identifying some cells

green1

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I have access to a large number of "junk" battery packs from medical equipment. Due to the highly regulated industry, and how they are taken out of service with the slightest hint of lost capacity, I expect to find a good number of high quality cells this way.

My first challenge however is identifying them. Each battery has 9 cells in it and is stamped "11.1V 5.7Ah 63Wh" The cells themselves look like Sanyo UR18650Ycells from the database (though I'd call the ring yellow rather than green?) But they don't say UR18650Y, instead they have a "B" near the top, and thenlower down they say"PD5V32" followed by a number that's different on each cell (possibly a serial number?) There is no other writing anywhere on the cells.

Any of this ring a bell for anyone? searching that PD5V32 on google or on this site gave me nothing, and it seems like I should find out more to be able to properly test/re-use these?
 

green1

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floydR said:
ok already looked in the database :)
Yup, already looked. Looks identical to the SanyoUR18650Y though I'd call it yellow rather than "light green" but the difference in colour wouldn't show up on camera as everyone's monitors are different.


image_hyglhk.jpg

image_gouxgt.jpg


I have to assumethey'rea Sanyo cells based on that, (though I could be wrong?)

Based on the numbers on the pack, they'd have to be 3.7v cells at 1900mAh (assuming I'm doing math correctly) Which would line up with the spec sheet for those UR18650 cells.
 

green1

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floydR said:
How many cells in parallel?
When were these medical batteries taken out of service?
The ring color looks like the cell below.
https://secondlifestorage.com/showthread.php?tid=3266
UR18650ZTA
Often times it is darn near impossible to see the inprinted codes on sanyo cells. have to hold them just right in the light.
Later floyd
It's 3 groups of 3, that makes 3.7v into 11.1V and 1900mAh into 5.7Ah.

The batteries I have now were taken out of service within the past month or two. More are available to me on an ongoing basis, usually within a week or two of being removed from service. a handful of batteries every month. They are taken out of service any time the charger shows a fault in the pack (red light vs green after charging) or any time the 4 LED strip on them only lights up to 3 after a full charge. Up until now they've been taken to the local electronics recycler, but I'm welcome to them as they are considered "garbage" by the health authority. (fair enough, any hint of a problem and you don't want to count on them in a life or death medical emergency, and in fact their contract with the manufacturer gives them a steady stream of new batteries whether they need them or not)

The ring colour looks like that cell, but the casing is a very different colour, but thanks for your tip about the light! I previously didn't see anything, but today I was able to (just barely) read the following:

Sanyo R1112
Japan P19B
 

floydR

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Are there different packs available if so I would suggest trying to finding ones with a higher mAh rating. But you can certainly make a powerwall from the cells. just takes more cells.

later floyd
 

green1

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While higher capacity cells would be nice, a large number of free cells from a reputable manufacturer and almost no effort on my part is too good to pass up.
As certification is such a pain for medical devices there is not likely to be much/any variation in the packs, and they're all the same capacity. If, in the future, this organization gets any new devices that use higher capacity cells (likely would only be a whole new device), I'd be first in line for the discards. But for the moment, the other devices they use are either ni-cd or lead acid (or alkaline disposables). As I said, certification for medical devices discourages minor improvements short of complete new versions of equipment.

Thanks for your help!
 

green1

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Apparently I was mistaken. There are 2 generations of battery pack. Most of the packs I have are full of Sanyo UR18650V, however some of them are UR18650E. The "E" packs are listed with a higher Ah capacity, but a lower voltage.

I've seen lots about how to combine different current capacity cells together. But how do you deal with cells with different nominal voltages? (the "V" cells are 3.7V nominal, but the "E" cells are 3.6V nominal) Both cells are designed to charge at 4.2V, but I don't know if that means I can ignore the difference in nominal voltages?
 

Overmind

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The V ones of 3.7V are normal current cells, older sanyos don't go over 0.5C (~1A), newer ones do.

The 3.6 E-ones are the high current ones, should give at least 10A.

Don't mix the 2 types unless you know exactly what you want to do.
 

green1

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Overmind said:
The V ones of 3.7V are normal current cells, older sanyos don't go over 0.5C (~1A), newer ones do.

The 3.6 E-ones are the high current ones, should give at least 10A.

Don't mix the 2 types unless you know exactly what you want to do.
I have found a spec sheet for the E cells with a rated max draw of 6160mA. I have yet to find a spec sheet for the V cells that includes this information, are you able to point me in the right direction?

I worry somewhat that to do any large scale project I won't have enough cells without mixing them, the question is, how to do it safely. (Again, lots of info around on mixing different capacities, not so much about mixing different nominal voltages)
 

Overmind

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6A is good enough.
Can you post a few pics with the others ?
Maybe we can find out more.

To mix them, it's a little complicated (assuming the others are low current).

You will have to make identical packs of parallels then put them in series to get what you want.

From here, you have multiple situations:

- when you don't exceed the current drain per low current cell - works continuously

- when you exceed it a little (and 6A ones will take the additional current) - here you may use the battery with pauses for re-balance (energy compensation transfer from 6A to the others) - works with breaks

- when you exceed it by a lot and the low current cells will overheat - not recommended - works only for quick bursts
 
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