[jr dragster]

were using mars 1003 mabye not the best one to use but that was what would fit , with out to much work.When looking for batteries you need something with a high c-rate like 20 and up.Some only have a c-rate of 3 or 4 .

[ken6881]

Why not use lipo cells for under $400 you could have a 74v 15ah 20c continuous pack(300a capable would that be enough)?

[tropes]

Originally Posted by jr dragster

were using mars 1003 mabye not the best one to use but that was what would fit , with out to much work.When looking for batteries you need something with a high c-rate like 20 and up.Some only have a c-rate of 3 or 4 .

Having used the Mars 1003 for the first year, you would have some idea as to the best motor for this application. Without any experience I purchased the K91-4003. It probably comes down to a motor/battery combination with weight and space being factors. What motor would you choose if you were starting over? As far as battery charge rate, my understanding is that any battery with a charge rate greater than 40 would probably not last as long as a battery with a C-rate of 20.

[ken6881]

C rate does not mean charge rate it is how many amps a batter can deliver compared to it's capacity. 15ah times 20c = 300 amps it can put out. Usually charge rates are less than discharge rates

[jr dragster]

Was looking around on the net found these what do you guys think thunder power tp 5000-10spp65l 37 volts they claim 350 amps, max of 650, do you think they would work. very light weight, very expesive, $449.each ,what are your thoughts. thanks

Originally Posted by jr dragster

Was looking around on the net found these what do you guys think thunder power tp 5000-10spp65l 37 volts they claim 350 amps, max of 650, do you think they would work. very light weight, very expesive, $449.each ,what are your thoughts. thanks

Looking at the specs, 5AH seems a bit shy of what you may want. You could burn through that 5AH real fast on the strip. One other mentioned a larger AH pack and a 20C discharge rate for bursts down the track seem more in line with what you should be looking at doing. Price is cheaper too.

Pete

[Yabert]

Hi Jr

I have always be interested by those high power Lipo cells for realy short burst of high power (relatively) and I think they can be good for your 10 sec application.

From long time now, I'm interested by those cells: http://www.hobbyking.com/hobbyking/s...&LiPoConfig=10

Theorically, you can discharge those cells in less than a minute and two battery in serie can give you 15-20 Kw of power. Not bad for 7-8 lbs of battery! I think you can try for only 300-400$.
But please take extremely care of the dangerosity of those cells. Putting those one in an insulated metal box is probably a good secure idea.

Oh! and don't forget to charge with balancer charger...

[ken6881]

I have ran turnigy cells for rc use and would say that i am very happy with the quality and the price cheapest way to buy 20c 5000mah cells is actually to buy the 7.4v 2s pack just fyi if your interested in buying alot of them

[jr dragster]

Originally Posted by Yabert

Hi Jr

I have always be interested by those high power Lipo cells for realy short burst of high power (relatively) and I think they can be good for your 10 sec application.

From long time now, I'm interested by those cells: http://www.hobbyking.com/hobbyking/s...&LiPoConfig=10

Theorically, you can discharge those cells in less than a minute and two battery in serie can give you 15-20 Kw of power. Not bad for 7-8 lbs of battery! I think you can try for only 300-400$.
But please take extremely care of the dangerosity of those cells. Putting those one in an insulated metal box is probably a good secure idea.

Oh! and don't forget to charge with balancer charger...

DO these cells CATCH FIRE EASY?? I need something safe, or as safe as batteries can be .

[ken6881]

Originally Posted by jr dragster

DO these cells CATCH FIRE EASY?? I need something safe, or as safe as batteries can be .

as long as you dont over charge them, or stick a nail in one, or short one out you will be fine.