Using and charging Lipo batteries

[Sumilidon]

Hello all,

Well I finally got all my connectors soldered on and it;s time to charge these lipo batteries.

Obviously they come with a warning the size of China but no direct questions, so hoping for some help.

I understand I can balance charge at a rating determined by the MWH

eg. 5000mwh = 5A maximum charge rate

Whats the rule therefore for things like fast charging? Avoid at all costs? Run at a lower rate?

[Steven Forster]

Originally Posted by Sumilidon

Hello all,

Well I finally got all my connectors soldered on and it;s time to charge these lipo batteries.

Obviously they come with a warning the size of China but no direct questions, so hoping for some help.

I understand I can balance charge at a rating determined by the MWH

eg. 5000mwh = 5A maximum charge rate

Whats the rule therefore for things like fast charging? Avoid at all costs? Run at a lower rate?

heres an example..........

7.4v = 2S

5400mah = 5.4 amps (1C rate)

never charge above a 1C rate (as above)

never charge above 8.4v

never discharge below 3.0v (per cell)

some say manufacturers state on newer LiPos a minimum of 3.2v per cell

most if not all manufacturers say to always balance charge your LiPos

so using the example above, set charger to.........

LiPo

7.4v or 2S

maximum rate 5.4 amps (can charge at lower rate but will take longer)

balance charge

then start charging

Always use a LiPo sack and never leave unattended !!!



ps check out youtube for over charged and/or over discharged LiPo batteries to explain the last sentence............

[Sumilidon]

Superb. Thanks. Is it the same for a fast charge?

[JCJC]

Thats good advice, you will get a quicker charge if you don't balance, but do balance sometimes.

[Steven Forster]

Originally Posted by Sumilidon

Superb. Thanks. Is it the same for a fast charge?

you can use fast charge, but some people/manufacturers recommend always balance charging the LiPos !!!

It wont take long to balance charge the LiPos as you dont (not supposed to) run them below 3.0 or 3.2 volts per cell.

for example last time i raced it was only taking on average 15-20 mins on balance charge to charge my LiPos up (around 1000-2000mah)

The use of faster motors, gearing, higher discharging C rate LiPo, 2wd, 4wd and different track surface's will change the amount of Mah's and volts being used which raises the charging times.

2 LiPos should be enough for 1 class of racing...............

[Sumilidon]

I have 2 sets of lipos so hopefully they should be sufficient. Ordered a lipo bag as well just in case.

Batteries have charged nicely and wow, what a difference to the motor output.

Thanks for help

[Steven Forster]

Originally Posted by Sumilidon

I have 2 sets of lipos so hopefully they should be sufficient. Ordered a lipo bag as well just in case.

Batteries have charged nicely and wow, what a difference to the motor output.

Thanks for help

Another thing to remember is if not using them for a while its best to store charge your LiPos at 3.6v - 3.7volts (per cell) so your LiPos dont degrade in performance (as some manufacturers would say)

[Sumilidon]

Originally Posted by dexter24

Another thing to remember is if not using them for a while its best to store charge your LiPos at 3.6v - 3.7volts (per cell) so your LiPos dont degrade in performance (as some manufacturers would say)

What kind of timescale are we talking? A week? Just thinking between meetings is all

[Steven Forster]

Originally Posted by Sumilidon

What kind of timescale are we talking? A week? Just thinking between meetings is all

http://robotwars.00server.com/tutorials.html

[JCJC]

we have had lipos sitting unused for months, half charged, don't leave connected in the car even with the switch off and don't run until flat, see how long it takes to forget all the hassle of your old cells