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Red Hornet

The " Red-Hornet "

A bit of history, back in 2006-2007, I contacted FalconEV " http://www.falconev.com ".

I wanted some Lithium battery packs ! After an exchange of emails, i purchased 2 x 36v LiMn and one 48v LiFePO4 with chargers. August 2006

The 36v 20ah LiMn packs are being used at 72v on the Chaos .

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The LiFePO4 however, 25ah . I received the picture below in June 2007 via email.

 

Battery not having been received yet, in July, I was informed that the battery above did not pass Qality check and i was going to receive a 2nd generation pack with a better BMS, 80 amp BMS!!! .. "worth the wait !"

And during this exchange of emails, an opertunity to get my hands on a prototype motor was proposed ! Considering the fun i was having with the Chaos at the time, I agreed.

I wanted to build a Chopper, I already had a folding bike, a MTB, the Chaos, etc.. and this frame on hand :

( Stingray Frame with rear X5302 and 4 x 12v 25ah Hawker SLA's ! Picture taken November 2006)

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In october 2007 i got this:

Oh No... !

 

As you can see above, upon opening the pack, i found no BMS, a test on the LBD revealed that even tho the cells were deformed and mashed from bouncing around the plastic box unsupported.. the capacity was as promissed.

Only problem is that as soon as i tested this on an E-Bike ( the BMX ) at 40 amps, the voltage dropped like a rock. 56v hot off the charger, dropped to 31v within seconds of 40 amp use, and the pack got hot in a hurry.

Some emails and tests later, I was given the ok to perform surgery,

Very carefully, and i mean.. VERY carefully i started removing tape from the battery tabs, on the positive lead, there was a big bundle of it all coiled up and as i discovered, the aluminum tab was barely hanging on for dear life.. without the tape, the weight of the 12 gauge wire was enough to finish it off..

The presense of spot welds on the positive tab, solder blobs and markings between the cells, etc ...lead me to beleive this is a pack recycled from other sources, and assembled in pairs of 12ah in paralell, I had to split this pack into 2 sections of 12v and 33v.

Above you can see the 2 seperate packs, and the cells at the back that could not be salvaged, I had to discard the chargers as well, they failed within a few hours of use, and the fact that when the chargers were connected to the battery packs before the AC outlet, the internal fans in the chargers ran, from the battery pack !!!!!

Numbered 1 thru 15, I purchased 18 single cell, 3.2v LiFe 2 amp chargers from www.voltphreaks.com . Installed 30 amp Anderson Powerpoles on every single cell junction and chargers.. This way i can charge each 3.2v section of the pack independantly. This not only assures me of a proper end-of charge for every cell, it ballances the pack by fully charging it to 100 % on every cycle. Safely without a BMS!

Ok, so now i have a 45v pack. ( 48 - 3 from damaged beyond repair cell ).

I cycled this on the LBD a few times, and re-charged, same as before, 200w load shows full 24ah capacity with moderate voltage sag but none the less, 24ah.

Back on the E-BMX at 40 amps confirmed my fears, these cells canot provide 2C ( See " C " rate info ) . For 1700 $ lets just say I was not very impressed !

A few days later, the Hornet arrived !

Many emails later, it was decided that the factory would not replace the bad battery pack, and my only option was to accept a different used battery in good condition ..

So trying to beat mother nature, I went shopping for Chopper parts

And got the front end built, 24" rim, Disk brake.

This brings us into November 2007, and plenty of snow, so the chopper had to sit in hibernation for a while.

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January 2008

 

Above, 48v 24ah LiFePO4, 32 cells ( 12 ah each )

This pack was sent along with 2 chargers, same as the one's that had failed before, but no matching wire harness on the packs, so more surgery.

I removed the original copper wire connections, and re-grouped the packs in single series 12ah strings. LiFe is 3.2v per cell so 8 cells make a 24v pack 12ah pack. Originally, the cells were grouped in 2 paralell, this is ok with well ballanced and matched cells. Only problem is that if one of the 2 cells has a problem, it drags it's pair along with it.

Borrom right, you can see the gauge of copper difference, i used 10 gauge solid copper and flattened the ends so that the nuts on the battery posts have a good surface flat contact.

Having spent 200 $ on single cell chargers, i refitted these packs with 16 gauge taps..+ and - with Andersons on each cell.

 

Once again, more strange markings, and glue residue from removed stickers.

More sticker pictures from the first pack.. these are all in-between the cells as well.. strange.

Yes, that is ALOT of Powerpoles !

 

Back to the LBD test.. and 10ah at 10 amps holding 49.2v ! ( devided by 16 cells equates to aprox 3v per cell )

LVC ( Low Voltage Cutoff ) for these cells is 2.0v, but LiFePO4 chemistry has a very flat discharge curve.. meaning that most of the discharge happens at 3.2v to 3.0v

A few tests on the E-BMX confirmed that these cells can deliver 4C ( info on " C " rate ), they get warm at 40 amps but not Hot like the previous pack... acceptable.

 

Quote FalconEV:

72V  Red Hornet   warp speed is classified

Powerful Mega-Torque

rear drive only, 20 lbs ( must be 21 yrs or older to purchase )

comes w 1000W controller - this motor is best for long distance commuting

$1200  - special order

$1500 - 1500W controller

2 person tandem's, very steep hills

or  military special transporters

End-Quote

 

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Uhm... classified ?

 

April 11, 2008

Just got back from a good test ride ! = Fun !

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April 15, 2008

Snow we had over the weekend, finally melted, + 2 celcius, but i had to know what the magic number was.

 

So.. Survey Says :

Max Speed = 54.9 Km/h

34 Mph

( Please disregard Odometer reading, i only reset the Max Speed before i left, actual test run was 4 kms )

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