ballancing a lipo

[christopher small]

I have a GT Power V5 charger,how do i do a ballance charge,do i connect both the ballance plug and charger leads(deans connector)as the instructions are not very clear,also how often should i ballence charge them.

Chris

[Delta Whiskey]

Not sure on the specific details of your charger, but yes you would still connect the balance plug and the main red & black leads to the charger to balance charge it.

[Delta Whiskey]

Not sure on the specific details of your charger, but yes you would still connect the balance plug and the main red & black leads to the charger to balance charge it.

 

I balance charge every time !

Edited By Delta Whiskey on 20/01/2012 18:53:23

[ken anderson.]

hello chris-the charger i use the lipro + has to have both the bal lead plugged in and also the + and - leads-or it refuses to do the bal........try yours i think you'll find the same..it'll refuse to do the bal bit without the lead plugged in.....i dont balance the batts as they are used week in and week out-used to - but read it wasn't reqd......

 

ken anderson ne..1 ..... plugged in dept.

Edited By ken anderson. on 20/01/2012 18:56:32

[christopher small]

Thank you for your quick replies,i shall get them charged up in the morning,I shall check both cells on them see if they are equal,I know one isn`t so that one will be ballanced.

Thanks again

Chris

[Peter Beeney]

I reckon the LiPo balancing subject is quite a good one, there are many different views, so I guess you can never really be right or wrong in what you say. So as I never know if I’m right or wrong I thought I’d have a little say.

It very much struck me that the fact that the charger won’t fire up until the balance lead is connected is an interesting one, although I suspect not for the reasons that I’ve considered.

So, thinking about Safety, as is my wont from time to time, I have noticed that there has been the occasional incident with a LiPo pack on charge where the cell count has either been set to either the wrong battery type or cell count. The result, it seems, can be a fire.

Thus it occurred to me a while back that the balance lead might play two roles. I thought wouldn’t it be nice if some enterprising charger manufacturer could use the balance lead to identify the number of cells in the pack when it was first connected; it would cross reference the cell count against the total pack voltage and also which cell count the charger had been switched to and so the charger would then not start charging until this was all verified as correct; and by the same token a nickel or lead acid could not be fired up either, no balance reading, so no danger of getting the battery type wrong.
Whilst I suspect that most folks will set the charger to the right number of cells most times, it seems to me there is a region for some error. How will the charger differentiate between a totally flat 5 cell pack at 3V/cell, 15 volts, and a fully charged 4 cell pack at 4.2V/cell, 16.8 volts? In fact, the 5 cell only has to be at 3.75V/cell to equal the 15 volts of the discharged 4 cell pack… … and then if the charger took off at full chat, thinking it was a 5 cell???
Even the 3 cell to 4 cell step is not entirely out of danger. The flat 4 cell has a voltage of 12, the fully charged 3 cell is 12.6V. Not a lot of difference, and perhaps most unlikely to get a crossover, but not impossible. Certainly fairly doubtful using my charger, though, if this were made semi-automatic and could only be overridden by the operator having to make two keystrokes, say, a set and an enter perhaps.
LiFe packs also have a balance lead, and some though would have to be given to these, hence semi-automatic. It’s possible the voltage parameters could fall within those of the LiPo packs. Perhaps if you did not use LiFe cells this could be deleted from the menu, if you did use both types it could ask you to confirm on connection.
I realise that these invariably take two major faults together to become apparent, but in a lot of searching for electrical faults for money in the past, once it was for 2.5 years examining every circuit on many standby systems for what could have been a dangerous situation, I found that many times one fault on it’s own could lie dormant for years. Then when another unusual or different situation happened by chance to met the first head on, it was suddenly apparent that something was very wrong. And, of course, that could be a fire, or perhaps someone being electrocuted; and when they were not actually doing anything wrong, to boot.

On the idea of the different views on balancing, I have read that that in the full size world they tend not to bother about balancing until they are in strings of about 7 or 8 in series. But that only hearsay, nowadays I have no contact with others in the industry. Also I was very interested recently in a magazine article written by a continental electronics engineer describing how to make your own balancer. It seems he was interested in cycling but needed some help, so this was for his cycle assist pack of LiPos, which he used regularly. I suspect the whole drive unit was homemade. He found that balancing every 10 cycles, sorry, charge/discharges, was sufficient. I think that it would also be nice if the cells could be balanced somewhat on the discharge, if you have a dodgy cell in a pack no amount of balancing is ever going to change this, and it’s highly like that our tame charger could be trained to recognise this condition. Take the very hypothetical case of one cell down to half capacity in a 6 cell pack. By the time the voltage of the complete pack is down to 18 volts this cell is going to be well below the requisite 3 volts, this could be flagged up as requiring attention. In practise I guess it couldn’t normally get this far out of kilter, but it wouldn’t necessarily need to be this serious, just more than the usual few millivolts would be enough.

Of course, this may already be happening, and I’m a long way behind the times as usual. I know very little about the up to date chargers, just idly reading some details they seem to be very versatile, but I don’t think I’ve ever seen this advertised. But reading some of the present day advice on charging LiPo’s does tend to make me question some aspects, particularly as there are no safety requirements at all for charging the LiPo’s in my laptop, simply because there is no human input needed to charge them, this is fully automatic. So I’m now wondering if it’s the battery that’s unsafe, or is it the operator?

PB

Edited By Peter Beeney on 20/01/2012 23:37:27

[Tim Mackey]

Posted by Peter Beeney on 20/01/2012 23:32:20:

Thus it occurred to me a while back that the balance lead might play two roles. I thought wouldn’t it be nice if some enterprising charger manufacturer could use the balance lead to identify the number of cells in the pack when it was first connected; it would cross reference the cell count against the total pack voltage and also which cell count the charger had been switched to and so the charger would then not start charging until this was all verified as correct;

 

Thats exactly what the chargers from Junsi (IC1010 etc) do.

[Cyclicscooby]

Balance EVERY time...

 

 

Luv

Chrisie.. xx

[Steve W-O]

Posted by Tim Mackey on 20/01/2012 23:37:38:

Posted by Peter Beeney on 20/01/2012 23:32:20:

Thus it occurred to me a while back that the balance lead might play two roles. I thought wouldn’t it be nice if some enterprising charger manufacturer could use the balance lead to identify the number of cells in the pack when it was first connected; it would cross reference the cell count against the total pack voltage and also which cell count the charger had been switched to and so the charger would then not start charging until this was all verified as correct;

 

Thats exactly what the chargers from Junsi (IC1010 etc) do.

 

 

I thought they all did now?

 

My "cheap" B6 chargers certainly do.

 

It seems that the biggest difference between expensive and not expensive chargers is in the analogue components in the voltage measuring, if that is accurate, then it is fine.

 

I just charge at the field to save time (I don't often charge at the field), and balance at home when time is not an issue.

 

Balancing, or at least the time taken over and above the normal expected charge time is one first signs of a cell reaching the end of its useful life. Also if you watch the cell voltages, you can get an idea if there is a problem, if one always takes longer or is ourt of sync with the others.

[Steve W-O]

This one didn't quite balance, so I just added a small one to one side, and it balances fine.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Vecchio Austriaco]

Most chargers do the cell check - even cheaper models. An exception may be the older chargers where you have a separate balancer.

Balancing doesnt do more work but may require more time. As Lipos keep their charge quite well - self discharge is very little - time should not be a big threat. Balancing gives you security that cells are equally charged. So why do people want to charge multi cell Lipos without balancing?

cheers VA

[Tim Mackey]

Im not talking about simply a cell check - the Junsi unit actually uses the plugging in of the balance plug to identiify the cell count, and then displays this for you to confirm.

Most chargers I know of ask YOU to select the cell count, and then ask you to confirm your selection versus its identification.

[Steve W-O]

Posted by Tim Mackey on 21/01/2012 09:06:43:

Im not talking about simply a cell check - the Junsi unit actually uses the plugging in of the balance plug to identiify the cell count, and then displays this for you to confirm.

Most chargers I know of ask YOU to select the cell count, and then ask you to confirm your selection versus its identification.

 

Yes, you are correct on mine, you select it, then it tells you if you are wrong, or if there are any disconnected leads

[Erfolg]

Steve, we seem to have the same charger.

 

As you have written, checks every time..

[Vecchio Austriaco]

Timbo, when I speak about the cell check it is asking me if I want to proceed.If not confirmed in time it stopps. My Turnigy accucell 8 - rather on the low price side does it - and also the Hyperion 720i- where you have the numbers of cells to program into memory and the charger checks for a matching number of cells. So both are doing it - the only one not doing it properly is my older Graupner Ultramat 14 with external balancer - so this is the one to use when the cell voltage is too low - so that the newer chargers don't bother in charging the thing any more

Edited By Vecchio Austriaco on 21/01/2012 17:04:54

Edited By Vecchio Austriaco on 21/01/2012 17:05:41

[Peter Beeney]

Thanks for those answers, it certainly looks as though the chargers are improving in terms of being rather more foolproof. Looks like I had the same idea as the manufacturers at about the same time… When we get to the fully automatic state that requires no input from the operator at all then this may be the safest condition. Although, of course, the provision to override the setting and use you own is desirable, but again with full approval of the charger. For instance, my now very ancient Schulze charger has a fully auto setting for nickel cells, you just connect them up and it gets on with it, it chooses it’s own cell count and charge rate etc. However, this can totally overridden in every respect but even then if you try to go too far the charger still refuses to play; on the basis it might damage your pack. If you still want to do it you have use external components, such as some low value resistors for a heavy discharge rate. Which Schulze will supply, of course.

I think the reason that some people might not balance cells all the time is because they consider it might not be necessary. Everyone has their own ideas, about most things modelling, really. From ‘I never balance’, I know one such person , it’s not me though, through to ‘every time I charge’; and I don’t know if there is any firm evidence to prove that it’s definitely detrimental either way? I suspect that there’s not too much proven evidence, in fact, rather just hearsay.

Like most things, LiPo’s can behave strangely on occasions. A mate bought 3 packs from HongKong, very cheap, for his small fleet of foamy’s, probably about a year ago. Two were ok, but his charger refused point blank to accept the third. Another mate’s rather more sophisticated charger tried ok but could never get one cell to balance over time. He was going to bin it, but I took it and found one cell voltage well down; so I just charged this cell with the bench supply until the voltage came up. It actually took quite a bit of charging, in fact. On a test discharge it was perfect and the total capacity was better than the name plate value. On recharging, the same thing happened, but not to quite the same extent, so after a couple of cycles I returned it, explain the situation, and saying lets try and keep it going for for a while to see what happens. Soon it improved to the point where his charger would accept it and when I queried it some time later it was still going strong, on a par with the other two. And checking again with him today, Sunday, he said this battery is still now every bit as good as the other two, he uses it regularly.

I wonder how many times this simple little situation has occurred? I have every belief in tying to find out what’s wrong with something and repairing it, I never did manage to decide what was actually wrong with this cell, but we certainly seemed to have fixed it!

So is it possible that with the chargers becoming more difficult to get confused on cell numbers and so on, they are now more observant, perhaps, and although the electrical model is gradually increasing in numbers, the rate of incidences related to these models, such as fires etc., seems to me to becoming less. Or, at least, the ones that are made public.


Or is that my imagination… … or even perhaps for some other completely different reason…

PB