testing new second hand batteries.

[offthegridandy]

Help and advice please.

I've just been offered a set of "recon" batteries. 24 volt lead acid fork lift type. 1000 AHr. Seller claims they are new set that ain't been used, just kept on standby. Set is in cage with straps and is "wet and charged" priced at £1150.  If they are new its seems a good price.

Question is what is best way to test the set to be sure they are as stated?

Undo the straps and check voltage on each cell is same/similar is my starting point. Any other thoughts comments welcomed

Andy

[camillitech]

Hi Andy,

check the SG's and make sure they are all the same, have a good squint down the filler hole and look for plate separation, check the underside of each cap to ensure they all look the same. There will be 'soot' for want of a better word under them and it should be the same amount on each cell. Actually if they are new then there should be nothing under them as they won't have been cycled, or so he says.

Check all the markings, numbers and dates to ensure they're all the same age/batch and then 'Google' for proper specs.

Personally I wouldn't go near a second hand battery bank but plenty of folk have had good luck on that score and others have had more bother with new ones. However at that price, even I'd be tempted 

Sure I've missed something out but someone who actually knows what they're talking about will be along shortly 

Good luck, paul

[rogeriko]

You need one of these. Check the voltage of each cell under load, this tester draws 200A I use a digital tester to measure the volts per cell exactly while I discharge each cell for about 30 seconds. Shouldnt drop below 2v-2.1v. Plus measure acid with hygrometer.

[clockmanFR]

Hers a trick i use.

I go look at them and test each cell with a digital read out to allot of decimal places. I ask them to take them off charge and then read every one, right details down, i then say oh yes they seem okay just popping to the bank or lunch or something but leave them for an hour or two, off charge, then use the gadget, (rogeriko shows) or load, for an exact time for each cell on your return and test the voltage against your original test readings. You should see that they all have dropped but the drop should be the same, but bad cells will show up.
 Get the chap to do it with you, its surprising the look on their faces when you get the meter out.

I have said several times to folk that i will not take that 'one' its showing a bad test result.

[offthegridandy]

Thank you

Paul,Roderico and Clockman. I can check SG no prob. I'll have to see if I can borrow a voltmeter or look on flea bay.  Thank you for your advice.

Andy

[Justme]

Dont pay more than the scrap value for second hand cells.

If they have been on float then they have been used.

Check the date codes.

My first bank that is still going strong (3 years) cost £130 inc del for 1550ah @12v its upgrade cost £450 for 2800ah @12v. I am now keeping the smaller bank on float till the bigger one has been cycled for enough times for me to be confident on joining them with no issues.