Questions about Battery Performance
Hi,
I have a Chinese electric Moped that I have been test riding for my own amusement since July. It has 5 batteries in a string for 60 volts to run a 2,000 watt brushless motor.
The batteries are called GreenSaver and are a silicone lead AGM type of battery, not the typical lead acid AGM type.
I have brand new silicone batteries in it now with about 200 miles on them.
I have installed a data acquisition system that allows me to record the voltage of each battery and amp loads every second.
The batteries are rated at 14.5 amps for a tad under 2 hours or 27 Ah.
I typically run in the area of 40 plus amps which I can do for about 30 minutes.
The first set of batteries that came with the bike died pretty quick, but I did everything wrong, rode them too low, didn’t recharge immediately, did not have a battery equalizer etc…
I also noticed on the first set that the first failures occurred on the positive end of the string, then the next bad battery was second from the positive end.
The way I set the bike up for new batteries, I increased the battery harness from 10 awg to 8 awg and used soldered terminal lugs everywhere, and I scrapped the bulk 73 volt string charger and wired each battery to its own 12 volt charger to avoid resistance problems within the string from causing some batteries to overcharge, and others to undercharge.
Now for my question, I am wondering if you have any experience in seeing this kind of an anomaly in dealing with strings of batteries.
As I analyzed the voltage drop characteristics of the batteries under load, I noticed what appears to be a disturbance in the batteries ability to provide a steady voltage under load.
The closer the battery is to the positive end of the string, the more disturbed it appears to become.
In addition to this, the closer the battery is to the positive end of the string, the more apt it is to have a short term downward voltage drop than the other batteries that are closer to the negative end of the string. This appears to possibly be a root cause for early failure of the battery located closest to the positive end of the 5 battery string.
Any comments or info you may have would be appreciated.
Tracy