Lipo advice

[RickRick]

Just looking into lipo's

whats the score with using crazy high power brushless motors 3.5/4.5 with a relativly low 25c 3500 lipo pack

does it just limit the current it can push out, or is there a chance of damaging the cell?

[JJ The Boat Wizzard]

Hi m8

If the motor is trying to pull 90-100amps and the battery cannot give this say a 3500 25c that can only give 25c so thats 87.5amps , the battery is at risk of 'puffing' where the cells puffup and can burst into flames if pushed too far (however this is highly unlikley) , also you wont get a motor and a spedo in a 1/10th car that pulls 100amp most spedos that say they can cope with 250A+ that is utter crap they cannot a 1/8th spedo can only just handle 150A , a 1/10th brushless motor will pull between 60-100Amp and thats 'silly motors' as you refer to them. so you dont have to worry.

Only worry if the battery is like a 2400 10c then your in trouble

Hope this helps
John

[mark christopher]

ignore the bit above about puffing and bursting into flames

the lipo will give its max, so if the speedo is needing 100amps, the pack will only deliver is 87.5 amps, very little chance of puffing or smoke as thats its rating

look for around 3600 30c or 4900 25c or above

[JJ The Boat Wizzard]

Ive seen it happen ! dont say its not possible just because you have never seen it! i have seen it happen just not in a long while and i dont expect to see it happen again especially with the new cells. I also know the technical reason why this happens but its too long winded to post i would gladly enlighten you if i saw you face to face :P

However he is right about what batterys you want to be looking for

John

[leeleefocus]

Originally Posted by mark christopher

ignore the bit above about puffing and bursting into flames

the lipo will give its max, so if the speedo is needing 100amps, the pack will only deliver is 87.5 amps, very little chance of puffing or smoke as thats its rating

look for around 3600 30c or 4900 25c or above

Your wrong there i'm afraid(Don't give advice about lipo's if you don't know what your chatting about). The pack can deliver more than it is rated at.

The rating is the safe ammount of current that the battery can deliver without damaging itself and or going below a useful voltage(voltage sag). If you pull more current from the battery then the other poster is correct there is a possibility of puffing, over heating the battery and/or damage to the cell internally.

The possibility of fire is there but you have probably got more chance winning the lottery.

What you need to know is the constant current and the peak current that your speed controller and motor combo will pull and then get a lipo that has a higher constant current rating and burst current rating than your setup.

If you treat lipo's correctly they will be one of the best purchases you make. If you abuse them there is a chance they will bite you back.

I advise you to spend a few hours reading up before you buy and watch a few of the youtube videos.

Once you get them though there is no going back.

[JJ The Boat Wizzard]

Originally Posted by leeleefocus

Your wrong there i'm afraid(Don't give advice about lipo's if you don't know what your chatting about). The pack can deliver more than it is rated at.

The rating is the safe ammount of current that the battery can deliver without damaging itself and or going below a useful voltage(voltage sag). If you pull more current from the battery then the other poster is correct there is a possibility of puffing, over heating the battery and/or damage to the cell internally.

The possibility of fire is there but you have probably got more chance winning the lottery.

What you need to know is the constant current and the peak current that your speed controller and motor combo will pull and then get a lipo that has a higher constant current rating and burst current rating than your setup.

If you treat lipo's correctly they will be one of the best purchases you make. If you abuse them there is a chance they will bite you back.

I advise you to spend a few hours reading up before you buy and watch a few of the youtube videos.

Once you get them though there is no going back.

THANK YOU FOR BACKING ME UP!

[Mike Haswell]

Remember that the C is the constant current rating - most have a higher 'burst' rating although it can be difficult to find. I have a 5,000mAh which is rated at 20C (100 amps) for continuous discharge and 30C (150 amps) for burst.
This has performed very nicely over the last year but having tried one of the latest higher rated packs then it would be much better to get one of those. Not only can it deliver more power comfortably but will be under less stress.