Charge controller distance

[champdog]

Hi, Im getting ready to install my set up. 200w on MH roof and 40a mppt so I can add a 3rd panel later. I have a couple questions. How far can I mount my mppt from my batteries. Im sure shorter is better but Ideal inside the motor home would put it a 12ft to 14ft of wire run from the batteries. I can make it within 2ft but it would be inside a closet and a little harder to get to to see, and surely not ventilated as well. Other question is in the searching of this site. Im pretty new here but seems like every time I try to search, if I put more that a couple words in it finds nothing, definitely cant put a phrase in, any help on that would be great. Would like to research more before posting new topic and asking peoples opinions on stuff like CC distance from batteries is tough. Thanks again!!!

[Almot]

westend wrote:
spade connectors

There you go.

[westend]

An inexpensive and elegant way to meet controller termination size limits is to use a couple of these spade connectors. I have two of them on my charge controller wires using 4AWG.

[Almot]

#8 max - means that CC terminals are small and won't accept a thicker cable. They don't care about length, they expect you to run the numbers and stay close to battery. Max #8 on a 40A controller shows stupidity of engineer, IMO. Luckily, you won't run 40A.

You could still run a thicker #6 or #4 spliced to a short piece of #8. Or trim #6 to thinner diameter on the stripped 3/4" length that goes into the terminal.

I wouldn't expect issues with controller running in a bedroom closet, though this would be pushing the limits in hot weather. With 300W solar it will likely run under 14A most of the time. Don't place it close to the ceiling though, and keep some clearance on the sides. There could also be an issue with accessing it, in the closet. I mounted mine on the wall under the bedroom closet, where the closet ends above the night table. Not too aesthetically pleasing, but safe and convenient.

[champdog]

Thanks, the manual says 8ga max. Nothing about length or distance. How much of an issue will it be in a small bedroom closet. It would be right next to the inverter. Inverter was installed at the factory in that location. Only a small 600w inverter.

[Almot]

champdog wrote:
200w on MH roof and 40a mppt so I can add a 3rd panel later. I have a couple questions. How far can I mount my mppt from my batteries.
...
Ideal inside the motor home would put it a 12ft to 14ft of wire run from the batteries.

Depends on the gauge of cable from MPPT to batteries.

200W will generate less than 15A post-controller at peak sun.

Voltage drop calculator
Enter 12.6V, 15A, Copper, Conduit, 2% drop, 14ft. You need #6 cable.

If you add the 3rd panel, you need #4 cable to stay within 2% drop at 14ft.

With a better controller I wouldn't worry (too much) about 2% since it would have a voltage sense wires, but I have a feeling that yours is not one of those.

[CA_Traveler]

I also considered the closet but tied into the large inverter wires instead. Visual was not a consideration due to remote display. My CC remote voltage sense is used for correct charging.

[CA_Traveler]

Your CC manual should tell you what size wire to use.

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