Making the Call: Knowing when your battery is toast

[stickboy]

So I';ve run into some issues with my batteries being a newb and all. It started with my quad flipping in GPS mode, and after another thread post and lots of testing I';ve definitely determined I';ve damaged my batteries. I';m still able to get 14+ minutes flights in hover but when I start any aggressive maneuvering it flips on its own in GPS.

Now my question is, how do I determine if any of my other batteries are damaged without test flying and waiting for a crash? I';ve got 3 x 3s@5000mAh and 2 x 4s@5000mAh. Two of the 3s I';ve definitely decided are toast, but I can';t imagine bagging the others without confirmation. Any suggestions?

[DebianDave]

Check the internal resistance of your batteries (most decent chargers can do this). If any are off the scale for that model, its likely you';ve toasted them

[XH558]

Check the internal resistance of your batteries (most decent chargers can do this). If any are off the scale for that model, its likely you';ve toasted them

Let';s just say you know someone, very close to you, who may not have a ';decent'; charger - and may have absolutely no idea what an ';internal resistance'; is - or should be ... AND have no real understanding of the mystery that is electrickery 

Then what would you advise 

[DebianDave]

What charger does your "friend" have? 

[flybywire]

Doesn';t sound like lipo trouble to me, (if you happily fly around for 14 minutes!) more like a dodgy ESC or motor failing under load?
I';ve only had one failed lipo so far, and that flipped the quad on first takeoff.

[kilby]

I';ve had 2 unhappy esc';s cause crashes,  if the quad hasn';t been so close to the ground it would definately have managed a fully fleshed flip both times

[stickboy]

I really hope you';re right - the ESC problem sounds so much more plausible to me. In fact, I had a rebuild where I thought an ESC had a short because it would arm and disarm while the others were spinning. I re-soldered everything and figured it was indeed just a short when everything then seemed fine (minus the first flip after 5 or so initial successful flights). So yeah, got one of those Skywalker Quattros so fingers crossed you';re right but sounds like a solid lead. 

Plus, just tried it, and I';m getting IR readings like this:

1) 12mOhms 2) 5mOhms 3)6mOhms

And this is consistent with a 3s 2200mAh batt that I';ve only flown once or twice. Worst I';ve got is a 3s with about 12mOhm in the two first cells. Does that sound alright? Can';t find specifics on my brands (Venom and E-Flite) but I';m hearing less than 20mOhms per cell is still flight worthy.

[XH558]

What charger does your "friend" have? 

Funnily enough he';s with me now and I';ve just asked him ...

He says has one like this ...
http://www.giantshark.co.uk/product/170694/gt-power-b606-balance-charger-li-po-ni-mh-battery


He says he has had a lot of success with it - but he just plugs batteries in to it and they charge - he has very little understanding of what';s going on 
He';s also taken to using a multi battery board like this ...

That way he';s successfully charged several batteries at once - all well balanced - he says 

He has one or two batteries that are showing early signs of puffing - in that the shrink wrap is getting ';tight'; and a bit raised. They are still charging and balancing ok but is worried about them ..

So he want to know what this internal resistance thing is and how to check it ... I would tell him myself -  but he doesn';t trust me 

[flybywire]

he has very little understanding of what';s going on 

Sometimes that';s the best way David ;-)

[Friskle]

Never charged multiple batts, just don';t trust it for getting them all Bob on, I charge one at once, yes bit longer, but imho, better to know each battery has had its proper fill.

[XH558]

Never charged multiple batts, just don';t trust it for getting them all Bob on, I charge one at once, yes bit longer, but imho, better to know each battery has had its proper fill.

Well if you trust a cell voltage counter that you plug in after charge then I my mate found that, after a multi battery charge, every cell of every battery is ';Bob on'; and properly ';filled'; ... so why not?

[DebianDave]

End of the day, batteries should be seen as a consumable. I';ve got a flying season out of my Zippy 1500s and Turnigy 2200s and they are all in good nick, will probably be fine next year. I tend to demote batteries from flight duty to testing and powering ground based FPV stuff.

Did have a couple of casualties though, 2 Turnigy 1000mah bent bang under extreme duress

[Friskle]

Well if you trust a cell voltage counter that you plug in after charge then I my mate found that, after a multi battery charge, every cell of every battery is ';Bob on'; and properly ';filled'; ... so why not?

Because I don';t want to ?

I usually test each battery with a meter that is not cheap and calibrated regularly, and its usually extremely "spot on" it was not bought for my lipos, but gets used with them.

Multiple charging was done to merely save time, personally I have no need to charge multiple batteries.

On the plus side for me, my batts are usually good for at least 18 months, and even those are more or less left fully charged for weeks at a time, then get topped up when needed.

[XH558]

Because I don';t want to ?

Fair point - that sounds like me   

[Friskle]

Fair point - that sounds like me   

lol