Excessive Voltage Draw, 96 txt

[yurtle]

When it sat for a month, did you jump on it and drive, or charge it first?

[JohnnieB]

You've got at least one bad battery, but it appears that you've been taking good care of them, so it is a true battery failure.

[haligen]

I guess I'll pull those three suspect batteries and take them to advance auto and let them test them. Hopefully its only that one that fails and I can get away with just replacing it. I pulled the date code and there not even two years old yet; Jun 2011. Yurtle, I charged the pack before moving it. I've had a DVM on it since I placed the pack into service. Wonder if a DPI charger would help keep something like this from happening in the future or if its just truly a bad batt and rare.

[yurtle]

We've questioned your care, and it seems like you were doing your part. No charger can prevent a true battery failure, which seems to be what happened.

While Advance Auto can't "really" test a golf cart battery, if they say it's bad, it's probably bad. Car batteries are for cranking, while golf cart batteries are a totally different beast.

Changing one to three batteries may not be the best solution either. Though no one wants to face a huge investment like replacing six batteries, especially if they are only two years old, that may be your best bet.

Before you go there, remove each battery cable and clean and inspect it. If you have a Run/Tow switch, be sure to put it in Tow. Given the symptoms, I don't believe this is your problem, but...

[JohnnieB]

However, there appears to be 1 bad battery, 2 that are weaker than the remaining 3 and those two batteries are not being used to power 12V accessories.
You seem to be doing everything right in the charging area, but then it dawned on me that your batteries are never discharged very much.

The mistake most people make is not charging their batteries often enough and/or discharging them too deeply, but your situation appears to be somewhat the opposite. I'm speculating and grasping at straws, but it might be possible that never discharging below 80% SoC is an issue.

So, it might be a good idea to take the cart on longer trips occasionally and discharge the batteries down to about 60% SoC.
I don't know if that would help, but it certainly wouldn't hurt.

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As for switching to a DPI charger, or any other that goes into a float charge mode after the regular charge cycle.
It keeps the batteries at 100% SoC, so aging (plate sulfation) is minimal and you start each trip with fully charged batteries.

[JohnnieB]

Eureka!!!!!
I think I might have figured this out.

Check out this thread: http://www.buggiesgonewild.com/elect...-readings.html
Post #4 is the key.

The US Battery engineer said that the Powerwise 28115 charger doesn't fully charge US batteries.

If that is the case, getting a DPI charger, which has a user selectable charge profile for US Battery, may be the answer.
It isn't going to fix the broken batteries, but it should prevent the same thing happening again.


This opens a whole new set of conditions for proper battery charging.
Looks like I've got some research to do.

[haligen]

Ok, armed with this new charging knowledge and a what can it hurt attitude I decided to try something. I jumped out the timer relay on the charger and just let it run. Once it hit 4 amps it was only showing a charging voltage of 44ish volts. I left it on overnight and by the morning it had reached 45.1v. I disconnected the charger and took it for a ride. Low and behold it ran just like it should. Cruising volts of 35.1-5v. I ran it, and ran it, and ran it, and ran it, the wife even ran it. All day its been fine. Soooooo, I'm going to recharge and try again in a few days. Way way odd.

[JohnnieB]

Wonder how long it will take a PW 28115 charger to get those batteries up to the 46.8V suggested by US Battery?

Keep an eye on the electrolyte levels, they ought to be gassing a lot.

After two or three charge/discharge cycles, please measure the individual battery voltages and post them.

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I understand EZGO and other are manufactures are putting US Batteries in their new carts and if US Batteries need a significantly different charge profile than Trojan batteries, it is going to get interesting.

[chasenfish16]

I would guess all the new carts coming stock with US Batteries would have their charger settings set up for the US Battery profile. This makes you think what happens when a individual replaces their batteies and does not go back with the same make. This opens a whole new can of worms. I know it has really opened my eyes to the complexity of charging different brands of batteries.

I wonder what the advantage/disadvantage is of having US Batteries require more voltage to charge compared to a different manufacturer's battery, if any.

[haligen]

Well I came back from camping for a week and my pack was still sitting at 39.2v. I rode it around for a decent bit and everything was as it should be. It did pull a little deep on initial take off though, dropping to 32ish volts before leveling at 35ish. Probably ran it about 10 miles or so and then it started to do the dropping out again. Dropping down to 22ish volts on take off. Got the cart home, plugged it up, and let it run overnight. The highest the charger got the batts after being on about 16 hours was 44.4v. I've seen the pack as high as 45.3v on the charger but that was after I plugged the charger in on an already charged pack. The 45.3v only came after another 12ish hours of charging. I guess I might have to really think about getting another charger. It looks like this powerwise one just will not charge US Batts if they need to make it over 46v.