Genesis Dual Battery System: Install Photos

[jacobconroy]

I think you could use an isolator. This would give you two separate battery banks. Both would charge when the engine is running, but would be isolated from each other otherwise. 1 bank would be the Genesis setup and the other the Dometic lithium.

The only problem is the "lithium" part. You might need one or two more inline gadgets to monitor the charge properties for the lithium batter. I don't really know anything about managing lithium, but I'm pretty sure they are tricky. Does the Dometic have built-in BMS?

 

[MattJ]

Thanks for your help. I have no idea whether the Dometic has a built-in BMS. Here the manual:

https://www.dometic.com/en-us/us/pr...atteries/dometic-plb40-_-197468#documentation

When I had the batteries connected as I described above, everything happened the way I expected it would: the YellowTop drained to zero, the Dometic battery charged to 100%, and then the fridge ran until the Dometic battery depleted to zero. Once I started the engine, everything recharged and the cycle started again.

The Dometic lithium battery only has two charging ports: one for the AC adapter and an Andersen 12v port. I think that port is made for use with solar arrays, as the manual describes.

 

[jacobconroy]

Thanks for your help. I have no idea whether the Dometic has a built-in BMS. Here the manual:

https://www.dometic.com/en-us/us/pr...atteries/dometic-plb40-_-197468#documentation

When I had the batteries connected as I described above, everything happened the way I expected it would: the YellowTop drained to zero, the Dometic battery charged to 100%, and then the fridge ran until the Dometic battery depleted to zero. Once I started the engine, everything recharged and the cycle started again.

The Dometic lithium battery only has two charging ports: one for the AC adapter and an Andersen 12v port. I think that port is made for use with solar arrays, as the manual describes.

I read the specs and it seems like it does have BMS (battery management system), thought it doesn't specifically say that:


So, I'd guess that you don't need any other fancy gadgets to charge it (Overvoltage protection)...and it would seem that when the digital readout says it's dead, it's not really dead. The BMS shuts off the battery before you can discharge it enough to ruin it (Undervoltage protection). That's good.

I've read that a big advantage of lithium is that it will charge very fast if you give it a lot of juice. That's why I would use an isolator to charge the lithium with a large gage wire from the front of the car. When using the lithium for the fridge it would be it's own system (having nothing to do with the yellow top). You could use the YT to run everything else in the car.

When you discharge the YT, do you mean it's going completely dead? If so, that's bad. You shouldn't let it get below about 12.1 volts between charges. Letting it go completely dead will dramatically shorten it's useful life.

 

[jacobconroy]

I just realized this is in the Jeep forum. I'd post it in the 12V forum. Guys like @dreadlocks and @dwh could probably sort you out. They know stuff!

 

[MattJ]

1) The guys at Genesis told me that the YellowTop is made to be drained and recharged, up to 400 cycles. The RedTop (cranking battery) is a different story, of course.

2) Yes - this thread started as some photos of the Genesis install in my Jeep. But it's now much more of a 12v thread. So I will repost this question there! Thanks again.

 

[dreadlocks]

you shouldn't mix lithium and lead on same load circuit, but you can use same charge circuit if the input parameters are okay for each chemistry.

@jacobconroy Lithium charging is simpler, just provide it a constant voltage, done.. if its going to be on a charging circuit long term a lower float voltage is pretty good, but just shutting off the charger til its needed is better.

 

[Vanhalo]

I connected a Dometic portable battery (512 watt hours) in line with the Genesis auxiliary battery (Optima YellowTop) and then connected it to my fridge. I was careful to make sure the power cable is secured so that it can't get pinched in the fridge slide (have heard some stories about that). With this configuration, I am assuming the Dometic battery will suck power from the YellowTop until the Genesis solenoid cuts it off due to low voltage remaining in the YellowTop. Then the Dometic will power the fridge (up to a full week) until it is depleted, too. Then when I start the Jeep using the Optima cranking battery, the Genesis solenoid will begin recharging the YellowTop and the whole cycle begins again. Make sense? Anything I'm missing?

How did you mount your Dometic tray?

 

[MattJ]

How did you mount your Dometic tray?

https://www.expeditionportal.com/forum/threads/just-five-bolts-fridge-slide-and-cargo-rack.184396/

 

[RandyP]

Does the Genesis hold two group 34s? I'm starting to get interested in LIfePo4...and I'm wondering how many Ah a guy can get in a group 34 LifePo4 battery?

LiFePO4 batteries will not hold up to under hood engine compartment temps well. They are not starting batteries. They are however the best deep cycle batteries you can buy. Just mount it in the back of the jeep away from the engine compartment.