Li battery recommendations

**Ampster** · 02-01-2021, 03:41 PM

I have been using Lithium batteries for almost ten years on various projects. There is at least one user on the Outback forum using SimpliPhi and SimpliPhi has specific settings that have been added to the latest firmware release on the Skybox.
I forgot if you mentioned whether you have to get building department approval, but be aware that the new 2020 version of NEC requires Energy Storage Systems meet UL standards. That may be an important consideration for future readers depending on when NEC 2020 is implemented by their AHJ (Authority Having Jurisdiction).

**df0rster** · 02-01-2021, 05:54 PM

Originally posted by Ampster

I have been using Lithium batteries for almost ten years on various projects. There is at least one user on the Outback forum using SimpliPhi and SimpliPhi has specific settings that have been added to the latest firmware release on the Skybox.
I forgot if you mentioned whether you have to get building department approval, but be aware that the new 2020 version of NEC requires Energy Storage Systems meet UL standards. That may be an important consideration for future readers depending on when NEC 2020 is implemented by their AHJ (Authority Having Jurisdiction).

We live in rural NE Oklahoma and there are no inspections around here. Even when we lived in a nearby town there wasn't anybody to do inspections on electrical work.

That being said, I want to comply with all of the safety standards and electrical codes. I'm not sure if you mean that some of the batteries are not UL approved, or if a particular setup would have to meet those UL standards if it were inspected?

So what are your preferred lithium batteries for use with your setup? I do want to start out fairly small, in the less than $5k range if possible. I'll have a generator for longer outages and we could squeeze half a day out of 4kwh without much problem.

**Ampster** · 02-01-2021, 08:37 PM

Originally posted by df0rster

........... I'm not sure if you mean that some of the batteries are not UL approved, or if a particular setup would have to meet those UL standards if it were inspected?

I don't know much about any of those batteries except that SimpliPhi seems to have a longer track record.

So what are your preferred lithium batteries for use with your setup? I do want to start out fairly small, in the less than $5k range if possible. I'll have a generator for longer outages and we could squeeze half a day out of 4kwh without much problem.

I have always used DIY Lithium cells from a variety of manufacturers and wired up a BMS. Initially they were costing $300 per kWh but now I have found a reliable source from China through Alibaba. Not many people want to take those risks but for less than $115 per kWh I am willing to take that chance. I already have the BMS from an earlier project. The only other name I have heard good things about is Battleborn but the prices I have seen are higher per kWh than you quoted. The good thing about Lithium is you can expand with the same batteries with no issues.

**df0rster** · 02-02-2021, 12:56 PM

Originally posted by Ampster

I have always used DIY Lithium cells from a variety of manufacturers and wired up a BMS. Initially they were costing $300 per kWh but now I have found a reliable source from China through Alibaba. Not many people want to take those risks but for less than $115 per kWh I am willing to take that chance. I already have the BMS from an earlier project. The only other name I have heard good things about is Battleborn but the prices I have seen are higher per kWh than you quoted. The good thing about Lithium is you can expand with the same batteries with no issues.

Thanks for the info!

I've been watching some Youtube stuff on putting the batteries together. The guy I've been watching just buys the 3.2v 100ah cells off ebay and puts 4 of them together to make a 12 volt 1.2 kwh. It doesn't seem too bad, the balancing is what seems to take some time. and I'm sure there is some cost in the rest of the BMS, not sure what all is involved yet.

I love doing little projects like this, I may buy some cells and make a 12 volt battery and see how it goes. The prices I see on ebay (usually from China), are a little less than $300 for 4 cells totaling about 1200 Wh, so the price would be about 22 cents/wh. so about 5x less than the commercial 48v batteries. So if it works out well I would have about 5 Kwh for $1200.

Any other tips you might have are appreciated!

**scrambler** · 02-02-2021, 03:16 PM

I recommend you look for an LFP battery (liFePo4), rather than Li-ion. They are a little bigger, but they have a much safer chemistry.

**Ampster** · 02-02-2021, 03:16 PM

Originally posted by df0rster

..........

Any other tips you might have are appreciated!

Yes I have lots of experience with Lithiums and would be happy to share. I seem to catch some flack here because I seem to be one of the few advocates of Lithium remaining on this site. Most of the others interested in that technology have gone to other forums. There is a definite bias toward Pb batteries on this forum. That is a good thing if you want more knowledge about that chemistry. Nothing wrong with the advice here and I have learned a lot about the other aspects of solar energy systems in my years here. I have no interest in additional knowledge about Pb batteries.

You will get different advice from other Lithium users in other forums. I will let you decide if it is better advice. Ironically I drive two EVs and have driven EVs since 2012 and all of them use Pb batteries for their 12 volt storage to boot the electronics. Pb batteries will be around for years to come.

As I may have mentioned I belong to a number of forums and each have their strengths and weaknesses. I am appreciative that Pete has made this forum available for the sharing of knowledge.

**df0rster** · 02-02-2021, 03:17 PM

Originally posted by Ampster

I have always used DIY Lithium cells from a variety of manufacturers and wired up a BMS.

I actually found a fairly local guy selling the 280ah cells (3 hours from me). He said I could buy 16 of them for about 14kwh for $2100. That sounded very reasonable to me. He also matches or balances them before selling them, and sells with buss bars and screws. I'm sure he resells a lot from China, but I'd rather deal with someone local than trying to find my own supplier on alibaba, been through that before and it takes some trial and error!

What do you suggest I look at for a good BMS?

**scrambler** · 02-02-2021, 03:23 PM

RV DIYer sites usually have references of good Cells and BMS you can buy to make your own.

**df0rster** · 02-02-2021, 04:03 PM

Originally posted by scrambler

I recommend you look for an LFP battery (liFePo4), rather than Li-ion. They are a little bigger, but they have a much safer chemistry.

Good to know. The 3.2v 100ah cells are very common on ebay and are LiFepo4. Not that I understand the different chemistrys..

**Ampster** · 02-02-2021, 04:41 PM

Originally posted by df0rster

I actually found a fairly local guy selling the 280ah cells (3 hours from me). ....

What do you suggest I look at for a good BMS?

Those appear to be the same cells I have been purchasing during the past nine months. If the model number is LF280 they are LFP chemistry which is the safest Lithium chemistry. He may be a familiar poster from one of the other forums that I am active on. He has a good reputation. He may also have a BMS recommendation.

A good BMS is one that meets your needs. As @Scrambler mentioned there are lots of helpful discussions out there. I use different BMSs for different systems. As far as I know, none are able to communicate with the Skybox directly and I have posted my approach on the Outback forum and received input from other Lithium battery users

**df0rster** · 02-02-2021, 06:29 PM

This guy is a truck driver in Kansas. A few hours from me. He and his brother sell batteries on the side. Has a good rating on eBay.

so do you mean the skybox wouldn’t work with the diy battery packs and bms without some workaround? I was hoping it would just charge them like my simple charge controller fla setup I used to have in my shop. I guess I can deal with batteries after I get everything else working.

**Ampster** · 02-02-2021, 07:23 PM

Originally posted by df0rster

This guy is a truck driver in Kansas. ....... .

Is this the guy? If so he is not the one I was talking about but there are several sellers in section of that forum.
https://diysolarforum.com/threads/ne...a-texas.17611/

My Skybox works fine with Lithium batteries. I am am happy to answer your detailed questions later when you decide on which BMS.

**df0rster** · 02-02-2021, 09:53 PM

Originally posted by Ampster

Is this the guy? If so he is not the one I was talking about but there are several sellers in section of that forum.
https://diysolarforum.com/threads/ne...a-texas.17611/

My Skybox works fine with Lithium batteries. I am am happy to answer your detailed questions later when you decide on which BMS.

No. The guy I found lives in Kansas and offered to sell me 16 280s for 2100 total. So I better make sure they are not b grade because now it sounds too cheap for in stock cells.

**Mike90250** · 02-02-2021, 09:56 PM

Just to make a fine point. This forum does not discourage Li based batteries. But this forum discourages Ampster's style over simplification of what is required to make a Li system safely work near a house.
Li batteries have the potential to have a very long life. They also need a well engineered BMS to insure nothing goes too badly wrong. Li batteries are very picky about under or over charge, and because they have such a flat voltage curve compared to lead acid batteries, many LA based systems can only crudely charge them and require individual engineering of just about every system.
A well engineered BMS should reliably outlive the Li battery it's monitoring. Cheaply made gear with lousy wire harnesses are unlikely to last as long as the battery can. in the future, that should improve but for now, it's a mess. Like the nearly brand new Skybox, which sort of works with Li batteries
(LiPo4 is the safest form, but it's not completely safe, and other styles of Li batteries can rapidly become unsafe)

Li battery recommendations

Li battery recommendations

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