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Small Cabin Forum / Off-Grid Living / Lithium for Small System
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cspot
Member
# Posted: 15 Sep 2019 12:30
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Ok. Looking for suggestions here as I didn't want to hijack paulz thread. First here is my solar panel and controller that I currently have.
https://www.amazon.com/Renogy-Polycrystalline-Controller-brackets-Trailers/dp/B00DCDZ OI0/ref=sr_1_5?keywords=renogy+50+watt+solar+panel&qid=1568564590&s=gateway&sr=8-5

Everything in my recreational cabin is 12V. I have a 105 amp hr marine lead acid battery on this system. This system has served my needs well. My lead battery is a few years old and while it is still reaching full charge, I have noticed that it is starting to lose performance and may need to be replaced in a year or 2.

So is there a cost effective lithium? It is my understanding that you discharge them lower than you would a lead acid? Would I use the same charge controller that I currently have? Do you use a typical battery charger if charging from a generator?

SCSJeff
Member
# Posted: 15 Sep 2019 13:17
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Well...

I'm going to say that you will need/want a new charge controller for sure. And if your location drops below freezing, you'll need to incorporate some automatic (or manual) way of stopping charging.

Regarding a typical battery charger... You can use it (set for AGM mode would be preferred), but again, I think you would want to disconnect it before it reaches full charge as they won't have the intelligence to stop charging (and lithium doesn't need/want float charging either)

cspot
Member
# Posted: 15 Sep 2019 16:17
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Quoting: SCSJeff
And if your location drops below freezing, you'll need to incorporate some automatic (or manual) way of stopping charging.


Hmm. That could be a problem as this is in Ohio.

ICC
Member
# Posted: 15 Sep 2019 18:03
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When you decide to get a new lithium battery you should get a new charge controller that is designed to work with it. Just like the charger for your phone the charger will charge until the battery is full, then shut right off.

Ditto for a charger that runs off 120 VAC.

Nice thing with lithium batteries is you can leave them partially charged; 60 to 75% is good for them actually. So when you leave you can turn the charge system off. They can sit through the months of a cold winter with no harm and be ready to gi in spring. You can charge them in winter if you warm them first. So either store inside and warm up the interior and battery(s) first. If it is not too cold using them a little can also be enough to get the battery above freezing and make it safe to charge.

cspot
Member
# Posted: 15 Sep 2019 18:06
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In doing a little reading it appears that some of these come with a bms system that will not let them charge below 25 deg F to protect them. It appears that you can use them in cold temps but not charge them?

Wilbour
Member
# Posted: 15 Sep 2019 18:29
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Quoting: cspot
. It appears that you can use them in cold temps but not charge them?

And that's why you keep them in your heated space. You can use then until you heat up the cabin, then when everything is toasty warm you charge them up.

SCSJeff
Member
# Posted: 15 Sep 2019 19:16
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Quoting: cspot
In doing a little reading it appears that some of these come with a bms system that will not let them charge below 25 deg F to protect them.


In my research, the only (reputable and somewhat affordable) 12v battery that had a low temp cutoff bms built-in was the battleborn (around $1000 for 100ah). Most others have a bms built-in with a high-temp cutoff, but no low-temp...

Since my setup is in a shed about 75' away, I don't have the luxury of having the batteries inside to get warm. Hence, as of now, the battleborn is the only one I am looking at. However, if I'm up during a 0 degree (F) stint, I don't think using the batteries will be enough to warm them up above freezing. So I'm thinking either battery warmers or just starting the big buddy heater up in there and then leaving it on low or pilot...

cspot
Member
# Posted: 15 Sep 2019 19:28
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Quoting: SCSJeff
In my research, the only (reputable and somewhat affordable) 12v battery that had a low temp cutoff bms built-in was the battleborn (around $1000 for 100ah). Most others have a bms built-in with a high-temp cutoff, but no low-temp...Since my setup is in a shed about 75' away, I don't have the luxury of having the batteries inside to get warm. Hence, as of now, the battleborn is the only one I am looking at. However, if I'm up during a 0 degree (F) stint, I don't think using the batteries will be enough to warm them up above freezing. So I'm thinking either battery warmers or just starting the big buddy heater up in there and then leaving it on low or pilot...


Those are the one's that I was looking at as well. I think I still have some life left in my current lead acid ones, but may need to do something in a year or two. My lead ones are under my cabin, but I could easily put the Lithium in the cabin. Only issue would be that I may have to warm the cabin a bit before they would charge. Still looking at the cost difference in lead acid vs lithium to try and determine if it is worth it or not since my cabin is only recreational use.

SCSJeff
Member
# Posted: 15 Sep 2019 19:55
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I think you'll have no problem with lithium if you can move them inside. If they are anywhere above 50-60% when you start the cabin up, you should be able to use them all the way down to 20% before you have to worry about charging. I would think by then your cabin should be warmed up plenty...

Check out this video regarding cost difference...

URL

cspot
Member
# Posted: 15 Sep 2019 20:16 - Edited by: cspot
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Yes I get the cost difference. My concern is I worry about what advancements that will come in the next couple of years and am worried that I may regret buying a $1,000 battery now when there is something better coming. I know my thinking is a bit weird at times. LOL.

What controller are you thinking of using?

Lithium doesn't vent so I don't really need anything special for keeping inside? Any clearance required?

SCSJeff
Member
# Posted: 15 Sep 2019 20:34
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I've been watching that YouTube channel for a few months now. He likes Victron and I know several members on here have them as well.

However, he recently did a review on a all-in-one unit (charger, inverter, transfer switch), albeit, Chinese, that I'm interested in as well...

I just re-watched that video and didn't remember that (1) 100Ah LifePo4 is equivalent to about 270-280Ah flooded lead acid. I currently have (2) 6v golf cart batteries at around 200Ah. So when mine die, switching would gain me some additional headroom as well as much faster charging... Since, you can move them inside, I would look at Renogy or Relion for a slightly cheaper battery too...

I don't think there are any concerns about clearance inside. Some models get warmer than others, so I wouldn't lay anything right on them, however.

cspot
Member
# Posted: 15 Sep 2019 20:48
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Quoting: SCSJeff
I've been watching that YouTube channel for a few months now. He likes Victron and I know several members on here have them as well.However, he recently did a review on a all-in-one unit (charger, inverter, transfer switch), albeit, Chinese, that I'm interested in as well...I just re-watched that video and didn't remember that (1) 100Ah LifePo4 is equivalent to about 270-280Ah flooded lead acid. I currently have (2) 6v golf cart batteries at around 200Ah. So when mine die, switching would gain me some additional headroom as well as much faster charging... Since, you can move them inside, I would look at Renogy or Relion for a slightly cheaper battery too...I don't think there are any concerns about clearance inside. Some models get warmer than others, so I wouldn't lay anything right on them, however.


My issue is for surveillance I have a cell cam to send pics at the cabin. I have a cell booster that I leave on so that the cell cam can send pics, so I need to leave my system on. I don't have heat on, so I need a battery that would automatically shut itself off from charging if it gets too cold. It is in SE Ohio so likely inside the cabin it wouldn't be too cold most of the time so it could still charge from my panel to get a full charge. We don't get many cold spells for very long that stays below freezing.

SCSJeff
Member
# Posted: 15 Sep 2019 21:09 - Edited by: SCSJeff
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My place is in Central PA. While there are stints of several days well below freezing, it will usually break and get up above periodically. I'm sure the cell booster doesn't pull much power (I wonder if you can get a 12v version and not have to leave your inverter on?) So even if you go a week or more without charging, it will probably be fine...

cspot
Member
# Posted: 15 Sep 2019 21:20 - Edited by: cspot
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Quoting: SCSJeff
My place is in Central PA. While there are stints of several days well below freezing, it will usually break and get up above periodically. I'm sure the cell booster doesn't pull much power (I wonder if you can get a 12v version and not have to leave your inverter on?) So even if you go a week or more without charging, it will probably be fine...


I have a 12V version as I don't have an inverter on my system. I wired everything for 12V. Only other thing I have is some LED lights, 12V fan on composting toilet, charging station for phones, and a 12v Shurflo pump for the water. The only thing that stays on while we are gone is the cell booster.

That is what I am thinking as well. Unlikely to run it all the way out as during the mid day it is likely to get above freezing which is when it would be getting sun anyway. A bright sunny day is likely to warm the cabin up some too. At least with lithium if the battery runs down it isn't the end of the world.

Thanks for your help.

Atlincabin
Member
# Posted: 15 Sep 2019 22:07
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I have a small system and we get below freezing a fair amount during winter. I bought a small thermostat (for garden seed starter boxes) and battery heating pad, and put the Li batteries in an insulated box. The thermostat comes on whenever the temp gets below about 35F and turns on the heating pad. Turns off at 45F. It uses power (not much) from the battery, so if the temperature were to stay really low for a couple weeks and at the same time we got no sunshine, there might be a problem. However, usually when the temps are that cold, the sun is shining, so the batteries get recharged during the day. Has worked well for a couple winters now. For reference, this is in western CO.

paulz
Member
# Posted: 15 Sep 2019 22:34
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As far as prices, the articles I've read predict a slow decline
lithiumionbattery.png
lithiumionbattery.png


creeky
Member
# Posted: 16 Sep 2019 12:22
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The Victron solar controller has a temp shut down for charging. I prefer to use this for my systems.

Of course the solar controller then either needs to be in the same box as the batteries (recommended) or you use a thermoresistor tied into the controller.

Like Atlincabin I use a battery blanket. Pretty common. I monitor mine and turn on as required. Other folks use timers and/or thermostatically controlled outlets. I've seen them for as low as 10 bucks.

A timer for weekenders is great. Have the timer go on Friday a.m. You're ready to go when you get up to the cottage. Done.

There are lower temp capable lithium. Lto or lito (lithium titinate) comes to mind. while they are a bit pricier. Hard to ignore 20,000 cycle lifespan.

razmichael
Member
# Posted: 16 Sep 2019 13:04
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I still have few more yrs left in my LA batteries and they handle my part time use just fine for now. The cabin is shut down for long cold winters but, even with snow on the panels at times, there is enough of a trickle charge to allow them to survive while continuing to power a camera, couple of motion sensors with floods and an alarm. I fully understand the advantages of Lithium and reading through the winter problem (especially where electrical heating is not likely to be a good enough solution, I was thinking that using a solar air heater might be a cheap way to provide more than enough warming to the batteries on sunny days to also allow a much more extending period of time when they could be charging.

Years ago I did a small DIY solar water heater to help keep horse watering trough from freezing (actually augmenting an on grid hook up just to reduce the power needed). During that period I also played with a screen solar air heater (small version just for fun - no actual use case at the time). Basic plan came from DIYSolar (and there are many other sites offering similar plans). This link compare the old PopCan type to a screen type.
It seems this could be easily implemented to provide heating to an insulated battery bank box/case - especially good as the warming would be strongest the same time the sun was strongest. It would need a small fan but, as I did with the water heater, I used a separate small panel to power the pump - sun comes out, fan starts up slowly, air heats up the batteries, charger comes on (assuming it is temperature controlled as noted in this thread).

I think I see a winter project in this!

cspot
Member
# Posted: 16 Sep 2019 16:55
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Hmm. Some more food for thought. My battery sits under my cabin (on piers), but is right along the side which is south facing. In the winter it receives a fair amount of sunlight. I am thinking that I could build an insulated black box that would probably keep the battery warm without a heater on a sunny day. Could also put a battery blanket on it and use my genny when we are there to warm it. Could both warm it and charge at the same time.

AffordableDCGenerators
Member
# Posted: 16 Sep 2019 19:42
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Out of curiosity, why the push to go lithium?

Your system is already outside in a shed and set up for lead acid. I'm guessing size or weight is of no concern (like portability isn't a factor). You wouldn't have to retrofit a compatible charger.

Why not just go with a lead acid, use what you have, option of charging in subfreezing temps to run a small load, and you would be less then a 1/4 of the price of lithium.

ICC
Member
# Posted: 16 Sep 2019 20:15
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IMO, the only advantage to lead-acid these days is the lower initial cost.

Changing from L-A to lithium can sometimes mean some changes to the basic system arrangement, such as sometimes switching the location of the battery or adding some heating or insulation.

But with lithium, you can forget all about adding water and checking the sp. gr. with a hydrometer. Forget about the concerns about not letting the L-A batteries sit in a partial state of charge. Forget about equalizing. The lithium batteries will re-charge faster than L-A as an extra bonus.

I have run lead-acid battery based systems in RV's and residential applications; RV since 1976 and my home (2000) and hunt cabin (1998). I switched them all to lithium two to three years ago and am very pleased I did.

I do understand why some people have trouble convincing themselves to switch to lithium; not everyone can find the ready cash for the initial outlay for lithium. For a small cabin, 2 to 4 6-volt lead-acid golf cart batteries can be bought very cheaply at Costco and Sam's Club.

cspot
Member
# Posted: 16 Sep 2019 22:11 - Edited by: cspot
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Quoting: AffordableDCGenerators
Out of curiosity, why the push to go lithium?



I can see in the long run that the lithium would be cheaper. In addition my current setup works great for probably 95% of the time. However when the whole family is there for an extended time and we have cloudy days, I know I am putting an overdraw on the battery. If I replaced in kind with lead acid, I would probably upsize to 2 batteries and go with a higher wattage panel which will run into some $$ as well. I think if I replaced the lead acid with the lithium, it would work better in my situation since I could discharge it farther when we are on an extended trip. On those I always have our genny there as well and I could give it a quick charge if it gets too low. In reading about the lithium batteries my current 110 volt battery charger would work fine. If I bought one for lithium, it would simply charge faster. I only need to get a new charge controller which would be less than $50 on my simple setup as I only need a PMV.

Like ICC said the disadvantage is the initial cost of the lithium. The cold weather not being able to charge is a bit of a disadvantage, but if I do an insulated box it would be a rare occurrence in SE Ohio to have that extended of a time when it is below zero. If we are there I can run the genny and put a battery blanket heater on which are cheap. Likely during that time of the year we don't do that many extended trips and are usually hunting so we use very little power anyway. The battery would probably have plenty to get us thru that weekend.

SCSJeff
Member
# Posted: 17 Sep 2019 13:00
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Quoting: Atlincabin
I have a small system and we get below freezing a fair amount during winter. I bought a small thermostat (for garden seed starter boxes) and battery heating pad, and put the Li batteries in an insulated box.


Atlincabin, do you have a link to the thermostat? I assume it is 12v?

bill_bly_ca
Member
# Posted: 19 Sep 2019 16:08
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Quoting: AffordableDCGenerators
Out of curiosity, why the push to go lithium?

Your system is already outside in a shed and set up for lead-acid. I'm guessing size or weight is of no concern (like portability isn't a factor). You wouldn't have to retrofit a compatible charger.


For myself it is options - As a lot of these LiFePo4 batteries can charge as fast as they discharge so you get

1) Faster to float if you have the sunlight. Once your batteries have floated you can use more of what the sun gives that day to run <what ever>

2) Faster to float when you have to run gas on a cloudy string of days.

e.g an Amazon 24V or 48V 50A power brick into your MPPT charger on that dingy day with no sun gets you from 50 to 100% in a fash without that ardious wait from 80 to 100% with LA, SLA or AGM.

On the Freezing side - I am toying on having the battery bank @ 3 or 4' underground where it is a pleasant 12C (54f ) through the winter up here in Ontario.

Steve_S
Member
# Posted: 20 Sep 2019 05:19
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I've posted this before but new readers so posting it here too.

I have a separate building that serves as my Power House & Pumphouse (14x6) which is 70' from the cabin. Because both my Water & 50 gal Pressure Tank + Solar system (batteries & electronics) reside in there I did not want to risk freezing up. I salvaged a Used Propane furnace from a 20' RV Camper. It's Direct Vent, uses 12V for the fan & a microvolt thermostat which I set to 35F / 2C. Without the batteries being charged, it used to use roughly 50 Lbs (20 Lb & 30Lb tanks) in a winter. With battery charging (makes heat as do controllers & inverter) maybe 20 Lbs a year +/-. Now the powerhouse IS insulated with 4" XPS in the walls & 5.25" ISO in the roof and 4" of foam under the Concrete Slab.

If you hunt through Craigslist / Kijiji and check RV service centres etc, finding an older RV furnace like this is not hard and they are cheap... direct vent ones are pretty common in RV's sold after 1975.

cspot
Member
# Posted: 22 Sep 2019 10:09
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Just came across these batteries that have a built in heater.

https://relionbattery.com/low-temperature-series-line

Not cheap though.

WoollyMammoth
Member
# Posted: 27 Oct 2019 23:36
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These Nissan Leaf batteries are quite intriguing, and I just picked up 9 myself. Most affordable lithium ion I've ever seen. They come used but the savings on the cost means you can easily afford to double down on storage.

https://www.techdirectclub.com/nissan-leaf-generation-2-battery-module-lithium-ion-0- 5-kwh-500-watt-h-4-cells/

Wire 3 in series to get 24v, then use a cheap step down if you need 12v.

beachman
Member
# Posted: 28 Oct 2019 09:34
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Creeky, and others, have you heard about the guy in the UK that appears to have developed a new battery storage system of eco-safe electrolysis and the use of aluminum? Is this hocus-pocus, voodoo, fake news? Or is there any substance to this? If true, could blow lithium out the window. Apparently the lithium guys are trying to destroy this process because of their heavy investment. True? Call me a skeptic - I also still have LA but see the benefits of LI or Lipo.

Steve_S
Member
# Posted: 28 Oct 2019 14:40
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@ Beachman, no Hokus Pokus, verified & tested by 3 universities in the UK and an Automaker has signed them up and is building production facilities. This is a different animal though and as such, worth waiting 5 years after it's "out there" to realize what the real world does to them.

@WoolyMammoth, leaf batteries are not suggested as they often have a lot of troubles with them and then there is the whole thermal issue. It's far better to use a Volt or Tesla battery packs even the original Tesla 18650 packs from the P95 & early S models. (floating around 1400 USD) for a 24V 5.5khw pack + bms etc.

rachelsdad
Member
# Posted: 28 Oct 2019 15:23
Reply 


I was down to the Volts and Kia batteries.

Lost a little on the top w/the Kias but either was a good option.

Frankly to replace my 8 trojans would have cost well over $1,600 at $200 per. I got my 4kwh worth of Volt goodness for half. Add a BMS and good harness and... as the wise one said..."I'm good for a few decades."

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