Hello, everybody.
I bought an Efun-D from Dan Cardenas a few months ago, and its had its share of problems, all of which were fixable.
Recently, though, one problem showed up that is actually a flaw shared by all electric scooters that use small batteries, especially the Lithium type.
I should point out at this point that I own three electric scooters, so I checked to see if they all had this flaw, and sure enough, they all do.
The flaw? No standardized battery hold down method! Every one of my scooters, and probably yours too, if it was imported from China, uses a press-fit method of holding the batteries in place. This would work, if the battery box was uniform. Well, its not, so certain groups of batteries are free to move about the smallest "footprint" dimension. In the Efun-D, it was left to right. So, during use, the batteries moved enough to fatigue the jumper connectors on a few of the cells, and finally one of them snapped.
But it didn't just snap and disable the bike. No, it snapped in-place, which meant that the broken part was still in electrical contact with the battery terminal. So, sometimes the bike had power, and other times it didn't.
My advice to everyone on this forum is: Open up your bike and take a good look at the pack. Try to move the batteries to see if any of them are loose. If they are, insert a durable, non-conducting shim in between the groups of loose batteries to take up the slack. This is something that affects every owner of an import electric bike. - George
All electric scooters' battery flaw
Tue, 07/08/2008 - 20:54
#1
All electric scooters' battery flaw
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Support V is for Voltage
Sounds like a job for a hot glue gun!
Mr. Mik
This information may be used entirely at your own risk.
There is always a way if there is no other way!
Woo! Hot glue!
I need to get a bigger hot glue gun. The crappy 10W one I have now doesn't work all that well. :/
The author of this post isn't responsible for any injury, disability or dismemberment, death, financial loss, illness, addiction, hereditary disease, or any other undesirable consequence or general misfortune resulting from use of the "information" contai
HMM interesting, my scooter the bettery fitr very well in place and you use the key on 2 corners kitty corners and it actually locks into place, so my battery is not moving at all....
I'm wondering if spray insulation would work better. It's good at finding and filling gaps.
"we must be the change we wish to see in the world"
I wouldn't do anything that would hinder getting the cells out later, in case you need to replace any of them.
The most interesting phrase in history is not, "Eureka!", but rather, "That's funny...."
Yep, I agree - George's original idea of a non-conducting shim sounds like the best idea offered so far. However, on an XM-3000 that won't work for one of the batteries that is mounted on top of three others and doesn't have any support around it to shim against. I use two strips of heavy duty Velcro - I agree that it's not a very secure solution but it seems to have worked well on my XM-2000 and allows for the battery to be removed. Also the SLA set up has flexible cables running between batteries so it's not susceptible to the stress fractures like the solid bars that attach the LiFe cells together. However, I'll still be making sure to shim the other four batteries to make sure they're secure.
Thanks for the tip!
John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.
... and while you're checking for hold down security on a repeating basis, check the terminals for clean secure attachment. There should be NO looseness or signs of heat at any terminal. Ask me how I know.
Heh, I'll second that. I had that happen with one of my skateboards. One of the connectors had come loose, and the vibration was making it loose and reestablish contact. The arcing eventually half-melted the smaller contact.
The author of this post isn't responsible for any injury, disability or dismemberment, death, financial loss, illness, addiction, hereditary disease, or any other undesirable consequence or general misfortune resulting from use of the "information" contai
Not every chinese scooter like that,
XM3500 is well tighten by aluminum alloy strap before put inside the battery room.
Man that sure looks pretty! I'm looking forward to getting mine ;-)
One question - how is the battery management system wired up? Surely it needs at least one wire to the +ve of each battery?
John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.
The picture above for the XM-3500 shows 20 batteries but the Xtreme web page says that the XM-3500Li has 19 batteries. Anyone know the real story?
http://www.x-tremescooters.com/electric_mopeds/xm-3500li/xm-3500li.html
As I recall reading in V, original plan was for 19, which is what the early prototype spoken about on V had, but Mountain has since added one for the production total of 20.
Mountain, is voltage/charge control built-in to the batteries themselves now?
Ross