Yes I am, just like a lot of other guys worldwide. Not only our national sport. Death and taxes, you cant avoid them
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write it off as a home storage system and an ev tax credit and a business expense because you drive it for your business. And those GM Products are the only ones with more then 150kwh of usable battery for all I know.
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CATL in china claims they have a sodium battery that is good to -40C that will go into production next year.
That would eliminate the concerns around heating your off grid batteries.
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So, yesterday as I was cleaning up part of a storage shed (out of character, I know 
) , I came across an old UPS battery. It was hidden under a full cow rawhide. Donāt ask. Anyway, I thought Iād try charging it before I recycled it. When I hooked it up to the charge controller (without the solar panel connected, the panel laying out in the grass on the hillside), there was a small spark. Hmmm. After a few hours charging at about 5 amps, it tested weak to okay on my precision Harbor Freight car batter tester. Best guess, itās been under the rawhide for six years, winter and summer. We moved in 2016, and it was given to me at least five years before that, when it was pulled from a large uninterruptible power supply bank because of low voltage. It must be at least 15 years old, probably more. For a while, it ran a small refrigerator in our 15-passenger van for trips.
I was surprised and impressed. Now the bad news: I looked them up, and a new one, slightly different, is $360. This is a 12v, 136 ah, 20 hour rate. So I donāt feel so bad about buying the LiFePoās, which are less expensive. I will not be storing the lithiums in the same careful way.
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what is the protocol for ārestoringā sealed lead acid batteries? I have a couple from a curbshopped e-scooter that judging by the rust on the chain, has been sitting for a number of years.
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Hi Sean , in my limited experience dealing with sealed lead acid is this , spend days and days doing all kinds of fancy charging profiles , then open up the non opening battery top up with fluid of your choice , then sit on another few days of a charge cycle of what you consider to be the best way , then and only then take the battery to the scrap yard get a few $ and go buy a new one .
I think Kent was lucky getting some life back into a old sealed unit that had sat around for years ,i too have managed it but it never lasted long enough to say all my time and effort was worth it .
Those type of batteries really suck i have played with many and yes you might get some voltage but i have never managed to get back any useful amps .
Unsealed lead acid you always had a chance of desulphating to a degree and getting some more use out of them i get great pleasure in bringing back to life old traction deep cycle batteries , but these days my age and health wont allow me to cart them around , so its been lifepo4 for me now for a few years and boy have i got lucky , getting hold of cells for cheap prices and even now just a month ago i found a 6KW house battery complete with inverter and bms all built in and then to top it off i found and engineer who sells the used stackable 48V batterys that fit this unit so i can increase the KWh of this unit and he is more than happy to do a exchange for my old victon charge controllers and lower voltage items as he fits them into caravans and 4x4 's .
Dave
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This is a quick check to see if the motor, and controller are working more then anything. The batteries will get replaced. If the motor is torched, I have to get a new motor, and then I might as well upgrade the thing to 36v or 48v. If I can find a pack that fits. 
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You can try the circuit on page 84 of this from Homepower Magazine :
It works pretty well for some flooded lead-acid batteries, and may for SLAās if you keep the charge voltage at the float voltage so you donāt dry them out. You can also try a long soak at float voltage or a bit above, without the desulfator. To tell the truth, which I do try to, like Dave, unless they charge in about the normal time, I havenāt had very good results.
The thing that was surprising about the big battery I found hiding, is that it still had a partial charge after all that time and abuse. What I when I was scrounging batteries when I was working, was that a voltage test was usually accurate: If the battery voltage was below about 10.5 volts, it was probably bad. Sometimes a couple of slow charges would bring one back, but not very often. And they rarely would have anything like normal capacity.
If you try to charge the scooter batteries, and get no current flow, theyāre probably shot, but you can try a power supply with, maybe, 40 volts or so, for a 12 volt battery. After five or ten minutes, it may start to slowly charge. Be sure to keep an eye on it, or set a current limit on the power supply. If it is recovering, the current can, possibly, rise quickly, and you can overheat the battery and destroy what was left of it. Not guessing here . Lower the voltage from the power supply until you reach the float voltage, to keep the current reasonable, say c/50 to c/20. When you get to float voltage, you can put it back on a battery charger, and see what happens. Again, itās not very likely to recover useful capacity. But you never know.
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Kent,
Can I like your post about a hundred times? It is similar to my experiences with Lead-Acid batteries in general. Thanks for the Home-power digital version, some good reading there!
Mike
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Mike i suspect the plates have gotten thiner on lead acid battery over the last few decades. I canāt find a battery that holds up well around my old farm equipment and the charging systems work on my old tractors. In the 90s when i was in college i was involved with the electric car program and back then we used lead acid batteries. You could take the batteries that you pop the caps off and boil them for about 2 hours 30 minutes at a time or so keeping them topped off with water and they would come back to life. But modern batteries donāt take boiling well in my experience. I think the connection between the lead terminal and the plate breaks on batteries today where it didnāt 30 years ago.
My hope is that we see low cost sodium batteries in a few years.
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That was an excellent article. I donāt see those types of in depth articles anymore. I might make that circuit.
The one battery got to 12v overnight but it quickly dropped to 10v so there has to be a short in one of the cells.
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Probably old news, but starter batteries have thin plates and plenty of them - lots of surface area to be able to deliver a lot of current.
I donāt know about the rest of the world, but I use what we call āleisure-time batteriesā, used in campers and such. They have fewer but sturdier plates. Not ideal for big engines or diesels, but they have worked well for what Iāve been driving. From what Iāve noticed they last longer and are even slightly cheaper.
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While not technically āoff-gridā CES 2025 had at least 2 good battery entries.
One is the most sustainable. Flint, a company from singapore, made a rechargable battery out of paper that uses cellulose instead of lithium. 100% biodegradable. because it is flexible, and probably really isnāt that great, they are going after the āsmartā market for portable devices.
The second one is Prologiumās battery they are out of south Korea. They developed a ceramic lithium battery that will allow you to recharge a vehicle 80% in 6 minutes. It is their 4th generation of the technology. None of the press releases mentioned a cycle life, but still impressive to be able to charge 80% of the way in 6 minutes, and good to -20C which I beleive is -4F. The density is pretty good as well 380Wh/kg and 860ā900Wh/L.
One press release for the last generation said the battery withstood 800 continuous charge/discharge cycles of 5Min charging without dropping below the 80% capacity.
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Finally tested a battery with my Sun Deye. Very easy setup, now with a diy 15 kWh 48 v battery. 60 kWh is coming. Very easy install compared to a Victron system, just plug and play.
Playing rules are changing overhere. In 2027 we cant use the grid as a season battery anymore (is that gridmetering?). Generator time in winter, woodgas is coming close for me. Still figuring out if it is the big Deutz or several Alie 48v range extenders.
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For the most part we call it ānet meteringā.
FormEnergy has iron air batteries they are marketing to grids. They are big, bulky, and have a slow discharge ie over 4 days but they are really cheap. They are sold for firming the grid up to 4 days when variable renewable energy may not be available. Supposedly it can keep the costs down to competitive with grid generated energy in the US. You guys pay more.
You might ask them if they have anything available or mention it to your utility company. It is a pretty common issue for grid management because managing the grid is a guessing game and this eliminates some of the guessing.
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Auw, around ā¬2000/kWh. We are around ā¬50/kWh diy. It might go up to ā¬80/kWh. So decided to go 48 V not like Dalathegreat on Youtube, HV, Nissan Leaf battery. Cheaper and , in my case, safer to go 48 v.
And grid? Not my problem, we pay a lot thus expect a lot. No bullshit, shut up big company and do what you get paid for.
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I have just checked battery market and found prismatic LiFePo4 cell of 120 Ah for 999 CZK (40ā¬). And up to 20s 200A BMS for 2500 CZK. It may amount to 20000 CZK for DIY 6kWh battery with BMS. Itās nowhere close to the prices @Pelletpower can get. But it starts to being attractive.
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Kamil, you are in EU and can order in the same shop as I did without to much hassle. My project didnt move since. To busy working. Only three crates IBC from the land so far. Burning only palletscrap. Why pay to get rid of it if you can heat the house.
Sun is getting stronger every day. Cant delay it much longer.
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Took the Deye down to where I can monitor/ see it. Connected a 15 kWh batt from a few years ago. Grid is giving some strange problems. Voltage is down to 370 V and dropping when a heavy load starts. In off grid mode the Deye generates a perfect 400 V.
Another thing is temperature and LFP. Advised charge discharge drops significant under 20 C/ 68 F. New battery supposed to be installed outdoors but maybe inside is better. Fire-risk is something. Not totally decided yet.
For the Skyjack I found these.
Salt battery from Eve. Looks good. Still expensive but hard to demolish. If there is some time I will have to read myself into charge curves. The Skyjack has lead acid now and are worn out. They need maintenance, salt batt not. Below freezing is no problem. Good to learn.
Easy path is buying lead acid. Charger is built in and I dont want to change the electronics. Wait is another thing. I dont want to tip over with lighter batt pack.
Choices and projects. And there is work 
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LFP drops output in cold weather. Some charge controllers have built in heater circuits to warm up the batteries. They have almost no fire risk. The fire from lithium batteries is from the electrolyte catching fire when the battery internally shorts in the NMC lion batteries but they donāt use the same electrolyte in the LiFeP batteries. The lithium polymer batteries also can catch fire.
The sodium batteries would give more power in a smaller spot, and you could offset that with additional weight if you want to go that route. I
Whether you do the work is up to you, but if you are going to keep the equipment I probably would, just because you probably wonāt ever have to replace them again. They do 3000-6000 charge cycles, and can fully recharge in 15 minutes.
sodium batteries also heat up when charging, I didnāt look to see if it needed cooling or not.
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