charging voltage on JL Rubicon

[FulThrotl]

my 3.6 gas JL has suddenly decided to regulate the charging voltage
at 12.9 to 13.0 volts. it'll spike to 13.7 for a second or two, and fall back.

no engine codes.

is there anyone who knows how jeep regulates the charging voltage,
and what i can do to solve this?

doesn't seem likely it's the alternator. it's a pretty new DC power 340amp
that charges normally at 14.4 volts, and will do a hot idle current of 200 amps.
it'll run a 3,000 watt inverter in the back of the jeep at idle. the voltage is just stuck
at barely above no charge at all.

dual battery optima group 25 with battery isolator. voltage is so low that it won't
even pull in the second battery for charging. lithium 300 AH in the back of jeep
won't accept charge at that voltage either. digital battery test says both batteries ok

everything seems fine except for the jeep won't let it charge.

any help would be greatly appreciated.

thanks.

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[Beachcomber72]

my 3.6 gas JL has suddenly decided to regulate the charging voltage
at 12.9 to 13.0 volts. it'll spike to 13.7 for a second or two, and fall back.

no engine codes.

is there anyone who knows how jeep regulates the charging voltage,
and what i can do to solve this?

doesn't seem likely it's the alternator. it's a pretty new DC power 340amp
that charges normally at 14.4 volts, and will do a hot idle current of 200 amps.
it'll run a 3,000 watt inverter in the back of the jeep at idle. the voltage is just stuck
at barely above no charge at all.

dual battery optima group 25 with battery isolator. voltage is so low that it won't
even pull in the second battery for charging. lithium 300 AH in the back of jeep
won't accept charge at that voltage either. digital battery test says both batteries ok

everything seems fine except for the jeep won't let it charge.

any help would be greatly appreciated.

thanks.

Is the 3.6 with or without Etorque?
@Genesis Offroad may be of better help/information

 

[FulThrotl]

Is the 3.6 with or without Etorque?
@Genesis Offroad may be of better help/information

without. just a vanilla 3.6

 

[RAO]

You can try resetting the IBS, as it typically controls charging of the batteries. It’s the little black box sitting on the negative terminal of your main battery. Disconnect it and your battery for a time - I do 15 min - then hook it up again and see if your voltage increases. It will go through a learning process once hooked back up.

 

[FulThrotl]

You can try resetting the IBS, as it typically controls charging of the batteries. It’s the little black box sitting on the negative terminal of your main battery. Disconnect it and your battery for a time - I do 15 min - then hook it up again and see if your voltage increases. It will go through a learning process once hooked back up.

that worked. everything is charging at 14.2 VDC. now, a quick test drive to marina del rey for work. what could go wrong on the 405 freeway?

thanks for your help.

 

[_olllllllo_]

that worked. everything is charging at 14.2 VDC. now, a quick test drive to marina del rey for work. what could go wrong on the 405 freeway?

thanks for your help.

Having driven on the 405 in that area the only thing that could go wrong is you could be on it for hours going a couple miles, especially by the Howard Hughes center. I will never understand why that part always became a parking lot.

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