diy solar

diy solar

Hello. I’m new here. 1st post. Looking for general input for electricity… remote cabin

I would anticipate you would have to run the generator a bit in the evening and morning, depending on previous days sun and power usage. The nice thing with a AIO is it would run the cabin from the generator power while charging the battery until solar kicked in.
This model supports much more solar, but is not as plug and play. You could wire it with extension cord ends like Will does for demos, make your own MC4 connections for PV and use Anderson connectors for the battery. All easy to do, just time and a bunch of little components to gather.
Price wise, this seems to be the going rate. MPP and Growatt have comparable models in the 24v range. MPP and EG4 are the seem to be the go to for 48v systems.

im comparing magnum to the mpp. Magnum is 3x the cost, and it doesn’t have a charge controller. What’s magnum got to justify higher price? What does mpp not have? Usually you get what you pay for.

but I really like these new all in ones. It’s been a few years since I was “into” solar. Things have changed.
 
Just some random thoughts……

next cabin season I’ll put a killawatt on the genny and ask everyone to write down the numbers.

off the top of my head we may need 2400 or so watt hours. Maybe more if I want to run power tools during the day.

since the cabin currently is one 1500 watt circuit do I buy a 1200w inverter? Do I buy 3000w inverter? (Shared by cabin and one out door outlet for tools)

12v? 24v? Don’t think I need 48.

possibly keep my Bogart, CC and buy a samlex evo inverter/charger

I dont want to over build the system (no one will help pay for it) I just want some power for convenience. We can always run the genny if need to charge battery or power bigger loads periodically (microwave, tools).

can someone tell me if I use a samlex evo inverter charger, when you run a generator through it to charge the batteries does it pass through power for my cabin, or does it just charge the batteries, and the in dryers just keeps inverting?
 
As above... I learned this recently too. If you want to charge the batteries AND have the 1500W available for the cabin then you'll need to get a generator that can provide 1500W plus whatever your charge watts are going to be. So I'd say a 3000W generator would be a good point to look at if that is the plan.

Otherwise look for a separate charger you can power from the generator only and use that to charge the batteries and leave the generator disconnected from the inverter/charger unit. Then everything runs on battery while you are charging. This means you'll be fine with a smaller generator just for charging.

As others have said too, if shared, make sure this is so dead simple to use a child could figure it out without needing to read more than an index card. If there is one thing people are fantastic at doing it's doing the worst possible thing you can't even picture why they would try to do with your stuff.
 
Thanks for the input. I like the samlex inverter chargers. All in one minus the charge controller. Have a bigger genny on standby as needed, and they can plug the generator in (as is the case right now). Solar would be fed into a female outlet so that the cabin can be “plugged into” the solar system.

this would be as dumb proof as it gets.

if I go smaller genny, seperate charger, then there’s more components, more points of failure, more to “think about”.

what do you suggest for voltage? The 1500w generator setup has been fine for decades. Stick with 12v? 24v?

use my boggart pwm charger @24v? I could buy 24v panels and if I upgrade to mppt I can always series connect. Don’t really need lots of panels (assuming sporadic use) as we can let the system “Catch up” when we’re not there. Only problem is others may use the place and deplete battery (which is why we need generator. )
 
Ha! Well, Im far from expert in this but my thoughts reading over your post

1.) I would lean towards going 24V myself. The current demands drop to much lower levels on the battery that way. If you already have DIY 12V units it's not too hard to reconfigure for 24V. That should allow for a bit more inverter capacity later on too.

2.) I'd think a 1500W inverter is good if you don't plan to rewire any time soon, it should have enough surge to beat the generator you are using. An upgrade later is not terribly expensive if you do get away from the 1500W single circuit wiring you have now. Bonus is lower idle consumption and with a small battery bank that will matter.

3.) If your total battery storage is staying around 2500 to 3000 WH then you can probably program the charge current to leave a reasonable amount to the cabin while charging and still not overload the generator with normal loads and keep the time to charge down as well on your existing EU2000. Make sure you are factoring in the 50% limit on LA batteries when you consider the amount you need.

These are just kinda my thoughts on it, only worth the price paid ;)

The solar side I have just not done much with at all yet so I have no room to recommend at all there.
 
Not planning a rewire but I was thinking more in terms of a separate outlet for power tools (more juice needed) might necessitate a bigger inverter. But yes, a smaller inverter uses less power and power saved is cheaper than power earned.

regardless of battery size I’d design to run off the top 15% or so of the battery. Not much current needed, and solar works best for this. (Current drops as battery becomes full)

im sticking with LA for now. I,don’t trust lithium (fire) and the cabin freezes.

im,also leaning towards 24v. Less current, longer runs of pv cable and I,can use my current CC unless I go to mppt.
 
Also at this point considering just buying my own little Honda genny. Use it during the day for my stuff (starlink, ac) and the cabin genny at night.

I considered a solar system and locking it up when I’m not there but that’d start a war. There’s one cabin neighbor that does just that. He paid for everything but his sister didn’t want to pay up so he locks his system and she brings her own gas.
 
I considered a solar system and locking it up when I’m not there but that’d start a war. There’s one cabin neighbor that does just that. He paid for everything but his sister didn’t want to pay up so he locks his system and she brings her own gas.

People are funny.
 
People are funny for locking things up, or funny for thinking it’s ok to not contribute to, but yet use things?
 
Have you had a chat to the other's about contributing. With the cost of fuel they may see the benefit of solar. You would have to explain how to operate and maintain the equipment. If they are not interested then you could ask how they would feel if you set up a system for your exclusive use. You could explain how if it is not properly taken care of, there are expense's to repair it. If they are ok with that, then build a cupboard or shed and lock it up and don't talk about it, just use it yourself.
 
It’s complicated. Some members don’t work and have no money. Some have money but choose to spend on beer and cigarettes.

if I. Buy a genny and bring fuel no one will say anything. If I lock solar it will start ww3.

was hoping to not have to carry fuel back and forth (it’s remote and a hassle to get stuff to and fro)

this,why I’m looking for a small system (lights/cpap) and to run everything else maybe run the genny.

I offered to pay for starlink hardware. Not everyone was keen on chipping in to defer the subscription.
 
I could maybe explain that batteries are like gas, and that I don’t currently pay for their fuel, so maybe I’ll pay for the system, but everyone contributes for batteries (and help to water them)
 
I think you reconsider FLA and go with a LFP. From what you described, you cannot count on anyone to properly maintain the FLA batteries.
An off the shelf LFP has a BMS, is maintenance free and idiot proof. I understand if you don't want to drop $1500 on a server rack style battery. 12v 100ah can be had for $300 and will be cheaper in the long run than a wet battery.
To leave it year round, you have to spend the extra to get a battery with low temp charge protection. Otherwise take it home at the end of the season.
You could get 2 of these https://www.amazon.com/dp/B094NN5KW...&pd_rd_r=46dd99f6-4a0e-4b19-a3e1-8fb3f820c8de
and run the system I suggested earlier. It would be plugged in during the season and everyone could use it. If there is no power the battery hit low limit (set by you) and they start the generator.
When the temp drops, unplug house from AIO, disconnect batteries and take home. Should be an easy discussion, "Hey these batteries don't work below 35f so I'm taking them home so they last". I don't see any reason to lock up the system when you aren't there. Just point out there is not a lot of battery power and it needs to be respected but they can't hurt anything. Tell them to use most power when the sun is out otherwise expect to run the generator. The ability to turn on a light in the middle of the night will make you a hero!
 
I tried explaining how batteries as they get full they accept less charge, so “run the dishwasher, charge your iPads, etc during the day as power is just being “thrown away”. Maybe I’ll just say lights and Tv at night. Everything else during the day.

can you point me to some “lfp for dummies” info? I know nothing about it. The low temp protection doesn’t that mean the battery uses its own power to heat itself?

what’s the advantage of a server rack? What if I leave the lfp at the cabin over the winter and just unhook it all and they can run off the genny?

I don’t know if my Honda can auto,start. It’s got a choke.
 
Have you considered designing it so that it's idiot proofed?

If you route the inverter "go" signal through a relay driven by the courtesy power on your charge controller you can be assured they won't overly drain the battery. Go one step further and put a mechanical timer on the coil side of that relay circuit and you can make the loads run for 45 minutes at a clip without recranking the timer, etc.

Making it idiot proof would be well worth the effort.
 
I guess I’m an idiot because I don’t understand “timer on the coil side of the relay” lol
 
There's two different things for low-temp LFP batteries. One is low-temperature charging cutoff. The BMS has a temperature sensor and stops charging if the temp goes below freezing. For your situation, you need low-temp cutoff in your battery.

The other is low temp heating. This is in addition to low-temp cutoff. Some more expensive batteries have heating pads internally that will turn on when the temp goes below freezing to bring the battery back up to temperature.
 
I guess I’m an idiot because I don’t understand “timer on the coil side of the relay” lol
Welcome to the club then, half of my idiot proofing is to keep myself from doing something stupid, not others. ;)

Most charge controllers offer a dry contact for courtesy power. This turns off at a preset low voltage and turns back on at a preset slightly higher voltage.

Run the battery positive [through a fuse and into] into one side and then run a wire on the other side of the courtesy power through a mechanical timer switch, then into the coil of a dc relay. (Edit- run the negative side of the battery into the other side of the relays coil)

Then run the "go switch" of the inverter through the load side of the relay.

Now you can be assured that they won't use the AC power down to a level that would damage the battery. And they'll have to crank a timer every now and then just to keep it powering their devices.
 
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