Upgrading MM E -1000 electric bikes to Lithium ion batteries.

I74

Well-Known Member
I stayed up ''way''' to late last night, & as soon as I woke up this morning,, I figured out the series thing.
It was actually really stupid on my part.:rolleyes:

It goes like this : + ___-+ ___-+ ___-+ ___-+ ___-+ ___-+ ___-+ ___-+ ___-+ ___-+ ___ -+___- +___-

Then like Dave said,, when you have top & bottom ones also,, plus some of the cells right side up or vis versa,, they just still stay connected like this, but with ''battery 'bus' bars'' of different sorts & sizes tying together going different directions.
I tried to find 13s 3p layout schematics, but had no luck.
The pics. Dave found,, is ''spot on'' & how these packs are configured.:)
What a conglomeration, looks real solid though !!
Am guessing these packs were configured with virtual programs on computers.
 
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I74

Well-Known Member
Went down to the metal supply place today, & got some aluminum out of their ''discount'' scrap pile.

Initial base frame work I made out of 3/32 plate,, & bent & cut it myself.
It did not want to bend even with lot's of heat.
Very ''stout'' stuff, & ''a lot'' of work with out having a press brake ect.. 100_6310.JPG
 
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You really have my interest for building an electric minibike but I am concerned about the danger of lithium cells having a melt down from the bouncing and jarring they would get with off road use. People have reported that shorts can happen up to 3 days after the damage occurs and as we have seen the results can be devastating. Is there any way to eliminate this risk other than storing the batteries outside?
 

I74

Well-Known Member
You really have my interest for building an electric minibike but I am concerned about the danger of lithium cells having a melt down from the bouncing and jarring they would get with off road use. People have reported that shorts can happen up to 3 days after the damage occurs and as we have seen the results can be devastating. Is there any way to eliminate this risk other than storing the batteries outside?
Hi Mariah, :)

The 18650 cells are generally pretty well contained, like reg. Energizer E2 lithium ones that you can buy in any store that sells batteries.
The 18650 cells are pretty much as safe as those.
The lithium packs that I have seen having problems are generally the ones for R/C applications ect, that are ''Lithium polymer'', & some of the cheaper ''LiFe'' ones that are pretty much used for transmitters & receivers.
Those lipo's & LiFe packs are usually wrapped in like a foil, & do not have protection circuitry.
They generally will ''puff'' from mostly being discharged below their nominal rated voltages.
You especially ''never'' want to over discharge a''Lipo'', as they can also catch fire & burn under water !

I think Lipo's is what took down the Malaysia flight. :(
Lipo's are the most volatile within the first 48hrs. that they are made,, & supposedly that plane was loaded with fresh crates of them.
You only need one of those to short ect. & set off the whole works,, especially if they are all packed together.

With the BMS protection circuitry ect. in the 18650 packs ect., they are generally pretty safe.
Lithium ion is ''way'' less volatile than Lithium polymer.

I am the part time outdoor power equipt. specialist @ Lowes,, & all of our batt. powered stuff now is pretty much ''Lithium ion''.

A lot of the larger packs are made up with 18650 cells, & they ''all'' have protection circuitry.

The main thing I tell customers & coworkers is: ,, when the cut off point kicks in on the unit,, do not try & keep running it.
Also,, store the packs for ''long term'' @ 1/2 charge,, between 35*f & 70*f, & don't store in sub zero temps, or direct sunlight,, & in high temps.

I have Dewalt Li- ion power tool packs that are still going strong after 9 years,, because I take care of them.
I also ''never'' leave any pack power leads ect. plugged in when not in use,, ''OR LEFT ON THE CHARGERS WHEN CHARGED'' ,, like you see ''a lot'' of your neighbors ect. do,, with them plugged in to the chargers 24/7,, on the back of their work benches ect.
That's an accident waiting to happen right there.... :eek::rolleyes:

I'am an avid R/C Guy, & have been along side the progression of rechargeable electric stuff since the mid 70's.
To me,, the Lithium ion packs w/ BMS,,, is one of the neatest innovations since sliced bread ! LOL :p

Lastly,,

If you go back & look @ my pics, when I put in the 2 - 36v packs in the MM-1000,, you will see that I glued & lined the batt. tray floor with ''foam tool box mat'',, & also used that mat between the packs & bottom on them.. ''Thicker, the better''.
You will also see that there is a foam frame work around them, & they are secured with Velcro straps ect.
Doing something like that,, you should be fine. ;)

I
 
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Very essential information and I for one am glad you took the time to explain the details so clearly. Thank you kindly 174 for bringing me up to date with the new battery technology!
 
beware of china ! batteries and cheap chargers!! serious fire hazard. i would only store those batteries outside and never charge them inside. and remember . if you pick up a battery charger ? and it weighs next to nothing? thats what you got!!! lol . seriously. just be damm carefull with those . but have fun electric . is very sweet done right
 

I74

Well-Known Member
Thanks for that gasgas300.:)
I definitely concur with the cheap chargers !
The 2 that I got with my 36v packs, ran ''really'' warm.
I strategically drilled a bunch of holes on each side of the plastic cases for air flow, & have a desk fan in front of both of them when charging.
Doing that cut the temps down over 1/2, & acceptable.

If you don't get chargers ''like mine'' with packs,, I highly recommend getting chargers with built in fans. ;)
 

I74

Well-Known Member
Look'ee what showed up today !!
Both packs arrived with exactly 52 volts ea.,, which is good.;)
Fit is snug, but their size description & my layout,, will work just fine.
Got the power leads, fuse harness,, & Y harness all done.
Fred decided he wanted to go with a cam key lock assy, instead of the latch types ''dzus'',, for race car panels & aircraft ect.
Still waiting on the throttle,, ''go figure''. :rolleyes:
Hope to get it finished up by the first week of Nov., as we are supposedly supposed to have a few really nice days then,,, we shall see …...

I
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I74

Well-Known Member
Just had an idea....
If this ''less than'' 75lb. AUW - 48volt 1800 watt Mini bike will do an est. 40+ mph, with a 170 lb. dude on it, with 6.1 - 1 gearing @5200 rpm's,, how about the same Dude riding it,, & gearing it to 3.4 - 1, & trying it out on the Bonneville salt flats & setting the land speed record for a 48v ''Elect Mini bike'' .. :p
Am figuring 70+ mph easy.
That motor has plenty of torque to do it. ;)

I
 
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I74

Well-Known Member
Added,,
I know they would want me to add a front brake.
You always want to brake with the ''rear'' brake on a bike ''first'' regardless.
Probably wouldn't use the front brake at all....
 
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