New sytem in motorhome !

ALSOGRAMPS
ALSOGRAMPS Registered Users Posts: 2
I just installed a Kyocera 140 watt panel on my motorhome . Since there are two other charging systems running some of the time what occurs in the solar panel as the other units produce power ? Does the solar controler just adjust the amps as needed or would a on off switch be better on the panel?

Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: New sytem in motorhome !

    welcome to the forum.
    the solar setup will give what its got as a paralleled charger no matter what the other sources are right up until the voltage setpoint for switching to absorb would be reached. after that it depends on how the cc is made or setup to handle absorb charging. multiple charge sources will bring it up to the absorb voltage quicker than any single charging source would do so you must be sure of what the battery can take for the current at one time. if you know it is getting too much current without being redistributed to ongoing loads then yes, you can put a switch on the pvs to shut down production. most of us recommend a means of disconnecting the pv power anyway. we also recommend a means of shutting the cc off to the battery along with proper fusing.

    in your case a battery monitor may be helpful so you know what is going in versus going out of the battery.
  • ALSOGRAMPS
    ALSOGRAMPS Registered Users Posts: 2
    Re: New sytem in motorhome !

    Thank you ! Thats what I needed to know !!!
  • mfoobar
    mfoobar Registered Users Posts: 13
    Re: New sytem in motorhome !

    One thing to bear in mind... I have a 64W panel on the roof of my motorhome and a Sterling B2B 50A charger from the engine to the leisure battery bank. The solar panel will raise the voltage on the batteries whilst charging, such that if you then drive off the Sterling believes the batteries to be already fully charged. This means that in my case I drive along thinking I'm getting 50A of charge from the engine, when in fact I'm getting 3A from the solar panel. I get to my destination, the sun goes down and then I find my batteries not nearly as charged as I hoped.

    I'm not really sure the best way to solve this. I did think about an ignition signalled relay the cut the solar connection once the engine starts up, but that does seem a waste of some free energy. Also not sure if the batteries would drop down to their true voltage before the Sterling then kicked in. Ideally you would have some kind of combined unit that knows what the state of the batteries is regardless of the power source. Also that way if the B2B charger went from bulk to absorb whilst driving, when you stopped the solar panel would continue on absorb and not just go straight to float.

    -Matt
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: New sytem in motorhome !

    Matt, usually it's the other way around: the 'house' battery is kept disconnected from the 'engine' battery while the engine is off so that power use can't drain both batteries. When the engine starts the two are connected so that the alternator can charge both up.

    If your house battery is not getting charged by the alternator while driving something else is wrong. Likely suspects; incorrect charging profile from the alternator (nearly always a condition but not necessarily crippling), or poor wiring/connections.

    Disconnect the solar, turn off the loads, and run the engine. See what Voltage you get at the house battery. If it's insufficient to charge it then you need to work around this. Quite often a vehicle system only runs at 13.8 VDC constant, which won't do much for a deep cycle that wants to be take up to 14.8 Volts and held there for a couple of hours.

    The usual solution to that problem is to add more solar, although some people do a little work-around on the alternator control circuit to boost Voltage. Be advised that the engine battery is not going to like being charged like a deep cycle.