I just upgraded my Cougar sg27 by replacing the one 12v lead acid battery with 4 6volt agm batteries with 250 AH each. I also added another solar panel to the roof to give me a 2000watt system. I did this because I have an "electric only" fridge. With only the fridge on (and possible small phantom drains), the batteries are down below 12 volts by morning. Shouldn't my system be enough to run my fridge through the night? I am assuming the solar panels are giving them a full charge during the day. I don't want to keep draining those batteries below 50% every day. Even though they're agm, I think that'll ruin them. Thanks for any help here.
New solar system. Batteries keep dying.
- Thread starter huntfish
- Start date
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HueyPilotVN
Well-known member
Welcome to the Forum.
Did you want to say 200 watts instead of 2,000.
Did you want to say 200 watts instead of 2,000.
Yes. Sorry, and thanks
HueyPilotVN
Well-known member
You will gets lots of good advice here shortly.
I assume the batteries are connected series then parallel to give you 500AH?
200 watt of solar might struggle if not in direct open sunlight. We also have an electric only fridge but run a generator for a couple of hours in the evening, even if we are parked in direct sunlight all day for our 420AH batteries. By morning, we are still around 12.4 volts.
200 watt of solar might struggle if not in direct open sunlight. We also have an electric only fridge but run a generator for a couple of hours in the evening, even if we are parked in direct sunlight all day for our 420AH batteries. By morning, we are still around 12.4 volts.
HueyPilotVN
Well-known member
He is also pretty far north in Maine and will not get as much exposure as he would get down south.
Utclmjmpr
Well-known member
And,,, the days are getting rapidly shorter...>>>Dan
HueyPilotVN
Well-known member
My Mom left me some "Ambush Give Away Money" and I used some of it to put together a dozen basic Solar systems to give away last year.
I considered a 400 watt system to be a good start for a dependable basic system.
I considered a 400 watt system to be a good start for a dependable basic system.
Thanks for the input everyone. I think I'm going to be in the position of still running the generator for a couple hours per day, in the evening to top the batteries off. I thought they would charge up full and quickly, being agm, but I guess I was being overly optimistic. Damned electric fridge!
Thanks TonyL. I do have them connect series and parallel. It seems as though you have a VERY similar set up to ours. I guess a couple hours of generator every evening will be required.
Truck camper: I have 200W Solar, 2x 6v (250ah ea) agm batteries that I bought last month along with an upgraded solar charge controller and a 7cf electric residential refrigerator. The batteries were down too low to run overnight (my stand alone inverter would be screaming). I decided that #1 the triple digit heat was not good for the BLACK batteries (they sit on the roof next to the solar panels as that's the only place for them) so I bought a plastic battery box, spray painted it white and strapped them all back in. The triple digit heat also isn't good for the solar panels. I also decided that #2 putting the refrigerator on a little timer would work well. Even in triple digit heat, the bags of ice we left in the freezer compartment would stay frozen overnight with no problem. So I have the refrigerator set to start turning on at 7AM (1 hr on/1 hr off) until it is set to turn off for the night at 6PM. This does what I need it to do. It keeps the bag of ice we leave in the freezer frozen (until we use it up) and it keeps the refrigerator cool enough to keep the stuff in it cool. Not enough to keep mayonnaise in the refrigerator all the time, in my opinion. I do have a thermometer inside the refrigerator so I can see how cool it is.
We use the truck camper to go get groceries and as a place to leave the dog with 12vdc fans going while we go grocery shopping (a thing that tends to eat up 5 hours - we like using clean bathrooms and that really isn't a thing in NM). We use the refrigerator as an electric cooler. I leave most of the shelf stable "keep in a cool place" type condiments in the refrigerator all the time as well as some protein drinks and sodas. It gets so hot that our sodas tend to explode. The camper is not plugged in to shore power unless we are going camping. This is the only way I can get my frozen groceries home and keep them frozen. I got tired of bringing home "ice cream soup" in the summer.
I do need another pair of batteries. I will be doing that by fall. Daytime solar charging keeps up, I need enough batteries to keep going overnight. If it isn't enough during the short summer nights, then it certainly won't be for the long freezing winter nights. And the inverter will go back to screaming that it's hungry for power.
We use the truck camper to go get groceries and as a place to leave the dog with 12vdc fans going while we go grocery shopping (a thing that tends to eat up 5 hours - we like using clean bathrooms and that really isn't a thing in NM). We use the refrigerator as an electric cooler. I leave most of the shelf stable "keep in a cool place" type condiments in the refrigerator all the time as well as some protein drinks and sodas. It gets so hot that our sodas tend to explode. The camper is not plugged in to shore power unless we are going camping. This is the only way I can get my frozen groceries home and keep them frozen. I got tired of bringing home "ice cream soup" in the summer.
I do need another pair of batteries. I will be doing that by fall. Daytime solar charging keeps up, I need enough batteries to keep going overnight. If it isn't enough during the short summer nights, then it certainly won't be for the long freezing winter nights. And the inverter will go back to screaming that it's hungry for power.
Gary RV_Wizard
Site Team
A typical residential-type fridge will consume around 1200-1600 watt-hours per day, a sizable amount but not horrendous. 500 AH @ 12v theoretically yields 6000 watt-hours, so you have plenty of stored power when the batteries get full. The question becomes how quickly your solar panels can replace what is used. 200 watts of panels pumping at around 14v would seem to yield 1800 watts per hour in full sun, but no solar panel is anywhere near that efficient. Lucky if you get 70% of that, I think (maybe one of the solar experts will comment). Nor does northern Maine get strong sunlight or for very many hours. I think you are just spending more energy than you can bank.
AGM batteries don't charge any faster or better than any other lead-acid battery - the lead-acid chemistry is exactly the same. AGMs don't suffer electrolyte losses or outgas as much as flooded cells, but electrically they are no different.
A residential fridge will consume at least 1200 Watt/hrs per day and in Maine your sun hours are typically low around 4 peak hours per day. with panel/charging losses you will need a minimum of 450 Watts to keep up with that demand.
Mark_K5LXP
Well-known member
Wonder and guess or measure and know. A battery monitor goes a long way towards answering the questions of system balance, and where you're at any point of the day. You can see what solar has contributed during the day and decide or not to run the genset before bed.
The bottom half of the battery works too. You bought it so use it. Charge efficiency below 80% is better too.
Mark B.
Albuquerque, NM
The bottom half of the battery works too. You bought it so use it. Charge efficiency below 80% is better too.
Mark B.
Albuquerque, NM
Thanks Mark. I've been checking the voltage over the past few days. Everything in the camper has been turned off. I know I have a few small phantom drains, like the little LD safety light on the stairs that comes on when you walk past, and the little red LD light on the radio when it's turned off, but I believe they are very small. I started checking my battery voltage every morning and late afternoon with everything turned off. I started at 12.5 volts. After 5 days with nothing on in the camper, I was down to 2.2 volts this morning. Even on the one sunny day we had, I never saw the voltage increase from the morning check to the late afternoon check. It appears as though, here in Maine, in late summer, I don't even get enough charge to keep up with a small amount of phantom drain. Or.......... something wasn't hooked up correctly at the dealership.
Thanks for the help. I'm considering getting a "suitcase" panel to help out my measly 200 watt roof panels. Do you have any suggestions? Over the past 5 days my roof panels haven't even kept up with the small "phantom" draws of the camper. With everything off and no generator going, my battery voltage has gone down from 12.5v to 12.2v. It has been cloudy, but yesterday was a sunny day. 12.3v in the morning, and still 12.3v in the late afternoon. This morning it was down to 12.2v. Thanks again.
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