Boondocking help needed

[JPin AZ]

Hopefully this is not to long and confusing. We have not done much boondocking but now have the opportunity to start doing more. Most of our trips will be a two night stay. I have one 27 series marine battery and an unknown solar panel. Our first attempt I brought an extra automotive battery for back up. Going into the second night my solar unit was showing voltage in the low 12s so I connected the auto battery with jumper cables and we did fine.
Now the dilemma, do I buy a second marine battery or buy two 6 volt Trojans? The current battery is less than a year old. To add to the puzzle I am planning on leaving the trailer in the woods (secure area) and returning every two weeks. The TT will get about six hours of sun on most days. I would like to leave the refrigerator on gas while gone. Do I trust the solar to charge the battery(s) while gone? Maybe leave the marine battery in the TT and haul the 6 volts home and charge them? Hoping to avoid buying a generator. Photos to follow.

[JPin AZ]

Looks like 2X3 feet

[JPin AZ]

2.2 amps?

[Bluepill]

I would recommend starting with a survey of the capabilities of your current system.

1. Discharge your battery until it has a resting voltage (sitting for eight hours or more with no charging or load) of 12.0 volts. This is approximately 50% state of charge, which is the lowest level of discharge recommended for wet cells.

2. On a full day of sun, take amp readings from your charge control panel every hour.

3. At the end of the day, you can calculate the average charging current to see if it is sufficient to charge your battery to 90% or better.

Simple calculation:

Assuming you have a 100 Amp Hour rated battery (the higher end for group 27's). If you discharge it to 50%, you will have used 50 amp hours. To recharge it, you would need that many amp hours generated by your solar panel. An average of 5 amps over 10 hours will give you that. Based on the size of your panel, I would expect it to be less, but your survey will determine that.

Some info on RV batteries here:

https://koa.com/blog/what-you-need-t...-rv-batteries/

[bikendan]

If you're serious about dry camping or boondocking, go with the two 6v golf cart batteries.
You'll also need to deal with dumpin waste water and acquiring fresh water.

[JPin AZ]

Originally Posted by bikendan

If you're serious about dry camping or boondocking, go with the two 6v golf cart batteries.
You'll also need to deal with dumpin waste water and acquiring fresh water.

Location has restrooms, water and dump. No power. So I guess I am off grid not boondocking.

[boondocking]

A 2' by 3' solar panel would more than likely be max 75 watt. Which would have a hard time keeping your battery charged when you are actually boon docking.

Get your yourself at least a hundred watts more, 200 watts would be better, even a portable set up for when you are boon docking. The panel you have already will keep the battery charged while running your fridge while you are away.

Pick up a couple of GC2 (6 volt) batteries at a place like Costco or Napa (much cheaper than Trojan).

Then you shouldn't have a power problem after that.

[JPin AZ]

Thanks for the replies. I picked up two Trojans and fully charged them.



http://www.forestriverforums.com/for...-a-191574.html


I will monitor them for voltage and also monitor the array current on our two day trip this weekend and let you know what I see. Hopefully it goes well.

[boondocking]

Have fun this weekend!

[JPin AZ]

Woke up Saturday am to 12.4 volts and .1 amps charging. As the sun came up and cleared the trees and clouds I managed 13.5 volts and 3.5 amps. I did not pay attention to voltage after the sun went down and the controller showed no more charging but I think voltage was 12.5. Neighbor camper has a similar set up with a 45 watt panel and has no problems so I think I am okay.