State of Charge Meter Help?

[gaston]

Originally Posted by bartoner

thats the whole purpose of me trying ot get this thing to at least let me know when to put it on the charger...but if its not accurate, and shouldnt be trusted, why even bother with it? I have read about calibrating it so that you know what point on the meter is when it should be charged, but in this case, the meter never dipped from below it was when i hooked it up, except under load. Am I wasting my time with this type of gauge? I read on here somewhere where alot of people prefered the analog over the digital, and were happy with them, but now im confused???

Digital is better, but of course is near to accurate, not perfect.
It will do the job you want MUCH BETTER than the analog. Period.

[dougmcp]

Back to my original post, I think you probably have a bad connection or a bad battery. If your lights go out or the cart loses power, when you stop, there is enough voltage to show good but with a bad/corroded connection/cable, not enough amperage to move the cart.
Get out the voltmeter, set it on the seat and attach it to your battery pack. Go for a drive and see what you battery voltages do when you start losing power.
Start with a recharge, let your batteries rest for an hour and post up your pack voltage and each individual battery voltage.
If it's a 36v cart it should read something like this:
Pack 38.2v
Batt 1 6.39
Batt 2 6.41
Batt 3 6.38
Batt 4 6.43
Batt 5 6.37
Batt 6 6.42

Then go for a ride and try to duplicate your problem.
Stop the cart and take the same voltage readings and post.
We should be able to narrow it down for you.

[bartoner]

Originally Posted by dougmcp

Back to my original post, I think you probably have a bad connection or a bad battery. If your lights go out or the cart loses power, when you stop, there is enough voltage to show good but with a bad/corroded connection/cable, not enough amperage to move the cart.
Get out the voltmeter, set it on the seat and attach it to your battery pack. Go for a drive and see what you battery voltages do when you start losing power.
Start with a recharge, let your batteries rest for an hour and post up your pack voltage and each individual battery voltage.
If it's a 36v cart it should read something like this:
Pack 38.2v
Batt 1 6.39
Batt 2 6.41
Batt 3 6.38
Batt 4 6.43
Batt 5 6.37
Batt 6 6.42

Thats the next plan of action. Have to pick up a voltmeter. Been meaning to do this anyway, just to check the pack.

[bartoner]

Ok, I put my cart on the charger, after the charger shut off, i let it sit for about 60min - 80min, (dont know exactly what time the charger shut off)...this is what readings i got...

6.48
6.39
6.49
6.45
6.50
6.48

39.1 total pack

I am guessing that I might have a problem with the 6.39 battery?

[dougmcp]

Batteries look fine so far, now drive until it quits and see where the voltages are at. Here's a state of charge chart to help:

[Paxdad]

Those are all good readings, 6.39 should not be a problem. You seem to have a connection issue. Hook the meter to each battery and observe reading when under load. This will tell you if you have an individual cell issue, etc. Post the readings when done.

[bartoner]

Ok, I think I might have determined the bad battery...after the last full charge reading that i posted above, the cart sat for a few days. Last night I took another reading and this is what it read...

6.46
6.38
6.47
6.44
6.47
6.48

39.0 total pack

So i took it out for a cruise around the neighborhood...about a 5 mile cruise, keep in mind that where i live its ALL paved HILLS. Cart ran fine, but just for the hell of it, when i got home, i let the cart sit for about 30min then checked the batteries again....and this is what it said...

6.38
6.12
6.39
6.37
6.36
6.38

38.6 total pack

I think that second battery is whats getting me? What do you guys think? I checked the water level and the connections and everything is good. Might be time to switch these out.

[dougmcp]

I'd call all of your batteries good. After a 5 mile cruise and still come up with 100% charge on the pack is good. Granted, #2 battery sagged more than the rest and may be a problem in the end.
I re-read the post and now I'm confused.
Your first post said you questioned the analog gauge because you only went 1 1/2 miles to a friend's house and didn't have enough power to get home.
Now, you can go 5 miles and still have 100% charge.
I suspect, the first time, you were already low on charge, or at least #2 battery was low, before you went 1 1/2 miles and the battery sagged to point of cut-off.
Until you have the same problem and confirm your analog gauge, everything is speculation.

[bartoner]

Originally Posted by dougmcp

I'd call all of your batteries good. After a 5 mile cruise and still come up with 100% charge on the pack is good. Granted, #2 battery sagged more than the rest and may be a problem in the end.
I re-read the post and now I'm confused.
Your first post said you questioned the analog gauge because you only went 1 1/2 miles to a friend's house and didn't have enough power to get home.
Now, you can go 5 miles and still have 100% charge.
I suspect, the first time, you were already low on charge, or at least #2 battery was low, before you went 1 1/2 miles and the battery sagged to point of cut-off.
Until you have the same problem and confirm your analog gauge, everything is speculation.

when i first hooked up the analog meter, the cart hadnt been charged in a while, and was driven around some by the wife, but the gauge showed it was charged, at that point, i was still understanding that the analog guages were pretty close to being accurate, so i drove the cart, only to have it die on me, and when it died, the gauge still read pretty much the same is it did before it died, so that was my question. the guage itself never seems to drop below full charge unless its under load....and i get conflicting info here, one post said the meter should be read while sitting idle, and the others say it should be read while underload??

[Katshot]

These gauges only read voltage on the circuit they are attached to. Amperage and voltage are two different things. A gauge that would show amperage would not show voltage, and considering that the amperage across the main power circuit of the cart would be constantly changing, the gauge would constantly be jumping all over.
State of charge is little more than an educated guess based on available circuit voltage. Battery condition as well as many other factors have to be taken into account before you can actually try to estimate how long you have before the cart will come to a stop.