Inexpensive charger for over-discharged lipo batteries?
Discussion
I've managed to run down 2 lipo battery packs from an airsoft gun through demo events beyond the point where they'll charge with a regular charger. I've read a few guides online that say basically get it to a minimum charge level with a smart charger, then carefully monitor it whilst charging with your regular charger.
Trouble is a quick google is only finding me smart chargers that cost more than the battery packs.. any suggestions?
Cheers
Trouble is a quick google is only finding me smart chargers that cost more than the battery packs.. any suggestions?
Cheers
You could try
Component Shop or Hobbyking
however I suspect new batteries may well be cheaper. Additionally when I played airsoft and got LiPos a friend of mine, who does know his stuff, advised me never to flatten them as they would be non-recoverable. I suspect that may be your situation.
Component Shop or Hobbyking
however I suspect new batteries may well be cheaper. Additionally when I played airsoft and got LiPos a friend of mine, who does know his stuff, advised me never to flatten them as they would be non-recoverable. I suspect that may be your situation.
100% bin them and buy new.
I had one catch fire during charging and it was pretty scary - it even burned through the "fireproof" charging bag it was in.
No names but it was an "imported" charger and LiPo, the bag was from a good UK supplier.
Fortunately I was able to get some oven gloves, grab the bag and throw it out the open window.
I stick to "known" name products now.
I had one catch fire during charging and it was pretty scary - it even burned through the "fireproof" charging bag it was in.
No names but it was an "imported" charger and LiPo, the bag was from a good UK supplier.
Fortunately I was able to get some oven gloves, grab the bag and throw it out the open window.
I stick to "known" name products now.
Lipo charging bags are a waste of time, pretty much - might buy you a few seconds.
Have a look a BattSAFE - fire proof charging and storage box.
They contain fire but vent smoke, so you’d still have smoke damage but no fire damage. I forget the rating but it states how many batteries it can contain.
Agree with above post, safer to bin them, I’ve binned model aircraft batteries with minor damage that were ‘probably ok’, not worth the risk IMHO.
Have a look a BattSAFE - fire proof charging and storage box.
They contain fire but vent smoke, so you’d still have smoke damage but no fire damage. I forget the rating but it states how many batteries it can contain.
Agree with above post, safer to bin them, I’ve binned model aircraft batteries with minor damage that were ‘probably ok’, not worth the risk IMHO.
Edited by mph999 on Thursday 31st August 19:13
What voltage are they? Plug them into a normal (lead acid / nicad) charger for a similar voltage - once they climb above the min threshold they will charge on your lipo charger.
i.e. lipo cells are pretty much deemed as dead below 3v per cell. If you have a 3cell pack (10-14v) chuck them on a 12v low amp charger and measure the voltage, as soon as then are above about 10v the original charger will recognise and charge them.
Done it many a time with over discharged cells. If you leave them over discharged for too long they'll puff up and lose some capacity. I still fly helis with puffed cells. They just lose come capacity.
i.e. lipo cells are pretty much deemed as dead below 3v per cell. If you have a 3cell pack (10-14v) chuck them on a 12v low amp charger and measure the voltage, as soon as then are above about 10v the original charger will recognise and charge them.
Done it many a time with over discharged cells. If you leave them over discharged for too long they'll puff up and lose some capacity. I still fly helis with puffed cells. They just lose come capacity.
Edited by Griffith4ever on Thursday 31st August 22:01
Not a bad idea - where weight isn't an issue. Be interesting to see if you can fit a similar Mah into the space you have for it. Lipo packs are unbeatable for energy density in terms of rectangular spaces, plus, weight - but we can ignore weight.
Give 'em a boost - they will prob be fine - the reason chargers won't start is simply because they look for a set min voltage (around 2.5-3v per cell) before they will start, as they use the voltage to work out the overall pack voltage....
e.g. put a 3s pack on a charger, empty , at 3v per cell (3.2 is more healthy) - you get 9v - the charger knows it's a 3s pack and charges it to 12.6v (3 x 4.2v).
Put a dead 3s pack on at, say, 1v per cell, the charger sees 3v and either makes the (incorrect) guess that it's a 1s 4.2v pack and undercharges it. Or it can make a guess at a larger pack but if it gets that wrong you get overcharging and overcharging is a big fire risk. So chargers tend to just not play ball if they can't see the "empty" voltage they are expecting.
Over discharging, if not ignored for a long time, is often recoverable, with some loss of capacity (especially if there is any puffing)
Give 'em a boost - they will prob be fine - the reason chargers won't start is simply because they look for a set min voltage (around 2.5-3v per cell) before they will start, as they use the voltage to work out the overall pack voltage....
e.g. put a 3s pack on a charger, empty , at 3v per cell (3.2 is more healthy) - you get 9v - the charger knows it's a 3s pack and charges it to 12.6v (3 x 4.2v).
Put a dead 3s pack on at, say, 1v per cell, the charger sees 3v and either makes the (incorrect) guess that it's a 1s 4.2v pack and undercharges it. Or it can make a guess at a larger pack but if it gets that wrong you get overcharging and overcharging is a big fire risk. So chargers tend to just not play ball if they can't see the "empty" voltage they are expecting.
Over discharging, if not ignored for a long time, is often recoverable, with some loss of capacity (especially if there is any puffing)
definitely don’t mess around and try and bring back to life, just dispose of in a safe manner.
my dad set his loft on fire (insurance job to repair!) when a lipo battery exploded/ went on fire when charging! he flies remote control planes, has decent batteries/ chargers etc…. but it can still go wrong!
my dad set his loft on fire (insurance job to repair!) when a lipo battery exploded/ went on fire when charging! he flies remote control planes, has decent batteries/ chargers etc…. but it can still go wrong!
hm. multimeter is showing 12.4v from an 11.1v pack.. and yet it's not charging and hasnt the juice to cycle the weapon.
I can get it putting out a spuriously high voltage, bit like a knackered car battery may read ok when it's not under load.. but surely a charger wouldn't have a problem because it's not under load?
edit : derp, the fuse in the gun is blown. Guess I'll be fixing that first
I can get it putting out a spuriously high voltage, bit like a knackered car battery may read ok when it's not under load.. but surely a charger wouldn't have a problem because it's not under load?
edit : derp, the fuse in the gun is blown. Guess I'll be fixing that first
Edited by shouldbworking on Friday 1st September 13:59
11.1v pack is a 3s pack, 12.6v full, so yours is almost full. Maybe has a bad connection between one of the three cells. Would be interesting to meter it when trying to use it, if possible. See what it drops to, if at all. NEver know,night have a problem with the gun and not the battery if it doesn't drop.
Edit.
AHH! Just read the rest of your post re. Fuse :-)
Edit.
AHH! Just read the rest of your post re. Fuse :-)
Griffith4ever said:
Joking aside, charging RC plane / heli lipos in the house is pretty stupid, so I'd not take that case as good guidance.
oh I agree!! and you’d think having a pretty major accident, and only by luck not burning the house down, that people would learn….. but some people dontshouldbworking said:
hm. multimeter is showing 12.4v from an 11.1v pack.. and yet it's not charging and hasnt the juice to cycle the weapon.
I can get it putting out a spuriously high voltage, bit like a knackered car battery may read ok when it's not under load.. but surely a charger wouldn't have a problem because it's not under load?
edit : derp, the fuse in the gun is blown. Guess I'll be fixing that first
Easy fix in theory, but generally they don't blow for no reason - has it had any work on it recently? Shimming might be too tight for example if the gears have been worked on.I can get it putting out a spuriously high voltage, bit like a knackered car battery may read ok when it's not under load.. but surely a charger wouldn't have a problem because it's not under load?
edit : derp, the fuse in the gun is blown. Guess I'll be fixing that first
Edited by shouldbworking on Friday 1st September 13:59
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