re battery hep

[whizzo]

Hi all- please can someone say if it is possible to solder 1.2 v -3.500 mah Ni-mh these are not the tag type ( because of the price )- I know they are normally put into the plastic battery holders (type for 4 ) however - I am fighting room in the boiler of the loco - on the plus side, I am quick with a soldering iron -- swmbo says it is the only thing /////////8|--- really just asking has it been done, as I do not want to s-d them up -- thanks for your time-----Dave

 

[Zerogee]

Waaaayyy back in the mists of time (OK, the mid '70s or so) when I first started using Nicads as replacements for lead-acid batteries in R/C model boats (scale stuff, not the racers!), I couldn't get nicad cells with tags, so the only way to make up packs was to directly solder on to the battery ends. The advice given in the modelling mags at the time was to use as large and powerful an iron as possible, to get the job done FAST - a Weller 100watt soldering gun was the recommended tool!
I did manage to get a couple of packs soldered up that way, not the easiest thing I've done and you do have to be damn quick while still getting a good joint.
Frankly, even if tagged cells cost a bit more I'd say it's probably worth it for the lack of hassle, I know I'd have used them back then if they'd been available!

Jon.

 

[CoggesRailway]

Re:re battery hep

Zerogee's experience from the 1970's holds true today. Yes it's possible but MUCH easier with tagged cells.You don't need a monster iron, i think mine is 40w but you have to try and be quick and it probably isn't great safety wise to be heating them up at all- but you can do it.

I am guessing these are sub cs. If you buy a 7.2v "stick" (tamiya style) you can carefully snip them apart and end up with a cheaper way of getting tagged cells.

Even at this toy size level do be careful- a short can get very hot very very quickly.

 

[whizzo]

Re:re battery hep

Hi again -- sorry should have said AA size batteries regards Dave

 

[Tony Walsham]

Re:re battery hep

DO NOT solder directly to the cell. Doing so will shorten the life (in terms of the number of cycles) of the battery, such that tagged cells will seem like a bargain.
AA size cells do not like to be charged or discharged at much more than 1/2 an amp.
Any higher current and their life is reduced.

 

[GAP]

Re:re battery hep

Soldering directly to the battery can be done but as Tony says the potential for damage is there.
Personally I use tagged batteries that I get via a components to the trade supplier at a fairly reasonable price even when compared to e Bay and places like Farnell and RS components.
UK eBay 5.64 pound my source $2.63 Aust.
Is there a place like I have here that will spot weld a tag for you? He does it for $1/ battery extra.

 

[dunnyrail]

Re:re battery hep

I have found Model Aircraft/Boat Shops to be a good source of Tagged Batteries. You can then create your own sized Battery Pack at will. Also look out for a Smart Charger. These are extremely good and turn themselves off when Battery Pack fully charged. I got mine from Peter Spoerer. He will also supply ready made Battery Packs. If your not sure or confident of what do do, perhaps this may be a good route to go down. I have also found Peter to be very helpful on the phone when asking about issues of size and ampage of Battery Packs required.
JonD

 

[tramcar trev]

Re:re battery hep

I have done this many many times with no cell degradation. The trick we used to use was to freeze the cells first, just freeze around -1/2 degrees. The idea is to stop the contents of the cell heating up while you are soldering. Also don't try and do it with resin cored solder as the flux is not reactive enough to solder to the plating on the battery so use a slightly more reactive flux, or use a solder that is described as suitable for "metalwork", tin the wire first, clean the battery ends as well with something like a track cleaning block or alcohol as the batteries as supplied will have a film or anti corrosive on the terminals...
Get it all prepared, cell 1 out of the freezer solder wire onto it, nice hot iron to do it quickly, then bring cell 2 out and solder to it and so on. If the cells start to feel warm pop them back in to chill, have a cup of finest Ceylon tea then carry on.
I can give you my personal assurance that this technique will give you success with no cell degradation...
When you master Ni Mh batteries you can then try with Li-Po same technique just let me know so I can hide somewhere while you do it.... Seriously have you thought of getting one of the blue Li-Po's and unwrapping it? You get a really small high density battery.... Wrap it in Gaffa tape when you take off the cardboard...

 

[gregh]

Re:re battery hep

Hi all- please can someone say if it is possible to solder 1.2 v -3.500 mah Ni-mh these are not the tag type ( because of the price )- I know they are normally put into the plastic battery holders (type for 4 ) however - I am fighting room in the boiler of the loco - on the plus side, I am quick with a soldering iron -- swmbo says it is the only thing /////////8|--- really just asking has it been done, as I do not want to s-d them up -- thanks for your time-----Dave

I do it all the time- must have 15 locos done this way. No freezing, just using normal resin core solder and a 25W iron. No problem.
I clean terminals with fine sand paper immediately before soldering. I use a clothes peg to hold each cell upright. Get the wire ready and plated and heat the pos terminal, apply solder till it melts and then attach pos wire. All in a couple of secs. It's the pos end you have to be quick with as the over-temperature venting system is there. Take your time at the negative end, there's no vent there. I usually do all the pos wires first, then the neg, to let them all cool down a bit. Then wipe any flux reside off with metho on a rag. I then coat with a smear of vaseline.
You can make up any configuration you like.