I have an RV with a solar system that has worked fine for us, but I am looking to upgrade a few items, to include the solar charge controller. From the factory, it has a pwm 30a controller. It works ok, but can be flakey at times. Currently only have 1x190w panel on the roof, but will possibly add more in the future. Would it be best to spend just a little bit more and go for a 40a EPEVER. I will probably only add another 190w panel, but you never know. Also, would I need to do any rewiring to/from the controller over the stock wiring?
Solar/Electrical Noob - Upgrading Solar Charge Controller ?
- Thread starter ScottL
- Start date
A 40A controller would let you make use of about 520W of solar meaning you could easily add about 700W of panels. Going with an MPPT SCC has the advantage of making better use of the panels you do install.
For a 40A controller you will want to make sure the wires from the SCC to the batteries can safely handle the extra amperage. Depending on the length of those wires you will want at least 8AWG, maybe 6AWG wire.
The wires from the panels to the SCC probably don't need to change, especially if you add a 2nd panel and put it in series with the first. If you put any panels in parallel you will need either 12AWG or 10AWG depending on the total voltage and current from the panels and the wire length.
For a 40A controller you will want to make sure the wires from the SCC to the batteries can safely handle the extra amperage. Depending on the length of those wires you will want at least 8AWG, maybe 6AWG wire.
The wires from the panels to the SCC probably don't need to change, especially if you add a 2nd panel and put it in series with the first. If you put any panels in parallel you will need either 12AWG or 10AWG depending on the total voltage and current from the panels and the wire length.
Ranger Rick
Here comes the sun
Yes, a controller with MPPT would be an important upgrade. MPPT is more efficient. The amp rating refers to the amps from the SCC to battery for charging. For a smaller system a 30 to 40 upgrade is good.
Some recommendations:
10awg wiring from the panels to the controller
6awg wiring from SCC to the battery.
It is better to not run loads from the controller but from a busbar from the SCC. Victron’s Lynx is an all in one unit with a + and - busbars plus fusing
Consider a switch (breaker switch) between your panels and your new SCC.
Some recommendations:
10awg wiring from the panels to the controller
6awg wiring from SCC to the battery.
It is better to not run loads from the controller but from a busbar from the SCC. Victron’s Lynx is an all in one unit with a + and - busbars plus fusing
Consider a switch (breaker switch) between your panels and your new SCC.
Thanks for the advice. I am pretty mechanically inclined, but 12v/solar stuff brings a whole new level of knowledge I am currently gaining a little at a time. Knowing me, I should probably just bite the bullet and do an entire redesign before starting with an item here and there as I see the entire setup getting upgraded to absolute overkill proportions...at least that is how i usually end up with other hobbies/projects. 
12VoltInstalls
life passes by too quickly to not live in freedom
That’s actually not spending a little bit more- that’s the lowest price range mppt SCC I would buy and it’s quite good. Plus on the grand scale it’s only a couple pizzas away from cheapos cost wise.
I have three now and have tried four.
They have a new 40A model out with interchangeable control modules. It’s more money still but well under the $300 price point and comes with temp sender, remote display, and comm cables. I just stole one (low priced return) but you should get the kit
Just got my EPEVER 40a scc delivered today. SCC, temp sender, remote display and comms cables. Probably be a few weeks before I have time to install. Actually will probably be a winter project.
Thanks all for the feedback,