5 days no hook up for newbie
 

My second camping trip next month to Mammoth Lakes. Last time after a few days battery dropping. Like to stay 5-6 days this time and be OK.

Sport 16
12v AGM
100 watt solar on roof and added 100 watt Renogy portable that connects in parallel. Tested in driveway and getting amps from both panels (topped 6.8 in full sun at 90% and to 100% in 60 min with refer on).

From research on forums should get about 40 Ah, maybe more? Roof panel in shady location and moving Renogy to sun when there

Use maybe 60Ah - refer (24?), parasitic (24?), no heater, water heater 1 hr/day, no 100 (no inverter anyway), some lights at night, water pump on only when needed. If after solar charge in the morning and not good I will turn off refer as I have cooler and fine with us.

Don’t want to pop $2k for Honda 2200/propane and prefer not to run them. When AGM goes south will look at lithium probably $$$$

Comments/suggestions?

We spend a lot of time dry camping. I have 400w of solar and 2-6v AGM batteries. We find we can go almost indefinately on power. Not so much on waste tanks. I get 7 days out of my grey tank so long as we shower in the CG facilities. So every week we pull up stakes to dump our tanks and fill our freshwater. I use a 400w inverter to power small stuff like TV and desk fan. Life is good.

With fairly low solar and battery capacity, you might want to consider a small gen/inverter fired on propane, like the Yamaha 1000 we got a year or so ago:

https://www.motorsnorkel.com/ef1000i...generator.html

Ours came already converted for tri-fuel, but they have a kit for it now, I see. Other brands offer similar sizes IMO.

This 1000 watt unit will keep our batteries charged, plus the fridge topped up on 120 volts. It is very quiet, and also lightweight and small, making storage in our van tow vehicle easy and safe [no gasoline].

We plan to get a small solar panel or two for redundancy, similar to yours, but the Yamaha 1000 makes us mobile in all weather/sun conditions.

Good luck,

Peter

Hi

We have gone over the numbers on this in your other thread. Just to get everybody up to speed:

Best guess is that your fridge pulls an amp off of 12V. That's a guess, but it seems to be what people who have measured things see. Since it's a 24 hour a day thing .... you are at 24AH right there.

Parasitic drain from this and that probably gets up around 1/4A. Some see more, others see slightly less. That's another 6 AH every day. It's also why batteries die in a couple weeks when you are in storage.

Just from those two, you are at 30AH out of your 40AH available. That assumes the battery is in good shape and that it's fully charged to start out. It's mighty easy to run through 10AH with lights and other random nonsense.

Simply put, your battery is good for roughly a day. Assuming that's the case, unless you can get ~40AH each day from solar, you are not going to make it. A second battery would help things a bit. ( = you can make it through one cloudy day).

Solar wise, will a 100W panel get you 40AH a day? Under ideal conditions it might. In the real world .... probably not every day.

If solar makes up 100% of your usage, you can go on forever and ever. If it doesn't, there's not much "pad" in your budget. You will crash pretty fast.... That can do a number on your battery. It then has even less capacity and gets more damaged the next day ....

You also have the gotcha of not running a current based monitor system. You can only guess at the condition of the battery. That will make running right up to the limit (without going over) a difficult task. In my trailer with the stock monitor gear, I could not do it.

I'd have some sort of backup plan. A generator, a second battery, or something .....

Bob

^
X2

Never could understand the stigma that developed against how some approach the 'power' problem.
Shore power... ck, Generator... ck, solar... ck, Hydro, wind...umm. 😂

POI...our 120w Zamp got 14ah in 4hrs of of direct afternoon sun.



Bob
🇺🇸

Hmmm “other thread” per uncle bob . . . Why two threads?

https://www.airforums.com/forums/f37/...ar-186022.html

:angry:

Hi

Trying to escape Uncle Bob and his nasty tendency to add the numbers up .... :)

Bob

Got it and a day is probably it but I do have 200 solar with one a portable in parallel. Not 100. The trip will tell me and probably need portable battery test meter. For now I have purchased a spare 12 volt deep charge flooded from Walmart for $75. I town is 10 min away so I can have either battery charged there as needed. Only way to know is go camping. If I need more permanent solution it’s pribably honda 2200, propane as lithium or 2 6v AGMs, and probably converter upgrade and solar controller upgrade if lithium cost about the same as the Honda. With it I can get 110 when I want

You can also charge your trailer battery using jumper cables from your tow vehicle. If you can run at a fast idle, even better. No need for a generator as a gasoline TV is quite and puts out a lot of amperage.

I spent a couple months off-grid with a similar setup to yours while farm-sitting. Two 100 watt solar panels and a 100 AH AGM battery with similar loads. I was fine unless we had two cloudy days in a row.

If you're parked in the shade, though, that would be a different story.

FWIW, my backup power source was to charge through the umbilical from the truck alternator, which got me around 5-6 amps. Did it twice in two months to prevent battery damage. Terribly inefficient, but works in a pinch. When I got back to home base I added two more panels.

If the issue is just to get minimum power then you could buy a very small generator and run it maybe 1 or 2 times during the 5 days to keep the battery powered. The 2200 is of course good for the AC but you are sorta apples to lemons with the solar versus big generator because you are not going to get AC on solar. I do not really enjoy camping unless I can run a fan some, some lights, my CPAP, and keep the frig. running. Sitting in a hot trailer or out in the bugs reading with a flashlight got old for me after a few times. Going without the furnace on some night got even worse.

Hi

... errr ... not so much ...:)

You own 200W of panels, as we went through in the other thread, getting 200W from them as you will have them set up is not likely.

Drop a second battery into the trailer with exactly what's in there now. Yes, both batteries need to be same /same for them to charge properly. No other upgrades required to the charger or controller. You now have 80AH rather than 40AH available. No need for 6V AGM's, you can go with whatever is on sale. Amp hours are amp hours ....

If you decide to go with lithium's, they *can* drop right in as well. There is no *need* to upgrade any of the other stuff, it just will work a bit better if you do.

The only type of meter that will give you better information is one with a shunt on it. That makes it a permanent install sort of thing. You can get a very good one for just a bit more than that Walmart battery cost. If you will be running off batteries on a regular basis (and don't want to destroy them) - yes, you need something like this.

Bob

Uncle_Bob, you mean a second 12v, same as one I have or 2 6v?

I have 160 Solar panel, two 6 volt AGM's and two Honda generators. Got them Costco for $500 each, free delivery. We're going to June lake next month, I'll see how we do also.

Have fun.

You got Honda generators from Costco, and for $500 each?? When, and was it an online purchase or an in-store purchase?

HI

I mean a second 12V battery in either group 24 or group 27 size. Exactly how you fit it (or two 6V batteries) in is very much up to you. A pair of group 24's get you to ~80AH usable. Two group 27's get you to ~100AH. A pair of (often a bit larger still) 6V batteries might get you to ~110 AH usable.

The trick always is that both batteries in a pair need to be same / same. Same brand, same model, same batch, same same same. If they are different, one will likely over charge and the other will just loaf along.

Any time you buy batteries you do need to look at the details on the ones you are buying. The case sizes are just an outer dimension. There is no guarantee that everybody fills that case with the same amount of working battery innards.

Bob

I have no problem with power to my AGM Optima battery for extended (5 or more) days between moving on & towing to next site with a set up like yours. 100w on roof and 100w on ground. I do avoid parking under trees and I do move my portable around to get max sun all day. I only use a few LED lights at night, and even eliminate lights by using LUCI solar lamps. My frig does not need 12v. But my composting toilet fan does, as does my CO2 alarm. These 200w even powers up single battery enough for hubby's CPAP use for 8-9 hours over night. The only time we had problems was near east coast where we had the perfect storm of several days of heavy rain with heavy tree canopy. Never a problem here in the west. Maybe Seattle area.

I don't know about you guys but this sounds like a lot of complicated stuff to solve a very simple problem.
I bought a Champion 3100 Inverter generator for $ 900.00. It will run quietly around the clock for pennies per hour. If I stagger starting them it will run both of my AC units no problem, and can use any and all our appliances we chose at any time. And best part it will do the job sitting in the shade of a tree or blazing sun. I call it the KISS method of solving a problem.

Unless you camp in an area that doesn’t allow generators. Different strokes for different folks.

One of the best things I have done to conserve batteries while boondocking is to install a switch on the Dometic refrigerators door heater. In my case saves at least 12 amp hours per day.