Anyone care to comment? Used LiFePo 12v batteries from medical equipment?

[Martinjmpr]

A woman in our camping group sent this link to me:


138 AH from such a small package is appealing. The 'story' I heard is that the various safety rules regarding medical equipment require medical providers to dump these batteries when they still have 80% of their useful life so there are (supposedly) a lot of them on the market.

Anyone tried it? I tried doing an eBay search but I wasn't able to find the "bargain" batteries he is talking about in the video.

EDITED TO ADD: Now that I look at the video I see the ones he is using are actually the 40ah versions. I tried doing an EBay search for the Valence batteries and the best price I could find on the 138ah was $499, so not really the "bargain" that the video made it out to be.

Current eBay auctions for the 40ah versions are running between $150 - $400 so I'm not sure "dirt cheap" is an appropriate description. If you wanted to spend $400 on batteries you could just buy a 100ah FLA battery for $100 and replace it three times.

 

[jonyjoe101]

lifepo4 is expensive, average price is about 1000 dollars for 100 ah. If you can get 40ah lifepo4 for 200/300 dollar that wouldnt be too bad, a goalzero 400 lithium is in the 600 dollar range and that is also 40ah.
40 ah lithium is comparable to a 80ah lead acid and maybe weighs about 15 pounds.

I been using lithium li-ion and lifepo4 for the past 3 years, would never go back to lead acid. I build my own but if I needed a drop replacement I would definitely be looking at 40ah batteries, you can parallel them and make a giant 100 plus ah battery. My 220ah lifepo4 is actually 4x 55ah batteries hooked up together in parallel. They will outlast any lead acid.

 

[shade]

A woman in our camping group sent this link to me:


138 AH from such a small package is appealing. The 'story' I heard is that the various safety rules regarding medical equipment require medical providers to dump these batteries when they still have 80% of their useful life so there are (supposedly) a lot of them on the market.

Anyone tried it? I tried doing an eBay search but I wasn't able to find the "bargain" batteries he is talking about in the video.

EDITED TO ADD: Now that I look at the video I see the ones he is using are actually the 40ah versions. I tried doing an EBay search for the Valence batteries and the best price I could find on the 138ah was $499, so not really the "bargain" that the video made it out to be.

Current eBay auctions for the 40ah versions are running between $150 - $400 so I'm not sure "dirt cheap" is an appropriate description. If you wanted to spend $400 on batteries you could just buy a 100ah FLA battery for $100 and replace it three times.

For perspective, a new 50Ah Battle Born LFP battery is $575. If you look at some of Will's videos, he has recommendations for other batteries, too.

IMO, buying a used battery is a crapshoot, especially online. You have no idea how that battery was treated, and it was pulled out of service for a reason. If you can find a reputable seller that honors a reasonable return policy, you may be able to save some money without too much risk of being stuck with a lithium powered doorstop.

 

[DaveInDenver]

For perspective, a new 50Ah Battle Born LFP battery is $575. If you look at some of Will's videos, he has recommendations for other batteries, too.

IMO, buying a used battery is a crapshoot, especially online. You have no idea how that battery was treated, and it was pulled out of service for a reason. If you can find a reputable seller that honors a reasonable return policy, you may be able to save some money without too much risk of being stuck with a lithium powered doorstop.

From what I know about critical applications the reason for a scheduled replacement period is that it's assumed the user will neglect something to the point of considering worst case as typical. So with a battery you may have to assume it was routinely run flat and timely charging forgotten, e.g. abused. How abused would seem to depend on the the application and how aggressive the preventative replacement is. If you could source them solely from ventilators and defibrillators I think would be better than pulse-ox machines or something like that.

 

[luthj]

Those batteries usually have an easy life (for lithium). Low temp indoor usage, minimal shock loading (no vehicles). They are generally run until the unit says "charge me" then recharged and cycled again.

For 150 per 40AH (30 usable due to age). Its worth a look. Mobile power packs etc could use them. Heck most of the "I need to run my fridge" Expo crowd could get by with one of these and a split charge relay!

 

[john61ct]

If the price is right, say well under half of new

and the seller has an excellent rating history combined with high volume

**or** you have the gear and knowledge to do a capacity test using precisely timed CC rate load discharging within a week or two of their arrival, trusting the eBay/PP guarantee

then risks are lower than importing from China.

Valence has an excellent rep, and pretty sure the internal BMS on those units keep a log of cycling history.

Coming off fleet truck e-APU is another good source, see more and more of those coming online now.

 

[john61ct]

From what I know about critical applications the reason for a scheduled replacement period is that it's assumed the user will neglect something to the point of considering worst case as typical. So with a battery you may have to assume it was routinely run flat and timely charging forgotten, e.g. abused.

The internal BMS on these will prevent most / the worst of such abuse.

Unless they were just stuck in high-temperature storage never getting topped for many months, with the BMS left on.

IMO very unlikely

 

[john61ct]

If you wanted to spend $400 on batteries you could just buy a 100ah FLA battery for $100 and replace it three times.

Yes, the best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club. Deka labeled same batts also sold at Lowes.

But a decent LFP bank usually costs many thousands, even second-hand should only be considered if you'd consider going to LFP new good value.

 

[luthj]

Those batteries look like they can be chained together via data cables. I wonder if they can be run in series for higher votlages, and then self balance each battery in the chain? Thats currently a big limiter for higher votlage systems made from chained drop-ins. Each battery needs to be balance charged, or one will eventually drop out due to SOC drift, requiring user intervention.

 

[DaveInDenver]

Those batteries usually have an easy life (for lithium). Low temp indoor usage, minimal shock loading (no vehicles). They are generally run until the unit says "charge me" then recharged and cycled again.

What do you think is using these batteries? They seem pretty large to fit inside anything so I assumed they came from ambulances, powered wheel chairs or something like that.

 

[luthj]

Patient lifts, floor scrubbers, breathing machine backup power.

 

[luthj]

Here is the common use for the valence battery , a mobile medical computer cart.

 

[MapJunkie]

These are the best batteries you can buy new, and the most expensive. If you can get them from and eBay seller that has tested the capacity, you could get lots of years of life. They have a great built in BMS that will protect them from severe discharge. I have a set of two I bought used, and they in parallel have 90aH of capacity. This is higher capacity than they are speced for. I have 50 cycles on them, and they are working great. Feel free to DM if you have specific questions.


Sent from my iPhone using Tapatalk

 

[Martinjmpr]

These are the best batteries you can buy new, and the most expensive. If you can get them from and eBay seller that has tested the capacity, you could get lots of years of life. They have a great built in BMS that will protect them from severe discharge. I have a set of two I bought used, and they in parallel have 90aH of capacity. This is higher capacity than they are speced for. I have 50 cycles on them, and they are working great. Feel free to DM if you have specific questions.


Sent from my iPhone using Tapatalk

Where did you get yours? Only source I'm finding is the above-mentioned eBay auctions which seem to be kind of hit-and-miss.

 

[Martinjmpr]

Those batteries look like they can be chained together via data cables. I wonder if they can be run in series for higher votlages, and then self balance each battery in the chain? Thats currently a big limiter for higher votlage systems made from chained drop-ins. Each battery needs to be balance charged, or one will eventually drop out due to SOC drift, requiring user intervention.

I'm not 100% certain but I believe the data cables are for the Battery management system (BMS), not for the battery voltage. If you watch the video above you'll see that he connects the data cables but he ALSO connects the batteries together at the terminals using standard battery cables like you would with any other big battery. In the video he is connecting them in parallel, don't know why you COULDN'T connect them in series, I suppose, if you needed a 24v battery for some reason. Why would you need higher voltage than 12?