EZGO Power Wise 28115 G04 charger question

[shrpshtr]

Experts...I have a question.

I have a Power Wise 28115 G04 charger I use to charge my cart. (Details in signature) You could say I am running an "unconventional" battery pack. (6 - 12v batteries in parallel series) I was discussing charging with an electrician and he raised a couple of interesting points. The one that most peaked my interest was concerning the amount of charge each battery gets from the charger. The skinny of it was that my batteries should read about 13.3-13.5v per battery. Of course, mine only ready 12.8-12.9 per battery. He believes because of this disparity (and made a compelling argument) my batteries aren't being fully charged and it is affecting the life and performance I get out of them. So, my question is specific to the charger's capability. Can I change a setting to allow it to charge each battery to the 13.3 - 13.5 range? Of course, I couldn't find a manual online for this particular charger or I could have saved myself a lot of typing...

Thanks in advance.

shrp

[yurtle]

If your battery readings were 12 hours after completion of charge, they are fine. 6.37 is good for a six volt battery, so double that and you're a little on the high side, likely due to reading them too soon after a charge.

[shrpshtr]

Thanks for the response yurtle. What about his thoughts about them being in the 13.3-13.5 range?

[Timoteo]

I don't see where you've stated whether you are using battery isolators or not. Connecting batteries in parallel can be troublesome as on battery we be at a different potential (voltage) than the one it's made to and it will try to "charge" the mated battery. This will ping-pong back and forth until both batteries are discharged. I would recommend and isolator and charge each circuit separately and the switch to combined for use.

[shrpshtr]

Not using isolators. I've never actually heard of them. Is that a separate charger or add-on to the pack? Does it change charge time? Thanks for the response.

[JohnnieB]

I suspect the electrician was not all that familiar with the care and feeding of Deep-Cycle, Wet-Cell, Lead-Acid batteries, however you didn't mention what type 12V batteries you are using, so his argument may have some validity.

Are you using 12V cart batteries or 12V car batteries?

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When multiple batteries are charged in series, or in parallel, or in series/parallel, they have to be closely matched or some get undercharged while others get overcharged, but batteries connected in parallel do not ping-pong back and forth.

When initially connected in parallel, they will equalize, but after that the voltage of both is the same and there will be no current flow between them. The amount of current flow during charge or discharge can vary due to differences in the internal resistance, which is why they must be closely matched to get optimal performance and lifespan.

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Battery isolators are commonly used in RV and Marine applications.

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Here is the manual for your charger, but there isn't much you can do to change the way it works. It is designed to charge 18 2V cells in series, but will charge your series parallel pack okay if they are well matched.

[Timoteo]

Battery isolators are commonly used in boats, RV's etc to isolate the starting battery from the accessory/back-up battery. Anytime batteries are connected in parallel, each battery is likely to be at a different potential (voltage) and will want to charge the lower voltage mated battery. It can be challenging enough to keep series wired batteries charging equally, hence to need for periodic equalization. Connecting in series/parallel just further complicates the circuit. This may be what your electrician friend was commenting on. You may have good success without isolators, but your battery life may get compromised.
http://en.wikipedia.org/wiki/Battery_isolator
YMMV (your mileage may vary)
Good Luck!

[shrpshtr]

Originally Posted by JohnnieB

I suspect the electrician was not all that familiar with the care and feeding of Deep-Cycle, Wet-Cell, Lead-Acid batteries, however you didn't mention what type 12V batteries you are using, so his argument may have some validity.

Are you using 12V cart batteries or 12V car batteries?

-------------
When multiple batteries are charged in series, or in parallel, or in series/parallel, they have to be closely matched or some get undercharged while others get overcharged, but batteries connected in parallel do not ping-pong back and forth.

When initially connected in parallel, they will equalize, but after that the voltage of both is the same and there will be no current flow between them. The amount of current flow during charge or discharge can vary due to differences in the internal resistance, which is why they must be closely matched to get optimal performance and lifespan.

------------
Battery isolators are commonly used in RV and Marine applications.

---------
Here is the manual for your charger, but there isn't much you can do to change the way it works. It is designed to charge 18 2V cells in series, but will charge your series parallel pack okay if they are well matched.

JohnnieB,

Neither, they are actually UPS batteries out of a Data Center UPS. I'll have to get you the exact model when I get to the house this evening. Thanks.

[shrpshtr]

Timoteo,

Only two of the batteries in each series are connected to their counterpart in the other series. Given your description, would each battery try and charge it's counterpart or each series try to charge the other? In other words, each series is measuring 38.6v. There is usually 1 battery in each series at 12.8 and the other 2 are at 12.9. It's not consistently the same battery in each series either. A battery may measure 12.8v one day and a week later measure 12.9 and vice versa. But each series always comes out to 38.6v. Make sense?

Thanks for all of the responses so far.

shrp

[Timoteo]

shrpshtr,
Whenever you connect two batteries in parallel i.e. your example of one batt. @ 12.8 and the other @ 12.9; the 12.9 will push current to try and charge the 12.8 to be equal. As temperatures and levels of discharge change, you may get to the point where the the previously "weaker" battery becomes the "stronger" or higher potential battery, hence the "ping-pong". All lead acid batteries will self-discharge with time. Connecting them in parallel will accelerate this. If you keep your charging routine up this may not be too much of a factor for you.
YMMV