48V battery charge percent

[umax2themax]

How do I figure percent of charge using my multi-tester? From the far end - to the other end of the bank of 6 batteries + I get a 48.7v . Each battery is as follows if anyone can comment on the different span of voltages and what they might mean? I know 1 battery has been replaced of the 6 as I just bought this umax cart and the guy had replaced 1 battery due to a corroded terminal.
8.10 8.16 8.18 8.08 8.11 8.07 which equals my other test of 48.7v . So, I think I have tested correctly, but how do I interpret the charge percent is my question. I found a chart of some webpage not relating to carts that said a 48v battery has 24 cells and if each cell has a voltage of 2.100 then it is 95% charged, 2.032v per cell would be 50% charge, etc.
so, is it correct for me to assume my total voltage of 48.7v divided my 24 (cells) equals 2.029v which equates to about a 48% charge using that chart? I am just unsure whether that chart is applicable to my six 8 volt batteries. any comments, corrections very much appreciated.
and I heard it is best to run down the batteries to 25% then to charge, anyone agree or differ?

 

[HotRodCarts]

Welcome to the forum...

I'm not sure how to tell the % of charge but the voltages you posted are low for fully charged 8 volt batteries. After an hour off the charger from a full charge you should be seeing around 8.5 volts per battery and around 51 volts for the pack. Hopefully someone else will chime in on the percentages.

 

[JRay]

I not sure this helps but my 90 with 02 batt. wont charge over 49.6, my 02 with 07 batt. will go to 51.7 i think they should go higher. These are trojan batt.

 

[gornoman]

I agree that your voltages look low. Is the water level correct in all cells? How long are they charging? I have seen 54v on my 48v pack (8-6v cells) after a full charge.

 

[JRay]

If your talking about my batt. i need to get a few more cycles on the new 07,s i don,t use that cart enough. Those o2 batt. i think are going down for the count, i have tried all the tricks with them. i have a brand new charger 48 lester so it shouldn,t be that.Those 02,s load test ok so i will run them till they drop.Then again it might be that cheap 5 dollar meter i have been using.Time to get a new one. Auto chargers and i run them till they shut off. I do keep my water levels correct, i check them once a week or after every charge.

 

[gornoman]

Sorry JRAY, but my comments were directed to umax2themax. I should have quoted to reduce confusion. Pretty poor forum technique on my part, eh?

 

[umax2themax]

I guess I should have stated that I had not even run the charger once since buying this used cart yesterday. I ran it a bit more today after my readings, let it sit for an hour, took some additional voltage readings, and have now plugged it in for its first full charge.
I'm not too concerned with what it will top out at fully charged. I assume I will be getting a set of batteries when the day comes this year or next, who knows. I just want to be able to figure out the percent of discharge where I should stop driving it and plug it in. Thats the info I am after. What voltage should I not drop below and what percent of discharge is that?
I didn't even know I had to check water levels till late this afternoon. I will plan to do that every week or after every charge, thanks for that advice JRay. I guess that explains why you can buy those water lines I have seen in a golfcart mag if you have to do it that often. Anyone use a good brand of those?
I found some battery info at trojan for my t-875's. I will check back in a day or so with my full charge numbers and see what everyone thinks of those. Still would like to figure out the exact % of charge/discharge, maybe I will talk to Trojan because I am starting to think it may be battery specific and vary from cell to cell for different battery types so my chart I found may be useless. Yeah, I'm new to this... Oh, the 6" lift with 22" dirt devils from Jakes will be here Tuesday. I probably won't care about batteries the day I put the lift and tires on! Why didn't I go bigger in the tire dept? My old lady barely let me get away with the lift.

thanks for the comments
Bruce
umaxtothemax

 

[HotRodCarts]

The batteries shouldn't be run down past 50% so you wouldn't want to go below 8.07 volts per battery. I would say don't let them drop below 8 volts. According to the voltages you posted you're at 50-60%. You should charge the batteries after each use even if used for short periods. They will last a lot longer if you don't run them down to 50% before charging. Just make sure you keep them full with distilled water.
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