Battery Forensics...Cover Me, I'm Going In

[Desert Bill]

Armed with DVM, hydrometer, combo 6V/12V charger, distilled water, batt watering container, rubber gloves and goggles.

Some read my previous post "Batteries taking a ton of water" where in about 24 hours I added almost 1-1/2 gal of distilled water because of excessive gassing. Finally got the pack to full charge allowing my 42V charger to shut down on its own. I had shut it off manually while checking/adding water. My cart is a 2003 Western on an Ezgo chassis, with 7 batts, street legal.

Gone for 25 days. Batts all have water above the plates. This is what I found. With the DVM.

1. 6.29
2. 6.29
3. 6.27
4. 6.29
5. 6.26
6. 6.30
7. 6.31

So, as of 9 AM cart is back on the charger. Will see what happens as it relates to my previous experience. Batts are Feb 11 Centennials, GC2200P. Bought cart a few months ago, so not sure about their proper maintenance.

[JohnnieB]

All 7 batteries within 0.05V of each other is excellent.

Only self discharging down to the 80%-90% SoC range in 25 days is also mighty good.
Of course, it is cooler weather, so the self discharge rate will be faster in the summer months.

If they were mine and I had a 6V charger, I'd give Battery #5 & #3 a few hours charge to see if they would come up closer to the other 5, but the voltage spread isn't enough to worry about by any means.

Let us know if they still guzzle water.

[Desert Bill]

Thanks JohnnieB. Always grateful for your input. As far as additional charging the lower two, I assume I wait until the charger shuts down. Still a novice at this, but having some fun educating myself with the help of this forum.

[JohnnieB]

Originally Posted by Desert Bill

Thanks JohnnieB. Always grateful for your input. As far as additional charging the lower two, I assume I wait until the charger shuts down. Still a novice at this, but having some fun educating myself with the help of this forum.

Yes, that would be the safest. Also, with the 42V charger on, the voltage on each battery would already be high, so the 6V charger probably wouldn't do much good.

I'd let them rest a couple hours and then use the 6V charger.

[Desert Bill]

Thanks JB. Will keep you posted about the 'thirst' issue.

[Desert Bill]

Ok, after 11 hours of charging, charger would not shut itself off. Still showing 5 amps. Unhooked, and added about 1 qt of water, but did let the spring loaded filler do its thing since I felt that the batts were near full charge.

After off charger for 12 hours, batts read:

1. 6.46
2. 6.45
3. 6.45
4. 6.43
5. 6.43
6. 6.44
7. 6.48

Did try my combo 6v/12v charger on batt 5 for a couple of hours this AM, but the green light indicated "charged" , when 1st connected. Checking 2 hours later batt indicated 6.55?

Reconnected the 42v charger to the pack. After a few minutes climbs above 15 amps, slowly backing down to 5 amps. Go back into garage 20 mins later...solid green light indicating full charge.

Not sure what is going on.

[simple man]

Originally Posted by Desert Bill

Ok, after 11 hours of charging, charger would not shut itself off. Still showing 5 amps. Unhooked, and added about 1 qt of water, but did let the spring loaded filler do its thing since I felt that the batts were near full charge.

After off charger for 12 hours, batts read:

1. 6.46
2. 6.45
3. 6.45
4. 6.43
5. 6.43
6. 6.44
7. 6.48

Did try my combo 6v/12v charger on batt 5 for a couple of hours this AM, but the green light indicated "charged" , when 1st connected. Checking 2 hours later batt indicated 6.55?

Reconnected the 42v charger to the pack. After a few minutes climbs above 15 amps, slowly backing down to 5 amps. Go back into garage 20 mins later...solid green light indicating full charge.

Not sure what is going on.

If I read this correctly, you're saying that when you start the charger, the ampere rate starts low and rises then falls? It should start high and progress to low. You may have a bad cell in one or more of the batteries. Try leaving the cart sit for several hours, then connect the dvm to the pack and try moving the cart. See if the voltage drops significantly. If it does, try a reading on each individual battery doing the same test.

[JohnnieB]

I'm not sure what is going on either.
The 42V charger is staying on too long and causing the batteries to use a lot of water, but why is it staying on so long, is the question.

The battery voltage after 12 hours is a bit high, also indicating the charger stayed on too long, but they are all close together in voltage.

Like simpleman suggested, try to see if any of them drop more under load than the rest of them do.

I'd get back on the horn with DPI and tell them the latest.

I'm not sure what your 42V Western charger (made by DPI) uses to shut off the charger, but the DPI I've got uses dV/dT (change in Voltage over change in Time) and shuts off (switches to float charge mode) when the On-Charge voltage doesn't climb more than a few millivolts over about a minute or so. (I couldn't pry the exact numbers out of them)

[Desert Bill]

Simpleman I may have not explained well. I mean it takes a minute or two for the charger to start...I assume the charger is reading the battery pack 1st.

JB thanks again for your input. I took the cart for a 20-25 min continuous ride and am now attempting another charge cycle.

As stated before, after cycling thru the start phase, red lights blinking, etc., then only red power light stays on, along with the yellow charge light..which is blinking while the pack is being read. Amps start climbing and the yellow charge light goes steady and stays that way. Once the amps are at about 8' yellow light starts blinking, which I assume this is gassing/final part of charge. May stay this way a few hours, then steady green...at least that is what it used to do.

[Desert Bill]

Well after my 25 minute jaunt and recharge...2 hours, green light, fully charged.

WTF? Have I been on a battery 'Magical Mystery Tour'?