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....
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
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