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

I74

Active Member
#1
I made a couple posts about the MM E -1000, 1000 watt / 36 volt minibike Lithium battery upgrade in the ''MM front suspension thread'', & after finding interest about it from others,, I thought it best to just start a thread.

Will start again from the beginning ……..

Am getting the wife a MM E-1000 mini bike.
It comes with a 1000 watt motor, 15 amp speed controller, & 3 - 12 volt 15 amp lead acid sealed batteries that run in series, to make 36 - 39 volts & 15amps.
These batteries weigh around 26.5 lbs. together.
They are real ''boat anchors'', & the way they set in the bike, is pretty high up in the housing,, setting on a tray,,, giving the bike a high center of gravity.

12v lead acid batteries are not really designed for fast discharge & power consumption.
They are really made for being constantly charge regulated with an alternator ect…
Generally, constant high amp fast discharge ect. permanently kills them pretty quick.

The plan is to replace these with 2 - 36 volt 10s 4p ''10amp'' lithium ion packs with built in ''BMS'' circuitry, & run them parallel.
The BMS is a circuit board that is integrated on top of each pack under the shrink wrap covering.
It monitors the voltages of the pack, & has protection circuitry against over charge, & discharge.
Each pack has 40 lithium ion ''AA'' size cells, that are divided up in a combination of 10 sets of 4 that are wired together in parallel, 3.7 - 4.2 volts a set.
They in turn are wired in series of 10, to make 36 - 42 volts. ''42 volts fully charged''. ''4.2 times 10'' = 42 volts

The 10s 4p description means , ''10 series'' & 4 ''parallel''.

The BMS circuitry also regulates the charge current to the cells to balance charge each one, & also regulates for balance discharge, so the cells draw the same.

Now for the real goody …..

These packs only weigh 4.4 lbs. each, & 2 of these packs together, weigh a bit less than 1 of the lead acid batteries !
That is a weight savings of over 66%, & almost 20 lbs. !!

2 of these packs in parallel , still have 36 - 42 volts together, but the amp capacity doubles, ''20+ amps'' .

The electronic speed control that comes with the bike, is regulated for a max current input off the batteries of 15 amps.
Both packs together have a capacity of 1000 watts, as the motor & ''ESC'' are rated for.
The ''ESC'' with these 2 packs in parallel, ''36 - 42 volts'' , also will still think that it is tied in with the stock batteries, & won't hurt it a bit.
The extra capacity of the packs, can best simply be defined as - ''reserve when needed''.

Both packs will fit on the stock tray, & take up only about 1/2 the room.

Figure the run time will go up from the advertised 40 - 45 min., to around 1 1/2 hrs.
Performance gains should increase pretty noticeably also.

Looked on aliexpress this morning, & they have these packs on sale for $83.30 ea.
They come directly from China w/ free ship.
You also want 2 36v - 2 amp chargers, so you can charge the packs separate.
They are $9.35 ea. & free ship.

After that, all you need is a parallel battery harness with connectors, to replace the plug in series harness that comes with the bike.
They are very simple to make, using 12 gauge ''high strand'' silicone wire & XT - 90 connectors, ''these are used a lot with large electric R/C stuff.

That's all for now,, hands getting tired from typing . LOL


Ian
 

I74

Active Member
#7
Ordered my packs, chargers, & connectors this morning.
The manufactures 15% off coupon expires in 22 hrs., so I figured I better get while the gettin's good....
83 bucks for each pack, & under 10 bucks a piece for the chargers & free ship, is a heck of a deal.
They will probably take 3 + weeks to get here from China, by then I should have the bike.
Am also getting 2 mini 36v. blue led read out volt meters, 1 for each pack.
They will be mounted in a car stereo face plate case on the handle bar cross bar, & wired down to each battery charge lead with plug in connectors.
 

I74

Active Member
#10
Did some research on the motor, & found out that it is pretty much the best & most powerful ''bang for your buck'' 36+v. 1000w DC brushed offering out there.
The armature shaft is full ball bearing on each end, & it has 4 ''very stout'' brushes, that are spaced around the commutator 90* degrees apart.

Think it should last for years …….
 

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I74

Active Member
#11
My packs just arrived here in the States from China.
They are getting transferred to UPS.
I will keep everyone in the loop, on how this keeps on.
I
 

I74

Active Member
#12
Just got my packs.
They weigh 4.3 lbs. ea. times 2, = 8.6 lbs. :)
The voltages of ea. pack are exactly 36v. ea. Nominal !!
Checked both charge lead / BMS on each pack also, & they are 100 % !!


Still waiting on the chargers ...….
They are supposed to be here within a week or two .....
 

I74

Active Member
#13
Just got the parallel harness & batt. connectors made up & soldered.
The XT -90 anti spark connectors is what I used, & are pretty much the top shelf offerings out there, for high current - high voltage applications of this size.
There is a resistor in the female +''pos.'' terminal that's connected between this terminal that is in 2 pieces.
That 's the side of the connectors where you see the ''green'' markings.
Basically what that does,, is when you push the +''pos.'' & - ''neg.'' connectors half way in, it allows just enough current to charge the capacitors in the ESC, but does not make a full connection yet until pushed all the way in.
In turn,, the first step pushed in, keeps from getting a power- current spike/ flash at the connectors from the capacitors.
I plan on replacing the motor connectors with these also.

Hope to get the bike here in March.
Breads just a little tight at the moment ......
I
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I74

Active Member
#14
Just got both my chargers in the mail, & they both work !! :)
Hope to order the bike in the next couple of days..
I
 
#17
Watch out for China & their power claims on lithium batteries. They tend to be a bit optimistic when it comes to capacity. I'm very interested to see how your numbers with their data coincide, with the actual use you get on the road. Please keep us up to date with test results, battery life, charge rates, etc.

Very interesting project!
 
#18
Late to the party again. Keep us posted. I was given one of those electric scooters and like you look at those 3 SLA batteries as boat anchors.
Still not sure whether to go Li ion or Lipo. I'm quite familiar with Lipos as I fly electric airplanes, but the Li ion's look kinda neat. If I go that route I'd build my own packs, already have a spot welder I built. Where did you get the resistor connectors? Hobby King?
 
#19
Just to throw a monkey wrench into things, after reading up on these systems. Wattage ratings! Are they "peak" or "continuous" watts.
Peak is what a motor can handle in short bursts, like if you have to climb a hill, and continuous is what the motor can handle continuously without overheating.
My scooter has a 350 watt motor, with a 20 amp controller. Well at 36 volts X 20 amps that comes up to 720 watts. How/why can you have a power system that can put out 720 watts when you only have a 350 watt motor? Only guessing here but I bet the motor rating is continuous watts, but can handle at least 720 peak.

And there lies the problem, companies and how they rate their motors. Some countries limit the wattage of a motor for bikes/scooters, so companies kinda fudge them to allow em to be sold. So you may have something rated in one place for 250 watts, where the very same thing in another place is actually 1000 watts rated. 250 continuous vs 1000 peak. And that's where it just starts! Something I learned playing with electric motors in planes.
Watts is the rule, how you get to there is the fun. And how you can get more out of a motor. You can fool a motor to get more out of it just by using watts. 10 volts X 100 amps is 1000 watts, so is 100 volts X 10 amps. A motor has a KV rating as in how many rpms per volt it can make.
So say you have a 50 kv motor. On 10 volts it will spin 500 rpm(theoretically) on a 100 volt input it will spin at 5000 rpms. Again not taking into account drag, bearing quality, etc. What does all this mean? Performance! Over volting a motor is like adding a supercharger to an engine.
Keep the amps and volts to match the watt rating and the motor doesn't care, how you come to that rating is where you can take a put put system and make it into a screamer.
No not black magic, and yeah you can sometimes damage things, I won't even get into modding controllers to carry high current, but hey that's what most of us are about, even with engines, we experiment with getting more out of them.
 

I74

Active Member
#20
Thanks for the interest in my thread, & the posts,, Guy's. :)
I' am an avid R/C ''electric'' guy myself , & have been for many years,, with following the progression of batt. technologies.
These packs I purchased, have a very good review, & feedback rating.
The 2600 ma - 18650 cells are said to be generally better than ones used in the Tesla's,, from a couple of feed back reviews.
Am supposed to get the bike Mon. or Tues.
I plan on trying it out with the stock set up first, maybe put a watt meter on it ect., & then go from there.;)

Am also going to weigh all 3 boat anchor batts. with the steel case they reside in.
I est. the steel case ect, with the 3 batts,,, probably weighs close to 30 lbs.:rolleyes:
I
 

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