Solar crunch time! Please review my plan.

Considering that your solar cost will be just over a $1 per rated watt, it really does not make sense to spend an additional $100 for a MPPT controller. It would cost less to expand the solar system by 100 watts, and then you will overall have more than 20% more energy.

I think that at 300 watts, it is sized properly. You will be able to use the furnace a lot, and with LED lights they do not present a significant load.

I would recommend a 100 - 300 watt inverter. It can be handy to charge a laptop, or run a small TV set, or something. Even a 150 watt can run a small flatscreen TV and DVD player.

I have #10 wire to a pair of 120 watt solar panels. While that wire is a 'little small' for a full 14 amp load, the distance is not 1,000 feet, so it really does not matter much. I only have about 20 feet of the small wire between the panel and controller.

That said, you will have a pair of 10 amp panels, so #10 wire to each is what I would do, because #10 is not 'good' for 20 amps, that would place a more significant voltage drop. The single advantage of the MPPT controller is that you could run 24 volts into most MPPT controllers with 12 volt output, so you can run both panels in series, having about 38 volts enter the MPPT controller at say 8 amps, with about 17 amps going into the 12 volt battery.

Have fun camping!

Fred.

Chilepalace wrote:
I've read good things about the Trimetric, and just haven't been able to find enough info about the Tracer 4215BN to make a comparison.

I would have the Trimetric over Tracer as the Trimetric will automatically adjust absorption time based on battery charge level. Storage-short absorption... Heavy use-long absorption.

westend, Thanks for the encouragement! Also for the tips on switches and spade lugs, I've been wondering about those items. Do you think 4ga. welding cable for the 6' run to the batteries is adequate? I guess an inline fuse on the pos. will be required.

You're welcome. Yeah I really dig the solar, batteries always charged, no generator noise, and I can pretty much do everything off grid.

4 ga, welding cable should be fine for a 6' run to the batteries.

Southwire calculator says around 1% V drop.

Yes, you should have circuit protection for any wires connected to the battery. The mfg of your controller should have a fuse recommendation for the controller. IIRC, I used a 30A fuse--these Midi fuses. An ANL fuse will break quicker but they are four times the price and when I mess something up in a DC circuit, it will usually blow any fuse, right quickly.:B

I just installed that 300 watt kit from solar blvd today in my class A. I ran the wires down the fridge vent and into the controller which I mounted on the wall next to the entry steps. Great system and everything went together perfect. The only thing missing was screws to mount the z brackets to the roof. I used #14 - 1" screws but I think I should have gone with 1 1/2 inch-didn't get as much of a bite that I expected into the roof with the 1".

Thanks for the quick responses.

Smkettner, That 12' run is actually 24' round trip. If my calculations are correct, maybe about 2% voltage drop. Could go with 6 or 8ga., but would like to avoid combiner box on roof. The kit is only $45 more than just the panels, figure it's a wash if I can use the 10ga. cables & mc4 Y connectors. Maybe sell the 20amp controller or keep for something else. No free shipping on just the panels.

BFL13, Thanks, I've really been on the fence about pwm vs mppt for this system. Lots of conflicting opinions out there. I've read good things about the Trimetric, and just haven't been able to find enough info about the Tracer 4215BN to make a comparison.

2oldman, Pretty minimal. Our dry camping style only requires a few led lights, water pump, radio/cd player, phone/camera/laptop charging. and the only parasitic loads I know of are co detector & fridge electronics. Maybe a little sat. tv in the future, but not much of that.

wclement1248, I should check on the Renogy 150W panels. What did you use for mounting hardware? No generator for us I hope. I have camped for 3 weeks with these batteries, conservative yes, but still used lights, fridge, water pump for dishes & showers. Charged from truck with battery cables maybe 4hrs. over the 3 weeks, batts. never dropped below 12.2V. Charging from the alternator is the worst way to do it, which is why I'm excited about solar!

westend, Thanks for the encouragement! Also for the tips on switches and spade lugs, I've been wondering about those items. Do you think 4ga. welding cable for the 6' run to the batteries is adequate? I guess an inline fuse on the pos. will be required.

I actually believe that with everyone's help on this forum I can pull this off & do it right! Thanks again.






















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Seems like a good list. I'd also choose the Bogart gear, I've seen how it was built and appears to be built with quality in mind.

Some things that be helpful- switch/breaker between modules and charge controller. First off and last on when working with downstream 12V. I went with one of these mid-range manual CB.

If the controller's output terminals are too small for the cable you want to use, spade lug connectors are available that fit the terminal space. I bought the gold plated ones for $5.

Heat shrink, get a bunch. I try to buy it local.

Good luck with the installation. Solar is better than sliced bread!:B

I just completed install of an almost identical system. Batteries are 240 amp hour crown 6 volt. Panels are 150 watt Renogy. Same tm2030 & sc2030. We are using 1000 watt inverter to power TV, stereo, tailgater and lan. My wire sizes are similar with longer runs. We have been able to get too 100% SOC by 2pm with partly cloudy skies. Batteries are down to 65% at 7am when we get up. My plan is to carry Yamaha 2400 generator for backup.

Let us know how it works.

Exactly how minimal are your power needs?

I have MPPT which depends on panel wattage. Panel wattage takes a dive in hot sun, and your output amps to the battery, which come from the output watts divided by the battery voltage at the time, then suffer too.

PWM doesn't do the amps to the battery that way, so it does not take a hit in the hot sun (panel heating---controller would, but is supposed it be in out of the sun!)

Therefore it seems camping where you intend, with a pair of 150w panels, you should stick with the intended PWM.

I agree with smk (usually do!) that since you are getting the Trimetric set, just get a set of panels for less money and not buy that kit.

I would not buy that kit if you are getting your own controller assuming a partial kit should be lower cost. And yes I believe the SC2030 controller and monitor combo will perform excellent. 12' run to the controller seems short but that cable should work fine. Available any custom length from SB.