Mountain Bike Reviews Forum banner
1 - 14 of 14 Posts

·
Registered
Joined
·
134 Posts
Discussion Starter · #1 ·
I have been using 2xpanasonic laptop batteries (wired in series to give about 21v )to power my front lights (triple P4) and found the batteries protection was shutting 1 of them down.
It was getting to be a pain as it would do this mid trail.
Weird thing is the light would work again after about 5 mins and go on again for about 10-15 mins.
Solution to the problem? rip all the pcb's out of course!
Tried it all out after i wired it all up again and it went for 2 hrs without blowing up or getting hot!
Only trouble is i had been charging both seperately with the old laptop but now the batteries had its guts ripped out i have had to use my poor little 3cell charger to charge them one at a time until i can get myself a decent charger!
If anyone had a nice little low voltage warning circuit tucked away somewhere point me in that direction before i have a meltdown and become my own firework display!
Saves buying a new battery though!
 

Attachments

·
Registered
Joined
·
134 Posts
Discussion Starter · #3 ·
I got the batteries for free so i think rather than spend money on them i will rig up a "quick release!" on my stem so if i smell burning i can pull the ejection cord and pedal off quick!!
 

·
mtbr member
Joined
·
890 Posts
heatstroke said:
go to united hobbies and order a 3s lipo battery monitor to hookup to your batt. its dirt cheap too .
http://www.hobbycity.com/hobbycity/...roduct=6589&Product_Name=Battery_Monitor_2-6S
I have one of these and it is a bit flakey - usually needs to be reseated a couple times before it works - though I bought mine on Ebay.

Here is a link I found, with a monitor that may work. I am planning to use one in my light with takes an 18V battery for similar reasons.

Just a suggestion, those exposed terminals are looking for trouble, I suggest using some tape on them so they don't short on your frame or each other.

BTW, is that 20 cells? What the heck are you running with that thing anyway :D
 

·
Registered
Joined
·
134 Posts
Discussion Starter · #7 ·
Its 10.7v each battery,3x3.6v x3 so 9 individual batteries in each pack.3xbat in parallel (older laptop) then wired together in series to give about 21.6v.(more when charged)
I am only running 3xSeoul P4 with 1000mA buckpuck so need about 14v but they were free and i am not sure of their condition so its nice to have excess voltage to play with.
 

·
Registered
Joined
·
134 Posts
Discussion Starter · #8 ·
Just a suggestion, those exposed terminals are looking for trouble, I suggest using some tape on them so they don't short on your frame or each other.

I left it part wrapped unil i was sure it wasn't gonna catch on fire!
Be assured it is all covered very well now mate!
Cheers
Tommo.:thumbsup:
 

·
Registered
Joined
·
134 Posts
Discussion Starter · #10 ·
They are tagged together so its not possible is it?
Anyway just been out for 2hrs didn't catch fire or run out of juice so all good so far!
If i do have problems i will have to dismantle it and hunt for bad cells but it all charges ok
so its all good!
 

·
Registered
Joined
·
134 Posts
Discussion Starter · #12 ·
I have watched various Li-ion fires on youtube and they look very impressive!
I have a mate building me a couple of voltage monitor boards at the mo to let me know when i get to about 18v. A visual green over20v,amber 19v,red 18v.
Will like you say just have to be careful.
 
1 - 14 of 14 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top