Has anyone experimented with step charging profiles?? :confused:

Seems there are several chargers on the market that offers this feature.

Track talk is that every battery has a different profile for step charging.

Does anyone have a good profile for say GP3300s, GP3700s??

I have heard, it doesnt seem to work very well on oval racing..The guys i talked to said there wasnt any noticeable difference.. but other may have diff results.. i heard in 6 cell it is more noticeable..

I have good things about using it in 4 cell modified, but can't confirm that since I haven't done it personally. I wouldn't rule it out though.

I have been experimenting for a week now and I think I almost have a new profile for GP3300's

I have found that step charging not only works but increases the input without adding to battery heat. :thumbsup:
Each battery type has its own unique profile. (that's the hard part!)
It also works for Oval!!!


Step charging increases voltage under a load and adds to the overall runtime
by about 15-20 secounds.

step charging is pretty cool but it take forever to charge... i tried it and didn't see much difference,that's why i stop..it look realy good on paper thought...

I tested it and personnaly saw no gain whatsoever.

I attached the (2) uploaded file from the GFX (discharge data) ... the linear charge (6A) was actually better.

Maybe I haven't found the hot setup for step charging ... this one was ...

2A for 300mAh
7A for 3800mAh
6A for remaining (approx. 400mAh)

Andre, this profile didn't take any longer and the battery peaked at 142F (initial peak).

I'm going to test this one in the next few minutes ...

4A for 200mAh (180s)
6A for 3800mAh (2280s)
7A for remaining (approx. 500mAh) (257s)

This profile will fully charge the battery in approx. 2750 seconds.

I'll post the results later...

Steve.
tqcells.com

I don't personnaly see an "on paper" benefit here...

Steve.
tqcells.com

Steve,
Can you test this profile...I see a lot of Road Course guys using it. They claim its the next best thing since sliced bread, LOL I would try it but I dont have a step charger yet.

Step 1
3050mA 7.0A

Step 2
3080 0.2A

Step 3
4900mA
Modified: 4.0A 19t/Stock 5.5A (they claim for more punch to step up this last step)

Step charging increases voltage under a load and adds to the overall runtime by about 15-20 secounds.

Any charts or graphs to back this up? Not trying to discredit you or anything but those are some bold statements.

Out of curiosity how did you determine step charging increases voltage under a load? Do you have one of those on-board data recorders?

Steve,
In post #6, was this the same battery tested? If so, how many days/hours rest between cycles?

To make it easier to compare for everybody, I took all 3 of Steve's .txt files, put them in Excel and did some calculations.
---------------------------Linear-----Step 1------Step 2
-----------------------------6A----2A-7A-6A---4A-6A-7A
Average Voltate @60 sec----5.061----5.065-------5.067
Average Voltage @120 sec--4.985-----4.981-------4.976
Average Voltage @240 sec--4.886-----4.877-------4.868
Average Voltage Overall-----4.772-----4.748-------4.751

Any charts or graphs to back this up? Not trying to discredit you or anything but those are some bold statements.

Out of curiosity how did you determine step charging increases voltage under a load? Do you have one of those on-board data recorders?

No on-board data recorders but that will be my next step.

I used the ICE charger with a thermal probe and a laboratory grade power supply, Raytek temperature gun and the Integy 30 tray.
I used voltage and internal resistance in mil ohms at discharge to determine
any gains made to the cells.

>>The trick is in the profile.<<

First, you must dead short the cells for 24 hours before step charging.(integy 30 tray)

Charging at a higher rate without putting alot of heat to the cells is key, having a cooling off period in the profile but thats not to lower the voltage as it continues to charge.
You need the temperature probe to monitor your cells.
I also used the Raytek temp gun to check each cells temperature.

Now, Timming everything together to peek the cells to the correct temperature or Delta V cutoff.

It's not easy.. finding the perfect profile it just takes TIME.

Step charging will take a little longer to charge your cells but will definitely
reduce the heat and increase voltage to your packs.. :thumbsup:

Do you see a gain in average discharge voltage or voltage while charging ?

To me I just can't see why step charging would be better than a regular linear charge.

Do you see a gain in average discharge voltage or voltage while charging ?

To me I just can't see why step charging would be better than a regular linear charge.

I thought that too until I tested with step charging.
I believe that step charging reduces heat to the cells as charging without resting the cells.
The step charging is using a linear charge mode just in steps.

I see a gain in average discharge voltage and voltage time the pack stays above 5 volts as discharging. As you know voltage is speed.
And I run Oval.

My biggest test will be at the next race this weekend...can't wait!

RPM
Where are your discharge graphs ??

you said you used the ICE charger, isnt that only a 10 amp discharge?
Why not a 35 amp discharge rate??

RPM
Where are your discharge graphs ??

you said you used the ICE charger, isnt that only a 10 amp discharge?
Why not a 35 amp discharge rate??

Yes the Ice is limited to 10 amp discharge but its all relative.
I repeat the same process on the same equipment.
So in respect you can call that my controlled baseline is the Ice charger.

''Without letting the cat out of the bag.''

Experiment with your profiles and it really works... its not rocket science but
I'm having fun! :thumbsup:

Yes the Ice is limited to 10 amp discharge but its all relative.
I repeat the same process on the same equipment.
So in respect you can call that my controlled baseline is the Ice charger.

''Without letting the cat out of the bag.''

Experiment with your profiles and it really works... its not rocket science but
I'm having fun! :thumbsup:


Yes where are your graphs, and go ahead and let the cat out of the bag, I would like to know just what you are up to in your laboratory.....hmmmmmm? What are you really up to MR. RPM? We are watching you Mr.........every single charge, we are watching..........................so until you can prove that you charge at 8 amps and then freeze your batts for 35 minutes then discharge at 15 amps then dead short them, then recharge at your # 5 profile which includes a step rate charge starting at 7 amps then goes down I will not believe you. The proof is in the pudding. Where is your pudding?

Ginsu - You will see the pudding this weekend! :thumbsup:

P.S. - My graphs are right in front of me... :cool:

I tested a step charge setup provided by RPM ... ... I won't even post the results here ... plain awfull ... discharge voltage curve was WAY down versus what I get using a continuous linear 6A charge (5mV per cell cutoff).

Steve.
tqcells.com