Sizing converter for charging RV battery bank

[rmulgr]

Hey folks. I have a 6 battery bank in my RV with 6 volt interstate flooded lead acid batteries wired in series parallel to make a 12 volt system. Each battery is 225 AH. My converter is failing and I am looking for a replacement converter/battery charger. I am replacing the stock WFCO WF9855 which is a 55 amp, 3 stage converter. I see that I can get up to a 100 amp converter. Are there any advantages to getting a converter with a higher amp output? Would there be any disadvantages? My RV is always hooked up to shore power and the batteries stay fully charged all the time. I calculated all my DC power usage and it looks like the most I would use at one time is around 55-60 amps DC. Thanks for any help you can provide.

 

[OzSolar]

A good rule of thumb for FLA is to charge at minimum charging rate of 10% of the rated amp hours.

225AH x 3 = 675 x 10% =~68 amps

Looks like your stock 55 amp converter was actually a bit too small to properly charge them but since you're always hooked up to shore power it did fine.

Side note: If you're always hooked up to shore power you really only need two batteries. And technically you don't need any since the converter will supply your 12v loads. Just some food for thought before when it's times for the next round of batteries.

 

[rmulgr]

A good rule of thumb for FLA is to charge at minimum charging rate of 10% of the rated amp hours.

225AH x 3 = 675 x 10% =~68 amps

Looks like your stock 55 amp converter was actually a bit too small to properly charge them but since you're always hooked up to shore power it did fine.

Side note: If you're always hooked up to shore power you really only need two batteries. And technically you don't need any since the converter will supply your 12v loads. Just some food for thought before when it's times for the next round of batteries.

Thanks for the fast reply and the insights. Should I buy the 75 amp or 100 amp model? The cost difference is negligible. Is there a downside to getting a 100 amp model? I think my stock wiring should be abler to handle either.

 

[OzSolar]

Thanks for the fast reply and the insights. Should I buy the 75 amp or 100 amp model? The cost difference is negligible. Is there a downside to getting a 100 amp model? I think my stock wiring should be abler to handle either.

If your wire size can handle it then there is no downside.