Lithium batteries and alternator protection.
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 look...
Forum Discussion
Tom/Barb wrote: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.
If the DC-DC is charging the house batts with 30 amps at 14.2v , that is 426 watts output. Input must be at least that in watts, more for charger efficiency say 90% to be generous so needs 469 watts.
If input is that 13.2v (not clear from the above info) that means input amps must be at least 469/13.2 = 35.5 amps draw on the engine side (engine batt/alternator.
If the engine batts are 13.2 (seems low) then with wiring loss voltage drop between engine batts and DC-DC charger input voltage will be less than 13.2 so the input amps would have to be higher than that 35.5
Best way to measure what is going on is with your digital multimeter right at the input and output terminals of the DC-DC charger itself for the two voltages.
