Looking for a LiFePO4 over/undervoltage + overcurrent protection chip or circuit

[philpem]

Hi there,

I'm building up a couple of LiFePO4 packs (lithium iron phosphate, lithium ferrophosphate... whatever the kids are calling them this week), and I figure it'd be a good idea to have some under/overvoltage protection in there. I've done Li-ion packs before (where OVP/UVP and a Polyfuse are basically essential, and active balancing is a Damn Good Idea for multi-cell packs) using a multitude of protection ICs from the likes of Benchmarq (er... TI) and Dallas, and these chips and their brethren are even available off the shelf from the likes of Farnell now... but I'm having all on finding a chip which can deal with the lower voltage thresholds of LiFePO4 cells...

Does anyone know of any LiFePO4 cell protection chips which are fairly easily available?

Cheers.
Phil.

[IdahoMan]

Bump.

[Fungus]

Have either of you searched for "LiFePO4 charge module" on eBay?

[BFX]

May be? 
http://uk.farnell.com/texas-instruments/bq25071dqct/battery-charger-lifepo4-1a-wson/dp/2450195?ost=BQ25071&selectedCategoryId=&categoryNameResp=All%2BCategories&searchView=table&iscrfnonsku=false

182 in stock for next day delivery (UK stock)

[suicidaleggroll]

Do you need a device designed for LiFePO4 from the factory, or would a multi-chemistry solution that requires you to send some I2C/SPI commands to set voltage thresholds work for your application?

[moffy]

Have a look at the following: http://www.hotmcu.com/tp4056-micro-usb-5v-1a-lithium-battery-charger-with-protection-p-176.html

[Chalcogenide]

Have a look at the following: http://www.hotmcu.com/tp4056-micro-usb-5v-1a-lithium-battery-charger-with-protection-p-176.html

TP4056 and DW01 are only suited for "normal" Li-ion/LiPo chemistries with 4.2V full charge voltage. LiFePO4 is a lower voltage chemistry.

[splin]

There's plenty of choice on ebay:

http://www.ebay.com/sch/i.html?_fspt=1&_mPrRngCbx=1&_from=R40&_sacat=0&_nkw=lifepo4+protection&_sop=15

and Aliexpress:

https://www.aliexpress.com/wholesale?spm=2114.01010208.0.0.BL3sFZ&site=glo&g=y&SortType=price_asc&SearchText=lifepo4+protection&initiative_id=SB_20161122142106&needQuery=n

Be careful though - some of these appear to be using Li-ion protection ICs with unsuitable voltages. One actually states that it uses a Seiko S-8261 G4E which cuts off at 3.9V.

If you really want chips the Ricoh R5478N184CJ and R5478N185C look like they should be suitable:

http://www.e-devices.ricoh.co.jp/en/products/product_power/bmu/r5475/r5475-e.pdf

Seiko have a number of ICs which at first appearance look OK with overvoltage detection voltages starting at 3.5V upwards but when you look at the datasheets they mostly all seem to start at 4V+.

http://www.sii-ic.com/en/semicon/products/power-management-ic/lithium-ion-battery-protection-ic/

Ones that might be OK include (I haven't checked them all) S-8240ACP-I6T1U, S-8211DAU-M5T1, S-8211DAR-M5T1U, S-8211DAS-M5T1U and S-8200ABK-I6T1U

Actually getting hold of any of these chips is another matter though and might require searching Taobao or the like. The Seiko S-8211 parts are actually listed by Mouser but labelled 'restricted availability' so probably a dead end. Digikey have MOQs of 3000 and no stock.

There are no doubt cheap Chinese devices but finding them may involve some detective work including examining device markings on the protection board photos listed on ebay/Aliexpress. Do let us know what you find.

[Solartracker2]

Hello,

I’m looking for spare parts by t I can’t find SMD codes:

358
G4EM / G4EN(?)
Blue little ‘fuse’ lifepo4 balancingboard

[cfbosch]

Hi everyone.

I'm also looking for a good protection solution, my application is a LiFePO4 battery on a gate motor.  But everything I can find costs more than the battery itself.

I found this unit, but it's waaaaay too pricey.

https://www.victronenergy.com/upload/documents/Datasheet-BMS-12-200-EN.pdf

I'm investigating doing something with a Mosfet to just disconnect the battery when the cell voltage goes below 2.8 V per cell.  I'll let you know If I have success.

[miceuz]

I was looking for the off the shelf undervoltage protection solution 2 years ago and did find nothing. So I had to roll my own.

[Dezmond2]

2.0 or 2.5 volt discharge cutoff?