2008 Off road, Lipo - Page 7

Chris Doughty · #**121** 22-06-2007

Neil, good background info....

so the reason RC started to use subC was becuase that was really the only thing that could deliever the output we wanted...

for LiPo, it seems most of them can do that, how what or why would be used to 'choose' a LiPo 'cell' size/type?

maybe this is not such a stable idea, like was said before, if tooling for cell sizes are relatively cheep for LiPo then we are not as restricted to a certain size.

neiloliver · #**122** 22-06-2007

If the cells are in parallel they balance themselves anyway. You only balance cells in series with each other. Computer batteries (well at least the ones we design) have the balancing built into the battery and it is done automatically during charge (a voltage detection IC senses the higher voltage cell in the string and bypasses its charge current through a resistor, effectivly allowing the other cells to 'catch up'. The balancing via discharge is the second way of balancing but is a bit crude.

I would love to get one of these packs to test, i might need to do that soon in the name of competitive product research

mark christopher · #**123** 22-06-2007

Neil which pack to test?

mark christopher · #**124** 22-06-2007

Quote:

Originally Posted by DoughtyUK.net

Neil, good background info....

so the reason RC started to use subC was becuase that was really the only thing that could deliever the output we wanted...

for LiPo, it seems most of them can do that, how what or why would be used to 'choose' a LiPo 'cell' size/type?

maybe this is not such a stable idea, like was said before, if tooling for cell sizes are relatively cheep for LiPo then we are not as restricted to a certain size.

thats the bueaty of lipo chris im in the process of doing recievers pack of various sizes, because it can be done.
i also run em in my handset. KO helios, and they last for ages and run at 12 volt! ( 3 cell of course)

neiloliver · #**125** 22-06-2007

Quote:

Originally Posted by mark christopher

Neil which pack to test?

The most popular one i guess.. The orion Kokam one woudl be a good start because Kokam are a 'proper' company.. I dont know who in Asia makes the cells for the other models out there..

Mark.. can you give me a summary of the main few 7.4V packs that come with proper hard plastic cases?

mark christopher · #**126** 22-06-2007

orion do two as i presume do peak, not sure if lrp are hard case (chris can you help)?
trakpower http://www.flighttech.co.uk/
to be honest im not sure other than them who does what as i consider these to be the top sellers

neiloliver · #**127** 23-06-2007

i did some browsing last night and I think the Trackpower (gold thing that Jimmy reviewed) with cells made by 'Enerland' and the Orion (with cells made by 'Kokam') seem to be the two most popular. I have not seen any hard cased saddle pack models though, just soft packed ones.

N

mark christopher · #**128** 23-06-2007

Quote:

Originally Posted by neiloliver

i did some browsing last night and I think the Trackpower (gold thing that Jimmy reviewed) with cells made by 'Enerland' and the Orion (with cells made by 'Kokam') seem to be the two most popular. I have not seen any hard cased saddle pack models though, just soft packed ones.

N

track power are working on some,
my thoughts is hard case is a must reguirment

Chris Doughty · #**129** 23-06-2007

LRP is just 'heavy' shrink wrap with 'heavier' end peices

its semi-transparant so you can see the 4 lipo cells (they are 4 stacked on top of each other)

neiloliver · #**130** 23-06-2007

Full injection molded cases are the way to go. Lithium polymers cells are very suceptable to mechanical abuse, even running your fingernail over the metal foil can create an abnormal resistive path within the cell which can degrade it's performance. The case would not help you if all hell broke loose within the cell, but it will help protect it if your saddle packs trail out of the side of your car like zombie entrails following a shunt!