Limiting current to Aux battery?
I have a campervan with a 90A OEM alternator. I am using a standard deep cycle lead acid flooded marine battery under the hood as my aux battery. I use a 100A relay to parallel the starting and aux ba...
Forum Discussion
Put it this way:
My van has a 120 amp alternator and thick #2 AWG wiring that is short and a mechanical isolation solenoid. 14.4 v volts cold output from alternator into my 2 GC2 golf cart batteries (232 AH) when at 40 % charge. I've measured 67 amps with a DC clamp meter under those conditions. Your alternator will be fine, and chances are at is heats up the voltage regulator will sag that back to 13.8 volts and current will go down to maybe 40 amps or less. So for your single battery, I can almost guarantee you won't see that level of current, since your wire probably isn't that thick and your single battery is NOT capable of accepting any more current.
I should add that I also run my fridge on dc under theses conditions, and I have never blown the 100 amp fuse I have installed.
I realize that it is a starting/ marine battery so in theory it could accept maybe more amps, but Ill bet it will not.
One time in my ranger truck I had a flat battery and I jump started it and immediately put a clamp meter on the charging lead. It drank 80 amps. But over 30 seconds the amps were dropping slowly. I Checked later after a 30 min drive, and it was charging at less than 20 amps.
The story is that as the alternator heats up, it output capability goes down, and the regulated voltage tends to sag too, causing the charge to taper down. The high load on the alternator is temporary and controlled, so I would not worry in my opinion.
Been doing this kind of thing for years, and no troubles.
My van has a 120 amp alternator and thick #2 AWG wiring that is short and a mechanical isolation solenoid. 14.4 v volts cold output from alternator into my 2 GC2 golf cart batteries (232 AH) when at 40 % charge. I've measured 67 amps with a DC clamp meter under those conditions. Your alternator will be fine, and chances are at is heats up the voltage regulator will sag that back to 13.8 volts and current will go down to maybe 40 amps or less. So for your single battery, I can almost guarantee you won't see that level of current, since your wire probably isn't that thick and your single battery is NOT capable of accepting any more current.
I should add that I also run my fridge on dc under theses conditions, and I have never blown the 100 amp fuse I have installed.
I realize that it is a starting/ marine battery so in theory it could accept maybe more amps, but Ill bet it will not.
One time in my ranger truck I had a flat battery and I jump started it and immediately put a clamp meter on the charging lead. It drank 80 amps. But over 30 seconds the amps were dropping slowly. I Checked later after a 30 min drive, and it was charging at less than 20 amps.
The story is that as the alternator heats up, it output capability goes down, and the regulated voltage tends to sag too, causing the charge to taper down. The high load on the alternator is temporary and controlled, so I would not worry in my opinion.
Been doing this kind of thing for years, and no troubles.
