Help should I buy used batteries?

[Honda lee]

Ok, here's the deal . I found 24 ea sonnenschein 12v 100ah for sale $40.00 ea seller says he bought 2 years ago from someone who was using them in a electric bus and they wer 2 years old when he bought them. His solar project did not happen they have been in his garage not being used but he says he has kept them topped off. He says he was told they have 75% of there life left ?I thought I would buy a batterie analyzer to check them out but looking at them on line you have to enter amp hrs on tester. Can these types of tester tell me what I need to know? I need to act fast so give me some advice if you can. Thanks

[mobile_bob]

my bet is they are agm batteries, maybe worse they are gell cells

if they are gell cells i would pass on them, but that is me

if they are agm's and you have confidence that they have been floated at the proper voltage
as evidenced by some form of smart charger and some form of racking that keeps the batteries up off the floor like someone cares about them, then the next step for me would be this

take a good voltmeter, something that reads to hundredths of a volt and check them all

i would want to see 12.6vdc at rest (at least) on all of the batteries that i would be buying, then

i would connect a 50amp load to each for 30 seconds and recheck the voltage, i would expect to see the batteries showing over 12.55vdc at least... any failing that test i would not waste my money on.  and...

any seller that would not allow these tests would not be getting my money.

40 bucks is a significant amount of money, and far more than most folks want to spend on batteries that are of little to no use?  at least for me.

about a year back i bought 4 such batteries i think they are the same you mention, i paid 15 bucks each for them on the basis that if they were of no use i could use them for the 15 dollar core charge they charge me for other similar size batteries around here. they were all nearly dead and i had little hope for them, i think the best showed 9volts and the worst 5volts... after a week of charging they all came back and are doing reasonable service on my test stand.  they were 4 years old, spending the first 2 years powering carts in a pharma lab, the second 2 sitting on some guys garage floor waiting to be put into an electric car project that never happened.

most of those batteries are meant as backup and not deep cycle batteries intended to provide hundreds of cycles?  at least i don't think so.   however if you have enough of them? maybe you don't have to cycle them so deep and they turn out to be pretty good for the money?

also, battery testers that need cranking amps in order to calculate will not work to test these batteries, nor will most other load testers that auto test them, unless you know how to use them.

bob g

[glort]

I bought a heap of N200 batteries from a Marina a few years ago. Most as I expected were toast but I did get 3 that were serviceable and were fun to play with for a few years till they fell over.
The upside was, I sold them all for scrap for more than I paid for them. I was a bit lucky as the scrappys were paying a LOT more for them at the time than they are now but I didn't think of that side of things when I bought them.

If you are unsure of these batteries, see what the scrap value per Kg is and offer the seller that or something close. That way if they do turn out to be no good, you aren't much out of pocket.

On that basis, You might even make the seller a lowball offer if any do fail your tests with the reasoning you'll take them and the risk to see if they come up at the reduced price.

[BruceM]

I can get new wet "marine" 110ah (rated at 1 amp draw) batteries at Walmart for $67 each last time I bought a set of 10. 
I think you're better off with a cheap new battery than fooling with used.   As it turned out, my winter daily DOD is rarely over 10% and I am getting 4 years out of a set (basically the shelf life of this type of battery).  I never did upgrade to AGMs, as I originally intended, as these served so well and were so cheap.  I'm now a couple years into my second set.

[mobile_bob]

it is hard to argue with success
thanks for the update Bruce

bob g

[Honda lee]

I have been watching on utube people using ebson salt to revive old batteries ,has any one here tried this?

[mike90045]

I have been watching on utube people using ebson salt to revive old batteries ,has any one here tried this?

It works, and you can get a couple weeks out of the batteries generally.  sometimes just enough time to get new ones bought and delivered.   I'd never add goop to a new battery under warranty.

[glort]

A bit different to the batteries in question here, but I have always bought used batteries for my Vehicles from wreckers for the last 20 odd years.
Pay anything from 20-30 Bux for them and the worst I have ever got out of them is a year.  Most have lasted around 3 which is all I ever got out of new ones anyway.

A couple of years ago I went and bought a new N70 battery for the wifes Diesel car which was oversize but I  moved some stuff under the bonnet to make it fit.  The thing cost $180 and didn't last 14 months. Took it back under warranty and they argued a bit with pro rata crap but did replace it outright with a new one. The guy came out to the car and tested the alt and had to admit it was spot on which was what I told him in the first place.

The replacement battery wasn't in the car long before I sold the thing and put a used battery I had in the thing which worked fine. Its just been sitting round powering projects since but I do keep the thing topped up very regularly.

Some months ago I picked up a few batteries off the side of the road around industrial areas. A couple seemed to come up OK. I put one in my wifes car when it's battery suddenly and inexplicably keeled over . I thought it may last a week or so but it seemed fine.  Took the car to my fathers workshop and put a proper battery load tester on the thing and it nearly smoked it. Very healthy battery indeed!  Someone probably replaced it when they had another problem not realising till later the battery was perfectly good.

As for recoing, Many years ago I tried " reconditioning " batteries by tipping all the acid out and washing out all the precipitate that had dropped to the bottom of the cells. There was loads of the stuff that came out and it took a long while to remove it all. I refilled with new acid and gave the batts a good long, slow charge. Some came up OK but you could see through the cell caps that there was a lot of the plate eroded away not to mention the piles  of lead waste left on the lawn.
I had one in a car I drove for a while before selling it and it started the car OK but was way down on capacity and ran down easily.

[Honda lee]

I have been viewing utube on batterie reconditioning and saw a lot of videos of people adding ebson salt and getting new life.has anyone here tried this?

[glort]

If you try it, you might want to ask for EPSOM salts.

You'll probably find more people stock it than Ebson salts.   

I haven't tried it but there is another product here called INOX which is a batter conditioner.
You can add it to new batteries and a number of manufacturers will extend their warranty on batteries so treated. I have read several reviews of the stuff by people not just chasing advertising $$ and they say after long term testing it works to preserve battery life and I have read one report it got weak batteries working much better.

I have not tried it myself so can't say.

The MSDS says it's 5% Cadmium sulphate.  Epsom salts is Magnesium sulphate. Don't know how the 2 compare but some chemically educated person here might.