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Discussion Starter #1 (Edited)
When I had my 110 volt, 48 volt system in the Yugo, I could run to town in the mornings even though the temperature was 35 degrees F.

Now that it is a 72 volt system, I hardly can get to town when it is below 40 F.

Thinking this over has brought me to the conclusion that the battery pack was warm from charging before, because I had the charger on a timer.

It would charge for 3 hrs and then be ready to go 10 miles if I had to, with the warm pack.

My 220 volt, 72 volt charger is not on a timer and it charges from 11: pm until morning with a tapering off charge. By 7:AM, the pack will have cooled down and lost power.

I don't want to go out at 4:AM to plug it in, so the next best thing is a timer for the 220 charger.

Should be able to locate one at a sale.
 

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I noticed a change in battery performance one afternoon that turned cool compared to 90 degree weather. Noticed the pack voltage was lower than normal, despite a full charge. I almost turned around, but soon the voltage increased due to the amp draw (that warmed up the batts?). This has happened several times (& not due to loose wires), but the batts perk up during some heavier amp draw. Some talk of batt warmers??? Just wondering about performance as we head for winter in SW Ohio. I notice on 50 degree days, I use 10% more AH. Could this be your situation, too?

US145 120V sys
 

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Discussion Starter #3
Yes. It is 31 F this evening and may be cooler in the morning.

I am planning to hook up the charger at about 6:30 AM and let it charge for 3 hours and then try a run to town and see how it goes.

I looked at heaters for the batteries but don't like the looks of the kind that wrap around the battery.

I use some flat, rubber, heaters in my work equipment and may see if they will work under the batteries.
 

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Discussion Starter #4 (Edited)
Well, I went about 1 mile this morning, with the 30 F temp, before I noticed that I was not going to make it to town.

I went back home and charged them until noon.
The temp by then was 50 something.

It went to town ok, but I noticed a higher amp reading.

I put it up on the hoist this morning, in the shop and noticed a very heavy drag on both front wheels.

I rebuilt the calipers, when I first built the car. I pulled them both off and found that the caliper seals had let moisture get to the aluminum cylinder outer edge.

This caused much drag on the pistons, which kept pressure on the rotors.

I rebuilt them again and sealed the boots with silicone seal.

Drove the car home at noon and noticed a big difference in amps used.
 
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