Battery recommendation

Hi samhain7,

It will be fine if used lightly.

The smaller the battery bank the higher the wattage should be on the solar panel. The reasonable maximum at 85% state of charge (when the battery starts to taper off charging current) is 12.5 amps per 100 amp-hours of capacity. In your case that translates to 210 watts.

What charge controller have you chosen?

Well I can only go by what he said and he mentioned he had the same set up in his rig...As I said, this is a battery shop only, so I would really hope he knows what he is talking about...
I must admit, I am not battery expert.
At the end of the day, we only do ONE trip a year without power, and if we have to NOT use the microwave, it isn't a big deal at all..

Specifications on the battery are:

Trans Canada DC31-280 BIG RED DEEP CYCLE BATTERY GR DC31 140AH 1000MCA 280RC

If the microwave draws 1200 watts it will draw about 120 amps DC. That will run the battery totally flat quite quickly. Read about the Peukert effect. That 120 amp load will be seen by the battery as about 281 amps DC. Five minutes will draw about 23 amp-hours from the battery.

150 watts x 5 hours = 750 watt-hours / 12.8 volts =~ 59 amps returned to the battery bank under perfect solar conditions and the battery below 85% state of charge. I would up the solar to 210 watts.

Group 31 batteries are generally considered to be a starved electrolyte design.

I have settled on this bad boy! 2 year warranty...



I will go with 150W solar power and an 1500w inverter.
We will limit the microwave to maybe a couple times a week just to speed up the baked potatoes...

The guy at the battery store assured me this would be OK. This is not a big box retail store. They deal only in batteries and solar... in fact he has the same set up and uses this in his trailer.

The power from this battery fully charged would operate my micro for 1.25 hours.
Since I will only be using it here and there for 5 min, and then solar to top it up during the day, this is gonna work great.

I should have added, that I would have a 150W solar panel as well.
That could or could not make a difference?

samhain7 wrote:
Like I said, when I do boondock, it is for 10 straight days.. So far, all the rest of our trips are with hook ups...
But for those 10 days, we would like to use the micro and TV occasionally.....

10 straight days of dry camping means you need to be serious about conserving as much of your battery reserve as possible but using a microwave especially doesn't fit that scenario at all, even with a couple of 6 volt batteries. Run that MW any length of time at all and you'll draw a significant amount of battery power that could otherwise be used much more efficiently for other purposes, such as running your LED lights as much as you want or for far more important tasks such as keeping your fridge electronics running. This is just not a realistic plan without a much more substantive battery bank and a means to efficiently recharge that bank on a regular basis.

My old Trojan 6 volts just gave out after almost 8 years of service. I got two of these My new maintenance free 6 volts

Shipping was free. Fedex wanted a signature, so I had them re-routed to their local shop. Each box weighed 72 pounds.

Using the microwave for one minute on my unit consumes about 16 amp-hours of battery bank. To put that in perspective that's 2 hours of charging from a 100 watt solar panel in perfect solar conditions. Solar systems are generally rated at 5 hours per day (even though charging starts just after dawn, and may last until dusk, in a well designed installation).

It may be better to have more battery bank, and probably more solar to cook with the microwave.

Thanks SoundGuy....
There is an actual Battery Specialty store here in Pickering. The 6 volts (Trojan and a lesser model) both come with 2 year warranty.
His top end 12 volt is not much less than the 6 volts...so I figured maybe I should go with the two 6's...

One point mentioned was that 6 volts were more durable. Not as fragile as the 12's...and that I would get more amp hours out of the 6...
Like I said, when I do boondock, it is for 10 straight days.. So far, all the rest of our trips are with hook ups...
But for those 10 days, we would like to use the micro and TV occasionally.....

You do need the solar, but 12 volt jars combined with a properly sized system will work just as well as 6 volt jars--and in some scenarios even better than 6.

samhain7 wrote:
I mostly camp at sites with hydro. However our one trip we do without power is 10 days.
That's when I think I need the two 6 volts with solar.