Battery charging from shore power?
Stock, do most trailers charge the batteries when they are hooked up to shore power? Or does that occur when the trailer is hooked up to the tow vehicle?
Forum Discussion
BFL13 wrote:Vulcan Rider wrote:BFL13 wrote:
You can guess at that, but you really need to see the amps to the battery for each method over some time.
It is not a guess.
A higher voltage measured AT THE BATTERY will charge the battery more/faster.
You also have to consider the amps the power source can supply, but given that those are equal, I am unsure who is right here.
With my 7-pin , using the Trimetric in the trailer to read the amps, I get about 10 amps at start up, (truck at 14.5v) which tapers to 6 amps within four minutes.(truck at 14v) I did not take trailer battery voltages then however, so I will do that to confirm.
OTOH, my 13.8v 7355 converter does about 35 amps at first at the batteries, then quickly tapers into the 25 amp range for the longer haul doing a recharge (it did about half those amp with the original wiring, but I did an up grade on that)
So to settle this, I need to run the 7-pin and now take the trailer battery voltages along with the amps.
Ok, trailer battery before start 12.8 volts, connect 7-pin, start truck, back to trailer and the Trimetric. Shows 31.1 volts 7 amps then 13.4 v 5 amps, etc. Out at truck, engine batt posts read 13.94 volts.
So as the trailer batt voltage climbs the rest of the way to what the truck is, less voltage drop, the amps will be tapered right down as the voltage spread shrinks.
Anyway, I cannot test for what amps you would get with trailer batts at 14.3 as Vulcan Rider does with my set-up, to compare with what the 13.8v converter does.
