Let me know how it works out; I will probably drop my pack on the Prizm again in a year for weeding batteries; putting in a BMS system will be a priority.
Chris Jim Coate wrote:
This topic has gone around a lot on the EV list as well. A 10-segment display doesn't really give enough resolution to see the small voltage changes that make the big difference. So... having something that reports the difference would indeed give more accurate results.The "green/good, red/bad" light could basically be done with Lee Hart's BattBridge. I don't know of anyone ever putting it on an ET, but I'd think it would work (famous last words) - it compares the two halves of the pack and lights and if one group of 3 is significantly different from the other 3. So it is an "off/good, on/bad" light.And being timely as ever, just this morning I ordered some parts including some indicators I decided to experiment with first on my ET (6 batteries) before trying on my truck (22 batteries). The concept being that each battery will have a low-voltage indicator that will light up if that particular battery voltage gets too low (~5.2 volts). Normally should tend to all come on at once if pushing too hard, meaning that it is time to shift to a lower gear or if in need of a recharge. If one keeps coming on sooner, then that particular battery needs some help. Rather than trying to indicate the actual voltage of each battery, it only indicates those that have crossed the threshold.Christopher Zach wrote:I've thought about this a lot. What you really need is not the individual voltage of the battery, but the *difference* in voltage between each battery.If all 6 drop to 6.0 volts while going up a hill, that's fine. However if 5 are at 6 and one is at 5.7, you would want to know that one of the batteries is low.I'd be happy with a simple red/green LED that would be green as long as the battery voltages were within a range of say .2 volts. If the range is different, the red light comes on and it's time to check the batteries.Chris Bill wrote:Wouldn't it be great to have instant dashboard readout of the voltage on each battery! This could be done with the little bar LCD meters. Multiconductor cable with AWG 22 wire would be sufficient for the hookup. Any weak or undercharged battery would be evident right away. But where do you get these six channel meters? Its time consuming to measure the voltage of each battery individually, and/or use a hydrometer. I make myself do it every month or so, but I hate it. My "fuel" current meter has never indicated anything useful to me. It may have dirty connections because it never reads "full". I realize I could do this with one meter and a rotary switch, but I'd like to see the bars of all six batteries at once for quick comparison. Bill/E-12/NE Kansas