The Grinhill Mk2 RC-motor drive

[liveforphysics]

Grin,

That's not too bad on a single 6S pack!

Luke has a point... it may be time to sink another 59 into a new pack...

also as odd as this may sound to some people, I have begun using 2 pieces of 1/16" ABS plastic when I build my packs... I clamp the packs within these ABS plastic "end caps" really just rectangular pieces the length of the packs then I wrap them in extreme duct tape before releasing the clamps.

End result is that since Ive begun this "process" (ghetto as it is) i've not had a single expanding battery due to heat and the temperature of my newer packs is 10-15 degrees f cooler than my old loose sided packs.

I assume this is due to the factors luke mentions above but I had no idea when I started doing it, I just didn't want to see the outter cells swell anymore = )_

-Mike

I've been doing the same thing 5lbs of tension on the electrical tape as I wrap a stack of packs, and I do 10 wraps in 4 places. It works out to be 200lbs of clamping force on the cells.

I played around with an old seriously abused (drained to 2v, over charged to 4.5/cell, lol) helicopter pack that was badly puffed. It was more like a sausage than a brick. lol. I hooked up my ghetto halogen bulb load bank with a voltage meter on it, and put the pack into my vise and started putting some pressure on it. The saggy voltage jumped up like 2 full volts when I put some squeeze on the layers I worked it out to have cut Ri by something like ~80% over no clamping on the poor damaged pack.

Packs like to be squeezed Just not so hard that the layers short inside

 

[liveforphysics]

Thanks guys.
The plan for my next build is to buy four 6S packs, and then combine them with my existing 8S2p pack to build a 4p10s pack.

This pack is my very first LiPo pack. It's already served me very well, even if it died tomorrow. I'm going to regret writing that aren't I?

Running cells in 4P is going to feel great. Say good-bye to voltage drop

 

[Grinhill]

I hope not! But if it does, can I buy the BMS from you?

BMS? What BMS? These RC Lipo packs are just slapped together and shrinkwrapped aren't they? The balance connectors are just tappings to measure cell voltage and do low-current charging at cell level, the smarts are in the chargers.

 

[amberwolf]

Ah, I didn't know that. I was just joking anyway (mostly--I *am* looking for BMSs that can be used for LiPo packs built from 18650s, preferably ones people might have tossed anyway due to being cooked or otherwise damaged but might still be repairable, because I might be able to afford those as opposed to new ones).

 

[recumpence]

Grinhill,

Your drive and what-not should be at your house within the next couple days. It shipped last week.

Any progress other than waiting on the drive?

Matt

 

[Grinhill]

Thanks Matt, check the thread in Ebikes Photos/Videos (although nothing recently). I had it over there so some of the hubmotor guys would be more likely to see it!

 

[Grinhill]

My replacement HV100 from Hobbycity arrived last week, I love those guys! All it cost me was $8 postage.

None too soon, as my little controller stopped working a few days ago!

Now back on 8S2P pack, much more civilised