The six 6 volt lead-acid house batteries in my class A DP have gone bad. I am looking to replace them with 6 Battleborn 100Ah 12v LiFePO batteries. Eventually I will be adding solar. I am not looking for recommendations on what batteries and components to buy, I have made up my mind so please don't try and change it. The reason for this post is, I am reading that in class A motorhome when you switch batteries you should install a DC to DC charger to protect the alternator of the motorhome from overheating. I would like to know if anyone here has done this to their motorhome, what did you use to do it and where inline did you install it?

This is what we did, A 30amp DC to DC charger gives you the ability to charge the coach battery bank while running the coach engine. This limits the engine alternator to 30 AMPs thus prevents overheating the engine alternator.The engine alternator will operate normally while charging the engine batteries.We have had the system in service for 2 years, with no problems.

Tom/Barb wrote:This is what we did, A 30amp DC to DC charger gives you the ability to charge the coach battery bank while running the coach engine. This limits the engine alternator to 30 AMPs thus prevents overheating the engine alternator.We have had the system in service for 2 years, with no problems.Tom/BarbWhat brand and model did you use??ThanksKent

N6WT wrote:Tom/Barb wrote:This is what we did, A 30amp DC to DC charger gives you the ability to charge the coach battery bank while running the coach engine. This limits the engine alternator to 30 AMPs thus prevents overheating the engine alternator.We have had the system in service for 2 years, with no problems.TomWhat brand and model did you use??ThanksKent4 Battleborn.. and victronOur system is....1- 3000 watt inverter /charger (VICTRON)4- 100 Amp Hour battleBorn batteries.1- 30 Amp DC to DC charger (victron)and 1 Blue tooth donggel (sp) to monitor the system on my phone.

A 30A DC DC could pull 45 amps. Output is 30

If you have time at one place I recommend measuring the charging amps and then decide if the DC-DC is needed. Depending on wire size and length along with alternator rating there may not be any issue. A DC clamp-on ammeter will tell the actual story.Also consider the DC-DC charger will isolate the house battery such that any existing combiner to maintain the chassis battery could become non functional.Going to really like the BB power.

Lithium batteries and alternator protection. | Good Sam Community

N6WT
Explorer
Mar 12, 2022
time2roll wrote:
If you have time at one place I recommend measuring the charging amps and then decide if the DC-DC is needed. Depending on wire size and length along with alternator rating there may not be any issue. A DC clamp-on ammeter will tell the actual story.

Also consider the DC-DC charger will isolate the house battery such that any existing combiner to maintain the chassis battery could become non functional.

Going to really like the BB power.
I have read about this and normally on a truck and trailer you may not need the DC to DC charger because of the length and wire size. On a class A motorhome the alternator is much closer to the batteries and I am assuming the wire size is bigger also ( I need to check the wire size).

Yes I am looking forward to the advantages of the lithium batteries.

Thanks
Kent
N6WT
Tom_Barb
Explorer
Mar 12, 2022
time2roll wrote:
If you have time at one place I recommend measuring the charging amps and then decide if the DC-DC is needed. Depending on wire size and length along with alternator rating there may not be any issue. A DC clamp-on ammeter will tell the actual story.

Also consider the DC-DC charger will isolate the house battery such that any existing combiner to maintain the chassis battery could become non functional.

Going to really like the BB power.

the size of the DC to DC charger you need will be determined by the size of the engines alternator.
The victron DC to DC charger can be set for the system requirements by blue tooth remote.
Tom_Barb
Explorer
Mar 12, 2022
BFL13 wrote:
A 30A DC DC could pull 45 amps. Output is 30

I never see that current in our system.

our coach batteries are monitored on the OEM gauge in the engine to 13.2 vdc
our house batteries are monitored on the Victron gauge at 14.2 vdc
the DC to DC charger is limited to 30 amps by two fuses on the + side of the circuit.
the house battery bank is controlled by 1-300 amp fuse in the + plus side and 500 AMP shunt and a shutoff switch in the Negative side of the buss.
time2roll
Nomad
Mar 12, 2022
If you have time at one place I recommend measuring the charging amps and then decide if the DC-DC is needed. Depending on wire size and length along with alternator rating there may not be any issue. A DC clamp-on ammeter will tell the actual story.

Also consider the DC-DC charger will isolate the house battery such that any existing combiner to maintain the chassis battery could become non functional.

Going to really like the BB power.
BFL13
Explorer II
Mar 12, 2022
A 30A DC DC could pull 45 amps. Output is 30
Tom_Barb
Explorer
Mar 12, 2022
N6WT wrote:
Tom/Barb wrote:
This is what we did, A 30amp DC to DC charger gives you the ability to charge the coach battery bank while running the coach engine.
This limits the engine alternator to 30 AMPs thus prevents overheating the engine alternator.
We have had the system in service for 2 years, with no problems.

Tom
What brand and model did you use??

Thanks
Kent

4 Battleborn.. and victron
Our system is....
1- 3000 watt inverter /charger (VICTRON)
4- 100 Amp Hour battleBorn batteries.
1- 30 Amp DC to DC charger (victron)
and 1 Blue tooth donggel (sp) to monitor the system on my phone.
N6WT
Explorer
Mar 12, 2022
Tom/Barb wrote:
This is what we did, A 30amp DC to DC charger gives you the ability to charge the coach battery bank while running the coach engine.
This limits the engine alternator to 30 AMPs thus prevents overheating the engine alternator.
We have had the system in service for 2 years, with no problems.

Tom/Barb
What brand and model did you use??

Thanks
Kent
Tom_Barb
Explorer
Mar 12, 2022
This is what we did, A 30amp DC to DC charger gives you the ability to charge the coach battery bank while running the coach engine.
This limits the engine alternator to 30 AMPs thus prevents overheating the engine alternator.
The engine alternator will operate normally while charging the engine batteries.
We have had the system in service for 2 years, with no problems.

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