hrs to be fully recharged . With the premium charger less than 4 hrs .

I live currently in Holland , and things here are more expensive than in the States . I can buy an 18 AH SLA for $60 , but the max time it can give me is around 4 hrs , and I do play 4 hrs , but that means full discharge , if with a SLA you go full discharge after full discharge , immediately your playing time dwindles a lot , then is buying time again .

I am not sure , but what I gather after reading some specifications is that Lithium batt with the same capacity than a lead acid , runs at least twice as long , so if for instance , a lead batt can give me 5 hrs playing time , from a lithium I can get 10 hrs .
I am not sure about this , that is why I would like to hear from someone who had had a Lithium batt .

Not that I am planning to play 10 hrs , but if they have the capacity to give you 10 hrs , and you play 4 , the depth of discharge is 40% and with such a low discharge , you can get 3,000 cycles .

You know what 3,000 cycles are ??? is playing everyday 4 hrs for the next 8 years . Then paying twice or thrice as much it would still be a bargain .

Topspin_80 · Jan 23, 2013

IdrinkYourMilkshake said:
I'm looking for the same solution. Currently I'm using a 35ah lead acid that sits externally behind the machine. I put a plug in the back. The best solution I could find was this, its not cheap, but if the user does get 5x the life then it more than pays. 50% less weight is nice. I thought about building my own pack from LiFePO4 cells, but they don't naturally add up to 12v, which is why the 12v batteries have circuitry to bring it down. Also they need to be protected from overcharge and discharge. So a specific 12v battery is the best solution, there just aren't many different ones available. A123 Systems is the top of the line cell, but I can't find any12v from them.

I can only imagine how much that 35 AH batt can weigh .
Lobster also have the external battery solution , but this is something I really want to avoid , the batteries I have weigh around 17 lbs , so 2x = 34 lbs , whereas a lithium battery is only 6 lbs . 28 lbs difference !!!!!

Topspin_80 · Jan 23, 2013

Chas Tennis said:
A friend of mine had a Tennis Tudor with a lead acid battery. He replaced the battery with two white plastic battery holder tubes that had 3 or 4 rechargeable D cells in each tube. I assume that they were Lithium batteries. They were very reasonable in cost.

I burrowed the machine. Although I did not do long hitting secessions I found the performance to be very satisfactory for running the machine. They are much lighter than a lead acid battery. I guess that you could analyze running time using amp-hours.

The machine manufacturers should research using them instead of lead acid.

I posted the details in this forum I believe but did not find searching so far.

Thanks for the input .

What I would like is to hear from someone who bought a brand new tennis machine , because they all come with lead acid or gel at the most , and then decided to switch to lithium .

I would like to hear from someone like this , because that person would know exactly the parameters of both batts , and that can really help .

IdrinkYourMilkshake · Jan 23, 2013

Topspin_80 said:
I can only imagine how much that 35 AH batt can weigh .
Lobster also have the external battery solution , but this is something I really want to avoid , the batteries I have weigh around 17 lbs , so 2x = 34 lbs , whereas a lithium battery is only 6 lbs . 28 lbs difference !!!!!

This is the exact one. Site says it's 25 pounds, but I carry it in a small pouch with nice handles. I have a Silent Partner lite and put the plug out the back. I am finally tired of lugging the battery around and was about to open the machine back up and put it in there, but since I saw this post, I think I'll try one more time to roll my own solution. It would be too heavy with the lead acid I guess.

BoingTennis · Jan 23, 2013

Topspin_80 said:
Thanks for the input .

What I would like is to hear from someone who bought a brand new tennis machine , because they all come with lead acid or gel at the most , and then decided to switch to lithium .

I would like to hear from someone like this , because that person would know exactly the parameters of both batts , and that can really help .

Topspin, I don't think we will find a lot of feedback on these batteries being used with ball machines.

I find this to be a worthy project to try, since my Lobster is in need of a replacement battery anyway. I myself do not live in the US, and that is the more reason for me to buy these LiFePO4 batteries since they are so light, shipping it to Asia would be cheaper.

After I did some google research, these are some of my findings:
1) This battery type will most likely work very well with our ball machines. They have been used extensively in many applications including automotive, EV, etc. Both high-discharge and sustained-discharge types of applications have been covered.
2) Some batteries has better electronic features than others. Shorai batteries (big with motorcycle owners) does not seem to have as much built-in protection and balancing features as the batteries from Powerizer.
Battery balancing feature seems to be an important one to have.
3) Price varies greatly and it looks like it depends on the electronic features I mentioned above.
4) Our stock charger (for Lobster owners) which are most likely made by Soneil are save to use with the LiFePO4 batteries. Pulse mode charging in the Soneil will only function when the battery is at 0.5V-5V. LiFePO4 batteries are not supposed to be discharged below 10V, so our charger will never have its pulse mode charging activated. Soneil charger highest charging voltage is 14.7V, which is below the max charging voltage for LiFePO4 batteries (15V).

Here are the alternatives (for Lobster owners) 7.13L x 3.03W x 6.57H:

1) Shorai 18Ah 5.83L x 2.60W x 4.13H
Only 2.12 lbs, prismatic cells, smaller than stock Lobster battery, same capacity as stock, doesn't seem to have built-in protections/balancing.
2) OEM Battery from BatterySpace with Balancing
7 lbs, prismatic cells, same size as the stock Lobster battery, 20Ah capacity, has balancing PCB but no built-in protection.
3) OEM Battery from BatterySpace w/o any extra features
6.6 lbs, prismatic cells, same size as Lobster battery, 20Ah, no balancing/protection, cheapest I've found.
4) Powerizer w/built in protection and balancing (PCM)
7lbs, cylindrical cells, same size as Lobster battery, 20Ah, complete built-in balancing and protection, expensive.

I'm going with option #2. Will purchase today and will probably get it within 3 weeks. I'll snap some pictures and test it ASAP.

IdrinkYourMilkshake · Jan 23, 2013

BoingTennis said:
I'm going with option #2. Will purchase today and will probably get it within 3 weeks. I'll snap some pictures and test it ASAP.

I checked the specs and it doesn't say anything about over discharge protection of course, so how are you going to prevent the machine from killing the battery? Same goes for charging it? I think the powerizer is the safe bet.

retrograde · Jan 23, 2013

Folks who know tons about lithium polymer and other types of batteries are radio controlled model airplane enthusiasts! Some of them are extremely technical in knowledge. You can find them hanging out in this forum:

http://www.rcgroups.com/batteries-and-chargers-129/

A very friendly group and willing to answer questions.

From what I know, lithium batteries are very sensitive to discharge levels so you have to stop using them after they drop below a certain voltage per cell. You can't necessarily run them until the ball machine drops below a certain performance level. Model airplane enthusiasts often monitor battery voltage with on-board electronics, or they use a timer.

Chas Tennis · Jan 24, 2013

Chas Tennis said:
........................He replaced the battery with two white plastic battery holder tubes that had 3 or 4 rechargeable D cells in each tube. I assume that they were Lithium batteries. They were very reasonable in cost.
.........................................................

Charging: For these D cell rechargeable batteries they were removed from the ball machine and individually charged in their normal chargers designed for maybe 2 batteries. This was inconvenient especially with just one charger.

jam54 · Jan 25, 2013

Batteries

Regarding batteries for tennis ball machines: SLA (sealed-lad acid) are still the most practical and affordable option. Lithium batteries are very expensive and may not work with all applications.

Ultimately, battery life and effectiveness has more to do with the owner's
charging procedure than the type of battery used. Depending on the type of charger, an 18Ah lead acid battery will last 3-4 years with normal use and provide over 2 hrs of playing time on a charge. I think it's pretty unusual for any individual to use a ball machine for more than 2 hrs at a given session unless you a teaching pro.

But a battery is only as good as how it is charged. Most ball machine companies, such as Tennis Tutor, only use "smart" chargers. Smart chargers
will not overcharge the battery (one of the enemies of batteries) and make it
very convenient to recharge. If a machine is inactive for a long period and not charged, batteries will deteriorate -- another reason smart chargers are effective to prolong the life of lead acid batteries.

There is always the chance of getting a "bad" battery but that is pretty rare. So ultimately, I think the answer is to follow the charging procedures and not try and reinvent the wheel.

retrograde · Jan 25, 2013

Sealed lead acid batteries should be stored for long periods with your smart charger attached (but not a dumb charger):

http://www.atbatt.com/faq/1.asp#4

I have a friend with a Lobster Elite. He left it in his gargage for over 6 months unattached to the charger - this killed his SLA.

This is the PowerSonic battery currently used on the Lobster Elite 1. See the datatasheet and battery care document for good info:

http://www.atbatt.com/product/3595/sla/power-sonic/ps-12180-f2/battery

IdrinkYourMilkshake · Jan 25, 2013

jam54 is right. And once again I tried to justify Lithium Ion, but after reading this, I decided it's unknown if the investment really pays off with the so called 5x the life claim. I think especially with these cheaper Lifep04 cells in the market, the odds are not good of making 10 years and to buy a top of the line cell from A123 doesn't add up. I think I'm better money and headaches ahead to wait for a real alternative to Lead in the next 4 years. I think some patents expire and hopefully a major revolution occurs for hybrid and electric cars in the next 5 years that brings forward a good lightweight and better battery over SLA.
A123's bankruptcy and Boeing's 787 problems aren't good signs for the viability of the technology.

jam54 · Jan 25, 2013

retrograde,
Your friends second mistake was storing his ball machine without it charging
for that length of time. Plus there are far better SLA batteries out there than PowerSonic.

His first mistake was buying a Lobster ball machine and not a Tennis Tutor!

IdrinkYourMilkshake · Jan 25, 2013

jam54 said:
retrograde,
Your friends second mistake was storing his ball machine without it charging
for that length of time. Plus there are far better SLA batteries out there than PowerSonic.

His first mistake was buying a Lobster ball machine and not a Tennis Tutor!

Can you recommend a good SLA? I'm looking for a source of information but I can't see any difference in the brands.

Chas Tennis · Jan 25, 2013

Chas Tennis said:
Charging: For these D cell rechargeable batteries they were removed from the ball machine and individually charged in their normal chargers designed for maybe 2 batteries. This was inconvenient especially with just one charger.

I asked the guy who installed some lithium batteries in a Tennis Tudor and here is what he had to say

"Originally it came with a small 12V lead acid. Then after that died, I replaced with 2 pairs of 4 Trustfire Lithium size 18650 from dealextreme.com that I had on hand for high performance LED flashlights that I was using for my mountain bike night lights. Lithium rechargables have a voltage through most of their discharge cycle of 3.7V with a max of 4.2 and min of about 3.2. So with my 4 in series, I had 14.8V. I also recovered 6 from my daughter’s dead laptop computer. Laptops usually use 2 pairs of 3 in series for 11.1V nominal.

Later after you had it, I bought some plastic holders to replace the copper tubes for about $2.50 each. I also bought an 18650 charger from DX. The only pain was the charger is only 2 batteries at a time. You can buy multipack chargers, but they are expensive."

Anyone pursuing should look into the safety of charging these batteries in any way not using the manufacturer's properly designed chargers.

Topspin_80 · Jan 26, 2013

jam54 said:
Regarding batteries for tennis ball machines: SLA (sealed-lad acid) are still the most practical and affordable option. Lithium batteries are very expensive and may not work with all applications.

Ultimately, battery life and effectiveness has more to do with the owner's
charging procedure than the type of battery used. Depending on the type of charger, an 18Ah lead acid battery will last 3-4 years with normal use and provide over 2 hrs of playing time on a charge. I think it's pretty unusual for any individual to use a ball machine for more than 2 hrs at a given session unless you a teaching pro.

But a battery is only as good as how it is charged. Most ball machine companies, such as Tennis Tutor, only use "smart" chargers. Smart chargers
will not overcharge the battery (one of the enemies of batteries) and make it
very convenient to recharge. If a machine is inactive for a long period and not charged, batteries will deteriorate -- another reason smart chargers are effective to prolong the life of lead acid batteries.

There is always the chance of getting a "bad" battery but that is pretty rare. So ultimately, I think the answer is to follow the charging procedures and not try and reinvent the wheel.

Regarding batteries for tennis ball machines: SLA (sealed-lad acid) are still the most practical and affordable option. Lithium batteries are very expensive and may not work with all applications.

How do you know that?? Do you have first hand experience ? On what grounds are you basing that affirmation??????
What applications are you talking about .

But a battery is only as good as how it is charged. Most ball machine companies, such as Tennis Tutor, only use "smart" chargers. Smart chargers
will not overcharge the battery (one of the enemies of batteries) and make it
very convenient to recharge. If a machine is inactive for a long period and not charged, batteries will deteriorate -- another reason smart chargers are effective to prolong the life of lead acid batteries.

All the big companies , Silent Partner , Playmate , Lobster , Tennis Tutor , Wilson , they all provide smart charger , and basically it is the only way you can recharge the battery , dumb chargers don't come with the necessary plug to be used on the tennis machine .
So , bringing this subject is really dumb .
Keeping the batteries well charged , is only one part of the equation , you fail to say anything about something that is also vital for any kind of battery and not only SLA .
How much you discharge your battery is instrumental for its longevity , if you discharge your battery 100% , like I do , that is gonna kill your battery in no time .
I run my batteries to the ground , because for me is more important to get my playing time , than the cost of a new battery .
You fail to provide that important fact the DOD , with a SLA you have to keep your DOD at 50% in order to get it to last over 3 years .
With a DOD of 50% , I don't get my playing time so I have to go beyond that , and that is how I run them to the ground , and that is why I am looking for alternatives other than the external battery .

I think it's pretty unusual for any individual to use a ball machine for more than 2 hrs at a given session unless you a teaching pro.

You think , well , thinking is just not enough .

To own a tennis machine is very unusual , less that 0.01% of the tennis players own a tennis machine , so it is pretty unusual to own a tennis machine .
If you think , playing longer than 2 hrs is unusual , then you don't know many tennis players , in my club there are a lot of senior citizens that play 4 hrs 3 times a week , a whole bunch of little kids play 3 hrs once a week .
I don't think that to play more than 2 hrs is unusual .

What is really unusual is that you open an account just to post in this thread .

Looks like you have an agenda , in your second post , you only post here , you belittle Lobster , and you praise TT , how come fella ????
This thread is not for this purpose , this thread is just to share experiences with lithium batteries , if you don't have any , you shouldn't waste your time here .

Topspin_80 · Jan 26, 2013

retrograde said:
Sealed lead acid batteries should be stored for long periods with your smart charger attached (but not a dumb charger):

http://www.atbatt.com/faq/1.asp#4

I have a friend with a Lobster Elite. He left it in his gargage for over 6 months unattached to the charger - this killed his SLA.

This is the PowerSonic battery currently used on the Lobster Elite 1. See the datatasheet and battery care document for good info:

http://www.atbatt.com/product/3595/sla/power-sonic/ps-12180-f2/battery

This is exactly the same battery I got with my Elite Grand V LE , probably mine was faulty, otherwise it is hard to understand why it didn't last longer .
The one I currently have is a Panasonic LC-XC1222P , 12 Volt, 22Ah/20HR .
Having 4 amperes more than the PowerSonic gave me more playing time .
I think is a great battery , but I need something with more capacity .
It can not be bigger size , otherwise wouldn't fit in its case , and the max I have seen for that size is a silicone greensaver 24 Ah , other option could be lithium , but no one is coming with a personal experience where you can compare them .
Panasonic costed me $130 , the greensaver costs $170 , and the Lithium one has a price tag of $370 .
I'd pay $370 if I knew it is worthy , but I am not going to take the gamble just for the heck of it .

Chas Tennis · Jan 26, 2013

Battery cost
http://dx.com/p/trustfire-protected-18650-lithium-battery-2500mah-2-pack-blue-5790

retrograde · Jan 26, 2013

Here's an 18ah Lipo battery designed for 12V applications made by Shorai:

http://www.batterystuff.com/powersports-batteries/LFX18A1-BS12.html

Weighs only 2.12 lbs. Compare that with the PowerSonic which weighs 13 lbs. Note the Shorai has smaller dimensions than a standard 18ah SLA battery and comes with some foam inserts to help with fitment. I might be tempted to make some shims.

It looks like the Shorai has NB connectors. The Lobster Elites use F2 connectors, not sure what the Grand Elites use - but you can buy adapters from any battery shop.

I am an electrical engineer but have not done due diligence on this battery (I have the flu and am about to pass out!). At least you now have something to Google on and see what other people are saying about this battery. I suspect this battery either has a regulator on it, or the per cell voltage of SLA and Lipo are similar enough where it's not a problem. I also would look into whether this battery has a circuit which shuts off the battery if the per-cell voltage drops too far ... it might not be needed if you can get a "feeling" for when the battery votage has dropped too far.

Note you'll have to get a Lipo-specific charger. You'll also need to read up on the care and handling of Lipo batteries - they are different from SLA. Lipo's have very low self-discharge so you can let them sit for long periods of time unused. That means you shouldn't leave your Lipo charger connected during storage.

p.s. If you live in a hot climate like Andre Agassi, or leave your ball machine in a hot car, that might explain some of the life problems with your first SLA battery.

retrograde · Jan 26, 2013

Chas Tennis said:
Battery cost
http://dx.com/p/trustfire-protected-18650-lithium-battery-2500mah-2-pack-blue-5790

When using small diamater batteries, one needs to make sure the battery can supply the current the application needs. The PowerSonic SLA can output a max of 54 amps. The trusfires have a capacity of C = 2.5ah ... if their current output is, as an example, 20C, the the current output would be 20 * 2.5 = 50 amps.

I guess your friend has tried this already, but just more due diligence before spending you money.

Here is an example of what radio controlled race car hobbyists used ... note this has a hard shell case, not like the soft (and easily damaged) cases the model airplane guys used:

http://www.amainhobbies.com/product...e=google_ext&gclid=CKKhrdffhrUCFQKRPAodW14A2A

retrograde · Jan 26, 2013

BoingTennis said:
Topspin, I don't think we will find a lot of feedback on these batteries being used with ball machines.

I find this to be a worthy project to try, since my Lobster is in need of a replacement battery anyway. I myself do not live in the US, and that is the more reason for me to buy these LiFePO4 batteries since they are so light, shipping it to Asia would be cheaper.

After I did some google research, these are some of my findings:
1) This battery type will most likely work very well with our ball machines. They have been used extensively in many applications including automotive, EV, etc. Both high-discharge and sustained-discharge types of applications have been covered.
2) Some batteries has better electronic features than others. Shorai batteries (big with motorcycle owners) does not seem to have as much built-in protection and balancing features as the batteries from Powerizer.
Battery balancing feature seems to be an important one to have.
3) Price varies greatly and it looks like it depends on the electronic features I mentioned above.
4) Our stock charger (for Lobster owners) which are most likely made by Soneil are save to use with the LiFePO4 batteries. Pulse mode charging in the Soneil will only function when the battery is at 0.5V-5V. LiFePO4 batteries are not supposed to be discharged below 10V, so our charger will never have its pulse mode charging activated. Soneil charger highest charging voltage is 14.7V, which is below the max charging voltage for LiFePO4 batteries (15V).

Here are the alternatives (for Lobster owners) 7.13L x 3.03W x 6.57H:

1) Shorai 18Ah 5.83L x 2.60W x 4.13H
Only 2.12 lbs, prismatic cells, smaller than stock Lobster battery, same capacity as stock, doesn't seem to have built-in protections/balancing.
2) OEM Battery from BatterySpace with Balancing
7 lbs, prismatic cells, same size as the stock Lobster battery, 20Ah capacity, has balancing PCB but no built-in protection.
3) OEM Battery from BatterySpace w/o any extra features
6.6 lbs, prismatic cells, same size as Lobster battery, 20Ah, no balancing/protection, cheapest I've found.
4) Powerizer w/built in protection and balancing (PCM)
7lbs, cylindrical cells, same size as Lobster battery, 20Ah, complete built-in balancing and protection, expensive.

I'm going with option #2. Will purchase today and will probably get it within 3 weeks. I'll snap some pictures and test it ASAP.

I didn't see you excellent post! I like Shorei because they are made in Japan. But I think having a balancing circuit and protection (is that for overcharging or too low a discharge voltage?) are very useful. Then again, my model airplane friends tell me Lipo cell balancing isn't as much a problem as it used to be.

Chas Tennis · Jan 26, 2013

retrograde said:
When using small diamater batteries, one needs to make sure the battery can supply the current the application needs. The PowerSonic SLA can output a max of 54 amps. The trusfires have a capacity of C = 2.5ah ... if their current output is, as an example, 20C, the the current output would be 20 * 2.5 = 50 amps.

I guess your friend has tried this already, but just more due diligence before spending you money.

Here is an example of what radio controlled race car hobbyists used ... note this has a hard shell case, not like the soft (and easily damaged) cases the model airplane guys used:

http://www.amainhobbies.com/product...e=google_ext&gclid=CKKhrdffhrUCFQKRPAodW14A2A

In the picture on the link, the batteries looked a little smaller in diameter than I remembered them. I am checking the part number that he gave me. I was surprised at the way the Tennis Tudor ran, it seemed normal in power.

jam54 · Jan 29, 2013

Wow, Top Spin....looks like a touched a nerve. I have no agenda, just a lot of experience with tennis ball machines. And sorry if I have a brand preference. Most do.

You make some valid points regarding draining batteries. The biggest enemy of SLA batteries is to be completely discharged. But I still think you are in the minority based on the amount of time you are on the court with a machine. If the majority of ball machine users played for 4 hrs or drained the battery like you do, ball machine companies would quickly see the current 18Ah SLA batteries they use as inadequate.

I don't quite understand why an external battery pack is such a bad option, esp. given the limited alternatives. But good luck to you finding one.

IdrinkYourMilkshake · Feb 7, 2013

Just put the big battery in. 35 cold cranking amp hours!!

retrograde · Feb 7, 2013

IdrinkYourMilkshake said:
Just put the big battery in. 35 cold cranking amp hours!!

Is this the battery you were connecting to externally before? What mods did you need to make to your SP Lite to carry it internally? Or maybe that's the stock battery size for the SP Sport so no mods needed?

IdrinkYourMilkshake · Feb 8, 2013

^^ Correct, this was the external battery. It lasts me close to 6 hours because I have automotive relays on the after-market remote that shuts down the motors when I pick up the tennis balls and make sure I don't waste the power. This is originally a Silent Partner Lite machine. There are a couple vertical tabs at the edge that need to be cut in half as seen in the picture and the opposite side has two vertical tabs that need to be removed. I put padding in the well of the stock battery footprint that sort of cushions the big battery.
Drill two holes on each end for an aluminum bar, drill holes, screw and nut, leave loose while looping the straps around, pull tight. Then tighten the aluminum bars down flat to the plastic base. It's pretty solid. I'm going to finish this today and put in a new mode so I can push a button on the remote to eject just one ball and stop.
I have a 4 button remote. Motors on/off, Ball Feed on/off, Oscillate on/off, One-shot ball feed.

Bolivian10s · Feb 8, 2013

That looks heavy, will your machine support the weight and not crack your plastic case?

IdrinkYourMilkshake · Feb 8, 2013

Bolivian10s said:
That looks heavy, will your machine support the weight and not crack your plastic case?

Doesn't look like it. The blue cover adds a lot of integrity, but I'm going to make it so the cover lifts on and off so the machine doesn't need to be put on the side to take the cover off. No doubt the machine can't be dropped even a little bit. The convenience of not carrying an external battery with plenty of capacity is worth it.

retrograde · Feb 10, 2013

IdrinkYourMilkshake said:
I'm going to finish this today and put in a new mode so I can push a button on the remote to eject just one ball and stop.
I have a 4 button remote. Motors on/off, Ball Feed on/off, Oscillate on/off, One-shot ball feed.

I think there was someone with the handle "rjw" who described some SP mods to add 3rd-party remote funtionality. As an electrical engineer, I'm intrigued. Is there a thread that discusses the mods?

mctennis · Feb 10, 2013

jam54 said:
Regarding batteries for tennis ball machines: SLA (sealed-lad acid) are still the most practical and affordable option. Lithium batteries are very expensive and may not work with all applications.

Ultimately, battery life and effectiveness has more to do with the owner's
charging procedure than the type of battery used. Depending on the type of charger, an 18Ah lead acid battery will last 3-4 years with normal use and provide over 2 hrs of playing time on a charge. I think it's pretty unusual for any individual to use a ball machine for more than 2 hrs at a given session unless you a teaching pro.

But a battery is only as good as how it is charged. Most ball machine companies, such as Tennis Tutor, only use "smart" chargers. Smart chargers
will not overcharge the battery (one of the enemies of batteries) and make it
very convenient to recharge. If a machine is inactive for a long period and not charged, batteries will deteriorate -- another reason smart chargers are effective to prolong the life of lead acid batteries.

There is always the chance of getting a "bad" battery but that is pretty rare. So ultimately, I think the answer is to follow the charging procedures and not try and reinvent the wheel.

Ditto on these comments. Check with the manufacturer about what they also recommend. At times we out think what we should do. Simple is better at times. I replaced my Tennis Tudor battery by the recommendations that Tennis Tudor actually suggested to me. I could have bought one from them but they also suggested another place to get one locally. Great service from Tennis Tudor!!

IdrinkYourMilkshake · Feb 10, 2013

retrograde said:
I think there was someone with the handle "rjw" who described some SP mods to add 3rd-party remote funtionality. As an electrical engineer, I'm intrigued. Is there a thread that discusses the mods?

I think I remember that thread...the guy basically made a new board for it and put a linear actuator in like the top version would have. All I did was put the simple remote in with some added wiring for indicator lights and relays and of course the big battery now. I was thinking about a CD Deck/MP3 player, but I ain't got time for that. Here's a link to the unit I put in, but I got it off bay for like 12 bucks.
And I just want to say Silent Partner is a great company and makes a great product, I just love tinkering with stuff.

IdrinkYourMilkshake · Feb 12, 2013

Finished this thing. The 35ah battery isn't as heavy as I thought it would feel. The red light goes out when the wheels are spinning and the green light comes on when the ball feed is running.

retrograde · Feb 12, 2013

IdrinkYourMilkshake said:
I think I remember that thread...the guy basically made a new board for it and put a linear actuator in like the top version would have. All I did was put the simple remote in with some added wiring for indicator lights and relays and of course the big battery now. I was thinking about a CD Deck/MP3 player, but I ain't got time for that.

Very nice and useful mods. Built in boombox would be unique for sure

Do you have a link for the relays? It sounds like you wired them up into a harness rather than onto a separate board? I'm curious how difficult it was to figure out where to connect the relays to the existing board(s). I've never opened up a SP machine or seen their boards.

IdrinkYourMilkshake · Feb 13, 2013

retrograde said:
Very nice and useful mods. Built in boombox would be unique for sure

Do you have a link for the relays? It sounds like you wired them up into a harness rather than onto a separate board? I'm curious how difficult it was to figure out where to connect the relays to the existing board(s). I've never opened up a SP machine or seen their boards.

It's a standard 12v automotive relay, 2 of the them, something like this.

In this picture you can see them in the lower right. The way it's wired is, start at the big rocker power switch on the panel, it controls two circuits when switched and just run wires off those connections. I made a wiring harness of sorts with plugs so it could be removed and put back to factory specs. The relays just do exactly what that big rocker switch does and the switch on the panel still works too.

jam54 · Feb 13, 2013

I'm surprised that some of you are so insistent on putting essentially car batteries in your machine. Portable machines like this are designed to be, well....portable. Which means light enough to easily transport. What good is it to have a machine that gives you 10 hrs of playing time if it weighs 70 lbs and collapses under it's own weight?? Or try and put something like lithium batteries that cost so much more and may have other issues? The majority of ball machine users are on the court for 2 hrs or less. Sure there are exceptions, like teaching pros, but again, they represent a small percentage.

Keep your SLA battery and charge it properly and you'll be fine.

IdrinkYourMilkshake · Feb 13, 2013

jam54 said:
I'm surprised that some of you are so insistent on putting essentially car batteries in your machine. Portable machines like this are designed to be, well....portable. Which means light enough to easily transport. What good is it to have a machine that gives you 10 hrs of playing time if it weighs 70 lbs and collapses under it's own weight?? Or try and put something like lithium batteries that cost so much more and may have other issues? The majority of ball machine users are on the court for 2 hrs or less. Sure there are exceptions, like teaching pros, but again, they represent a small percentage.

Keep your SLA battery and charge it properly and you'll be fine.

I agree with you on lithium batteries, but a 35ah SLA is not a car battery, it's about as big as you want to go though on a plastic framed machine. It's no where close to collapsing. Some of us want to be out there all afternoon with breaks in between.

retrograde · Feb 13, 2013

That Powersonic 35AH battery weighs 25 lbs. Typical car batteries weigh 40-50 lbs depending on the group size.

The "standard" batteries used by SP and Lobster Elite are 18-20AH and weigh around 13 lbs. The SP Lite/Lite-R come with a smaller 7-8AH battery that weighs around 6 lbs (and I believe you can upgrade the Lite/Lite-R with the larger 18-20AH battery).

I think folks who have their own court or nearby court can wheel around a 50-60lb ball machine. For people like me who have to drive to a court, portability/weight is more of a consideration. I ended up building a ramp using two 6'x10"x1" wood boards so I can easily roll any SP or Lobster Elite sized machine into the back of my wagon.

retrograde · Feb 13, 2013

IdrinkYourMilkshake said:
It's a standard 12v automotive relay, 2 of the them, something like this.

In this picture you can see them in the lower right. The way it's wired is, start at the big rocker power switch on the panel, it controls two circuits when switched and just run wires off those connections. I made a wiring harness of sorts with plugs so it could be removed and put back to factory specs. The relays just do exactly what that big rocker switch does and the switch on the panel still works too.

Looks like TT didn't like that relay link but I figured out it was pointing to the bay and fixed the link ... they were 12VDC 30A Tyco 5-pin automotive SPDT relays, part number V23234-A1001-X036.

Great photo. I can see the relays on the right and the remote board on the left plus your orange wires.

Can you tell me what happens when the big rocker is flipped on and what the silver toggle switch does when it's flipped on? I'm trying to figure out how you get your 4 functions:

Motors on/off, Ball Feed on/off, Oscillate on/off, One-shot ball feed

I'm guessing turning on the big rocker causes motors to go on and ball feed to go on (the two circuits you mentioned?). If yes, did you wire the remote relays in series or in parallel with the rocker? In other words, does the rocker need to be turned on for the remote to work (series connection) or can the remote and rocker work independent of each other (parallel connection).

Similar question for Oscillate ... did you wire the remote's relay in series or in parallel with the Sweep toggle switch? In other words, for the remote to control oscillate, does the Sweep toggle switch also need to be flipped on?

IdrinkYourMilkshake · Feb 14, 2013

retrograde said:
Looks like TT didn't like that relay link but I figured out it was pointing to the bay and fixed the link ... they were 12VDC 30A Tyco 5-pin automotive SPDT relays, part number V23234-A1001-X036.

Great photo. I can see the relays on the right and the remote board on the left plus your orange wires.

Can you tell me what happens when the big rocker is flipped on and what the silver toggle switch does when it's flipped on? I'm trying to figure out how you get your 4 functions:

Motors on/off, Ball Feed on/off, Oscillate on/off, One-shot ball feed

I'm guessing turning on the big rocker causes motors to go on and ball feed to go on (the two circuits you mentioned?). If yes, did you wire the remote relays in series or in parallel with the rocker? In other words, does the rocker need to be turned on for the remote to work (series connection) or can the remote and rocker work independent of each other (parallel connection).

Similar question for Oscillate ... did you wire the remote's relay in series or in parallel with the Sweep toggle switch? In other words, for the remote to control oscillate, does the Sweep toggle switch also need to be flipped on?

On the big rocker, one of the circuits has large gauge wires, presumably for the motors. The other circuit is definitely lower amp draw, with small gauge to power the rest of the board. I'm sure it didn't need a large relay on the one circuit, but I went with it. You can follow the orange wire around to a relay from the remote board terminal, that controls the solenoid for the relays, the second black relay has 2 solenoid wires from that point, so they both turn on at the same time. That's why a couple wires appear to tie the two relays together. They both turn on simultaneously and connect the two circuits the same way the rocker is wired, but two separate isolated circuits. This leaves the rocker alone to work by itself if need be.
This picture was taken last summer and predates anything done today. I found out I had a bad optical sensor for my one shot ball feed, so I didn't get that put in, but it's very possible. The sensor is a kit from Velleman or you can google optical relay for some other 12v sensor. I was going to use an optical sensor because I don't have confidence in a switch holding up long term to getting whacked every time a ball drops into the ramp.
The 12v remote board relays just interrupt one of the wires running to the ball hopper motor and oscillate motor. This picture doesn't show that. Very straightforward. Series connections for everything.

IdrinkYourMilkshake · Feb 14, 2013

Forgot to answer, yes the oscillate switch must be kept on to allow the remote to turn it on. The other silver switch upside down in the picture on the right of the panel with orange wires is power to the remote box. Turn that off to store the machine, there is some power drawn for the remote receiver box.

kopfan · Feb 14, 2013

Newer LiFePO4 battery, those designed as a direct replacement can charge with SLA smart charger. Size of the battery should fall in the spec within a 12v 18/20ah. If they fall within the same capacity, they should have the same usage time. No? For long run, LiFePO4 seem to hold it max charge better which eventually will outperform SLA. Since LiFePO4 do not sulphate like SLA, these battery do not need to tinker charging all the time. Just top up once a week or before court time should be good enough to maintain the life span. Unless you want to reduce the battery weight, it seem like SLA is still more economical at this time. I wanted to reduce my machine weight and had been researching on LiFePO4 but the cost about $270 seem too much compared to SLA $65.

retrograde · Feb 19, 2013

IdrinkYourMilkshake said:
Forgot to answer, yes the oscillate switch must be kept on to allow the remote to turn it on. The other silver switch upside down in the picture on the right of the panel with orange wires is power to the remote box. Turn that off to store the machine, there is some power drawn for the remote receiver box.

Just catching up. As far as silver toggle switches go ... I think there is an original one to control sweep (on the control panel) and one you added to cut power to the remote that is mounted on the bracket that the two relays are mounted to. Did I get that right?

IdrinkYourMilkshake · Feb 20, 2013

retrograde said:
Just catching up. As far as silver toggle switches go ... I think there is an original one to control sweep (on the control panel) and one you added to cut power to the remote that is mounted on the bracket that the two relays are mounted to. Did I get that right?

Not on the bracket inside, but on the panel also. It can be partially seen on the right side of the plastic panel piece, but it's upside down with two orange wires coming out. It's effectively the on/off for the entire system.

Lithium battery for a ball machine

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