Lift batteries

[hotwheels_75]

I have a lift that takes 2 x 12v batteries. They’re little rectangle batteries. 12v 2.3ah. 7” long, 1.3” wide and 2.6” tall. Wondering what settings I would use on my revo charger to try to revive/condition them? Probably a lost cause but thought I’d try. They sat for a few years. I somehow have 3 batteries, one appears to be ok the other 2 only had 1 - 2 volts. Had them on a regular 12v charger but that malfunctioned and died.

[Burgerman]

The ones that reads a really low voltage you should just throw away.
If you do want to try it then first connect each to one of the other good batteries for a while until the charger can see the battery has the right cell count.

Set charger to 14.4V CV and to .5A (500mA) and set to manual termination of as low as it allows. And no time limit. If after a day it has dropped to a few mA then its done! At least as much as its possible. If it drops to a low current then starts rising again, its toast.

When you capacity test it it will still be junk.

As for the others just set the same but terminate after 8 hours.

[hotwheels_75]

Thanks for the info. Decided to take your advice and just toss them and order 2 new ones.

[Burgerman]

I keep looking at swapping them out (lift batt) for a bunch of 18650 or 21700 Lion cells. Fit and forget with BMS as they work ok on lithium ion. 21700S at 5Ah fit eaily enough. Laptop style. Would get around 5 times the number of lifts. So only having 500 cycles would still last 5 times longer. Both in operating time before needing charge and service life.

When my camera and lens budget gets "caught up" £££... That wasnt a cheap xmas present. Currently re-saving my rainy day cushion. Need about another 3.8K before I feel comfortable. If I dont have 5k in reserve I am not doing it right. You never know what may be needed and I dont do loans. So no battery just yet. Also want to do the Salsa and Q700 with x 230Ah lifepo4 packs at once at the same time.

[Burgerman]

Just checked with ruler...
14 of the 21700 cells just fit in these common sized lift battery casings.
So say, 14 of these, https://www.fogstar.co.uk/products/vapc ... 00-battery
This is 7 series, 2 parallel.
That will gve a much much better performance, as you get around a 3A draw when lifting a human.

So the tiny lead battery it uses is hammered as thats around 1C or the same as pulling 70A continually from a 70Ah lead brick. At 1C that would give around 1/4 of the rated capacity! Meaning you really have a 1Ah fuel tank with lead.

This 14 cell 21700 pack will fit same case (just) require a BMS for balance only, and will allow you to have 10 Ah. So it will give you at least 10x as many lifts. And lithium doesent care about being sat discharged. So charge it every few months if you can be bothered. Should then last many many years. At that rate I wont bother with a BMS or he lift charger. I will charge every month or so with the PLB so will leave a balance tab hanging out underneath. Where it cant be seen.

Just in case you want to do yours! Makes it almost fit and forget. Downside? £96 so theres that! What price freedom from charging for months at a time.
Charge 4.2V per cell.
Discharge to lowest 3.6V (3.7V for safety which will be about a weeks use earlier)

[ex-Gooserider]

I have also heard of a few folks using 24V lithium cordless power tool batteries as a relatively cheap and cheerful approach for lift type loads - they at least claim that they will give about as many cycles / charge as the lead bricks, and recharge much faster... Biggest challenge might be to make an adapter / mount to fit the batteries as they all tend to be different... However I think that at least some have 3D printer files available (check on Thingverse, etc...)

ex-Gooserider

[hotwheels_75]

Both good ideas. But I’m selling the lift so just opted to chuck the failed/failing batteries and order some new ones, if they ever arrive.