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

[Nan_wpg]

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.

can I leave lfp all winter (with them not being used)? I understand not charging them (which means I shouldn’t use an inverter/charger) in the cold.

 

[shampeon]

can I leave lfp all winter (with them not being used)? I understand not charging them (which means I shouldn’t use an inverter/charger) in the cold.

Yeah, they can be stored in sub-freezing temperatures. They can even be discharged sub-freezing. You just can't charge them below freezing.

 

[AnarchyJet]

Yes you can leave them all winter, just don't charge them below below freezing. That means disconnect them from any charge source, for best results don't store them 100% charged up. Use them to 50% and unhook. Look at https://www.us.sokbattery.com/products as these are more expensive but have built in low temp protection, also have models with heaters. If you use LFP there is no way anyone can over use the battery and damage it because it has a BMS. If you use a AIO inverter, you can program the voltage shut down to kick in before the BMS to limit the cycle range of the battery and extend its life.

 

[Nan_wpg]

If I go the lfp route I’d just unhook everything and take the battery home or just leave it. Do they freeze?

what are the advantages of a rack style lfp

 

[Nan_wpg]

I dunno, lithium doesn’t,seem very safe. Lots of fires, no way to extinguish. Am I missing something?

 

[photomankc]

Not all “lithium batteries” are the same. Lithium Ion and Lithium Polymer are pretty prickly about being abused and can get into thermal runaway through damage or bad charging practice.

Lithium Iron Phosphate is pretty forgiving and unlikely to runaway. You’d likely have to really put some effort into sending one into flames.

I understand the concern though.

 

[shampeon]

LiFePo4 is a lot safer than LiIon or LiPolymer, and doesn't require maintenance like FLA batteries. The overall TCO of LiFePo4 is better than FLA as they have more cycles and don't degrade as much, but it's more up-front cost. Server rack batteries are a better package for homes since they have an individual breaker, communications connections, and a good form factor for adding multiples, but probably aren't the best for a remote cabin.

In your case, maybe it's simpler to just keep the FLA batteries and deal with the maintenance yourself. You can't solve a social problem through technology alone.

 

[Nan_wpg]

I have no problem maintaining fla batteries. Why wouldn’t,a,rack lfp be good for a cabin? I like the breaker idea.

 

[Nan_wpg]

LiFePo4 is a lot safer than LiIon or LiPolymer, and doesn't require maintenance like FLA batteries. The overall TCO of LiFePo4 is better than FLA as they have more cycles and don't degrade as much, but it's more up-front cost. Server rack batteries are a better package for homes since they have an individual breaker, communications connections, and a good form factor for adding multiples, but probably aren't the best for a remote cabin.

In your case, maybe it's simpler to just keep the FLA batteries and deal with the maintenance yourself. You can't solve a social problem through technology alone.

Not all “lithium batteries” are the same. Lithium Ion and Lithium Polymer are pretty prickly about being abused and can get into thermal runaway through damage or bad charging practice.

Lithium Iron Phosphate is pretty forgiving and unlikely to runaway. You’d likely have to really put some effort into sending one into flames.

I understand the concern though.

I need to brush up on the lithium because all I’m reading is how dangerous they are. The phosphate ones… that’s life pro4 ?

 

[AnarchyJet]

Like said before, server rack is a form factor for permanent mount solar. Also a good value when looking at Wh per $. Lifepo4 and LFP are the same, just different ways of saying Lithium Iron Phosphate. https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery
They are very safe and are best suited for what you want to do.
Seems we have established you need min 2000w inverter, ability to still use geny, and user friendly. Do you have a target budget? I think a 24v AIO form MPP, Growatt or Midnight Solar are your best options. Then add as many panels and batteries as your budget allows.

 

[photomankc]

No reason you can’t use LPH at a cabin. Im doing exactly that. Plan is to locate the 3 position rack on the loft floor above the inverter closet on the lower floor. Its going in a small insulated nook ill build around it and put a top on it that can be used as a table surface. If your place is below freezing a lot you may want heaters in whatever battery you get so that you can charge them even when its cold but Im going to try a 150W chicken coup heater in the rack to use when nights are really cold. Near the Arkansas border those are not all that frequent.

 

[photomankc]

This is my work in progress so battery cables are not routed yet but its 5.1KW of battery and a (much oversized) 6500W inverter and generator inlet with cutoff switch. Ill eventually switch to using the two external chargers in the bottom of the rack for charging the battery at 36A. I’ll eventually add a second battery for 10KW total and that means my generator can charge the battery bank up from 20% to 100% in just over 4 total hours assuming no solar input.

Currently sitting in my cabin waiting for the freezing weather to arrive ?

 

[Nan_wpg]

Like said before, server rack is a form factor for permanent mount solar. Also a good value when looking at Wh per $. Lifepo4 and LFP are the same, just different ways of saying Lithium Iron Phosphate. https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery
They are very safe and are best suited for what you want to do.
Seems we have established you need min 2000w inverter, ability to still use geny, and user friendly. Do you have a target budget? I think a 24v AIO form MPP, Growatt or Midnight Solar are your best options. Then add as many panels and batteries as your budget allows.

Not really any budget. Buy once, cry once. But I don’t like to waste so if I can use my cc (Bogart sc2030).
Im thinking: 2224 samlex evo fed by “x” amount of panels, into lfp (rack?). Come winter I just unhook battery and turn inverter off.

id get the inverter,with an outlet, and use an extention cord to connect to a small panel (I’ll,have a male outlet). The cabin can be “plugged” into,the inverter, and then won’t it plugs into the genny like it is now.

the samlex is a clean instal. Panels go into it. (I suppose an AIO is cleaner)

what chemistry do ev cars use? I’m still concerned about fire.

 

[Nan_wpg]

No reason you can’t use LPH at a cabin. Im doing exactly that. Plan is to locate the 3 position rack on the loft floor above the inverter closet on the lower floor. Its going in a small insulated nook ill build around it and put a top on it that can be used as a table surface. If your place is below freezing a lot you may want heaters in whatever battery you get so that you can charge them even when its cold but Im going to try a 150W chicken coup heater in the rack to use when nights are really cold. Near the Arkansas border those are not all that frequent.

Heating with solar isn’t feasiable? Seems counter intuitive.
we have wood heat at the cabin. Was hoping to not use the solar in the wintER.

 

[photomankc]

I don’t have solar yet. Most internally heated packs draw off the battery. Charge batt with solar or whatever and the heat pad kicks on if cell drops below freezing. If the cell gets below freezing there is no charging it. Solar or otherwise. The temp must be raised to charge. They can be DISCHARGED at temps down to a bit below 0*F. Discharge generates some self-heating.

 

[Nan_wpg]

All,the smaller portable lithium packs, are they lifepro4? The specs just say lithium (jackery). Also looking at that type of solution. Easy to take home for the winter

 

[AnarchyJet]

I think you are over thinking it. I don't know why you would pay so much for the Samlex when better, cheaper solutions exist.
We gave you multiple options for a 24v, 2000-3000watt AIO from MPP, Growatt and Midnight Solar. These were designed to do exactly what you are looking for, a low power off grid solar setup. LPF is the best battery for your setup, it's been running 1000's of systems like this for years. It's limit is low temp charging, which you see OK working around. I think you misunderstood about the heating. The recommendation was to build a small heated box to keep the batteries warm enough to use year round. That is something you could explore down the road. I feel you are hung up on just how easy the newer tech has made it. Yes you get a MPPT, pure sin wave inverter, ac battery charger and transfer switch all in one little box for under $600. Add $600 for 2500 Wh of LFP battery. A high estimate is 1$ per watt for panels, lets say 600w.
Couple hundred for odds and ends and for $2000 you have a nice little system, and it can be upgraded with more battery and panels if you find your needs change.

 

[Nan_wpg]

I,just equate cheaper with not good. usually You get what you pay for. But yes it’s been a few years since I’ve researched solar. It’s quite possible cheap,can be good. Magnum is expensive and apparently,crap now.

and even if it was all crap, for 2k I could just replace everything every 5 or so years.

what would heat the small box? Battery could be kept in the cabin and when it’s heated up with the wood stove the battery could then be charged.

I didn’t realize lithium could be left without charging. And not freeze.

 

[Nan_wpg]

Just read lfp can’t be charged over 30.

I think I’ll give the AIO a try. I’ll just make sure batteries are disconnected from the cc under 0 and over 30. I should be able to get Compliance.

wonderimg If I,should,just start off with a rack battery? Maybe start off with 2 24v panels, in series. I can add if needed. Same with battery but I’d like to start off with more battery cause I have a limited charging temp range. Sounds like lfp doesn’t get,damaged sitting partially,charged so we can just run the genny if it’s too hot or cold.

 

[Rednecktek]

Just read lfp can’t be charged over 30.

Under. Gotta be above freezing all the way down in the cells.

I think I’ll give the AIO a try. I’ll just make sure batteries are disconnected from the cc under 0 and over 30. I should be able to get Compliance.

Breakers are a handy thing for that, built in disconnect.

wonderimg If I,should,just start off with a rack battery? Maybe start off with 2 24v panels, in series. I can add if needed. Same with battery but I’d like to start off with more battery cause I have a limited charging temp range. Sounds like lfp doesn’t get,damaged sitting partially,charged so we can just run the genny if it’s too hot or cold.

The advantage to rackmount batteries is that it's becoming a common form factor. The downside to them is that it's really hard to find 24v rackmounts anymore. If you were to go with a EG4 3Kw unit, or the MPP-3048LV, both would get you 3Kw of inverter, the charge controller, generator hookup, etc and get you into the 48v range where rackmount batteries are common. If you go that route spend the bit extra on a Trophy battery and it takes care of the heating and low temp and all for not much more than a basic 48v rackmount battery. The Trophy batteries also come in larger capacities than 100Ah which is pretty handy for those long winter days.

Just put in the notes that when the alarm goes off go fire up the generator. When the generator winds down (not charging the batteries anymore and just idling) and gets quiet go shut it off.