jbalat

The lipo I got from fung for my Zoom400 came with a bad connection (1500mah 3 cell)

I pulled back some of the heat shrink to have a bit of a look and moved some of the connectors and wires to see what the problem was. To my dismay 2 of the connectors broke off. 1 broke right at the edge of the sealed cell and the other less than 1/2 mm from the edge.

I cut away abour 1/2mm of the plastic around the 1st connector to give me a bit of area to solder to, but I cannot get any solder to stick properly on any of the connectors.

I assume that the connector tabs must be aluminium ? I am thinking of using some acid from a car battery to remove the oxide layer and try to solder it this way ?

Any ideas ?

Supermerlin

Hi Jbalat,

Sounds desperate!

I wouldn't try the battery acid idea, it will just corrode it badly.

I have heard of electrically conductive epoxy, though I'm not sure that it can handle high currents and it may be hard to find.

I have heard of repairing PCB tracks using car rear defroster repair paint. This is a very conductive paint made of silver powder in a kind of adhesive base. Some auto parts stores sell it in little containers about the size of nail varnish bottles. My thought is that if you dip the wire into this material and tape the wire so that it is in good mechanical placement you could then coat the joint area and after drying overcoat with epoxy resin. Tricky stuff eh.

Good luck!

ticketec

My Feedback: (2)

You might try and scrape the surface of the contact. this sometimes cleans/exposes the raw undersurface and allows you to solder on the tag. seeing as your from Melbourne, Oz as well, where did you get your Zoom and for how much if you don't mide me asking.

I want another indoor heli 'cos were having too much "standard" melbourne winter weather and i haven't flown my Raptor 50 for ages.

My sticks are getting rusty!

jbalat

I got it from Fung (although he is not my favourite person right now). I know Tedani sells it also and he charges much less for shipping. Before I get into trouble... you may want to try some of the local guys (maybe the sponsors also ?). I spoke to hobby headquarters (Sydney) at the Melbourne toy fair a while ago and they said that they were bringing them in. Most of the other dealers knew nothing about them. O'Reileys were looking at the Graupner variant... At the time I bought mine, no one else had them and to be honest I havents seen them around. Even Nick from NC Helicopters is not interested. He does have the Robbe though which is a real work of art but too expensive for me

Dont expect to fly them indoors, they are not a toy like the Dragonfly. Those rotors spin very quickly and you dont want to hit anyone.

I agree the weather here is shocking, nothing but wind and more wind (there is always FMS) !!!

Scraping the surface does not help since the oxide layer forms quickly, especially at hgher temp. The conductive epoxy could be a goer if I can find some but I dont want to introduce any resistance. The window repair paint may be easier ?

warren52nz

LI-Po batteries are dangerous so I'd be wary about fiddling with them especially in the way you're talking about. Some of the stuff I've read about them suggests Lithium will self ignite if it "sees" atmosphere (although I don't think that's the case).

I'm more willing than most to have a go at bashing something "unfixable" back together (you should see all the epoxy on my helicopter) but I'd probably either try to get the seller to replace it or just buy another one.

Having said all of that, I haven't had much experience with Li-Po yet. But I've seen a video on the Net where someone intentionally overcharged one just to film the catastrophe and it looked nasty!

jbalat

Dont worry, my spare room has 3 large black char marks on the floorboards from the Li-ion battery that blew up there a few months ago. There were spot fires all around the room, it was like a scene from Backdraft. Lets hope I have learnt something from that.

Whatever I do I will be very careful not to overheat the battery or puncture the cell...