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Who charging 20+ amps or more now??

Who charging 20+ amps or more now??

Old 01-13-2015, 05:31 AM
  #631  
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Originally Posted by Skiddins
Why not get the usable voltage test to stop at 7.5V etc for the pack?
No-one will be running a pack below as low as 6.6V unless they've forgotten to change it from the last run

3.3V under 200W load.... the voltage bumps back at rest to about 3.6V/cell... meaning it is more or less empty

Why 3.3V/cell -> to see how much cells are matched in a pack. Poorly matched cells can differ up to 0.2V! Good come under 40mV.
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Old 01-13-2015, 11:06 AM
  #632  
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Originally Posted by jedi
John, are you using a 24 volt power supply to charge 2s batts at 25amps or will a 12 volt power supply do? If not, what is the maximum charge rate using a 12 or 14 volt power supply? Thanks.
12V Car Battery so I can discharge at over 20 amps (cannot do that with a power supply on the ICHARGER). Don't know what the max charge rate is for a 2C pack with a 12V input power, but I've done 25 amp and no problem from the charger point of view (just make sure your battery has enough C rating to take that charge rate), but I usually charge at 20.
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Old 01-13-2015, 11:53 AM
  #633  
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Originally Posted by John Wallace2
12V Car Battery so I can discharge at over 20 amps (cannot do that with a power supply on the ICHARGER). Don't know what the max charge rate is for a 2C pack with a 12V input power, but I've done 25 amp and no problem from the charger point of view (just make sure your battery has enough C rating to take that charge rate), but I usually charge at 20.
Sure you can discharge at 40 amps on the icharger using the power supply if you use a resistive load such as bulbs or resistor bank. I do it all the time.

With my 12v power supply I can charge 2 2S packs at 40 amps each with no issues either. 24V is not required.

EA
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Old 01-13-2015, 12:37 PM
  #634  
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Originally Posted by Miholc
Capacity winner of 2S HC pack: LRP 7500, 7200mAh usable from 4.2-> 3.3V/cell @ 200W constant discharge.
This may be a silly question but how can you measure capacity?
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Old 01-13-2015, 03:35 PM
  #635  
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Originally Posted by EAMotorsports
Sure you can discharge at 40 amps on the icharger using the power supply if you use a resistive load such as bulbs or resistor bank. I do it all the time.

With my 12v power supply I can charge 2 2S packs at 40 amps each with no issues either. 24V is not required.

EA
Thanks EA and John. That's the info I was looking for.
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Old 01-13-2015, 04:19 PM
  #636  
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Originally Posted by dave-man
This may be a silly question but how can you measure capacity?
Fill it up, then discharge it, measure how much comes out.
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Old 01-13-2015, 05:35 PM
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Originally Posted by EAMotorsports
Sure you can discharge at 40 amps on the icharger using the power supply if you use a resistive load such as bulbs or resistor bank. I do it all the time.

With my 12v power supply I can charge 2 2S packs at 40 amps each with no issues either. 24V is not required.

EA
Of course Eric, with enough light bulbs you can discharge at very high rates and don't even need the ICharger (just like we did with Nicads and NIMH cells). But with only the ICharger, the max discharge rate in the non regenerative discharge mode (at least on the 306B that I have) is 20 amps unless you attach additional light bulbs and/or resistors. I just bought a car battery and use the regenerative discharge mode and I discharge at as high a rate as I'm comfortable with. BTW Those light bulbs came in handy one night when I was racing in Ohio and the power went out during my race. All the NiMH batteries being discharge with light bulbs provided enough light to find all the cars that were racing when the lights went out.

Last edited by John Wallace2; 01-14-2015 at 04:14 AM.
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Old 01-13-2015, 07:24 PM
  #638  
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Originally Posted by Miholc
You are obviously not understanding how 4010 charger measures the IR.

IR can only be measured on the 4-wire Kelvin method, you can see more here: https://www.youtube.com/watch?v=N8QhXewcAXY

http://www.allaboutcircuits.com/vol_1/chpt_8/9.html

If you read instructions carefully you will note the charger gives you few different IR readings :-)


Now the answer what causes the IR to change. It is the temperature! Generally - more temperature gives lowe IR, but not all LiPo chemistries have the same behaviour. If you can controll the temperature you can heat up the cells from room temperature up to 110 F you will definately see IR decreasing.

Charging at higher amps heats up the cells, thus IR goes down. You can also cycle the lipos fast in sync mode on 4010... 1S goes nice with 40Amp discharge

Edit: Yes, you need to have also balancing conector setup for 1S to have IR measured correctly. Sorry...

I measured a lot of LiPos lately. No time for report yet :/

So far:
IR winners: LRP 7500 big mama at 40C only 0.7/0.9 mOhm/cell on the test sample.
Capacity winner of 2S HC pack: LRP 7500, 7200mAh usable from 4.2-> 3.3V/cell @ 200W constant discharge.
great info thanks.ido have the balance plug set up for my 1 cell.i was told you need it for the icharger 4010
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Old 02-09-2015, 12:38 PM
  #639  
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What are the optimal volts for:

Storage
&
Discharge right before recharge before run
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Old 07-16-2016, 03:14 PM
  #640  
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Default Great info

Originally Posted by Outlaw 44
All that high charge/discharge rate hoopla is bull**** if you ask me.

Been racing oval for 22 years now. I think I have a decent feel for what actually makes my car go faster, that stuff isn't one of them.

I race in St-Hyacinthe Quebec, TOUR Spec class with the Salvas Brothers every two weeks, 146 foot runline on new CRC carpet. Two Sundays ago I was part of a 5-car field which all finished on the same lap (an average lap is about 3.6 seconds) after a 100-lap race. The race lasted about 6 minutes.

This past Sunday at the New Year's Dash in Oneida NY, Steve Salvas finished 2nd in the TOUR Spec A-main against some of the best drivers in the business, Eric had a 2nd or 3rd place car before getting involved in a wreck. this is just to give you an idea of who these guys I race against are.

I charge between 6 and 8 amps between qualifying and feature rounds, and never discharge between runs. I'll charge at 12 amps during practice just so I can hit the track again faster. There's no point in charging at a higher rate, my battery will just be done charging before my motor gets a chance to cool down from it's last practice run or before I can finish making changes to my chassis.

I've been running the same SMC 7000mah battery for all my practice/heat/main runs since I bought it new in June. I don't see the need for high charge or discharge rates period, I truly believe that the life span you lose in the battery isn't worth the infinately small extra ''punch'' I can't even feel on the track anyways. The battery still feels like it did back when I bought it, I think a less aggressive approach to charging has helped me keep it in good shape.

Before June 2014 I was running a used battery I bought from a fellow racer. When I went to the new battery, I couldn't feel any difference in speed. What helped me is working on the chassis, and managing my tires. Some hints from the Salvas brothers helped me on the chassis setup end of things.

Don't give into the hype
That is the best info and true to the point.I don't see a big difference in ridiculously high charge rates either.I race 17.5 TC class and charge at my SMC 2s 6000 mah cells at 2c and I place in the A mains consistently at Club races as well as state and national events.And I race a against some big names that totally just heat the packs up charging at 5c discharging at 5c. Just to get a tiny bit more punch.And lower ir readings. Man I'm pulling the same lap times as these big name factory guys lol.So I back up the statement don't believe the hype!

Last edited by matt2810; 07-16-2016 at 03:24 PM. Reason: Add more
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Old 12-19-2018, 12:19 PM
  #641  
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