is this battery duff ??

[justlooking]

i just received a battery today in the post ,, it was advertised on ebay as new old stock from a shop clearance that closed down ,,

the battery is a "Lithium Ion Polymer" 24v 10ah

when i got it this morning it was low in voltage enough that the L,E,D`s would not light up,
i bought a 3 pin plug as the charger only had a EU fitting, i have now put it on charge and fingers x it will charge,
how can i test it once i have charged it ,, can i use 2 12v bulbs if so how will i know how long the bulbs should light up for ??

i can check the voltage once charged, but if im right this will not give a true indication of the power of the battery ampage ?

 

[el_walto]

Please post pictures of your battery. Please don't charge your battery with any random charger, it could explode.

 

[justlooking]

the charger came with the battery,
here is a picture of the battery,

 

[el_walto]

24Vx10Ah is 240wh.

It should light 2x12v lights in series for 1 Hour if they were 240Watt bulbs, 140Watt bulbs = 2 hours, I'm sure you can figure out the rest.

If you are adventurous I'd suggest taking the pack apart and measuring each cell voltage to see if the pack is good, and to figure out what kind of battery it is.

 

[dogman dan]

If it gets charged, it should show somewhere around 28v fully charged when you check it with a voltmeter. But till we know how many cells of which chemistry of lipoly it is, we can't really say exactly what fully charged should be. 6 cells of lipo would be 25 volts fully charged, while 8 cells of lifepo4 would be 28v.

You could then do a discharge test with light bulbs, heating elements, or a motor. Once discharged, some fairly simple math applied to the recharging time could get you a ballpark estimate of how much capacity you have. For example, if the charger says 2 amps, and it takes 5 hours to charge, then you might have 10 amp hours of capacity.

Idealy, you'd put a wattmeter on it and just measure the discharge for the exact capacity.

 

[dnmun]

leave it charging forever. get a voltmeter.

 

[justlooking]

its charged, i put the volt meter on it for 5 mins and its showing a charge of 28.8volts, i will see what it reads tomorrow morning ,,

 

[999zip999]

Like Dmumn said if you leave on the charger the bms if it has one will charge the low cells and bleed off the high cells.

 

[dogman dan]

That's a good sign. The advice to leave it on the charger overnight regularly is good. The bms will take time to balance the cells. This takes time, after the light on the charger turns green.

 

[justlooking]

thanks folks,
this morning it read 28.4v ,
i have put it back on charge, the light is green, i will leave it on till tomorrow,,

 

[dnmun]

like the dogman said, if we know what chemistry it is we will know more. is there a label on the charger that says what the actual voltage is and is there a label on the battery that states whether it is lifepo4 or 'lithium ion'?

 

[justlooking]

the battery is a "Lithium Ion Polymer" 24v 10ah
the charger is 3amp 29.2volts

 

[Jason27]

Lessons learned. People need to stop buying old batteries sold on eBay. I wouldn't be suprised if that battery sat in a warehouse in china for months or even years.

 

[dnmun]

what lesson. there is nothing wrong with it. duh? 29.2V!

 

[justlooking]

People need to stop buying old batteries sold on eBay..

the problem is that, here in the uk, there is no where else to buy the batteries, ok i could buy them from a hobby shop and link them together like alot of people do in this site,but then i have to get a BMS and there is the way to charge them,
like some i just want to plug and play,ie, just plug the battery in ,
i have priced the batteries from hobby shops, and the cost is to much, so at the moment this only leaves Ebay,
if i buy from other countries, then by the time 20% is added for import tax, and the extortionate postage costs, again the cost is to much,
the seller i buy my batteries from give me a 7 day return policy, so if a battery turns out to be dud then i can send it back for a full refund,

 

[dogman dan]

Seems to have fully charged. We still don't know if there is any capacity lost. Maybe he got really lucky. Mostly, we just hear from the unlucky here in the battery section.