Is there any reason a power source other then from a solar panel shouldn't be used as the power input to a MPPT charge controller for charging a battery, assuming the alternative input source parameters are within the required values?
asked
Can I use an MPPT charge controller with an alternative supply than a solar panel?
Hi Jeiby. A number of people have reported doing this with success.
But it's not a supported application, and you'd need to be careful not to exceed the specs of the mppt with regard to potential supply V and Amps.
Depends what you want to do, but Victron have a wide range of kit for specific purposes. What are you proposing to do?
Hi JohnC and thanks for your answer.
I will be setting up a travel trailer and I was wondering if I could use one MPPT charge controller with portable solar panels when camping and then connecting it to the tow vehicle when towing. I'm thinking I could use a DC to DC converter to boost the tow vehicle alternator voltage to say 20V and port it to the MPPT controller as I'm assuming the controller can only step down the input voltage to the proper battery charge voltage.
But this DCDC converter as to have enough power.
Don't you think a separate DCDC charger like a Orion-Tr Smart 12/12-18A or 30A would be better?
(or a cheaper model of an other brand)
Yes, I would assume a DC to DC charger would be better since it's designed specifically for that purpose but on paper what I am proposing seems like it should work just fine also, unless I am missing something. I most likely will go the DC to DC charger route along with a separate MPPT charger for the solar panels but I was just wondering if what I was thinking about could work.
I think it would work, but:
A good DCDC converter with enough power is not much cheaper then a DCDC charger.
Plus with a DCDC charger you don't have to struggle with the connecting/disconnecting of the MPPT every time.
But it is up to you.
Hi Jeiby,
I have been doing just this for some years. 100/30 bluesolar mppt with portable panels when camped, and an Ebay 12 to 19V waterproof dc-dc 20A converter (cheap at about $45 Australian) when driving. Have set the mppt to 20A limit, mainly to protect the less-than-optimal manufacturer supplied wiring in the tow vehicle. Andersen plug to connect when driving or camped. Works perfectly, a steady 19V on the mppt input, everything stays cool to touch, measured 98-99% efficiency for dc dc converter and 97-98% for the mppt. About 24 Amps from alternator to the dc-dc converter which is located in the trailer, so more loss in the vehicle wiring, which does get just warm to touch.
Cheers, Leslie
Voltage and current are voltage and current - and, the MPPT charge controller cannot discern what the source is. So, as long as you do not exceed the voltage and current parameters for the charge controller, you should not have a problem. I can see the potential of using a wide array of DC power sources in such an arrangement, with flexibility being the main advantage. As long as your source is between Vbatt + 5V and Vmax for the controller, and less than Imax for the controller, it should work fine. I would not, of course, recommend any kind of a pulsing DC or AC source connected to the input of your MPPT charge controller. One other consideration is losses in the cable from your tow vehicle to your travel trailer. The smaller the gauge of wire you use, the greater will be your power losses through the wire. To mitigate this problem, I would suggest you boost the voltage even more than your proposed 20 volts. Since, the controller can likely handle up to at least 75 volts, you should use a DC-DC converter that will supply a higher voltage to reduce losses. Alternately, you can use larger gauge wire for the connection. But, of course, that brings with it added expense and potentially greater difficulty for installation.
