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au
02-12-2010, 06:57 PM
i am about to replace the batteries in my TennisTutor Plus ball machine which originally had Yuasa np7-12 (7amps - 12v) batteries. can i replace these with heavy duty ones from a hardware store? are there any advantages to doing this? any input appreciated!

tpotter
02-13-2010, 09:40 AM
As long as the replacement battery has the same voltage...i.e. 12 volts, you can add a larger amperage battery.

I've never been quite sure what Tennis Tutor means by heavy-duty batteries - I think they are simply referring to higher amperage batteries.

In general, one 14 amp battery will last longer than two 7 amp batteries wired together in series (or so I'm told).

rich s
02-13-2010, 11:06 AM
As long as the replacement battery has the same voltage...i.e. 12 volts, you can add a larger amperage battery.

I've never been quite sure what Tennis Tutor means by heavy-duty batteries - I think they are simply referring to higher amperage batteries.

In general, one 14 amp battery will last longer than two 7 amp batteries wired together in series (or so I'm told).

you wire two 12v 7 a-h batteries in parallel (not series) otherwise you get a 24v 7 a-h battery instead of a 12 v 14 a-h battery.....

rich s
02-13-2010, 11:11 AM
i am about to replace the batteries in my TennisTutor Plus ball machine which originally had Yuasa np7-12 (7amps - 12v) batteries. can i replace these with heavy duty ones from a hardware store? are there any advantages to doing this? any input appreciated!


yes, you can....

you want a battery that is 12v and an amp-hour rating greater than or equal to the amp-hour rating of your current battery.

The more batteries you wire together in parallel the longer play time you will have....

as an exagerated example, you can wire up a 12v car battery if you don't mind lugging it around.

tpotter
02-13-2010, 12:26 PM
you wire two 12v 7 a-h batteries in parallel (not series) otherwise you get a 24v 7 a-h battery instead of a 12 v 14 a-h battery.....


Rich, thanks I always screw that up parallel versus in series...you seem knowledgable on this subject do you know if...

(1) 14 amp battery last longers (play time and/or number of charges) than
(2) 7 amp batteries wired in series?

I was told this, but couldn't confirm it.

au
02-13-2010, 08:22 PM
thanks guys!

floydcouncil
02-14-2010, 06:08 AM
Rich, thanks I always screw that up parallel versus in series...you seem knowledgable on this subject do you know if...

(1) 14 amp battery last longers (play time and/or number of charges) than
(2) 7 amp batteries wired in series?

I was told this, but couldn't confirm it.

If you wire two 12v batteries in series, you will FRY your machine b/c you are feeding it 24v.