solar panel connectors

This is exactly what they called - Splicer Reducer. $5 in Home Depot. Each end accepts from #14 to #1. You need to put a heat shrink or insulation tape on it.

NinerBikes wrote:

CJW8 wrote:
I have never used a junction box for roof top connections I use a connector like this and put some heat shrink over it.

Brand and where to buy?

I get them at HD or Lowes. I don't know the brand. They come same on both ends and reducing. You can easily put a #4 in one end and 2 or more #10's in the other end.

Colo Native wrote:

the cost for the big panel system with 45a MPPT about $906 and the 4 small with a 40a MPPT is $903 but I called Solar blvd and he said I could use a 30a MPPT and solar Blvd carries Tyco wire.

They saud to use 30A with what?

30A with 400W is OK, as long as total Voc is within the controller specs.

30A with 510W at sea level is marginal but usually OK. You'll probably end up losing some watt-hours in Co with this.

Roof top combiner box made with a 1 1/2" plastic LB and two terminal strips:


MC4 cable entry of combiner box (I filled the entry rubber insert with silicone after pulling the MC4 through):


I ran #4 AWG from these terminal strips to a manual circuit breaker and then to the controller. I used the 1 1/2" exit of the LB and piped the cables down but a user that wishes to not pipe cables could use a 4" plastic box and do the same thing with a smaller exit hole, mounting the box directly to the roof. Those solar combiner boxes are nice but not $50 more nice.

CJW8 wrote:
I have never used a junction box for roof top connections I use a connector like this and put some heat shrink over it.

Brand and where to buy?

I have never used a junction box for roof top connections I use a connector like this and put some heat shrink over it.

I'm still reading. Dunno, might learn something...;)

If the front storage area is a good location for the controller, it's fairly easy to vent battery cases or add some ventilation. If you allowed for exterior air to the compartment, mounted the controller low in the compartment, you might get away with no hydrogen or sulfur dioxide wafting across the controller. Most Morningstar controllers are somewhat encapsulated. If the one you're going to use is like that, the only real issue would be heat. A small 12V fan blowing across the heatsink, would aid with that.

FWIW, I'm using a small 15 amp Morningstar MPPT controller. It is only seeing 8 amps and 38 V input from the module in really perfect conditions. It is mounted inside a cabinet space inside my trailer. It is never more than warm to the touch.

Nice trailer and check. I might have to start a new thread because I think this one might of run it's course.

I'll let others with more experience comment on it but you could cover the batteries and vent that box out to isolate them from the controller. General ventilation for the controller is important too.

The storm took out both of our vent lids, tore up the awning and beat up the front pretty good. The awning side was dinged just enough for the adjuster to see and that got it totaled. We ended up with the trailer and a check.

JiminDenver wrote:
In the compartment you run the risk of the acid fumes damaging the controller. It may be okay if the compartment is vented well enough or with AGM. What's the distance outside of the compartment?

I believe they are sealed Group27 batteries, The other place is in the storage compartment on the other side of the 3/4' wall the compartment which would interfere with storage. I really want to use the front compartment on under the over hang and it is vented because the propane are on both sides divided by a small wall that is open on top plus the batteries are covered