solentlife


I used an old tired 4S .... but it may be better to use a 3S if its better condition.
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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DualDesertEagle
No clue where u grabbed that 1.4V from, but NiCd and NiMH cells both have 1.2 Volts per Cell, not 1.4. Also, going out through the bottom of the shell wasn't the best idea either, coz usually the battery packs are designed to have the drill resting on them upright.
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solentlife
1.2V is nominal .... fully charged NiCd / NiMh is higher at ~1.35V. That's after resting as often they will attain 1.4V or more when they then drop a few mV to delta peak.

Even if they were only 1.2 at full charge (they are not but assume they are) ... 12 x 1.2 = 14.4

A 4S at 4.2 full charge is 16.8 .... a 3S is 12.6 ... slap bang inbetween.

I would prefer LiFe as cells are 3.6V full ... meaning a closer match to the NiCd pack ... 4S LiFe ... 
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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solentlife
After charging the 4S and giving the drill a burst ... it was warm ... so that small difference of ~0.5V is obviously once a load is on just a little much for it. The LiPo would throw as much amps as it demanded pushing the watts higher.

I dropped her back to a 3S and she is running slower but I now feel I can trust it to survive. Its also a 2200 3S nearly doubling the original NiCd capacity.
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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solentlife
My next 'trick' is to see if I can split a pack - remove dud cell and use remaining to power a tool. I have a number of 3S packs with bad cell. My 7.4V drill could likely use such ... and it would only need a 2S balance lead to charge it via one of those cheap RTF balance lead only chargers.
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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csitas
splitting the pack is easy. U tube is full of how to's. E bay has the balance leads. I ordered all sizes for a little more than dirt.The out come has been as thought.
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solentlife
I have the balance leads and even plugs for crimping.

My point is that it needs care to keep the contact that you can solder to. Most packs have 'welded' leads to the packs.

Its a job in hand to do soon.
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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