Sprintpack Lithium Ion batteries

[jefferso]

My ventilator has a battery pack which takes two long thin Li-ion batteries. It's made by a company which seems to have gone through a number of name changes. Pulmonetic, CareFusion, Vyaire, Aquilant, Healthcare21.
Each LTV Sprintpack Ext Battery is about 9 x 3 x 1in (23 x 7.5 x 2.5cm) with 6.6Ah each at 14.4 volts. I think they weight under 1kg each.

The batteries cost around £230 each ($350 in US) new. When new each will drive the ventilator for about 3.5 hours. I have them on the back of the ventilator on the back of my chair so if the chair battery ever ran out, I'd have another few hours of breathing support (since they stay charged all the time when the chair powers the vent).

Does anyone have a guess what kind of cells might be inside them?
The label says Cells made in Korea, assembled in Mexico
There is a company which offers refurbishment on ebay, https://www.ebay.co.uk/itm/264664856800 for $720 for a pair (more expensive than new?).

I have a few dead ones now (a few nearly 15 years old) so maybe I'll try taking one apart if I can figure out how to without tearing the casing apart too much.

[shirley_hkg]

Very likely 4 of this Lithium-ion cells in series inside.

[shirley_hkg]

A power bank of same voltage will also work.
Charge it via BMS or PL8.

You can swap to LiFePO4, which is safer and will last forever. (outlast your ventilator at least)

Pack of 4 cells below will give you 20--30 hours of run time per charge.


https://www.wheelchairdriver.com/board/ ... 69#p207369

[Burgerman]

Or it will likely be full of simple 18650 cells.
I use them all the time for various things.
Again easy to replace.
There will be 3 parallel, and 4 series. 12 CELLS TOTAL.

https://www.fogstar.co.uk/collections/18650-batteries
Open to check which type.

You can solder these, I have been doing that since they came out in the mid 90s. Same type of cells used in laptops and 101 other things including teslas... They use 21700 cells (a little bit bigger.

It should be ossible to make a pack that is bigger Ah in the same case. Cells iproves some and larger capacity up to 3.5Ah 18650s are available now. Your ventilator takes about 1.9Amps. So a 2Ah cell lasts about an hour.

Those eBay replacements will soon be 720 + trumps 25% import tax from mexico, starting today? And so after adding the us companies percentage will be a grand ir more...

You could likely also fit common hobby lipo batterry packs. Those are already assembled. You need low C ones, used in quadcopters etc.

[shirley_hkg]

I thought in the wrong direction.

12 18650 cells @2,200mah, which are common a decay ago. That met the physical size and specs with 3p4s setup.

Then, local computer (notebook) repair shop may replace it with new cells.

Of course, now you can replace with 3,500mah cells, that boost Ah up to 10.5Ah.

[Burgerman]

3 x 4 isnt 14! =12.

[jefferso]

Thanks. Looks like I'll have to open an old one.

I got a quote of £300 each for replacements, but their stock is "a few years old" and their supplier has discontinued them, so I guess that will be the only way to replace them going forward.

The SprintPack battery pack and LTV ventilator is certified for use during flights (including takeoff and landing) so it's unfortunate they're discontinued.

I have a letter with RTCA/DO-160F Sections 20, 21 Certification for it which I used to show when flying.

[c500user]

I use a Breas Vivo 50. It has an internal battery (up to 4 hours) and a so-called click-on battery (up to 8 hours). The click-on batteries are 192Wh, so illegal to use or bring on a plane according to the IATA rules (max 160Wh).

I needed to take a long flight (Europe to Australia) and was not allowed to use on-board power (liability issues probably), so had to bring enough battery power for 36 hours. Sealed lead-acid was way too heavy.

The Vivo click-on batteries are rated 36V. I opened one up and it contained 2 banks of 10 Samsung 2600mAh Li-ion cells. I had a few old click-on batteries and asked a repair shop (they repaired TV's and other electronics) to replace the old cells with new Samsung cells of a lower mAh rating to stay under the 160Wh maximum. He installed Samsung 2200mAh which gave me 159Wh, just within spec.
I also asked him to supply each "downgraded" click-on battery with a certificate (printed on letterhead paper), specifying the serial number of the click-on battery, that stated he had "downgraded" them to 159Wh each to comply with IATA regulations. The airline accepted this without any issues.

Although changing to LiFePO4 would be nice for safety and longevity, I don't know how critical the voltage of the pack is. Four LFP's might be ok when they are full, but at which (voltage) point does the ventilator assume the pack is empty and disconnect?

Luckily, I can still get new click-on batteries, so unless I need to fly again I am not bothering going down the "replace cells" route. You don't have that luxury, so I would open up an old one and you will probably find standard 18650 cells, just like I did.
Whatever you do, don't opt for cheap Li-ion replacement cells. It has to be safe and reliable, so ensure that good cells are put in. My experience with the Samsungs has been fine.

[Burgerman]

There are good quality branded samsung/panasonic etc 3500 and 3600mAh 18650cells available now. So a swap of cells might be quite a worthwhile option.

[Burgerman]

He installed Samsung 2200mAh which gave me 159Wh, just within spec.

2 strings of 10.
So thats 20x 2200mAh @3.7V nominal, or 2.2Ah x 3.7 x 20 cells if you prefer, = 162.5wh.

But its all a technicality anyway. You could fit the 3600mAh cells, get extended use, 266watt hours. And nobody could ever know the difference.

[Burgerman]

Voltage at which it cuts off is determined by either the device or the BMS that it must use.
Full charge voltage is 10S so 4.20V. Lowest safe discharge level on those cells is 3.00V. So 30V.

So absolute limits of working voltage is 42V down to 30V. It likely cuts off a little above this point.

LiFe would need 12S so 2 extra cells. If you used the stock charger that will charge at 42.0V and allow the BMS to balance etc. You will need a 12S BMS for the LiFePO4 and thats 42V div by 12 or a perfect 3.50V per cell charge voltage. At that level they will end up full, take a little longer, and last a very long time.

LiFe lowest possible voltage is 2v per cell. But 2.5V per cell is the safest daily usaable level. And guess what? Thats the same 30V as your Lithium Ion cells are now.

So it will work out perfect with 12S. It will read lower on its battery fuel gauge sooner. Then it wont drop as fast for 2/3rds of the charge. And then at the end will start to catch up.

[jefferso]

I finally got one of these cracked open. It seems like it's glued shut, not just snapped together, so the plastic had to be broken to get inside.
It has 12 CGR18650CG Li-ion MH12210 cells.
It seems like at least one in this set is split open.
It might be a gamble to even replace the cells to see if the attached electronics still work. £60 or so for the 12 cells to try. I can't tell yet if they're soldered or if the connector strip is just stuck on with adhesive.

[Burgerman]

Those are when new 2250mAh.

You can relace with various 3000mAh ones, and even soe 3300, 3400 ones.

So could gain a 50% increase in run time over a new pack. I use a few different 3000mAh 16650 cells here for hobby stuff.

They will be spot welded with a nickel strip.

Toy can but the nickel strip in rolls on ebay/amazon. Also you can spot weld them but you need a cell welder... So I ust do what they say you cant and solder the nickel strip. Its fast and easy. Never had a problem doing that.

[Burgerman]

Buy from hobby shops or vape shops, molicell, sony, panasonic, samsung, ignore the rest!
Beware many fake capacities on ebay, amazon etc.

https://www.hobbyrc.co.uk/sony-vtc6-300 ... 18650-cell

For e.g.

[jefferso]

These EVE cells are significantly cheaper at a place you sent a link to previously. I think EVE made the LiFePO4 cells I got.
Are they likely to be significantly lower quality?

https://www.fogstar.co.uk/collections/1 ... -18650-35v

https://www.fogstar.co.uk/collections/1 ... ts/eve-25p

[shirley_hkg]

Look for big names, Panasonic, Sanyo, LG, Sony …

Here we can order assembled pack.

With connection strips pre-
welded cells @£2.5, so you can diy at home.

[Burgerman]

These EVE cells are significantly cheaper at a place you sent a link to previously. I think EVE made the LiFePO4 cells I got.
Are they likely to be significantly lower quality?

https://www.fogstar.co.uk/collections/1 ... -18650-35v

https://www.fogstar.co.uk/collections/1 ... ts/eve-25p

Maybe but never had any so cant really say.

[jefferso]

I never made progress on this project of replacing the 18650 cells on these battery packs and I'm not sure when I'll have time. Does anyone know a shop or someone who might be able to do the work of replacing the cells in a couple of these battery cases?

[ex-Gooserider]

You don't say where you are at (it helps if you add that in your profile...) but here in the US, there is a big chain, Batteries Plus https://www.batteriesplus.com that may be able to help you - I have never done business with them but my understanding is that one of their services is putting new cells into old pack shells. Of course they will probably want you to buy the new cells from them, but might be an option...

ex-Gooserider

[jefferso]

Thanks. I'm in Northeast London in the UK.
I remember reading something about a local "Maker space" that seemed like it might have some people who would like that kind of project but can't find it now.
Batteries Plus looks interesting. Maybe if a friend or relative is going to the US they could try it, but shipping with those batteries might be a nightmare.