A couple of speculations:
1) Sometimes the battery BMS can turn off if it measures a high enough voltage. On an budget battery setup, maybe the BMS voltage reading is slightly off and it is triggering / chattering as it gets to that upper limit.
Maybe try setting the charger so that it never goes over 14.0 volts and see what happens.
2) Impedance / resistance
Your system might actually have too low of resistance / impedance. I know that sounds odd but I have built a power system before with ultra low impedance like this and it was unstable. I had to add fuses for each component to make it run in a stable manner.
As an example, consider the idea of using a fuse block for all of the connection points instead of the bus bars.
Here is a good quality example - try to avoid going cheap on these fuse blocks:
Compact ATO® / ATC® fuse block consolidates branch circuits and eliminates the tangle of in-line fuses for electronics and other appliances.
www.bluesea.com
Just use 30 amp fuses for all of your items listed.
Run everything, including the batteries to a fused connection point.
If you can, run the wires as twisted pairs when possible, especially from the solar charger to the fuse block.
3) Renogy controller failing
- I have seen those fail commonly in van power systems that customers bring in.
- I replace them with the Bogart controller
Just set the external pin to 12 volts and AGM and it will work just fine. No need for anything else.
It will self limit to 30 amps no matter what your panels are doing.
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