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Old 10-29-2006, 05:29 PM   #136
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The text it out in the manual but a picture or numbers printed on the unit would have been nice..

Looking at the unit From LEft to RIGHT it goes 1,2,3,4,5,6
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Old 10-29-2006, 06:21 PM   #137
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Quote:
Originally Posted by Joel Lagace
The text it out in the manual but a picture or numbers printed on the unit would have been nice..

Looking at the unit From LEft to RIGHT it goes 1,2,3,4,5,6
I thought that is what it meant, but wanted to make sure before I start moving cells.

Thanks!
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Old 10-29-2006, 06:44 PM   #138
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does any shop have stock of the DPD?
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Old 10-29-2006, 10:51 PM   #139
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Default Horsham RC racing

Horsham RC racing has a few in stock and ready to go...
and for a pretty good price, give them call in the am, think they open around 10am eastern time.

www.horshamrcracing.com

Ask for Terry if he is available, he knows the stock on hand pretty well.
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Old 10-30-2006, 07:39 AM   #140
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So now here is the thing. I am going to get this unit because I have seen it work and believe it is a good item to have if you are serious about maintaining battery power. Since I am just getting into the 1/12 racing program I figure to keep the batteries that I have I will need help. I am not really a battery guy but have been bitten by the bug.

So post best ways and methods to help the new-jacks, please.... Thanks
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Old 10-30-2006, 02:03 PM   #141
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Quote:
Originally Posted by wyl03
does any shop have stock of the DPD?
try this
http://www.losipartshouse.com/servle.../17/Categories
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Old 10-30-2006, 04:48 PM   #142
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Quote:
Originally Posted by TheCoolCanFanMan
i "add to cart" and was told "0 available"
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Old 10-30-2006, 04:59 PM   #143
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Superior hobbies shows them in stock @ $124.95
here
http://www.superiorhobbies.com/istar...11&class=DISCH
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Old 10-31-2006, 12:43 AM   #144
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Quote:
Originally Posted by EAMotorsports
If you mean like a bullet style connector then yes they will fit.

EA
Hi Eric

i'm running some of your matched ib 42's and was wondering how you rate this unit compared to the MM ctx-d?
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Old 11-04-2006, 02:50 PM   #145
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As there is a lot of speculation about how the DPD works I tried to support my assumptions made in the "other DPD thread" (search for my user name).

My experiment uses some math and the information the DPD gives voluntarily via its display. First math: If you know the capacity that has been taken out of a cell and the time that was need for that amount of energy beeing wasted one can calculate the (average) discharge current used. current = capacity*3600s/time. 3600s is in the formula because we are used to the unit mAh.

Again my theory to be validated:

The DPD uses a 2 stage discharging process. In stage 1 the whole pack is dischared as one. In stage 1 the discharge current is user selectable (5A linear or 30A pulsed discharge). In stage 2 each cell is individually discharged by a discharge current that is signifivantly lower than 5A linear/30A pulse. The transition from stage 1 to stage 2 is made when the first cell hits the selected cut off voltage.

Proof for a transition:

This can be observed by watching the DPDs display. One cell will be the first to come close to the cut off voltage. As soon as it reaches the value the voltage of this cell increases again as the load is reduced. A few seconds later the internal fan is also switched of.

The experiment:

I charged an old pack with approx. 700mAh (so it would not take to long) and observed the display. I noted all events and transferred them to an Excel sheet for easier analysis. To minimze errors I put a resistor in parallel to the cell that would trigger the transition a few secondes after as it hit the cut off value so to bring it into the state "done!". Discharge mode is 5A linear.

Analysis:

As all cells are discharged equally in stage 1 the capacity value displayed in the DPDs result summary for the cell that hit the cut off first (the lowest capacity value) sets the reference value. All cells are discharged up to the transition time to the same value (206 mAh in my experiment). After that each additional mAh of each individual cell is wasted by the stage 2 process. So taking the difference from the individual cell result and the reference value brings the capacity to light that was converted to heat by the stage 2 discharge current. Same goes for time (delta C and delta t). Applying the math above produces the fact. In stage 2 the DPD reverts to roughly 1.5A discharge. That it is individually discharging is proven by the fact that the times for each cells are different.

As I was using 5A linear I also verified this. 206 mAh in 151 seconds equals roughly to an average of 5A. Well done Trinity. Btw: 30A pulsed discharge mode would have produced roughly the same result in stage 1 due to the puls width ratio of 1:6 and stage 2 is independant of the selected stage 1 mode. Try it ...

MHA
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Old 11-05-2006, 03:24 AM   #146
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Repeated the measurement with 30A pulsed discharge to verify the pulse/width ratio and effective (= average) discharge current in stage 1. Result: 1053 mAh in 13:06 (= 786s). 1053*3600/768 = 4823 mA. So assuming it really does 30 A pulses the on/off pulse cycle is 1:5 (1 duty cycle followed by 5 off cycles). When I get hold of a scope I will report the cycle length. I reckon it's in the area of 100-200ms.

Now we can easily calculate an estimated discharge time for a full pack. Assume an average IB4200 which accepts 4500mAH of charge. Further assume the difference between the best and the worst cell in the pack to be 500mAh. This would be a good value even for matched packs.

Stage 1 is discharging regardless of pulse or linear with an average of 5A:

4000mAh/5A = 0,8*3600 = 2880 seconds

Stage 2 as demonstrated averages to 1,5A

500mAh/1,5A = 1200 seconds

This results in 4080 seconds (68 minutes)

In the average racers pack the capacity difference (at 5A load) will be far greater. 1000 mAh difference will lead to:

3500mAh/5A+1000mAh/1,5A = 82 minutes


Maybe someone can confirm my measurements and I still think the DPD is a good product that does the job.

MHA
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Old 11-05-2006, 05:53 AM   #147
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I just won a black version off ebay. Yay.
Anyone wanna buy a Rayspeed discharger? LOL
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Old 11-05-2006, 08:32 AM   #148
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Quote:
Originally Posted by mha
Repeated the measurement with 30A pulsed discharge to verify the pulse/width ratio and effective (= average) discharge current in stage 1. Result: 1053 mAh in 13:06 (= 786s). 1053*3600/768 = 4823 mA. So assuming it really does 30 A pulses the on/off pulse cycle is 1:5 (1 duty cycle followed by 5 off cycles). When I get hold of a scope I will report the cycle length. I reckon it's in the area of 100-200ms.

Now we can easily calculate an estimated discharge time for a full pack. Assume an average IB4200 which accepts 4500mAH of charge. Further assume the difference between the best and the worst cell in the pack to be 500mAh. This would be a good value even for matched packs.

Stage 1 is discharging regardless of pulse or linear with an average of 5A:

4000mAh/5A = 0,8*3600 = 2880 seconds

Stage 2 as demonstrated averages to 1,5A

500mAh/1,5A = 1200 seconds

This results in 4080 seconds (68 minutes)

In the average racers pack the capacity difference (at 5A load) will be far greater. 1000 mAh difference will lead to:

3500mAh/5A+1000mAh/1,5A = 82 minutes


Maybe someone can confirm my measurements and I still think the DPD is a good product that does the job.

MHA


IT DUMPS
IT EQUILIZES
IT gives valuable cell data
Im over how it does it!
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Old 11-05-2006, 09:17 AM   #149
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Default Trinity discharger in stock

Quote:
Originally Posted by wyl03
does any shop have stock of the DPD?
Try this link.
http://www.teambrood.com/catalog/ind...e21eed8b2cd36f
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Old 11-05-2006, 10:53 PM   #150
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I have a question for you guy's that already have this.

Can one place a pack while charging it on the DPD. that way you can collect the date how each cell is charging.
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