battery overcharge due to solar and truck charging concern

[bmiracle]

I just installed a 160 watt solar and was concerned that the truck charging and solar could over load the batteries. Thought about looking into tying the charging from the truck into the solar charge controller. has anyone done this?

 

[michgoblue]

I don't think you should put your truck though the solar controller. Basically the controller should make sure the solar panels don't over charge your battery, and your alternator should make sure the truck doesn't over charge your battery. I have had both connected to my camper, on two different campers, and this has not been an issue. I do use an ACR for connecting to the truck as well.

My previous camper had 3 x 120W panels on it and 2 x 220AH 6V batteries. My current camper had 2 x 120W panels and I just added a 3rd with 1 x 155AH 12V battery.

 

[PaulT]

With smart chargers for shore power, solar power, and whatever the intelligience (?) if the alternator's voltage regulator, I have had no problems in bright sunlight, plugged into shore power to prechill the fridge, and running the truck to prechill the cab for a summer trip.

Remember that each smart charger is looking at the same voltage in the batteries and while they are each likely in different places in their charging protocol, one will be at a higher voltage than the others and that one wins in charging the batteries. With the batteries at low charge, getting almost 14 amps from solar, 30 amps from the Iota and whatever the alternator can force down the truck to camper wiring is still likely less than the recommended charging current for the batteries. If one battery wants 50 amps in bulk mode, two 12 volt batteries in parallel would be happy with 100 amps. They aren't likely to get anywhere near that much.

Paul

 

[Vic Harder]

I just installed a 160 watt solar and was concerned that the truck charging and solar could over load the batteries. Thought about looking into tying the charging from the truck into the solar charge controller. has anyone done this?

I thought of doing this as well, and as it turns out, it isn't necessary. A lot depends on your particular truck/camper/alternator/solar/battery combination. I have enough metering in mine to know what is happening at all times.

When the batteries are discharged, they will gladly gobble up the amps... I see the full 15A coming from my solar controller AND 70A from the alternator. As they charge up, they start to resist the push, and the solar controller and alternator compensate. When fully charged, the don't take a charge at all from the alternator. The solar controller is smart enough to not try at that point.

 

[ntsqd]

Most controllers specifically state what the acceptable charge sources are, and most vehicle alternators don't put out enough voltage to properly drive a solar charge controller.