The battery game

[Fuzzo]

Not quite, I get more Wh from the extra battery. This means more range, which was my goal.

 

[machiasmort]

This is why people ride gas bikes. No E=MC2 stuff...

I've read several articles on Internet about it but I have to ask you guys, Has anybody ever soldered wires onto a NiMH battery like you'd buy at home depot?

Your experience is appreciated.

Also wanted to say thanks for the thoughts on the electric motor. I think I'll hold out for a few although I've got an old drill (dc)motor laying arround, probably to small.

 

[Fuzzo]

I'm about to try it. Being similarly advised by the internet, it seems that the hotter the soldering iron the better, to minimize contact time. But a cautionary note is that solder might melt if the batteries get hot, which is why when you buy batteries with tabs they're usually welded on.

 

[safe]

Solderless Tubes (what I've done) is the ideal because as the inevitable cells go bad you can pop them out and replace them.

Soldered packs are best done when you start with cells with tabs so that you don't damage the cell. NiMh is rapidly damaged by heating.

Also... you usually don't get very high Wh with the typical electric drill packs. They are typically rated somewhere around 2 Ah per cell and you can easily get much better cells than that here:

http://cgi.ebay.com/50-Pcs-of-Match...34.c0.m14.l1262&_trkparms=|301:1|293:2|294:30

 

[duivendyk]

If you manage to increase the gear reduction,you get more torque at the wheel for the same engine current (torque)which fits with increasing motor speed by going to 36 V(about a 50% speed increase).Wether or not rewinding can reduce the winding resistance depends on unused winding space available and is certainly not sure thing.

 

[safe]

That's true.

However, machine winding tends to produce a fairly loose fit because in a rapid assembly process you can't spend that extra time to wiggle things into place. Because of this hand winding seems to always open up some extra space that machine winding can't do.

My recent examples have been:

MY1016Z3 - Stock 21 Turns - Rewind 28 Turns (33% increase)

MY1020 500W - Stock 18 Turns - Rewind 22 Turns (22% increase)

...it's far easier if you can change the gearing rather than change the motor windings.

 

[duivendyk]

That's certainly not to be sneezed at,and an extra bonus if you want to rewind anyway.I think Fuzzo might be ahead of the game if he could manage to increase the size of his rearwheel sprocket by 30% + ,or so,for more torque at the rear wheel.Would still get a bit more top speed and better climbing eff.(more motor rpm at low speed ).If not,he could consider rewinding for 36V or somewhere in between,more turns= more motor torque but similar motor speed and, with improved winding practice, possibly not all that much increase in armature resistance hopefully.

 

[machiasmort]

Safe,

I thought your idea was brilliant (w/tubes). Are the sub C's the same physical size as AA? At $3 a piece + shipping, a good source for batteries might be Craigs list $2.50 for your old drill battery, and check individual cells!

My idea for the NiMH cells was to put them in the fridge until I was ready to solder but then thought of condensation.

I even thought of powdering aluminum and mixing with epoxy for a cold solder joint! Thoughts appreciated!

If I mess arround w/Nimh's I'll post my results after testing. Thanks!

Oh, I don't give much creedence to the idea a battery would melt a solder joint directly on it for the simple reason, I've never seen one get that hot w/o direct short. Does anybody know different? Maybe I'm wrong?

 

[machiasmort]

Fuzzo,
If you try it, wear glasses Brother! I'd melt the solder on the connecting wire first and sandwich the blob of solder between battery and iron till it melted!

 

[Fuzzo]

There's quite a few good clips on YouTube showing people soldering battery packs.