LEV60F 48V DIY Build

[rtsbars]

Hello. Can anyone suggest a BMS and adjustable charger for a 48V pack made using LEV60F 3.2v 74ah Lifepo4 Power Cells. I was looking into ordering a JK BMS 300 Amp (JK 300A BMS B2A24S30P-HC 7S-24S 2A Active Balancing for LiFePO4) based on other reviews...It sounds like folks have had success and recommended this one. So that is one option I'm considering. I would also like to find a reliable, very safe charger that is adjustable current / voltage so it can be set around 55.2V to 56V for this pack. The LEV60 cell range is 2.0-3.5V (nominal 3.2V). Thanks in advance for any recommendations.

 

[Justkeepitsimple]

I am in the study phase of doing almost exactly the same thing. It’s my first go at a diy raw cells to battery assembly. I like the LEV60F made in Japan cells. I figured there’s got to be a way to make a good lithium battery without buying questionable Chinese cells or overpriced pre-assembled battery. Any progress on your project or BMS selection ? I also saw those BMS on the same site that’s selling the cells. I would kind of like to get a BMS of better known quality. Not saying that one may not be fine just weird to throw a random Chinese name BMS on some nice Japanese lithium cells. So much of this new stuff from China. So little chain of a accountability with it.

 

[Justkeepitsimple]

Upon further research it appears there are two potential issues with these batteries others may want to keep in mind if considering using this LEV60F type of lithium cells:

1) According to anecdotal information and the one spec sheet I was able to find they are a sort of unicorn in the lithium battery world. They were engineered to use as a replacement to the standard lead acid starter battery. They can deliver unusually large amounts of current (for lithium) in brief surges. This design philosophy choice may negatively effect the longevity of the material engineering of the cell design when used for stationary solar storage. They also take a lower top end charge voltage 3.4V per cell to full charge and not more than 3.5V per cell to top balance. A higher top end charge may damage the cells. (Most lithium likes 3.6 volts per cell to top balance). This means you need a programmable BMS and the capability to configure one properly.
2) The ones on the market appear to be a surplus of new old stock from 2019-2020; and therefore are already subejected to 4-5 years of idle calendar aging degradation at this point. No telling how good they really are if they been stored at elevated temperature of a cheap warehousing solution.

TLDR;
-May not last as long as a “storage” lithium celled battery

-Requires a programmable BMS to accommodate unique charge profile. (Top end charge/ top balance charge is lower than most LIFEPO4 cells).

-Batteries on market are likely a large batch of old stock from 2020-ish. 4-ish years of Calendar aging degradation to start with and unknown temperature storage conditions.

 

[rtsbars]

Yes, I did buy the JK 300A BMS B2A24S30P. Just received it today. Good info. on the cells. I'm still searching for the charger, and that was my concern as to not overcharge the cells. I was wondering if the standard Lifepo4 charger would be a problem as they typically go up to 58.4V. I'm using mine for a golf cart lithium battery. Some folks on Buggiesgonewild have recommended getting an adjustable DC power supply for this reason, so as to be able to set the voltage and current. I'm having trouble finding one because most are made in China and there seems to be so many out there it's hard to find quality. I called one place and was looking at TEquipment website for DC power supplies. Siglent (one of the mfr's) said their unit would not have over-voltage protection?? [Note that the supply does not have built-in monitoring and control to specifically protect the battery from overcharging and damage.] Just the information I have so far...

 

[Justkeepitsimple]

I was planning to use a Victron Mppt Solar charge controller to charge my lithium batteries primarily. Victors charge settings are easily customizable through the Bluetooth app. A power supply may be a good option if your willing to monitor it closely through the charge profile. (Don’t want overbulk it ie: leave it in constant current for too long). A true battery charger would be the best option. Don’t know do they make settings adjustable LiFePo4 battery chargers 48V?
I know of Victron has the Phoenix Series chargers which would be perfect for your use case but they only come in 12 volt and 24 volt models.

https://www.solar-electric.com/lib/wind-sun/Manual-Phoenix_Smart_IP43_Charger_120-240V.pdf

They have user defined mode where you can customize every variable of the charge algorithm.

I am still somewhat contemplating using the Japanese cells. Even if the cycle life is a half or a quarter of standard LiFePo4 new cells @ $22 ea. it may split even vs. buying new EVE cells and be a low risk way to try learning building a battery. Even if they only deliver a 1500 cycle life it works out way cheaper than new good lead acid.

Someone turned me on to this option is another post I made inquiring about good battery cells. Apparently these do not require compression or addition cell separator insulation. Also a good price, albeit used cells. https://batteryhookup.com/products/...1&_sid=a8b0ff29b&_ss=r&variant=40777326362786
Meh. Looks like they sold out actually.

My planned use case application for the battery bank is an independent secondary workshop solar system. Leaning toward 12 volt as I already have a perfect sine wave inverter for the mini system. Got to figure out an appropriate 4 series BMS and balancer solution. Hope to build about a ~400 Ah twelve volt bank. Need a BMS for each series string of cells.

Less BMS cost to do a higher voltage battery up front. The whole point of my intended project is to build a mini 12V system around recycled hardware after upgrading main system to 24 volt.

 

[rtsbars]

I was considering similar cells as well (CALB); however, I couldn't get past the risk of used batteries and not knowing the condition. FYI... Something I learned was there is a CALB USA store, which could be considered. At the end of the day, I ended up going with the Japanese made cells due to what I heard about quality and the price seemed good. Just took the risk on the calendar aging... We will see how it ends up going. I became increasingly frustrated by all the different companies selling Chinese made cells and it seemed like it was hard to find a trustworthy seller. Ask for a test report with recent production dates...Most of them were 1.5 years old that I received.

So I take it you would make 5 or 6 series sets of 4 cells each for each 12V set. (I.E. Weighing the cost of BMS vs other costs of a higher voltage system and buying equipment needed for that set up). So you would be monitoring 5 or 6 separate BMS units?

I haven't seen an adjustable lifepo4 charger; but, I have seen where it's possible to input a user specified voltage when ordering a lifepo4 or lithium charger from a few different companies on Aliexpress. So, it would be possible to order a 55-56 volt lifepo4 charger. However, I am skeptical of the quality.

 

[Justkeepitsimple]

Yeah it’s a jungle out there. Chinese cell manufacturers industry seems cutthroat and bipolar. Life cycle seems to go like this: Battery cells good quality, get popular, manufacturer cuts cost to maximize profits, quality tanks. Manufacturer sees popularity of rivals good cells, counterfeits color shape and qr codes with clever one letter change rebranding. Old/ used cells get a cosmetic cleanup and sold as “new”. Grade B cells get sold as 20,000 cycle capable marketing hype. Just seems like such a gamble. The Chinese economic cultural mentality is cutthroat and lacks any steadiness. I don’t know . At this point I feel like I’ve learned a lot but it’s not making sense for me to build 4 or 5 12v batteries with the BMS cost. I’ll wait until we onshore some lithium production and I can buy cells from someone who speaks my own language or by then there may be another battery chemistry worth experimenting with. Don’t know. Just seems like the direction china wants to take free market capitalism is incomparable with my values and cultural philosophy.