Upgrading my little solar power system.

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Aerindel

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Oct 20, 2020
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On some scarred slope of battered hill
My flooded lead acid batteries are dying after about four years use.

I notice that the price of Lithium iron batteries has radically fallen, to the point where it was only about 20% more cost to replace my lead acids, with lithium.

While I'm doing this, I plan to get a better charge controller PWM to MTTP, and do some more DC wiring in my house to use my power more.

But.....one concern I have is from explosion/fire from the lithium batteries.

My current batteries are stored under my stairs in the living room. It would be a bad place for a fire that can't be put out.

I am thinking of moving the batteries outside, however, I have concerns about temperature, namely it can get down to -20 here, not commonly, but it happens.

I am thinking of moving them to the same crawlspace where I keep my water tank, which stays at about 35-60º. Only problem is, this requires an additional 50 feet of wire run from the panels.

Thoughts?
 
Most of the fires are with Lithium Ion (often just called "Lithium" batteries) and Lithium Polymer Batteries (often called "LiPo" batteries).

Good quality LiFePO4 (Lithium Iron Phosphate) batteries that are charged within the specified parameters, are actually pretty safe from fire.

Most high end camper trailers are now getting equipped with LiFePO4 battery packs......and there are no significant number of fires being reported with those.

Most of the Lithium battery fires are cheap Chinese scooters with Lithium Ion batteries.

The extra 50' of wire can be solved with heavier gauge cables......the charge current is not very high.....so losses will not be too bad with heavy cable.
 
In my battery bank I'm using 12 Rolls 2 volt batteries for a 24 volt system. I love these batteries. In the 2+ years that I've had them I've only needed to add water about 3 times a year. I don't have any idea how long they'll last, but so far they're doing great. My battery bank is located in a shed that houses my inverter, charge controllers, 12kw generator with auto start, a 55 gallon day tank, tools, etc. This building is unheated except for when the generator is running. This time of year the generator will start usually once a day and is programed to run for 4 hours.
So far I haven't seen the need to buy more expensive batteries.
 
So far I haven't seen the need to buy more expensive batteries.
I was fine with my lead acid batteries, but since they have to be replaced anyway, I wanted to try something different and with a looming 25% tarriff on China, I'm thinking most of the cheap batteries (and most other cheap stuff) is going to vanish soon.
 
I was fine with my lead acid batteries, but since they have to be replaced anyway, I wanted to try something different and with a looming 25% tarriff on China, I'm thinking most of the cheap batteries (and most other cheap stuff) is going to vanish soon.
Personally I think that would be a good idea. Just beware of cheap stuff from China. You might be better off paying a little more for quality. I don't remember what I paid for my Rolls batteries, I'll have to look it up.
 
Our 24 lead/acid batteries are from Costco with the Interstate label on them, since the U.S.A. no longer smelts lead the batteries are more than likely made in Mexico. This last batch of batteries we bought all have the same manufacturers date on them and they are 210 amp hour, the orignal batteries were 205 amp hour and half had a months different manufacture on them which wasn't a problem in connecting them in series. I'd loved to have been able to have bought Rolls batteries but we just didn't have the money to do that, due to a fixed retirement income. Anyway this last set of batteries from Costco are working great and I've only had to add water once in a year, but then they haven't been abused like the first set which were mainly used to test the backup solar system I had put together, so in reality the batteries surviving 10 years did a good job, considering some of the discharge and charge amperages I saw them go through.
 
Most of the fires are with Lithium Ion (often just called "Lithium" batteries) and Lithium Polymer Batteries (often called "LiPo" batteries).

Good quality LiFePO4 (Lithium Iron Phosphate) batteries that are charged within the specified parameters, are actually pretty safe from fire.

Most high end camper trailers are now getting equipped with LiFePO4 battery packs......and there are no significant number of fires being reported with those.

Most of the Lithium battery fires are cheap Chinese scooters with Lithium Ion batteries.

The extra 50' of wire can be solved with heavier gauge cables......the charge current is not very high.....so losses will not be too bad with heavy cable.
And

Wire batteries in series for a higher voltage and less current to reduce losses in the wire runs.

Ben
 
Our 24 lead/acid batteries are from Costco with the Interstate label on them, since the U.S.A. no longer smelts lead the batteries are more than likely made in Mexico. This last batch of batteries we bought all have the same manufacturers date on them and they are 210 amp hour, the orignal batteries were 205 amp hour and half had a months different manufacture on them which wasn't a problem in connecting them in series. I'd loved to have been able to have bought Rolls batteries but we just didn't have the money to do that, due to a fixed retirement income. Anyway this last set of batteries from Costco are working great and I've only had to add water once in a year, but then they haven't been abused like the first set which were mainly used to test the backup solar system I had put together, so in reality the batteries surviving 10 years did a good job, considering some of the discharge and charge amperages I saw them go through.
Rolls batteries are made in Canada, Nova Scotia I think. Our 2 volt batteries are 1169 ah each and I think cost around $600 each.
 
Well, its only been a couple weeks, but so far there is a massive difference in how well my system is maintaining charge.

I went from 120 Ah of lead acid, to 200 of lithium iron, no name, Temu batteries that cost about $1 per Ah, hooked up to the same PMW controller and 200 watts of panels, and so far the voltage hasn't dipped even a 1/10th of a volt under normal usage.

During the day it reads 13.2, at night, 13.1.....and nothing I've down so far as been enough to draw it down further, and whatever is being used, is being replenished each day by the sub 1 amp charge I've been getting this time of year.

Tonight I'm going to switch over the whole house to batteries, draw them down to the lower shut off limit (12.4?) and then see how they come back over the rest of the week. (Not expecting to get a full charge in one day this time of year)
 
Ran for 6 hours.....just usually stuff like the tv, lights, fridge, etc....only drew down to 12.7

There might be something to this solar power thing....

Now I have to see how many days it takes to get back to 13.1
 
...I went from 120 Ah of lead acid, to 200 of lithium iron, no name, Temu batteries that cost about $1 per Ah..

Posting to track Progress.. :cool:

I chose to go w/ 4x 'SLA', 200 Ah, 12V'ers, to wire in series for either a 2x 24V-sys config, Or, a 1x 48V sys.. Rationale was, I'd see 'which paradigm performed Best', once all up / running (only Tested, not-yet "using full time") as If the 24V / 200Ah worked "OK" for our load / panels (800Ws of Polycrystall'ers + another 200Ws for a 12V 100Ah sys, for 'smaller things' (PCs / Macs / small-device charging, etc) - Then we have either 'Immediate Back-up' @ 24Vs - Or, as $$ permits, get Another 800-1K W's online, for bigger loads, etc..

..But I'm Very keen on Data Points of the 'LithFe's ;) - Especially if, now, they're That 'cheap', Wow..

Curious what Brand ya got (we got 'MightyMax's) if yer willing to 'share'. 👍

jd
 
Curious what Brand ya got (we got 'MightyMax's) if yer willing to 'share'. 👍

No brand. They literally just say "100Ah Li Feo4 on the side" ;)

The rather large instruction book that came with them is the same. No brand name at all.



Perhaps weirdly, I liked that about them.

So today, I'm getting one watt of my panels. Going to be dark in an hour, I'm back up to 12.8

Gonna take days to recharge this time of year.
 
I'm using LiFePO4 batteries. Just a heads-up, they shut themselves off below about 35° to protect themselves. If you use this type battery, you're going to have to keep them above that temp.
We have some friends who just bought a lithium battery bank. I believe they paid around $3000 each for 4 batteries. Since they can't be exposed to freezing temps, they're having to install a propane heater in the battery room. My battery bank is lead acid batteries, cost far less and don't need to be in a heated room.
 
We have some friends who just bought a lithium battery bank. I believe they paid around $3000 each for 4 batteries. Since they can't be exposed to freezing temps, they're having to install a propane heater in the battery room. My battery bank is lead acid batteries, cost far less and don't need to be in a heated room.

That is nuts. May as well just use that propane to run a generator. Especially since they make self heating lithium batteries. Sure, they use some of the power to heat themselves...but at least that is renewable and can just be accounted for with more panels etc.
 
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