alternator type in 392

[Chris-AZ]

What type of alternator does the 392 use? Is it variable voltage OR a BMS design? Does it use a current shunt and battery monitor system to turn charging on and off based on what it thinks the main battery needs?
Info needed in order to properly configure my Redarc BCDC1225D to charge my Odyssey PC1100 auxiliary battery. Basically there is a wire which either needs to be connected to ignition or left floating depending if the alternator is an old school continuous output design or a modern BMS or Variable output design. Since the 392 does not have the auto start/stop 2nd battery, I guess the charging system might be completely different too?

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[Left Field]

What type of alternator does the 392 use? Is it variable voltage OR a BMS design? Does it use a current shunt and battery monitor system to turn charging on and off based on what it thinks the main battery needs?

Info needed in order to properly configure my Redarc BCDC1225D to charge my Odyssey PC1100 auxiliary battery. Basically there is a wire which either needs to be connected to ignition or left floating depending if the alternator is an old school continuous output design or a modern BMS or Variable output design. Since the 392 does not have the auto start/stop 2nd battery, I guess the charging system might be completely different too?

Correct, the 392 does not have ESS and hence only has the main battery. That was one small perk for me with the 392 package.

I've been watching my battery voltage over the the last 1000 miles and have never seen it read anything other than 14.1 while running. It does have the battery management dongle on the negative battery cable, but does not appear to actively vary the charging system based on battery status and driving conditions like the ESS models.

Based on this, I'm planning to charge my 92Ahr AGM camper battery directly through the tow connector and have been hoping to avoid a DC-DC charger. It will be slower, but in my use case (solar charging during camping / vehicle charging while traveling) It looks like there's a good chance it will work. It worked fine with my last non-BMS vehicle anyway. The Redarc would get the job done a lot faster though, and if I get a 12V fridge will probably go that route due to the deeper charge cycles.

 

[Chris-AZ]

Correct, the 392 does not have ESS and hence only has the main battery. That was one small perk for me with the 392 package.

I've been watching my battery voltage over the the last 1000 miles and have never seen it read anything other than 14.1 while running. It does have the battery management dongle on the negative battery cable, but does not appear to actively vary the charging system based on battery status and driving conditions like the ESS models.

Based on this, I'm planning to charge my 92Ahr AGM camper battery directly through the tow connector and have been hoping to avoid a DC-DC charger. It will be slower, but in my use case (solar charging during camping / vehicle charging while traveling) It looks like there's a good chance it will work. It worked fine with my last non-BMS vehicle anyway. The Redarc would get the job done a lot faster though, and if I get a 12V fridge will probably go that route due to the deeper charge cycles.

So the 392 does have a modern smart alternator with a BMS. I'll be using a dc-dc converter style charger for the aux battery instead of an isolator or direct charger.

On my Ford Raptor, which has BMS, I used a Hellroaring isolator system for my Aux battery and found that after a couple months the starting battery was no longer able to start the car. Turns out the aux battery was hogging the charge and the BMS thought it had charged enough leaving the starting battery without adequate charge. Ford replaced my starting battery twice without getting to the root cause. Finally I figured out what was going on and eliminated the isolator and instead I took a common 110v garage battery maintainer and plugged it into the OEM on board inverter then hooked it to the aux battery. Then I installed a manual battery switch, just an ON/OFF to short the batteries together to use for self jump starts. No more dead batteries as the BMS is now properly charging the starting battery and the aux battery gets a multi-stage charger/maintainer to top it off each time I drive. BTW, my voltmeter never showed voltage variations while engine was on. I could not tell it had a variable output alternator based on voltmeter (the voltmeter I was using is one built into an aftermarket Lowrance GPS I installed for topo maps with trails). Anyway beware of adding an aux battery with modern cars that use BMS technology in the charging system (almost all new cars have this now).

 

[Left Field]

Your experience with the Raptor charging system is interesting and tells me I need to proceed with caution tying in my camper battery - might get the same vehicle battery charging problems.

On your Raptor, where did you connect the ground of your Odyssey battery? Wondering if upstream/downstream of the BMS sensor changes things.

Do you have any concerns that the BMS will still have problems managing the vehicle battery with the load created by having the Redarc tied in? If it works well for you I might just cut to the same route.

 

[Chris-AZ]

On your Raptor, where did you connect the ground of your Odyssey battery? Wondering if upstream/downstream of the BMS sensor changes things.

Do you have any concerns that the BMS will still have problems managing the vehicle battery with the load created by having the Redarc tied in? If it works well for you I might just cut to the same route.

I grounded the aux battery to the frame. It lives in the truck bed in a custom chase rack for desert racing support. The rule on BMS systems is never ground anything direct to the battery, always tie it to the chassis/engine or to the chassis side of the shunt that is on the battery. I think this even includes the winch ground.

The Redarc will only draw current while the engine is running and will appear as a normal load as opposed to a battery which is a source of EMF.

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