Jump to content



Help Support IntlWaters by donating using the link above.
Photo

40 Amp discharging of 4S Lipos


  • Please log in to reply
12 replies to this topic

#1 Bill Brandt

Bill Brandt

    World Racer

  • Members
  • PipPipPipPipPip
  • 1,727 posts

Posted 02 February 2018 - 07:38 PM

I recently discharged a couple of my 5500 4S 50C lipos using a 40 amp discharger add on to my icharger 406..All went well and I used a 3.75 cutoff per cell..I read these dischargers are used mostly with 1 to 2S lipo packs.

 

Any thoughts why I shouldn't continue use on 4S packs?

 

Bill





#2 RaceMechaniX

RaceMechaniX

    National Racer

  • Members
  • PipPipPipPip
  • 1,362 posts

Posted 03 February 2018 - 04:27 PM

Bill, which external discharger are you using?  The risk is the load is only meant for 7V instead of 14V.  The nice feature of the Junsi is it will regulate the voltage up or down to match what the load can handle up to a maximum of 40V and 40A.  Although it can only do a maximum 1000W.

 

There is a good thread on OSE about the discharger I  put together.

 

https://forums.offsh...light=load bank





#3 Bill Brandt

Bill Brandt

    World Racer

  • Members
  • PipPipPipPipPip
  • 1,727 posts

Posted 03 February 2018 - 07:57 PM

This is the discharger I used. I found as each cell reached 3.75, as I set, it stopped discharging that cell and continued with the others.
The discharger reached about 270 degrees inside with 4 fans running. About 180 on surface. Batteries only increased about 10 degrees from ambient temperature.

Attached Files



#4 RaceMechaniX

RaceMechaniX

    National Racer

  • Members
  • PipPipPipPip
  • 1,362 posts

Posted 03 February 2018 - 08:54 PM

Bill,

Those resistors are probably only good for 100W max each, so 500W total for the set-up.  What you will see if the resistors start to fail. 

What you are seeing is the balance charger discharging the higher cells.  You have your storage voltage set to 3.75V, so when any cell above that will likely be balanced down to the lowest cell it the pack.

 

The main load is applied to all the cells through the main battery leads.  The balancing current is done through the balance terminals.  

 

 



#5 Bill Brandt

Bill Brandt

    World Racer

  • Members
  • PipPipPipPipPip
  • 1,727 posts

Posted 03 February 2018 - 10:28 PM

Bill,
Those resistors are probably only good for 100W max each, so 500W total for the set-up.  What you will see if the resistors start to fail. 
What you are seeing is the balance charger discharging the higher cells.  You have your storage voltage set to 3.75V, so when any cell above that will likely be balanced down to the lowest cell it the pack.
 
The main load is applied to all the cells through the main battery leads.  The balancing current is done through the balance terminals.  

My main concern is will this hurt my icharger? I like what the results are. I just dont want to hurt the charger.
 
 



#6 RaceMechaniX

RaceMechaniX

    National Racer

  • Members
  • PipPipPipPip
  • 1,362 posts

Posted 04 February 2018 - 08:51 AM

Bill, you should be able to set the voltage and current levels for the load bank.  

Look up the specs specs on your resistor bank and enter these into the Junsi.  This will protect both charger and load bank.

 

-Tyler



#7 Kris Flynn

Kris Flynn

    World Racer

  • Members
  • PipPipPipPipPip
  • 2,864 posts

Posted 05 February 2018 - 01:45 AM

Love the discharger tyler assembled for me :-)

Now to get one that does 100amps :-)

#8 Bill Brandt

Bill Brandt

    World Racer

  • Members
  • PipPipPipPipPip
  • 1,727 posts

Posted 05 February 2018 - 11:32 AM

Kris,
Do you use in conjunction with an ichatger?
Do you use on 4S packs?

#9 Bill Brandt

Bill Brandt

    World Racer

  • Members
  • PipPipPipPipPip
  • 1,727 posts

Posted 05 February 2018 - 11:33 AM

Tyler.
I find YouTube vids but cant find specs.

#10 Kris Flynn

Kris Flynn

    World Racer

  • Members
  • PipPipPipPipPip
  • 2,864 posts

Posted 05 February 2018 - 02:03 PM

Hi Bill. Yes with a 4010 duo and yes with 4s mostly but does 6s also. Pretty sure it doesnt get to 40amp discharge with 6s though.

#11 RaceMechaniX

RaceMechaniX

    National Racer

  • Members
  • PipPipPipPip
  • 1,362 posts

Posted 05 February 2018 - 04:20 PM

Hey Chris,

 

You should be able to draw 40A on the 6S pack.  40A@22V=880W.  You may need to crank up the allowable voltage on the load side if you are hitting a limit.

 

Bill, I will try to make a video on how to set the load up.

 

Tyler



#12 Bill Brandt

Bill Brandt

    World Racer

  • Members
  • PipPipPipPipPip
  • 1,727 posts

Posted 05 February 2018 - 11:12 PM

Very kind Tyler
Bill

#13 Kris Flynn

Kris Flynn

    World Racer

  • Members
  • PipPipPipPipPip
  • 2,864 posts

Posted 07 February 2018 - 04:13 PM

Hey Chris,

 

You should be able to draw 40A on the 6S pack.  40A@22V=880W.  You may need to crank up the allowable voltage on the load side if you are hitting a limit.

 

Bill, I will try to make a video on how to set the load up.

 

Tyler

 

I have not done much 6s, so I couldn't remember :)

 

Glad to know it goes to 40amps on 6s!