Any update? Mine does pretty much the same thing batteries at 78 volts, one red bar, some times i accellerate and it goes 15 then shuts down until I remove power and reconnect. Does anybody know where this thing gets its SOC info? I think it is the circuitry around the shunt in the PSDM but there is a comm line with the display so maybe the display decides. Sometimes mine reads all green bars like it should be.
The SOC display does not dictate the operation of the vehicle, it’s a display and if you see it showing lots of bars and then quickly goes down and your vehicle stops then you are probably seeing a failed battery. One or more of your 6 lead batteries is failing and has so little charge CAPACITY it quickly depletes and drops the whole pack voltage.
FYI the system goes like this:
Controller<- BATTERY1 ← BATTERY2 ← BATTERY3 ← BATTERY4 ← BATTERY5 ← BATTERY6<
-> ----------------------------------------------------------------------------------------------------------------------------------|
As you can see each battery feeds into the next battery so if one goes bad the whole thing looks bad.
Pay no attention to the SOC display at this time. It appears to be confused.
As dougl points out, This is not a SOC meter issue, it is a battery/power issue.
Put a volt meter on each battery and check their V. Note each one. I am betting they are out of balance. One or more will probably be way off from the others. If wet cell, when was the last time they were watered?
Then do a load test on them and see how far they drop under load.
If they read OK at the batteries themselves then look for a bad connection.
Put your meter directly on the POS and NEG on the controller and monitor what it is seeing for voltage when you are driving. If you see a huge drop, then it comes right back up then you have a bad/loose connection. Check/clean all of your cables on the batteries, at the fuse block, up at the front where the power goes through the PSDM(all 3 connections), the Main Contactor, or even the Main flippy switch that shuts down the power to the car. Sometimes you can see this as signs of heat, otherwise you will need to meter voltage drops through each connection.
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