wiring plan for new LFP batteries

[Jc180]

Not true. Have two Duo Charge units in service on my boat. They have selectable smart charging profile output for four different battery types. An ACR is simply an electronic switch.

 

[twistedtree]

Not true. Have two Duo Charge units in service on my boat. They have selectable smart charging profile output for four different battery types. An ACR is simply an electronic switch.

Ok, I must be confusing it with another Balmar product.

 

[SteveK]

I don't understand. Can you do a sketch of the wiring.

Take the 4 batteries you have drawn and draw a busbar on either side to which you attach a cable of same length from each battery respectively to +/- terminals. one line from each to the load and inverter. 100% balanced. Add a battery still balanced without changing existing cables.

 

[Jeff F]

This thread might be of interest as well.

https://www.trawlerforum.com/forums/showthread.php?t=65714

 

[Jeff F]

All things being equal. DC to DC chargers do not charge slower. It's in the amperage. But maybe I am missing something? Anyway, Li banks charge up faster than lead acid/AGMs. So that in it self my work for you.

To each their own???

I think it depends on the current you're working with. My alternator can put out ~130a continuously, and I wanted to prioritize and maximize the charge to the house bank. The AGMs don't require immediate or fast charging. That informed my decision to charge the house bank directly. I have an APD, but recognize that there is some risk to my systems in the case of an unexpected total bank shutdown.

For the OP the 120a alternator is likely to get derated to 60-80 amps with a conservative heat limit. So a 60a cap on house bank charging imposed by a pair of 30a chargers may not be a big deal. In that case your approach has lots of merits with no real downside.

That assumes non-communicative BMS. If you have the BMS able to alert the operator and shut down charging then there's no reason not to charge the house bank directly. That's clearly the best approach, and the way of the future.

 

[Jeff F]

Ok, I must be confusing it with another Balmar product.

I think the Duo charger is a sleeper. A dc-dc charger that was around long before the term became trendy. They never really differentiated their product from ACRs enough, IMO.

 

[Iggy]

Take the 4 batteries you have drawn and draw a busbar on either side to which you attach a cable of same length from each battery respectively to +/- terminals. one line from each to the load and inverter. 100% balanced. Add a battery still balanced without changing existing cables.

Yep! I am not good writer! So I have a hard time getting my point across.

DaveM mentioned a temp sensor for the Alt. Good point. I added one and it was a two wire install and bolt the sensor to the frame of the Alt. Cheap protection and 5 minutes to do.

 

[brewgyver]

I don't understand. Can you do a sketch of the wiring.

REO,
You might want to check out Victron's library of system drawings https://www.victronenergy.com/support-and-downloads/systems#item=system-ve-bus-bms-ve-bus-bms-v2