EEVblog #508 - Can You Test Battery Charge By Dropping It?

hi this is just going to be a quick video confirming a claim that Kipkay made in a recent video a day or two back about how you can determine the state of charge in an alkaline battery by actually dropping it onto a surface and one that is fully charged will won't bounce at nearly as much as one that is empty so I thought I'd just test this now I was originally going to do this as like a more scientific like investigation because in the Kipkay video it was ridiculous he used two different brands of battery you know that's that's just crazy so I thought I'd at least do like a proper scientific investigation controlled experiment kind of thing where I draw a controlled the drop height out of tubes and I got different brands and makes of battery and I controlled the discharge rate and measured the capacity and all sorts of stuff like that but I just decided no I'll just do a very quick video to see it's just off the bat just drop in a couple of the same brand same batch battery and see if it actually works so here it goes so this is not my scientific investigation this is just a quick confirmation and I'm going to do it in one shot here so that nobody thinks you know there's any trickier trickery or anything going on here now the claim of course is that if you drop batteries like this here we go if you drop them like that a fully charged one a full battery will sort of won't bounce as much as an empty battery and what I've got here is I've already discharged well I've got Duracell ones here and I've got varta brand alkaline and I've already discharged one and I've marked those with the black marker on top so they've already been discharged and i discharged him on my electronic load over here at half an amp and this has got a battery discharge mode on it i discharged at half an amp until they reached naught point eight volts and you can see that the vital ones are definitely you know there it is trying to draw half an amp it's only half a volt okay so this is pretty crap up if I can get that back out sorry there we go and the Duracell one is how it has a little bit more charge but it's down 2.8 volts at half an amp so not a problem now I'll measure these with my meter and the to make sure the other ones are good here we go sorry I got to get them the one shot otherwise people will think I'm having them on so these are the flat ones of course they've regained a bit of the voltage because they're under no-load there but trust me they're well they're fully discharged if you know your battery chemistry there you go the brand new viola and the brand new jerusalem and yes they're from the exact same batch same packet okay so we have a nicely fully charged and essentially an empty one and I was going to weigh them with precision scales and all that sort of stuff but this is not my scientific investigation so I'm going to just switch my GoPro on here so I can capture this and here we go and in high speed so maybe I'll get some high-speed footage out of this thing and I'm going to drop them onto my rubber ESD mat here which of course isn't the best experiment it isn't the best surface because this thing is going to vary based on surface now I originally thought that you know it'll be hard to differentiate this thing it wouldn't be as simple as the Kipkay video but here it goes okay here is a fully charged one I'm going to drop it from the height of the battery and and it almost went with a thud and I can actually get them to stand up as claimed in there we go as claimed in the qk video now i will drop the discharged one and you'll notice that it bounces more it most definitely bounces more than the other one and it is caught there we go I can get it to stand up but it even on this rubber ESD mat which is going to absorb some of that impact and dampen that you can clearly see that the empty one does bounce more so there you go I'll try a few different surfaces let's get a red perspex base here and let's see what happens here we go empty you can see that it bounces a couple of times so let's get the full one and see more of a thud you don't get that second bounce really it's it there we go I can't get to stand up it's often a bit difficult from that height we go from a lesser height you've got more chance to that and I was going to do a proper drop rig with like a tube that control drop them and stuff like that but as you can see you can see even on this kind of surface it makes a difference now let's get the varta ones here the vada brand here we go here is the fully charged one and you can see it just does that sort of single thud there we go and the empty it bounced at least that second time you see it it bounced much higher maybe I should be able to get that on the GoPro there we go I got it to stand up but as you can see it really does bounce a lot higher it's hard to see them both at the same time but yet this isn't the best surface so let's try some other surfaces I will have to eventually swap camera shots fully charged there we go we really only get that single sort of thud there's little bounce in there but now the empty see look at that definitely you can get it to stand up still but it certainly is there's much higher bounce on that and at the same time there you go so that's definitely confirmed on you know most surfaces but yes it does make a difference what surface you're on let's try another table surface here here we go full charged thud empty definitely huge bounce look at that same time yep big difference oh so you almost got the empty to stand up there and the vital one empty huge bounce and full not nearly as bigger bounce thud so there you have it that is a myth confirmed really it does do it but it's in practices probably not as easy as Kipkay makes out because you sort of you know you have to know about the surface I am able to get some of the empty ones to go thud I haven't done you know a complete scientific thing here this was just a quick test to confirm it but definitely it does do it but really I think in practice you've got to have a good one and a bad one to be able to compare on a given surface I think so there's obviously some sort of electrochemistry effect that's happened inside there that effects the dampening inside the battery the vibrational mode and dampening of the battery but like I said to get you know to really understand this process you'd have to go into the chemistry of these things should you know have to do proper vibration and drop testing with accelerometers on them to get some you know really good data and stuff like that I don't have the gear to do that anymore I used to but anyway I thought that was rather interesting and yeah myth confirmed would you want to use it day to day I guess in a pinch you could use the technique to determine whether or not it's empty but the easiest way to do that is to stick the battery in your product let's see if it works if it works it's good ah catch you next time you you you

Channel: EEVblog

Views: 224,555

Rating: 4.7022409 out of 5

Keywords: alkaline battery, battery test, kipkay, drop test, battery charge, charge, capacity

Id: PRf9JTg3QwA

Length: 9min 25sec (565 seconds)

Published: Thu Aug 15 2013