Sorry, posted this in a buried post. Update on my problem- My 2002 Gem has new lead acid batteries and the range is only about 3 miles now. Drives with plenty of power til it gradually slows to 5mph. I have a new RFF motor and a reprogrammed controller. After driving till it got slow (about 3 miles) one battery was showing “replace” on my battery tester. Like 10 percent capacity and 11 volts. I had that battery warranty replaced (Deka lead acid) and figured I was good to go. Just drove it (haven’t been driving since it’s been pretty rainy) and it did it again. And once again, the battery in the same spot (front compartment, closest to the dash) showed “ replace “ on the tester. This was the brand new replacement battery. Any thoughts on why the same battery in the series keeps dying now twice? Terminals are tight, batteries are pretty much brand new.
If you look at the connections on that battery in that position, are there ANY other cables/wires going to it other than the big thick ones?
When you install a battery, it is super important that V be brought up and matched to the others (even a new one). This is called balancing.
Charge that suspect battery back up with an external car charger and make sure V matches all of the other batteries. Get to within 0.10v or better. Take it for a 1 mi test lap and check it again. A good battery should be still be balanced with the others.
Even more important, the general rule is to never let any of the batteries drop below 50% state of charge. A good pack is only as good as it’s weakest battery. For a 12v battery, this is about 12v. Every time this is done(trying to limp it home) damages that battery just a bit.
Yes- this is difficult to do without special test monitors and wires all over the place, but you should be aware of your battery state as you are driving. If speed suddenly drops off you need to know what is going on.
What are you charging the pack with? Make sure the charger is set to the proper battery type. Is it finishing?(green light). Measure each battery and see what top V (as it is finishing) and then after the pack has cooled down after an hour.
I have a new RFF motor and a reprogrammed controller.
How new? Is this a very recent change? Was your old motor still working?
Report back with what you find.
No other wires to the battery. I did check the water levels last night and they were a tad low. Not dry but added probably 10cc to each. After a charge the battery tested “good” but that’s what happened last time. Car ran and limped home, all batteries said fine except this one. This was with the old (two month old) and brand new battery. The one thing I didn’t do was balance the battery before putting it in the car. I’ll charge it by itself. I am using the onboard Zivan charger. The updated one with selector dial. The RFF motor is brand new. The controller was already modified by an unknown source because it was before I got it. (It came with a seized D&D motor that I tried to resurrect but the commutators were pitted beyond helping )
To clarify, I’ll charge the new one by itself with my external charger and check the volts compared to the rest.
Yes, Check V first so you have a baseline. Then, if not same, charge/rest and compare again.
In a perfect world, they should all go up/down several cycles and still be the same. This is rarely the case with LAcid, so we are hoping for close.
Whats the condition of the battery cables when you slide to boots back? Clean copper or white powdery shyt?
Volts are 12.8. All other batteries are within 3 tenths of a volt. I’ll drive it again and check. Because it’s saying good battery now after a charge.
Cables look good. Clean, no white junk.
Update. Batteries all tested good on my battery load tester. 12 plus volts and 100 percent capacity. Drove 3 miles and hardly made it home. All batteries tested good except that same one- front, closest to firewall. Says 11.8 v and 5 percent capacity. Gauge on dash said 85 percent till I rolled into my driveway and it says 30percent.
How far away are you? Shipping is a bit of a biotch, delivery radius is limited, but pickup can be arranged… running a new special this year, buy two medium gas gans plus a side of crazy flares with your choice of ranch or house made marinara sauce and get free membership to the “I blew my Gem… up” club.
Switch positions of the wonky battery with another one that works normally and see if the problem follows it.
Haha sounds good. Yeah I’m about there. But in the meantime I’ll try switching the batteries around.
Can you post a pic of this battery? Part number and label? Show us a pic of how it is installed with cables to the other battery up front.
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What battery tester do you have? The newer style capacitive testers do things a bit different vs the old school resistive coil type. The battery stats need to be entered for them to grade them accurately. If stats for a small battery are used, ALL batteries tested will be given a passing grade and considered Good. This is not an actual real time load test.
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When you say “12 plus volts is good” does not mean much to me. The error between 12.2 and 12.7 is huge.
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Also- When you are taking the reading is important. Right off the charger is very different than letting it sit and cool down for an hour.
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Your assignment was to get the batteries balanced. 12.8 and fresh off the charger (guessing) with all others still 0.3v off is pretty far off. Were the other batteries higher or lower? Keep in mind the window between a charged battery and a dead one is only about 0.5v
The display on your dash is a voltage based guesstimate device that looks at voltage and shows you what it thinks is the state of the pack. This is not a very accurate way of doing this task. It samples at some unknown times as you are driving and updates the screen. It was probably holding the higher reading and took another look as you were pulling into the driveway.
Stop doing these 3 mile test laps. I only want you to do less than 1 mile. Every time you dip a battery below 12v it hurts the battery.