Jump to content

Drained Life rx battery, how to revive as charger giving low voltage error.


Recommended Posts

I hope someone can suggest a hack to revive my Life 6.6v ignition battery for my model, although the switch was in the off position the battery has drained over the winter and now won`t charge as my Elysium charger gives a low voltage error. I did try to fool it by setting it on NIMH to put something in but i still get the same error message. is there any way of reviving this or is this virtually new battery gone ................

Link to comment
Share on other sites

Advert


Many years ago I made a simple constant current charger for the nicad packs I used in my model racing yacht.  I have occasionally used it to revive similarly exhausted batteries but only as a temporary measure - I certainly wouldn't trust them in any critical application.  You could try using a simple 'wall-wart' charger which doesn't care about the state of the battery.  I'm afraid your battery needs to be replaced.

 

In fact, I used my old charger to revive the 6 cell 2 AH NMH battery in my Multiplex 3030 35Mhz transmitter which gets almost no use.  However, I still have a few rarely flown models on 35Mhz so I've bought a new battery.  I really must remember to check it regularly.  Our bathroom radio has a 7 cell 3AH NiMH battery which still soldiers on after over 10 years regular use. I recharge it every few weeks at 3 amps and it still takes a full charge.

Link to comment
Share on other sites

Using a constant current charger as Paul and Geoff suggests is certainly a more eloquent way of forcing a little charge back into a totally flat lipo/life type cell, I just give em 12V @ 1A or so for 20-30 seconds from a bench power supply. It's not like there is any energy in the cell to explode with and it will either accept the charge or remain short circuit.

Link to comment
Share on other sites

For your safety Martin, your charger shows a " Low Voltage error " because the charger wants nothing to do with your lipos lack of life.

If you try any of the revival hacks, then have your Eyes on the set up at all times, and check for anything warming up.

as suggested, and my view too, just buy a new lipo.

Edited by Denis Watkins
Link to comment
Share on other sites

Another way is to connect it and another live battery to a balance board at the same time, in effect you are connecting the batteries together, give it a few minutes then try it on the charger. If it's been dead for a while it might not respond though, certainly works with a freshly depleted pack.

Link to comment
Share on other sites

martin

Remember if any cell in a LiPo is much below 3V at rest it is chemically damaged. Such damage is not reversible.

There are some tricks you can do to persuade the charger to put some capacity back but likely no more than 50%. Then you are faced with the issue that not all the cells are damaged. In use the damaged cell(s) will discharge first but the others will continue to provide current. This will damage the "weak" cells still further so making things worse each time that LiPo is used. Perhaps even more important with such a LiPo the risk rises that something might go seriously wrong.

 

It the charger doesn't like a LiPo for low voltage it is a safety feature built into the charger to stop you using that LiPo. You should consider yourself warned.

The advice is always get a new LiPo. 

 

Link to comment
Share on other sites

Thanks for all the replies, i used my wall mounted rx/tx charger on it for 15 min and my proper charger has now accepted it. I will see how much it puts in and check it in a weeks time to see how much it has lost. The morale to this story is disconnect the batteries when not in use, it was switched off and has a digital display when on. This battery is on the ignition, i would not use it again if it was on the RX but as it is the ignition one i will use it if it takes a full charge but will certainly keep an eye on it. 

Link to comment
Share on other sites

9 minutes ago, martin collins 1 said:

 This battery is on the ignition, i would not use it again if it was on the RX but as it is the ignition one i will use it if it takes a full charge but will certainly keep an eye on it. 

You wont need to keep an eye on it, you'll hear it when the engine stops!

  • Like 1
  • Haha 2
Link to comment
Share on other sites

2 hours ago, Phil Green said:

Generally speaking, as Simon & Steve said - once a LiFePo4 is discharged to that level then its beyond recovery.

If you do manage to get it to 6v6, it wont hold it and its charge capacity will be gone.

 

That's what I found, when I inadvertently let a 3s1p LiFe transmitter pack run down to dead flat. Below 3v a cell they were goosed and even after getting them to take a charge. they were slightly puffy,  they ran down rapidly and couldn't deliver under a modest load. I wouldn't consider using such a pack in a critical location and it went to the tip.

Link to comment
Share on other sites

38 minutes ago, martin collins 1 said:

 😅 I have plenty of ground running to do on the model before it goes airbourne so i can get a good idea if it is still useable or not. The charger has just finished, 1911 put in and showing 7.08 volts. 

You might have got away with it, but do a discharge test at say 1 amp to check first, I did this with a 2s life and found under load it's voltage dropped dramatically.

  • Like 1
Link to comment
Share on other sites

Martin, you seem to be ignoring the fact that the battery self-discharged (the switch was off), I think it is likely to do the same again, perhaps when you least want it to.

 

It will be perfectly fine for home running the engine etc. but you don’t want to find a flat ignition battery on the one day that is both wind and rain free….

 

Brian.

  • Like 1
Link to comment
Share on other sites

I will be disconecting the battery from the switch as i am assuming the ignition has still drained it with the switch off. This was a new battery which has been charged once and the switch was only operated a couple of times to check it, the engine has not been run since it was fitted. 

Link to comment
Share on other sites

 

50 minutes ago, RottenRow said:

It will be perfectly fine for home running the engine etc. but you don’t want to find a flat ignition battery on the one day that is both wind and rain free….

 

Or just as you've taken off...... 

Link to comment
Share on other sites

As you state this is an ignition battery, I assume it's on a gasser. And therefore I assume the model has an onboard electronic ignition cutoff. FWIW:

I've had two instances of where these 2 different ignition cutoffs have, over days/weeks, drained the ignition battery. Clearly there is some form of leakage through the cutoffs. So still needs a isolation switch between the ignition battery and the cutoff, and don't forget to turn it off! Since learning this, all my gas models have Rx and ignition switches mounted adjacent each other, and fitted with some form of indicator light to assist with preventing the slow discharge as above.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...