First I would like to say that I have some experience with 12V battery solar installs in the 20-125 watt range over the last 10-15 years. (boats, remote wifi relays, remote security cameras, etc.)
I bought a used motorhome last month where the previous owner had started upgrading the electrical system, so I have been handed a partially complete project, which I intend to continue and perhaps alter a bit.
First let me describe my current situation which is basically as I bought it, but the addition of installing a 2000 watt pure sine wave inverter (Xantrex ProWatt SW which is a stand alone inverter along with its associated external 15 amp transfer switch and remote panel), Not my first pick of the way to do things, but the inverter came with the motorhome, just not installed.
Back to the current setup, I have 4, 100 watt panels for a total of 400 watts worth of panels on the roof feeding into a Schiender C35 (35 amp which seems kind of marginal to me) PWM charge controller, which seems to be a nice variable set point PWM controller, which charges a pair of 12V deep cycle batteries.
My goal is to aim for 800+ watts worth of panels on the roof if possible while mounting around various obstacles (vents, etc.), at a minimum I would like to get up to 600 watts worth of panels I would also like to switch to Lithium batteries (probably LiFePO4) when the current deep cells need to be replaced in a couple of years (they were installed in 2014). Ideally I would like to do this in stages as I get time and money for this project.
The catch is I want to do this without removing the existing 4 100 watt panels, as the motorhome has an Aluminum roof and I want to minimize the number of roof penetrations and being an Aluminum roof it is hard to patch the screw holes from the existing mounting brackets.
Now here is the question, what is the best way to achieve this, I know mixing and matching panels is usually a bad idea?
Some thoughts I have so far:
option A,
Add 4 more panels to the roof and wire them series / parallel with the existing panels and feed them into a MPPT controller so that each old panel would be wired in series with 1 new panel then let the MPPT controller handle the voltage reduction.
option B
Keep everything as is, and add separate circuit with the new panels and another charge controller, then adjust the voltage on the current charge controller so that it only operates for the bulk charge range, then have the new panels and their controller handle more bulk charging in parallel then let the new panels handle topping charge until I convert to Lithium. I am still researching al the special lithium charge controller issues, with the hope that more and better options will be on the market in a year or three.
option C ??????
thanks for your thoughts
I bought a used motorhome last month where the previous owner had started upgrading the electrical system, so I have been handed a partially complete project, which I intend to continue and perhaps alter a bit.
First let me describe my current situation which is basically as I bought it, but the addition of installing a 2000 watt pure sine wave inverter (Xantrex ProWatt SW which is a stand alone inverter along with its associated external 15 amp transfer switch and remote panel), Not my first pick of the way to do things, but the inverter came with the motorhome, just not installed.
Back to the current setup, I have 4, 100 watt panels for a total of 400 watts worth of panels on the roof feeding into a Schiender C35 (35 amp which seems kind of marginal to me) PWM charge controller, which seems to be a nice variable set point PWM controller, which charges a pair of 12V deep cycle batteries.
My goal is to aim for 800+ watts worth of panels on the roof if possible while mounting around various obstacles (vents, etc.), at a minimum I would like to get up to 600 watts worth of panels I would also like to switch to Lithium batteries (probably LiFePO4) when the current deep cells need to be replaced in a couple of years (they were installed in 2014). Ideally I would like to do this in stages as I get time and money for this project.
The catch is I want to do this without removing the existing 4 100 watt panels, as the motorhome has an Aluminum roof and I want to minimize the number of roof penetrations and being an Aluminum roof it is hard to patch the screw holes from the existing mounting brackets.
Now here is the question, what is the best way to achieve this, I know mixing and matching panels is usually a bad idea?
Some thoughts I have so far:
option A,
Add 4 more panels to the roof and wire them series / parallel with the existing panels and feed them into a MPPT controller so that each old panel would be wired in series with 1 new panel then let the MPPT controller handle the voltage reduction.
option B
Keep everything as is, and add separate circuit with the new panels and another charge controller, then adjust the voltage on the current charge controller so that it only operates for the bulk charge range, then have the new panels and their controller handle more bulk charging in parallel then let the new panels handle topping charge until I convert to Lithium. I am still researching al the special lithium charge controller issues, with the hope that more and better options will be on the market in a year or three.
option C ??????
thanks for your thoughts
Comment