Powerwise Troubleshooting

[msdeer]

I have a 94 Series Cart.
The Batteries I thought were bad, but I don't believe my charger is charging long enough.
I plug it up, and it only runs for a couple hours and then shuts off.
I have read voltages and SG of the batteries.
The SG isn't coming up to but 1.210 or so.
The voltage on the pack is 38.4 while on charge. But after a resting period of 8 hours the voltages are back down to 36.1-36.4 on all batteries.

If the Batteries are in fact bad, would the charger shut down prematurely?
The ammeter comes up to 25 amps or so and slowly falls to aroun 5 amps and cuts off about 20 minutes after reaching that point.

[bigstik40]

I'm assuming you have a 36 volt system. The output current seems to be ok (at least it acts about the same as my charger), but you are missing out on some voltage somewhere. A reading on individual batteries would be a good start to help find out what's wrong. Take individual battery voltage readings and post here for help. I'm sure johnnieb will be along to help and he'll need that among other things. - RAY

[msdeer]

Individual voltage readings imediately after charger are as follows:
6.9
6.7
6.7
6.3
6.8
6.5
After an 8 hour wait:
6.6
6.3
6.3
6.0
6.4
6.3

I am in the process of charging each battery individually tonight to see if it is my charger or the batteries.
It just doesn't make sense why the charger is cutting off within a maximum of 2 hours from 36v even after only a 30 minute ride..

[bigstik40]

Looks like battery 4 is the worst of the bunch, but like I said, it seems like the output voltage is low. I know from reading some of johnnieb's posts, the voltage while under charge is in excess of 40 volts and chargers drop out around 42. You very well may have charger problems. Johnnieb knows those chargers like the back of his hand and I'm sure he will be along soon to help. Another thing to check in the meantime would be the wires going from the charger jack on the cart to the batteries. They may be dropping some voltage due to corrosion issues. - RAY

[msdeer]

I replaced the terminals on the charging cables this weekend and it did the same thing. The positive cable only had 3 conductors left in the terminal.
The guy swears they are 2009 and 2010 batteries. I am wondering if he may have had a problem with the charger the entire time though. While on the charger I get a voltage reading of 41v across the pack. Each battery with the exception of 2 are 7.1 the other 2 are 6.7 and 6.8.

[bigstik40]

Your original post said your "on charge" voltage was 38.4 volts. With your latest report of "on charge" voltage of 41 volts, it's beginning to look like maybe the charger is ok and you may have a battery problem. What brand are the batteries?? If Trojans, they will have date codes stamped on the terminals. If another brand, not sure if they have dates. (anyone???). Try to determine the age of the batteries. You said you were charging the bats. individually. That's a good check, or maybe try to borrow a known "good" charger to get a full charge on them. Report "rested" voltages after re-charging so we can see where you stand. RAY

[msdeer]

I had my on charge voltage wrong in the first post. Sorry about that it is in fact 41 volts across the pack.
The 38.4 which I put was typed wrong. Pack voltage imediately after charging is 39.4. Voltage of pack while charging is 41.1 volts.
Man I have really screwed this up.

[JohnnieB]

Originally Posted by msdeer

...............It just doesn't make sense why the charger is cutting off within a maximum of 2 hours from 36v even after only a 30 minute ride..

Automatic chargers cut off when they sense an on-charge pack voltage in the 44-46 volt range (36V charger). Basically, the charger is current limited at about 25A until on-charge voltage climbs to about 40V and then tapers down to 2-8 Amps as the on-charge voltage climbs to about 44V and stays there until the on-charge voltage reaches the charger's predetermined cut-off voltage. Using an automatic charger, the recharge cycle is based on voltage, so time doesn't enter the equation, unless the battery pack's on-charge voltage fails to reach the cutoff voltage before the back-up (safety) timer times out. (12 -16 hours typically)

Originally Posted by msdeer

...............
After an 8 hour wait:
6.6 = Too high - Bad reading???
6.3 = 90%
6.3 = 90%
6.0 = 50%
6.4 = Too high - Bad reading or rounding error?????
6.3 = 90%

Attached is a State of Charge chart.
The voltages given are for "Rested" batteries. (At least 6hr, preferably 12-24hr after being charged.
As you see, individual battery voltages have to be measured down hundredths of a volt to determine SoC.
Pack voltage down to tenths will usually suffice.

Looks like you have at least one bad battery and three that are a little weak, but two that are off the chart, so I question all the voltages.

It sounds like your charger is behaving normally. Let it run until it shuts off, wait about 12 hours and measure individual and pack voltages.

Check the electrolyte level and only add enough distilled water to cover plates if they are exposed. (Normally batteries shouldn't be watered unless fully charged)