Setting up solar for a camping trailer

Rednecktek said:

to buy a new one for my shed a few weeks ago and with tax and core charge it was $106 out the door.

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Ya. They had been like $67 and were when I bought three this past spring but now they’re like $20 more. Needs an “I did that sticker” maybe.

Scixxor said:

buy a couple of branch connectors and wire 3 and 3 in series then connect those 2 sets of three in parallel

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You only need one branch/Y connector for that. Series just plugs into each other. So three series two parallel only needs one branch connector.

Scixxor said:

beginning to look like a sweet deal since it will be close to half the price of what I paid for those 2 gel batteries

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Don’t forget to never go below 12.1V and never let them stay 12.1-12.3 more than a day. You can get 3-5 years or perhaps even more if you are kind to them.
Two months without power! I couldn’t do that. Get that thing together! Lights, hot water shower, and a coffeemaker are daily comfort.

Hello once again! I am now online but had some questions about many things. How low (in terms of volts) can I get my batteries to go without damaging them? I have 2, 200ah gel batteries wired in series for 24volts. I wanted to add on more batteries in the future, I know I need to add them in sets of 2 but does the ah matter? I already have one used 100ah gel so if I buy another could I add the 2 100ah batteries in parallel? Oh and one last thing when my panels are in direct sunlight (no clouds or shadows) how much power should I be getting if they're 100w panels?

Scixxor said:

when my panels are in direct sunlight (no clouds or shadows) how much power should I be getting if they're 100w panels?

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It depends on several factors. The angle between the sun and panels, the temperature, and the air quality. If the panels are aimed directly at the sun, if it's 25ºC/77ºF, and if it's a perfectly clear air blue sky day then you will get close to 100W. If the panels are mounted flat, it's before 11am or after 1pm, and there's a little haze, then you might get 20W-40W.

Scixxor said:

I wanted to add on more batteries in the future, I know I need to add them in sets of 2 but does the ah matter? I already have one used 100ah gel so if I buy another could I add the 2 100ah batteries in parallel?

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There are several threads discussing putting batteries of different capacity in parallel. From what I've seen it can be done. Try scanning through these search results for more info:

Scixxor said:

How low (in terms of volts) can I get my batteries to go without damaging them? I have 2, 200ah gel batteries wired in series for 24volts

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I wouldn’t want to go under 24.2 volts ever.

12VoltInstalls said:

I wouldn’t want to go under 24.2 volts ever.

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That's good to know, the all-in-one when set for AGM (it only has 3 options, AGM, flooded, and user defined) cuts itself off at 21.0volts so I'll probably want to set that higher.

Scixxor said:

cuts itself off at 21.0volts

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Ya that’s too low for agm even for the habitually successful battery abusers. IIRC that’s like a full volt under 100% discharged
I can’t remember agm ranges atm. I use flooded batteries so…

12VoltInstalls said:

Ya that’s too low for agm even for the habitually successful battery abusers. IIRC that’s like a full volt under 100% discharged
I can’t remember agm ranges atm. I use flooded batteries so…

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So hello again, many a thing, one even on a very sunny day with tilt on my panels and all that good things I could only get a high of 370-watts from my 500-watt array. Is this normal? It's also the highest I've seen since I got it set up. The second thing is those batteries, I can not keep them above 24.2. Fully charged is 25.4 (something like that anyway) And as soon as I turn the inverter on and plug my heater in (800 watts about) it drops .9 volts and after 30-ish minutes it's gone below 24.2. Is there any way to fix that? Also, I left my heater on overnight and was woken up by the low-voltage alarm to find it at 21.0 volts but my heater was still running fine sooo dunno about the full volt undercharged. So can you help me out and clear this up for me?

Scixxor said:

could only get a high of 370-watts from my 500-watt array. Is this normal?

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Depends on your situation. You have distance on the solar wires, and other factors. You’ll basically never see 500W unless it’s very cold and conditions are perfect. 25% loss seems more than I’d hope for, but the distance sun travels through the atmosphere this time of year shrinks potential anyway. So it’s not alarming.

Scixxor said:

The second thing is those batteries, I can not keep them above 24.2. Fully charged is 25.4 (something like that anyway)

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For AGM 25.4 is not fully charged
24.2 is essentially fully discharged.

Scixxor said:

as soon as I turn the inverter on and plug my heater in (800 watts about) it drops .9 volts and after 30-ish minutes it's gone below 24.2. Is there any way to fix that?

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That initial drop is voltage “sag”

Your inverter and other factors have “efficiency losses” - let’s say 15% loss not for accuracy but for demonstration ease.
800W heater with 15% is ~34A draw and you have ~200Ah of useable battery. So you’re pulling a strong load of ~35A that with fully charged batteries, “C-rate,” and peukert effect : in an ideal world that electric heater will only be able to run for a hopeful 5 hours- tops.

1) you are not fully charged
2) your heater use for one hour alone will take almost 3hrs of charge time never mind that you probably only have 4-5 hrs of good output from the panels in a day. It’s a losing game.

Scixxor said:

Is there any way to fix that?

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1600W of solar and 400Ah or more of llithium batteries maybe

Electric heat on solar is a bad idea

Why are you not running the RV furnace? New 12V 16KBTU units only use 3A running. I forget where you mentioned wanting to run electric heat I guess.

Iirc you wanted lights. An 800W heater just doesn’t sound sustainable with your setup. A fridge, lights, maybe a coffeemaker might be ok.

If you get a second job for a while you can save up and buy more panels or a new RV furnace if that’s not running. It was -21*F this morning, floors feel cool but it’s 65*F in my 24’ at the moment. I’m charging at 14.5V cuz the sun is out. With “ish” 300Ah of flooded batteries I can sustain maybe 8-9 hours tops of furnace and fridge after dark- because it’s winter and I have a sustained 3-5A draw on the batteries.

First order of business is to get the specs on the batteries snd get them fully charged five days in a row.

Your SCC settings need to be correct and verified appropriate for AGM

And don’t use electric heat.

Hello once again,

thank you for all of that input it is very helpful. I didn't even know my camper had a furnace it was made in 1987 so it might not. Is there any way to find out? Besides that, I have a propane stove but after 3 days of using it for heat, it runs out. It's $20 a tank so it's not very sustainable for me to keep using it for heat. Here's the batteries I'm using I have 2 of them in series if you can figure out the specs: https://www.renogy.com/deep-cycle-hybrid-gel-battery-12-volt-200ah/ I've already emailed Renogy asking them about it but being that it's Renogy they might not ever get back to me. As much as I would like to get a second job and begin buying the hell out of used panels and eventually batteries I'm only 15 so I can't work at most of the places in town. Besides that, I have a landscaping/gardening job but with all the snow, ice, and cold conditions it's been put on hold until the summer. I'm about to add another 100-watt panel in the meantime since I already have it. Update: just found out my camper doesn't actually have a furnace it has an electric overhead heater / ac.

Scixxor said:

So hello again, many a thing, one even on a very sunny day with tilt on my panels and all that good things I could only get a high of 370-watts from my 500-watt array. Is this normal? It's also the highest I've seen since I got it set up. The second thing is those batteries, I can not keep them above 24.2. Fully charged is 25.4 (something like that anyway) And as soon as I turn the inverter on and plug my heater in (800 watts about) it drops .9 volts and after 30-ish minutes it's gone below 24.2. Is there any way to fix that? Also, I left my heater on overnight and was woken up by the low-voltage alarm to find it at 21.0 volts but my heater was still running fine sooo dunno about the full volt undercharged. So can you help me out and clear this up for me?

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So when you put a load on a AGM or lead acid battery you get what is called voltage sag and its ok to go below the 24.2 voltage when there is a load , you just don't want to go below the 24.2 after the battery has rested for awhile and that makes monitoring the capacity of AGM and lead acid a pain in the ass.
Now before I had lithium batteries I would run my lead acid ones down to 11.6 volts sometimes lower with a heavy load and when I let the batteries rest for 20 minuets (no load whatsoever) the voltage would come up above the 12.1 minimum of my 12 volt system.
After doing this for awhile you will get a feeling for where your batteries are at at rest when there is a load on , and its not the end of the world if you go below 50% discharge , I have seen where people recommend and have ran em down to 30 or even 20% but that will shorten the max life of the batteries , so the goal is 50% but while your trying to get the feel for it if you go slightly below 24.2 at rest dont panic .
Lots of luck and get LiFePO4 ASAP and avoid the grief
Eddie

Scixxor said:

didn't even know my camper had a furnace it was made in 1987

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That’s hilarious! My 1958, 1974, and the current 1978 each had furnaces ?

1987 wasn’t that long ago…

Scixxor said:

have a propane stove but after 3 days of using it for heat, it runs out. It's $20 a tank so it's not very sustainable for me to keep using it for heat.

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something is wrong. That’s a lot of propane
But $200/month for propane for a few months compared to rent…is cheap!

Nevertheless I had a 120 gal propane tank dropped. Holds ~100 gallons roughly. Dec 6th? $270 and it’s 40% still. Before that I was about 3-4 days on one 20# cylinder for $120 or so in November.
And this is Vermont. You shouldn’t use as much. Seal air, storm panel windows, reflectix in the ceiling vents. This one has an insulated and skinned floor from the factory but I’ve replaced a lot of fiberglass with foam board for double the insulation value.

Plus there’s carbon monoxide to worry about if the burner gets dirty. Don’t use the stove.

Scixxor said:

I'm only 15 so I can't work at most of the places in town.

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So it sounds like you’re in a tough spot. That changes some things. Since you’re 15 I’m confused as to the camper for housing. But that’s a different matter.

Scixxor said:

Update: just found out my camper doesn't actually have a furnace it has an electric overhead heater / ac.

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Holy cow. That’s not fun. A 16K btu propane furnace is $650 new.

You are in school? Do that. Graduate.
You sound smart enough to do well for yourself.

In the meantime: how many feet from the house are you located? You need to work it out with your dad to maybe use electricity for heat. I’m assuming you can shower at the house? I’m hoping the camper is perhaps optional and choice is involved. Anyway, electric is expensive to heat with but compared to propane it’s close in $$/btu. Propane furnace and its inefficiencies with an RV - actual cost could be less with electric?

Spring is coming. Get something in place to get by for now; come April have a written plan to be prepared for November by July. No sense having another emergency next winter.

ed6269 said:

Lots of luck and get LiFePO4 ASAP and avoid the grief

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He has a limitation on income.
And he’s a teen.
LiFePo might be a Maserati

Plain flooded might be his needs.
I’ve never been excited about AGMs anyway except for ups backups.
They never seem to last, and I’ve never personally seen a mistreated AGM recover like a flooded sometimes will- they’re just used up.

Scixxor said:

I'm only 15 so

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Nothing wrong with that.
In fact knowing that now? I’m impressed with you.

Keep on my friend

12VoltInstalls said:

He has a limitation on income.
And he’s a teen.
LiFePo might be a Maserati

Plain flooded might be his needs.
I’ve never been excited about AGMs anyway except for ups backups.
They never seem to last, and I’ve never personally seen a mistreated AGM recover like a flooded sometimes will- they’re just used up.

Nothing wrong with that.
In fact knowing that now? I’m impressed with you.

Keep on my friend

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just seen a zooms LiFePO4 100 ah battery for 319.00 on amazon , not that much more than a couple of AGMs and when I wrote that I didnt know he was 15 (thats so cool)

I think this kid is brilliant. At his age I was playing basketball and computer games. Here he is learning critical life skills like sustainable off-grid living and taking care of his own needs...that is an important first step to being able to help/take care of others.

I think he is in a great spot right now with a basic working system. No better way to learn than monitoring the heck out of it and experiencing what works and what doesn't. Hopefully some adjustments to config and usage will optimize what is there now, and later can be expanded.

Scixxor, one thing I haven't heard is how close you are to a grid-connected electrical outlet. Perhaps a short term "this winter" option is to ask the owner if you can run an extension cord to that and pay them for your usage. Get a Kill-a-watt meter (or similar) and measure what you draw to pay them back at their kWh rate. That may also help you understand your minimum power needs for next winter.

ejfluhr said:

Perhaps a short term "this winter" option is to ask the owner if you can run an extension core

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ejfluhr said:

Get a Kill-a-watt meter (or similar) and measure what you draw

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You make a separate ’entrance’ and keep it 100% isolated from the camper; it ONLY runs the heater through a GFCI and verified polarity of the home’s outlet and verified bare/green/ground to the home/house.
(You only need one meter, $15-$20; the second one tracks my just installed 100W soon to be 300W that is pushing back to the “grid.” Interesting side-note: the friend I’m connected to is only $0.06/KWh due to powerco windmill offset agreements.)

12VoltInstalls said:

1987 wasn’t that long ago…

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When you're 15 years old, 1987 was a long time ago. In fact it was last century.

HRTKD said:

last century.

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That recently?!!

12VoltInstalls said:

That recently?!!

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He probably thinks we're a bunch of old geezers. And, we are! LOL!

@Scixxor, keep learning. If you get your system running good, it could be enough of a working resume to get a job at an RV repair shop doing solar installs. The storage space where I keep my RV trailer is four stalls down from the RV maintenance shop at the storage lot. The main mechanic there wandered over a few times while I was working on my trailer. He's offered me a job twice. That's not going to happen as I like my software development job just fine.

Hello everyone! Reading all of your messages but a seriously big smile on my face so thank you. Currently, I'm living in the camper with my dad, long story short house we were living in got sold we were given 10k to get out in a couple of weeks. We used that + all of our savings to buy a property, a camper, and a new car. The plan has always been get solar for now and eventually get a meter (my all-in-one inverter works great with grid power.) There is no house nearby to go to. The closest electricity is about 300 ft away at a nice neighbors house, besides that the powerlines are actually on my property but on the other side of where the camper is currently parked. I wanted to get LifePo4 from the beginning but it's so expensive, both me and my dads work seriously slows up in the winter so right now my budget is basically $0 unless my boss finds some work for me. For now, the plan is to save up money, buy a generator, buy used panels (finally convinced my dad to go with used), and then get more batteries. I wanted to thank all of you guys again for the help along the way, I don't know if I would have been able to do this without all of your guys' help.