Currie Mongoose 450 watt Electric MTB

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Currie Mongoose 450 watt Electric MTB

cpuaid
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This post was updated on .
Since i didn't see very many E-bikes here, I thought i'd post my current project. Bought this thing on Craigslist with a shot battery pack. The original owner purchased it through a local scooter shop so it had some pretty nice components like front disc brakes and upgraded Shimano parts. Aluminum frame is a big plus. The way the battery is mounted keeps it pretty well balanced as opposed to my other ebikes (battery pack for Currie Trailz are mounted on each side rack and are HEAVY). The OEM battery pack are (2) 12V 12A SLA batteries and was a snap to replace. I re-wired the main wiring harness with tab/spade connectors so I can also mount a custom soft bag SLA battery pack on the Rear Rack to double my distance. Had an extra LIFEP04 battery pack for the Trailz which I also rewired with tab/spade connectors which I can carry in my backpack since the seat post mounted Rear Rack is only rated for 20 lbs.
I can make the commute to work 14 miles over many, many steep hills on the OEM battery pack alone (with lots of pedal assist of course). The 450 watt motor is a huge improvement over the 250 watt motors that comes with the older Trailz. This project is not finished yet. I have switches on the way so I can switch over battery packs without having to disconnect every time. The best part of all about this ebike is the upgraded Shimano components. It has similar performance to the mid end quality bikes. It peddles and freewheels so easily compared with the Trailz which just feels cheap. Top speed is about 17-18 MPH with no peddle assist. There is no PAS function so you've got to peddle if you want it to go long distance on the single OEM battery pack.


Currie Mongoose 450 watt MTB
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Re: Currie Mongoose 450 watt Electric MTB

Jeff K.
Mon. 11-25-2013 @ 4:55 pm EST

Welcome to the forum.  That is a very good looking bike.  The battery pack fits in nicely.  I've been running gas bicycles for five years -- no electrics as of yet -- but thank you for sharing yours.  Jeef K./ Hoser
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Re: Currie Mongoose 450 watt Electric MTB

cargo-master
In reply to this post by cpuaid
Thank you cpuaid. You have drawn me in.  Received a currie e-kit w/ twin sla batteries just the other day. Might be borrowing some of your build ideas. My intention is to pull the old battery & rip out the components on an older IZip.  Looking forward to the "new & improved" 450 watts of power vs the 180 watt motor the IZip currently has in it.  Pictures will follow as I tackle this.  
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Re: Currie Mongoose 450 watt Electric MTB

cpuaid
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In reply to this post by cpuaid
Close up view of LifeP04 battery pack from the popular Trailz e-bike that has been modified so that I can also use it on the Mongoose e-bike. Ran the wires through the fuse hole (which is not used in the LifeP04 battery pack) and tapped into the internal wiring. I run the Trailz LifeP04 as the primary and the OEM Mongoose battery pack (SLA's) as the secondary to extend the life of the SLA's. Primary wiring on the Mongoose has been modified with tab connectors for quick connects to the 4 or 5 battery packs that i rotate. wiring length was intentionally staggered to prevent accidental shorts. i can get about 14 miles per pack on the 450 watt motor with lots of peddling which is not the greatest but considering the terrain of my commute route, I am satisfied with the results.

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Re: Currie Mongoose 450 watt Electric MTB

cpuaid
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less than 50 cycles on each pack.
24V 15AH Lifepo4's VPOWER Brand ordered directly from Hong Kong
lots of money down the drain!
makes me want to cry looking at them!
prolong exposure to heat, stored with a full charge.
several dead banks in each pack.
will have to take apart and try to salvage whatever i can.

on another note, the Currie 24V 10AH Lifepo4 pack which was stored with the VPOWER battery packs is still alive and kicking.



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Re: Currie Mongoose 450 watt Electric MTB

augidog
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I have to say I'm pretty happy with my decision to use sealed packs, my K2 Energy and CTC batteries have proven themselves reliable and predictable, and I'm betting one of the reasons is above-par BMS boards. At this time, Sabrina2 has sat for months and reads 26.6, and I know if we took a ride (with onboard recharge) and parked for another extended period, I'd be able to say the same thing in a couple months.
Even looking at a map takes on a different feeling, than it did in our pre-MB years. -bamabikeguy-
Get a bicycle, you will not regret it. If you live. -Mark Twain-
The bike saved my life by giving me one. -augidog-
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Re: Currie Mongoose 450 watt Electric MTB

cpuaid
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This post was updated on .
In reply to this post by cpuaid
pack 1 is pretty much shot.
should be showing 3.5v
the way it is now the BMS is shutting down the charger.
will try and individually charge to bring them up to at least 3V if possible.






pack 2 may be able to be saved.
looks like just a balance problem.



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Re: Currie Mongoose 450 watt Electric MTB

cpuaid
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This post was updated on .
V-Power pack 2 after six hour on the charger.
Batteries still not balanced.
will have to drain, recharge, and repeat the next couple of cycles.
if that one bank still won't balance, will have to try and do a spot charge on the low bank.
i think the 6V mini solar panel i use to charge my flashlight batteries will put out enough juice to bring up that low bank.
you gotta love the cheapo BMS used for this pack!
~bleh

this bank is running high


this bank is running really low.


what the other banks are running



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Re: Currie Mongoose 450 watt Electric MTB

augidog
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This brings to mind the fires onboard aircraft. I always knew the problem was going to be that they cheaped out on their BMS's and pushed the envelope instead of over-spec'ing for safety.

The batteries I mentioned above will output 40 amps continuous AND accept a 40 amp charge, this makes them perfect to run in parallel OR series. Rocket science!
Even looking at a map takes on a different feeling, than it did in our pre-MB years. -bamabikeguy-
Get a bicycle, you will not regret it. If you live. -Mark Twain-
The bike saved my life by giving me one. -augidog-
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Currie Mongoose 36V to 24V DC converter!!!

cpuaid
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This post was updated on .
In reply to this post by cpuaid
***Disclaimer: try this at your own risk if you are using electric motor power alone and a Li-ion/LiPo/LifePo4 battery pack with BMS!!!!***


since I built the 36v 13.2 Ah Samsung DIY Li-ion battery packs for the Fezzari ebike, i've been thinking of how i could get to use them in my 24V ebikes.
i've seen these items around but have never seen anyone attempt to use it in an ebike application.
i figured at $15 it would be a cheap attempt so why not give it a try.
i needed a 36V to 24V DC converter rated with the highest Amperage i could find.
this item was rated at 15A, 360W.
item was ordered through ebay from China and arrived in 20 days.

Input Voltage:  DC 36V
Output Voltage: DC 24V
Output Current: DC 15A
Price: US $13.17
Shipping: $0.17 Economy Shipping from outside US

Specification:
Material: aluminum
Frequency range: 100k
Working temp: -40 ℃ ~ 85 ℃

I just used a couple of twist connectors and a snipped extension cord.
used as short length as i could get away with, 5 inches, in order to minimize voltage drops.
wasn't sure if the 360W output was going to be enough power for the ebike but it can actually do about 10-12 mph with no peddle assist.
I had done the DarkAngel 13T drive sprocket upgrade a few years ago so with PAS mode i could actually go about 17 MPH.
the unit gets warm to the touch but the large heatsink enclosure did a good job to prevent overheating even in the 100F Texas heat.
took it on the paved urban bike trail and the Mongoose went 22 miles on the 36V 13.2 Ah Li-ion battery pack using PAS mode.
i was worried that it couldn't handle the areas where there were very steep grades
low gear with lots of human assistance and it conquered them all
I would have to give this item a rating of exceptional value!

36V to 24V 15A DC converter!



after 22 miles usage, it still has 23.7V charge!!!



ebike battery bag $10, Green seat $9, Stealth Factor - Priceless!!!



DarkAngel 13T Drive sprocket mod, with custom green drive chain!!!



Green Foam and Black Grips .99!!!



Looking good for the Trails!!!


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Re: Currie Mongoose 36V to 24V DC converter!!!

augidog
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This post was updated on .
Something's been bothering me about this, and it finally dawned on me. You may be aware, but I'm mentioning it just in case. It's based on what I'm seeing in the pictures and my own experience to date.

It's my understanding that a step down converter (regulator) will reduce any input voltage that's higher than it's rated output, and that's what this opinion is based on. It's possible the 23.7v out is not good news.

If your 36v battery doesn't have low-voltage protection on the bms, this setup could discharge it below a safe level, and damage the pack. It's also possible that when the output reads 20v, the pack will be at 30v, and therefore automatically cut out.

I definitely want to know what you know about this. Reading the battery itself should tell you the whole story.
Even looking at a map takes on a different feeling, than it did in our pre-MB years. -bamabikeguy-
Get a bicycle, you will not regret it. If you live. -Mark Twain-
The bike saved my life by giving me one. -augidog-
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Re: Currie Mongoose 36V to 24V DC converter!!!

cpuaid
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This post was updated on .
thanks for bringing up the BMS warning.
I have edited the previous post with a disclaimer.

you are correct that the output of the converter is not an accurate representation of the discharge rate.
i should have measured the battery output at 36V with the converter unplugged after the ride.
my thoughts that the 22 miles would be a safe limit on the converter was probably based on faulty math, past experience, and pure assumption. i based the safety distance margin based on the 36V 10Ah DuraB battery shutting down @ the 9 mile mark on 800 watts (PAS mode). my thinking was that if the DIY 36v 13.2Ah battery pack was good for 17 miles @ 800 watts (PAS mode) then it would be safe for me on 24V / 350 watts to get at least 22 miles on the converter (PAS mode).

from information gathered online:
 "With Li-ion and LiPo batteries the recommended per-cell safety zone is usually between 3V (fully discharged) and 4.2V (fully charged), although they can normally discharge down to about 2.8V without any problems. Discharging below that level may cause irreversible/irreparable damage."

like you stated earlier, a properly functioning BMS has to be taken into consideration for the above statement to work.

in my situation where the BMS tolerances and specification is unknown, i chose good old fashion guestimation.
unlike most ebikers, all of my riding is on peddle assist and never strictly on electric motor power alone.
with 900 miles under my belt on these DIY 36V Samsung packs i think i didn't push it too hard downconverting it to 24V / 350 watts @ 22 miles (PAS mode).
this is the fun part in trying out something that not many have done and real world documented before.
will try the ride again this weekend for more data and report back.
 
***Disclaimer: try this at your own risk if you are using electric motor power alone and a Li-ion/LiPo/LifePo4 battery pack with BMS!!!!***

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Re: Currie Mongoose 36V to 24V DC converter!!!

augidog
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This post was updated on .
Once I figured out the Volts Amps Watts thing, and realized "a watt is a watt no matter what" this got easier.

I never doubted you did your math, but sometimes shi...er...surprises happen. It's that less-than 24V output that has me wondering what the battery reads.

Regarding your disclaimer, if there IS low-voltage cutout on your bms, it's likely the 30v norm, and that's a good thing. The important thing seems to me to be "know your bms."
Even looking at a map takes on a different feeling, than it did in our pre-MB years. -bamabikeguy-
Get a bicycle, you will not regret it. If you live. -Mark Twain-
The bike saved my life by giving me one. -augidog-
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