Newbie solar questions

specv510 wrote:
This is for a family of five with three teenagers and we boondock for 2-3 days at a time. Will this system work? If I decided to get two panels would the Tracer 30 amp controller be able to handle them?

I don't remember what the rule is for solar wattage per battery capacity, but I think it was to have about equal wattage per ah? Besides wasting energy, are there other negatives to having too many watts? We are very conservative with our electricity usage, but if we wanted to splurge would having a second panel be beneficial considering the small battery bank?

Will it work? Yes, with some drawbacks. I agree with Don Piano - you should get a remote temperature probe, maybe even a different/costlier controller if you have to. Temp probe is worth a lot more than fancy display of controller. I don't see such probe mentioned on Tracer website - only a built-in temp compensation.

Will Tracer 30 will handle 2*250W? Yes, but with some clipping at peak hours in summer, i.e. you will lose some energy. Not much, 5 percent of daily harvest or less. But, if you connect them in parallel, you need a lot better cable than gauge 8. The beauty of series wiring is that you can use a standard MC4 extension cable, Unlimited Solar have it in gauge 8. Make sure you order a DOUBLE length, because you will cut it in half to make 2 leads each with one MC4 connector.

I see that you're trying to make it on a very low budget, but it would make sense spending more and getting Rogue 3048 with temp probe and everything else included. It's not as cheap as Chinese made and Chinese designed controllers, but it's worth it. Don't know how this Oregon company is able to do it, but I couldn't find a cheaper 30A controller with these features and quality. At 30A there would be same clipping though, no matter what brand.

Is more watts beneficial for battery? Yes, it is, in your case. The "rule" is 1W per 1 AH but this isn't really a rule. With a small battery bank you can (and should) get 1.5-2.0 W per 1 AH, so that it will bring the charge up to 90-100% sooner.

Energy budget is an individual thing. Some people can live on 20 AH a day, some need 120 AH or more. With a family of 5, one 250W will be sufficient if your kids don't over-use their electronic toys - laptops, video games etc. Flat 250W in summer will collect 60 or 70 AH on the best day, and 10-20 AH on a dark day. Your LP fridge alone will need 8-15 AH over 24 hours, so on a dark day 250W will barely cover it even if you don't use any lights, pumps or radio/CD. So the battery will gradually go down, though it won't go down too much in 3 days.

In winter these numbers of daily harvest will be roughly 1.5-2 times lower, while your consumption remains the same or even higher. Get 2*250W if you can.

pianotuna wrote:
Hi,

Looks like a good price--how much for shipping?

Included in price.

Hi,

Looks like a good price--how much for shipping?

Muddydogs wrote:
I have been looking at this kit from Windynation,http://www.windynation.com/Polycrystalline-Solar-Kits/WindyNation-Inc/200-Watt-Polycrystalline-Solar-Panel-Complete-Kit-for-RVs-Boats-and-Off-Grid/-/322?p=YzE9NDY=, do you think it’s worth the extra money for the wire and mount brackets? Do you use the connectors that come on the solar panel or just butt connect some twin lead to the panels?

Looks decent to me. Only gives 40' of MC4 cable so if the panel/controller is more than 20' you will be short. Probably need to have a second 40' wire to make the connection unless your install is very direct.

pianotuna wrote:
Hi Muddy,

Link doesn't work.

Fixed it.

Hi Muddy,

Link doesn't work.

RJSfishin

I have been looking at this kit from Windynation,http://www.windynation.com/Polycrystalline-Solar-Kits/WindyNation-Inc/200-Watt-Polycrystalline-Solar-Panel-Complete-Kit-for-RVs-Boats-and-Off-Grid/-/322?p=YzE9NDY=, do you think it’s worth the extra money for the wire and mount brackets? Do you use the connectors that come on the solar panel or just butt connect some twin lead to the panels?

$325 total ?
I like two 100w panels, ($225) and a $12 controller, add a $3 voltmeter, what do we have,....$240 ?
Oh, but the controller won't have temperature compensation, perish the thought !

I always love it,........
one side of the fence talking 15-18 volts to keep a battree in good shape,
the other side insisting on temp comp 13 volts to keep the battree in good shape.
Almost hay-larious !

Thank you everyone for the answers and advice. It sounds like the single panel will be more than enough. No CPAP and when we camp in the winter we will use a catalytic heater instead of the furnace. Like MEXICOWANDERER said, we won't be camping in any extreme temps. We'll head to the national forest in the summer and the coast in the winter.

MEXICOWANDERER-we have ridden bikes past Manzana Co numerous times with the kids, but I've never tried their apple sauce. I'll have to look for it now.

Thanks again everyone,
Ken

Boondocking for 2-3 days at a time, insisting on thermal temperature compensation is like covering a mail truck delivery seat in mink. Sta Rosa California, is not Yellowknife NWT nor is it, Badwater. Summer temps average 80-90F and a winter cold snap can put temps into the 30's. Experience comes from staying at the end of Guerneville Road for several months while they put my wrist and hand back together. PS I wculd kill for for some gravenstein apple sauce from Manzana Co, In Grayton :(