100 Watts Solar with Deep Cell 31s or Trojan 6 Volts

Another short answer: Yes.

Longer answer: 100W is only enough for a very light use, and only if there is some sun. On a dark day 100W panel becomes a "battery maintainer", providing few AH a day, enough to compensate for self-discharge but not enough for anything else.

If you are a very light user, say, your energy needs are 20-30 AH a day, with this setup you can live without a generator a couple of weeks with 50% sunshine. After 2 weeks you'll have to run a generator for 5-6 hours, and then again 2 weeks on solar. Theoretically, when there are no clouds at all, such a minimalist user could stay indefinitely. In practice, you might want fans when it's hot, TV when it's windy, and furnace when it's cold.

With today's cheap panels and expensive gas you should get another 2*100W. 300W array will pay for itself in a year or two, if you camp a lot. To me, it would pay for itself from the day one since I wouldn't have to put up with noise and smell of generator, but other people are more tolerant to this. You will (probably) have to upgrade the cable to #8 or #6 then, and also upgrade controller to 25-30A.

Or, a shortcut - use those additional 2*100W as a portable add-on. Lean them to the wall outside, connect in parallel, and buy 15A controller just for this 2*100W pair. No beefy cable, no installation. But if you are staying less than 3-4 days at the same place, you are not going to like folding/unfolding it every time.

Portable kit for those lazy: $460. Controller, cables and Y-splitters are included. Controller is of course cr.ap, Z-brackets are a poor choice for roof setup and are useless for portable setup. I wouldn't buy this kit for roof-mounting, and wouldn't buy it at all. But as a quick and dirty portable, it will work.

PS: forget about recommended 150W solar per 100 AH battery. The more W, the better. The only thing you should worry about is that max post-controller amps should not exceed max charging current for your battery bank.

100 watts and 2GC's will do fine. With extended no-sun days you might be forced to use the generator.

I have 2-60watt panels flat mounted, they usually have the batteries fully charged well before the end of the day. I have a 100 watt portable panel, seldom need the portable (only in totally shaded sites where more on the roof wouldn't help anyway). I run my gen dry after servicing in the fall; it hasn't been run yet this season.

I'd use it as-is for a year before considering adding more panels.

Regards,
Doug

Mike@Asheville wrote:
I'm looking at a new truck camper that comes with 100 watts solar panel and control. I use minimal lights, water pump, etc when dry camping solo. Is that sufficient to maintain two batteries while dry camping?

I've had The same Trojan 105 golf cart batteries in my Fiver for 9 years and they are still in good shape. So I'm leaning towards them instead of traditional deep cycle. I know 6 volts have more amp hours but do they charge as quickly?

Thanks

You have some mis information there.. First

I know six volts have more amp hours"

Normally when we speak of six volt we are talking about GC-2 size batteries of which the T-105 is a class member,, These are aroudn 220-250 amp hours depending on the precise model number 105 is the low end (220).

A pair of Group 31's. 260 amp hours.
A single 4D 230 amp hours

The fork lift battery I once borrowed.. I have no clue but on a guess I'd put it in the thousand amp hour range.

Now chrging 100 watts = about 8 amps max, you will likely get no more than 4 amps, this is a very slow trickle charge for the T-105's. Reasonable charge rate for a single Group 24 (75 amp hours) but anyting bigger it is a trickle charge, Good for maintenance, but not for charging.

Still... Most of the time, that is exactly what the RV needs.

Hi,

My first set of Trojan batteries lasted 13 years. You might as well try to get another 3-5 years out of yours.

As for the 100 watt panel, it will help more than not having one at all. However the CO meter, propane detector, and refrigerator will use about 35 amp hours daily, or about what the 100 watt panel will recharge in about a day of good sunlight. So your 220 amp hour batteries would last about 4 days without the solar panel, and close to a week with it. A little time charging with a generator, or some sightseeing in the truck will also top off the battery when solar is there.

Fred.

I would not get AGM just because you are on solar. Solar has nothing to do with it. AGM vs Wets would be for other reasons entirely.

I have been very happy with the Duracell EGC2 batteries I got from Sam's Club.

Thanks guys, I have a Honda 2000 to charge when necessary. I'm hoping the 100 watts solar will make that less often. If not I'll add another 100 later.

I'm still unclear on the batteries. I leave my Fiver plugged in all the time with a Progressive Dynamic converter with a float charge and check the water every few months. I'm not sure if the converter in the TC has a float charge but if not I'll add one. Under this situation my Trojans in my Fiver still get me thru a weekend of dry camping.

So do you recommend AGM in place of 6 volt Trojans to use with Solar Panels?

Mike@Asheville wrote:
I'm looking at a new truck camper that comes with 100 watts solar panel and control. I use minimal lights, water pump, etc when dry camping solo. Is that sufficient to maintain two batteries while dry camping?

I've had The same Trojan 105 golf cart batteries in my Fiver for 9 years and they are still in good shape. So I'm leaning towards them instead of traditional deep cycle. I know 6 volts have more amp hours but do they charge as quickly?

Thanks

12v charge as quickly as 6v in pairs. It is the AH capacity vs the charging rate at that voltage that decides how quickly.

Find the thread, "My Screwy 31" before considering getting one. Takes some work to "run" one of those successfully. 6v golf car batts are easy to run.

Once your panel wattage meets your daily usage in AH, then the panel ratio to battery bank size doesn't mean anything really. You can have two or a dozen batteries, you are still running daily on solar.

Where the bigger bank comes in is when the weather goes bad so you can last till the sun comes back out. You might still need a generator powered recharge to catch up though.

So as others have said, your 100w panel might be enough for your usage. If not you can get another panel (if your controller can do the extra amps--so get a controller up front that can do two so you don't have to get another and toss that one) Then your pair of 6s is what you can fit in the camper so that's it. Now it is all up to the weatherman whether you will need a generator powered recharge anytime soon.

short answer--yes.
With your minimal usage you should be fine.
Always remember you can add another panel.

You have received great advice and suggestions in the responses so far. I'll just add my two bits worth:

I seem to recall from Pianotuna that the ball park ratio (Solar to battery) is 50 to 160 Watts of solar per 100 AH of battery. This would indicate that your 100 Watt panel is minimal and 200 hundred Watts would not be over the fence but right in there. The higher wattage range charge faster and will probably allow you to reach an equalizing voltage.

We run 484 Watts into 420 AH (4 GCs) and usually find it adequate. We are heavier users of power than you are though, often running the TV and Satellite receiver for a couple of hours daily and the microwave for short spurts once in a while. We don't equalize with solar.

If money isn't a big factor, double or even treble up. Make sure of course that the wiring and controller are adequate for the increased current.

OR, try the 100 watt panel on its own and see how you go. Remember though that chronic under charging is death to batteries.

Follow some of BLF13 solar threads; he has tone a lot of trials and testing and has lots of numbers.