Forum Discussion

jodeb720's avatar
jodeb720
Explorer
Aug 05, 2018

Solar Controller question

Evening all -

I'm up here with my cousin in ashland, or - helping him convert his dry TC to a somewhat livable space. We installed a sink, pump, fuse block, and other items today - and it's been highly successful!

He's got a solar panel and charge controller (Blue Sky 2000e MPPT) -and the name on the panel isn't visible from the top or sides.

It's a 12v 25amp max controller. He's got a single panel that's about 24 x 26 - and this afternoon in hazy sunshine (there's loads of fires nearby) it was putting out about 19.5 volts on my volt meter.

I'm not a solar expert by any stretch of the imagination - but I saw on the back connections for battery, PV, Thermometer sensor and the output voltage (max) as well as other settings.

What I was struck by was the size of the connectors on the controller. They are relatively small.

The wires from the roof are 10 gauge - and I know bigger is better, but we can't change those. The distance from the panel to the controller is about 8-9 feet.

The distance from the controller to the battery is about 10' and I'm planning on running some 6 gauge wire.

My question is this.

The screws to connect the Panel and the Battery are at be 8 gauge machine screws - how do you connect such small screws to the larger wires without sacrificing some voltage drop?

I have some crimp on adapters - and I can ciip down the width of the ring terminals to fit - but I don't know what I'm going to do for the 6 gauge wire to the battery.

Suggestions would be super helpful

Josh

P.s. Right now he's got some cheesy Deep cycle 12v battery - and when this one dies (and it will shortly because of poor charging and he doesn't have a good battery charger - all being remedied - he'll move to 2 GC2's.

Thanks so much!

Josh
  • Almot's avatar
    Almot
    Explorer III
    It's a 50W-60W panel. Won't generate more than 2 or 3 Amp on a good day, you may trim that 6ga cable all you like.

    Ebay seller that I and many others here bought SMD from: 2011_led

    This little panel is good for battery maintenance in storage. Not for boondocking. Though, after upgrading the lights to LED, he should be able to camp a day or two without running a generator. 50W is only enough for lights, radio and water pump, not much else.
  • I'll keep that in mind. This is a TINY camper (Truck camper) which I think he and his wife are going to out grow in the near term. I think that he'll end up with a couple of GC2's and he's got a samulex? PSW inverter (which we're going to wire in today.

    he doesn't have a 3 stage battery charger and I'm going to check the voltage on his jar this morning (he's only got a battery tender - 2 amps at best) and that voltage/amps, sometime in the spring of 2019 it'll be fully charged!

    The thing about batteries is longevity. If you care for them, they will last you - but if they are not cared for, they will fail, quickly.

    I'm looking online this morning to find the Fleaby site that sold me my SMD panels of LED's with bayonet bases. he's running incandescant 1141 bulbs.

    Baby steps. If I can get him water, electricity a couple of extra cabinets and a reversible vent fan he'll be cooking!

    Thanks again!
  • You measured Voc (open circuit) which is good. Measure Isc (short circuit) which will indicated the maximum charging amps in clear skies and bright sun.

    That panel won't provide much charging but the controller is capable of more panel power. Something to consider for the future batteries.

    BTW One excellent place to buy panels is Solar Blvd in LA. And since you live there... Sometimes they have used panels as well.
  • Richard & Ed,

    Thanks so much for the help!

    We didn't measure the current, I just measured the voltage in the afternoon sun. I'll have to see if he has a volt meter that measures the current on the panel.

    I'm kinda hoping to find a brand name and model under it and stick my phone under the panel to find it.

    Thanks again.

    josh
  • There will not be enough current from that small solar panel to cause even a measurable voltage drop at that crimp connection. Do as Richard suggested.......and you might consider add more solar panels. That size panel is just a maintenance charge for a pair of GC2 batteries when you get them. Did you measure the short circuit current that panel puts out?
  • Cut enough strands off of the 6 gage wire until it fits in the connector. There will be very little loss by doing that.

    Richard