Battery or charger problem?

[Copperhand]

I recently bought a new set of batteries(US 2200) for my 98 txt, I have charged and used them for about a month now but I'm still only getting about 80% capacity after I let them sit for 12hrs after a complete charge. I have checked my voltage on charger during charge cycle and it seems to be correct, starts out at in the 37 range and goes up to 46 before charger cuts off. I have also checked voltage on all batteries and they are all within .1 of each other. The charger starts out charging between 15-18 amps and slowly goes down as it charges. It's a power wise charger. Any thoughts from the battery or charger experts? I'm just thinking after 15 to 20 charge cycles I should have started seeing better run time by now. I have called myself breaking in the batteries the way that was suggested on this very informative web site, thanks in advance for any suggestions or advice.

[JohnnieB]

Originally Posted by Copperhand

I recently bought a new set of batteries(US 2200) for my 98 txt, I have charged and used them for about a month now but I'm still only getting about 80% capacity after I let them sit for 12hrs after a complete charge. I have checked my voltage on charger during charge cycle and it seems to be correct, starts out at in the 37 range and goes up to 46 before charger cuts off. I have also checked voltage on all batteries and they are all within .1 of each other. The charger starts out charging between 15-18 amps and slowly goes down as it charges. It's a power wise charger. Any thoughts from the battery or charger experts? I'm just thinking after 15 to 20 charge cycles I should have started seeing better run time by now. I have called myself breaking in the batteries the way that was suggested on this very informative web site, thanks in advance for any suggestions or advice.

The US 2200 has a 232 Amp-Hour rating, so you ought to be getting slightly better run-time than from the standard 220AH pack.
If you are not, something is amiss, but the numbers look good except for the 80% SoC 12hr after charger shuts off.

Please, bear with me while I pick your brain a bit.

For starters, were the batteries ever charged to 100% SoC?
New batteries only have about 75% of their maximum storage capacity until they've been broken in, but they do charge to 100% SoC.
It is a bit confusing, but State of Charge and storage capacity are different animals.
Basically a new US 2200 is a 174AH battery (75% of 232AH) and doesn't reach its rated capacity of 232AH until it is broken in.
However, it will still measure 38.2V (or more) 12hr after the charger shuts off.
In other words, in the beginning you will have fully charged 174AH batteries (~38.2V) and they evolve into a fully charged 232AH batteries (~38.2V) as they mature.

Is the electrolyte level above the plates in all 18 cells?
New batteries gas a lot, so distilled water needs to be added fairly often.
Only add enough water to cover plates before charging and fill to proper level after charging. Do not overfill!

The voltages I highlighted in red are correct, but only if the reading were take at the main terminals of the battery pack.
Resistance in the charging loop can cause false readings, so exactly where the readings are taken is important.

Put fresh batteries in your DVM. Weak batteries will cause a DVM to do mysterious things. (Don't ask how I know. )

Just to be sure, your pack voltage settles down to about 38.49V after sitting about 12hrs after charger shuts off?

If so, you may have a parasitic load of some kind or another.
36V to 12V converter that stays on all the time or audio equipment in a stand-by mode?
Try disconnecting everything from the battery pack except the 5 cables that connect the batteries in series and the two cables from the charge receptacle and unplug charger from cart when it shuts off.
If the pack is at 38.2V after 12Hr rest, it is a matter of finding what is drawing the current.
It shouldn't be hard to find, it will be 5A or more of current follow.

If the battery pack still doesn't stay at 38.2V or slightly above after 12hr rest, we need to look at the charger, but if it is taking the pack to an on-charge voltage of 46V, the batteries ought to be fully charged, whatever their storage capacity currently is.

Hang in there, we will figure it out.

[Copperhand]

Good morning Johnnie, I was hoping you would chime in, I bought the batteries at my local cart shop took them home installed and then let charge overnight. The ezgo led battery indicator showed a full charge but I'm starting to see that it isn't accurate enough. I do know the charger ran for a very long time the first time I charged them. The cart is at my weekend cabin and I will not be back up there till Thursday so bare with me and I will try to answer as much as I can till I get back close to the cart. The batteries seem to be gassing good when charging and the voltage I stated is at the main battery pack terminal, I have already installed a new battery in my meter but will carry a different meter with me for comparison when I go back. The one thing I'm concerned about is how the amps on my charger don't stay up above 10-15 for very long may be a couple hrs max then they drop down to less than 5. I have checked and added distiller water but I did add more than just covering the plates, I have the level half way between plates and top cover of battery. I have not gotten a voltage reading after 12hrs from charging higher than 37.6 and this is what I'm most concerned about. The voltage reading a couple hrs after charging is pretty decent but I will have to get you the exact numbers later this week. I will try disconnecting everything from the pack except the main terminal leads also. Thanks for advice and help.

[scottyb]

A good SOG test on each cell would be interesting information at this point too.

[Copperhand]

SOG test? Please bare with me I'm still earning.

[Copperhand]

Learning, learning to type too!

[JohnnieB]

That miserable LED bar-graph meter probably recalibrated 100% to whatever the pack voltage was when the last cable was connected.
Do yourself, and your batteries, a favor and replace it with one of these: http://www.cartsunlimited.net/Digita...ry_Meters.html

Good idea to try more than one DVM.
Like Scotty suggested, this would be a good time to measure the Specific Gravity of the electrolyte is all 18 cells.
Just in case you don't have one, here is a chart showing SG as well as voltage for State of Charge.

From what you've said, you've got a Powerwise charger with an ammeter on it, so it is a ferroresonant Transformer design and if the on-charge pack voltage is reaching 46V before it shuts off, it is fully charging the batteries unless there are one or more bad cells in the battery pack, or the cables and connections in the charging loop are bad.

Here is a picture of what I think you have, or something similar.

All the control board does is turn the charger on and off. Everything else is done by the matched transformer and capacitor pair.
The current output is limited to about 18-20 amps until the on-charge voltage climbs above about 40V and then it starts tapering off to abound 8-10A as the on-charge voltage climbs through 42.5 voltage and the batteries start gassing noticeably. Then the current reduces down into the 3-5A range and stays there until the on-charge voltage climbs into the 44-46 volt range and the charger shuts off.

Since you say the current stays above 15A for a couple hours (Usually it is 30 minutes or so), I'm leaning toward something being wrong in the battery pack. OR there is a parasitic load of some kind that is sucking up some of the charging current as well as draining the batteries when not on charge.

As for fluid level in the batteries, the electrolyte expands while charging, so you only want to add water before charging if the plates are exposed.
After they are charged, fill to recommended level.
Check the US battery website for proper fluid level.
Here is a generic guide that will work, if you cannot a specific one for US batteries.

I'm also concerned about the batteries not being above 37.6V after a 12hr rest.

[Copperhand]

Johnnie I'm not real sure on the time that the charger stays on the higher side of the amp range, you are probably more correct on how its working than what i was thinking so I'm going to wait till I go back where the cart is before I give you any more numbers or time. I will take my IPad with me so I can post and reply. Will you be able to check back on this thread say Fri and look at what I find are accurate numbers and conditions and may be offer farther guidance? Thanks Johnnie and Scottie for all the advice you guys freely give to help complete strangers that need help with carts.

[yurtle]

Originally Posted by JohnnieB

New batteries only have about 75% of their maximum storage capacity until they've been broken in, but they do charge to 100% SoC.

Can you explain why this is? A "technical" warning is probably warranted.

[JohnnieB]

Originally Posted by yurtle

Can you explain why this is? A "technical" warning is probably warranted.

I've had some questions about that also, and have yet to find a definitive answer.

The only thing I've found is that the plates are "hard" and need to be exercised.

Check out the video named "Understanding Battery Capacity & Life Expectations". It is the third up from the bottom on this webpage.
http://www.trojanbattery.com/Product...bedPanels1#top

If I ever find an explanation that goes into the technical details, I'll post it with the proper technical warnings.

I have found various percentages for how much the capacity of new batteries is reduced, some as low as 5% and other as high as 25%.
I went with the high number for visual impact.