Thanks for the info Wrangler!
When the Jeep has been running but is shut off in ess, what does the battery voltage show for you guys?
After thawing out from our -30s temps last week my ess system has finally charged my battery up to work and I noticed that when the Jeep shuts off for ess, in less than a minute my battery gauge reads about 11.5v. It was 18f today and I had my seat heater on low with the alpine radio. I’m fairly certain this isn’t normal but I wanted to see what everyone else was seeing. I also haven’t had a chance to actually measure individual battery voltage since it’s been freezing rain the last few days.
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When your JL shuts down on a normal ESS operation the relay opens and the main battery and ESS battery are separated and the accessories you have on like lights, radio etc ... are powered by the ESS battery, initially the EVIC displayed voltage you see once it shuts down should be in the 12.5-12.7 range but the more you have running the quicker the voltage will drop and I have seen mine as low as 11.8 while testing.
When you let you foot off the brake and ESS disengages the relay from my understanding closes back and the engine is cranked off the main battery and while running both batteries act as one and are charged together and the voltage is monitored by the IBS that is connected to the negative battery terminal.
From talking to a few FCA techs my understanding is the voltage displayed in the EVIC can vary from 12.8-14.3 and anything in between as the JL only charges when needed and the amount of charge is dependent on how depleted the batteries are so the days of the alternator constantly throwing 14+ all the time is gone but like I said it depends on how depleted the batteries are.
Hope this info helps
Thanks, that’s a bit different than what I heard before on the system. I’m use to batteries holding 12+ volts but I guess the electrical system is enough to pull it down... part of me just feels like something isn’t right if I drive my Jeep 30min each way to work with limited stop and go and since last week the ess said it wasn’t engaging because the battery was charging.
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