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LiFeYPo4

TommyD

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Feb 20, 2020
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Greetings!
This is my first post to this Forum. We currently have an old 24v 850Ah lead acid battery bank. I am intrigued by Lithium when I need to replace the battery bank and believe I have sufficient skills to build a 24v 1000 Ah replacement along with an increased PV Array.
When snooping around I saw there was a battery with “Y” - Yttirium (sp) in its chemistry which seems to provide more cycles and works better in cold climates; ie can charge batteries below 0C. Where we are we can expect -5C for a week or so and maybe 1 week might touch -10C.
So, is it worth considering this chemistry or just use the Generator if need be when cold?
 
we can expect -5C for a week or so and maybe 1 week might touch -10C.

We tend to have -20C for several weeks, -10C for months easily, and days where it goes down to -35C and lower depending on the year. If you put the batteries in a well insulated place, and provide e.g. heating pads as suggested, and/or maybe a small propane heater for the building you should be fine. Even having a 100 Watt incandescent bulb can make a big difference, depending on how large the space is where you put the batteries.

I did consider the Yttrium cells, but they tend to be quite a bit more expensive and not as common. For example, I haven't found any selection of aluminium cased cells. Most common ones are the Winston cells, but not worth the extra costs in my opinion when looking at the overall battery availability situation today.

I'm also experimenting with insulating the batteries with foam (essentially encasing them in it). We'll see how that will work out :)
 
I looked at the 'Y's for the exact same reason and reached the same conclusions as @upnorthandpersonal .

If you have R30 insulation all around your battery box, you only need a few watt-hrs/day to keep it above freezing if the ambient is -20C.

I assume your lead-acid is nowhere near your living space. LiFePO4 is safe enough that a lot of people put it in their heated living space.... problem solved.

Also, do you need more storage than you have now? If 24v 850Ah of Lead Acid is doing the job for you, 24v 500ah of LiFePO4 would probably meet your needs.
 
Thanks for these helpful comments. Will forget about the “Y” Lithium cells. Yes, have the space and yes, can make adjustments to keep room warmer. Like both the idea of upping insulation & and the warmers.
 
Hold on! The market in Germany in Marine Service for Sail boats and power boats and RV DIY application service shops is with Y-chemistry LifeYPo4 (ThunderskY/Winston cells). My reviews and research on this showed that this is purley due to the better low temperature profile performance. When I contacted expert shops for design recommendation there was almost no acceptance to use Lifepo4 design in regions with low temperature condition. The higher costs get's accepted as a trade off to lower the risk on low temp. malfunction.
 
I have my (LiFePO4) batteries in an unheated garage. They experienced low temp cutoff once this year. I have the low temp on the BMS set for 2°C and recover at 3°C for charging. The ambient was -11°C outside. I opened the garage door to the house for 2 hours and it warmed enough.

Put a small heater on a temp switch.

 
@Walef That's because in mobile applications it's much harder to guarantee that you won't charge when below 0C. The environmental conditions are just not under control compared to when you have a well insulated and potentially heated room. Naturally, any design recommendation where this can not be guaranteed (and where low temp cut-off might not even be feasible) will be to use what gives you the best defense for liability and warranty and then it's worth the extra cost.
 
@Walef That's because in mobile applications it's much harder to guarantee that you won't charge when below 0C. The environmental conditions are just not under control compared to when you have a well insulated and potentially heated room. Naturally, any design recommendation where this can not be guaranteed (and where low temp cut-off might not even be feasible) will be to use what gives you the best defense for liability and warranty and then it's worth the extra cost.
Yup. Nothing exists in isolation. You have to look at everything as a system. Some things you can control, other things you have to design to handle.
 
@Walef That's because in mobile applications it's much harder to guarantee that you won't charge when below 0C. The environmental conditions are just not under control compared to when you have a well insulated and potentially heated room. Naturally, any design recommendation where this can not be guaranteed (and where low temp cut-off might not even be feasible) will be to use what gives you the best defense for liability and warranty and then it's worth the extra cost.
No objection! The point I wanted to make is, that lithium battery technology is available to protect for low temperature malfunction. What I don't understand is why the Ytrium chemestry technologie doesn't get more spread into the market? There might be design protection issues I don't understand!
 
Greetings!
This is my first post to this Forum. We currently have an old 24v 850Ah lead acid battery bank. I am intrigued by Lithium when I need to replace the battery bank and believe I have sufficient skills to build a 24v 1000 Ah replacement along with an increased PV Array.
When snooping around I saw there was a battery with “Y” - Yttirium (sp) in its chemistry which seems to provide more cycles and works better in cold climates; ie can charge batteries below 0C. Where we are we can expect -5C for a week or so and maybe 1 week might touch -10C.
So, is it worth considering this chemistry or just use the Generator if need be when cold?
Greetings Tommy
 
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