How long does it take Automatic Charging Relay to charge 1000 AH battery setup. or do ineed 2nd alternator

[peallen]

should i go with a 2nd alternator to charge battery bank or will an auto charging relay work for me?

 

[John Frum]

5 hours to charge at .2c

Lithium-Iron (LiFePo4) Battery Calculator Ah to kWh Battery Charge or Discharge.

Australian Micro Power Grids, Importer of Energy Storage systems.

micropowergrids.com.au

 

[peallen]

5 hours to charge at .2c

Lithium-Iron (LiFePo4) Battery Calculator Ah to kWh Battery Charge or Discharge.

Australian Micro Power Grids, Importer of Energy Storage systems.

micropowergrids.com.au

what is 2c

 

[John Frum]

Its 0.2c.

Battery C rating explained - Quad Questions

Quadcopter battery C rating explained. How to choose the right c rating for the job when building drones quadcopters or any lithium battery application.

quadquestions.com

Typically but not always lifepo4 batteries are rated for 1 c discharge rate and 0.2c charge rate.
The fortune batteries you are interested in have better specs https://www.electriccarpartscompany.com/Fortune-100Ah-Aluminum-Encased-Battery
but I personally would not discharge them at higher than 1c and even getting to 0.2c with an alternator is likely going to stress out more than just your battery.
200 amps @ 51.2 volts = 10240 watts.
10240 watts = 13.732066 horse power at 100% efficiency.
You won't get 100% efficiency.
Anyone got a WAG number to plug in for efficiency?

What engine is in your vehicle?
What transmission?
What fuel?
And again, do you have a high idle switch in you your van?
If it was me I would only want to engage this alternator on >=high idle after the engine and ancillary systems were up to temp.

 

[peallen]

3.0 diesel
4x4 tranny
no high idle

 

[John Frum]

3.0 diesel
4x4 tranny
yes high idle

might work.
Is there a high temp cutoff on the alternator?

 

[John Frum]

The next hurdle is 1000ah of lifepo4 is going to draw a stupendous amount of current if the batteries volatage is low.
Enough current that I would worry for the safety of the alternator and for the battery.
Does the alternator have a current limiting feature?

 

[peallen]

actually no high idle, blue sea has a charging relay, primary objective is charge the starter battery, then does the house/rv battery. This may give warm up time. Other sprinter vanlifers recommend it.

Are you suggesting I go to a dual setup with a balmer voltage regulator?

 

[John Frum]

Are you suggesting I go to a dual setup with a balmer voltage regulator?

Nope I am suggesting that you make sure that the lifepo4 batteries don't kill your alternator or themselves.

 

[asinc]

Nope I am suggesting that you make sure that the lifepo4 batteries don't kill your alternator or themselves.

The lithium batteries will likely draw too much current from your alternator and kill it. You will likely want to use a charge controller or dc-dc converter which will limit the current flow to reasonable load the alternator.