mmm not really
if the internal resistance of the cells is high then when you try and pull current the output voltage of the battery will drop meaning less current is put through the circuit.

the batteries that cook themselfs generally have low internal resistance so they will put out bucketloads of current which allows that small resistance to become a dominant heat generating factor.
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Mechanical engineers build weapons, civil engineers build targets

Is the rated current limited only by the cells ability to disapate heat?

Meaning if i used one of these blowers in my robot so that it points at the open end of my nimh battery pack with heat rings in it so the cool air can blow threw the pack would the cells be able to give out more contin current without killing them selves?

http://www1.jaycar.com.au/products_uploaded/productLarge_7871.jpg
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Tim Team Reaper.

Based on our in-house experience and some testing, we've updated our storage recommendations for NiMH battery packs. See the Storing your cells section of our Tech Tips page for more information:

http://www.camlight.com/techinfo/techtips.html#storing

In summary:
- If storing NiMH packs for a month or less, leave them discharged down to 0.9V/cell. Do not partially charge them.
- If storing NiMH packs for over a month, discharge them to 0.9V/cell and partially charge them (20% or so) to prevent any self-discharge from possibly causing cell-reversal. Be aware that the packs might have to be cycled a couple of times to regain their original capacity and voltage under load.

We've always discharged our NiMH packs down to 0.9V/cell without problems, no matter how long we stored them, but feel this is the safest advice for NiMH battery pack users.
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John Muchow, CamLight Systems
http://www.camlight.com

For those of you who thought the pre-made battlepacks were gone, then think again.
http://www.robotcombat.com/marketplace_battlepack_ultra.html
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Get Some!!!

Secretary of the Queensland Robotics Sports Club inc.

Iv just made up some of my drill nicads into packs for running my bot at home untill they die to save my good cells for battles.

How long before the drill batts die?
BTW im running two drills and a ev.
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Tim Team Reaper.

Are heat saver rings realy worth worrying about?
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Tim Team Reaper.

If you've ever felt how hot the sanyo's are after the end of a taxing heat, you'de definetly think so. They cool down faster with the gap between the cells too, allowing you to charge them sooner.
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Jeff Ferrara
fb@ffej.net

ffej.net

Dose anyone know locally where i can get some?
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Tim Team Reaper.

Just head for your local bearing or auto parts shop and buy some rubber O-rings to go around the cells. they're cheap (around 10c each), add some shock protection and give you nice spacing, with a variety of sizes and thicknesses available.
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Great minds discuss ideas. Average minds discuss events. Small minds discuss people

The other thing you might try if you can't get O-rings is PVC water pipe. it doesn't come in the right size, but the 25mm stuff can be slotted and expanded to make a C shape around the cell. Its a bit more rigid if you wanted something to glue together and shrink-wrap like the battlepacks. This would probably give you a bit more space than the O-rings for ventilation, at the expense of the shock absorbtion.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

we use 2 foam sheets with holes cut in them to space our cells
with a 60mm fan sucking air through the pack (2x 14.4 V strings) it cooled from 80C down to room temp in about 10-20 minutes
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Mechanical engineers build weapons, civil engineers build targets

I like the "intercooled" design but what a pain to cut out! any tips on drilling all those holes (apart from laser cutting )? I was thinking this might be a good use for the cheap 5mm chopping boards from Woolies.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

I was thinking of makeing an inter cooled pack with the chopping boards too.

BTW i have found some cardboard tube from spotlight to make some heat saver rings that will fit c and d cells and i think i can find some stuff to fit sub c's too its the stuff they us for there material rolls you can get it for free
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Tim Team Reaper.

we used foam so like it was pretty easy to cut out,
its only 24 holes per sheet (and if you stack them 24 holes in total)
for our complete pack. I believe we used a hole saw to cut them.
hard part was insulating under the connections so that the steel / copper links wouldnt wear through the heat shrink on the batteries and short them out.
one old floppy disk to the rescue.
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Mechanical engineers build weapons, civil engineers build targets

Cool idea with the material rolls! I will have to check that out. I thought it would be hard to get a tight fit between the bateries and the plate with a hole saw? Perhaps the 29mm battery and a 30mm hole saw is OK?

I was going to use an adjustable wing cutter and a chopping board cut-off for a no cost test - just as soon as Master Instruments has our batteries.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion