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Mamba Max and 8XL - not alot of Amps lol
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cdis
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Mamba Max and 8XL - not alot of Amps lol - 05.11.2008, 12:19 PM

Hi all,

I have a odd question. Hit the track today with the new B-Revo.

Running a Mamba Max ESC with a CCBEC, 8XL and 5S A123 batts. I chucked the DPRII in for a run, and noticed that I'm only getting around 48A max.

Not that I'm complaining, considering nothing was getting too hot, just nice and warm, and temps were quite cool.

I tried a run with the stock 38t spur, and again with the 40t spur, neither of which pushed the amp draw above 48A.
I'm running the standard clutch, which is 15t I believe.

If I change motors to a 7XL, I assume the amp draw will increase with the same gearing?

The reason I'm asking is that I pre-ordered a Monster Max, so I want to give it some hard work to do lol, otherwise I may as well just keep using the Mamba Max.

If I go up to 6S packs, would that also give me a substantial increase in amperes?

thanks guys :D
   
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magudaman
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05.11.2008, 12:34 PM

That does seem low. I have a similar setup running 5s2p A123 on my emaxx with a MM and 9xl motor. I am geared for about 34 mph but I see peaks of 75 amps. I was also running low start up power, lowest timing, ect. With a 8xl you should be seeing even higher!

You are using the DPR-100 right (100 amp version)? I know my watts up adds enough extra resistance through the extra connectors, wires, and shunt that I hit my LVC. To see the true max amps I have to drop that a little just to be safe (notice it later in the run).

I just saw in another thread that you are only running 1p so maybe with voltage drop you are only seeing around 50 amps. 2p might push you up to high but you will also have to carry all that weight.

Last edited by magudaman; 05.11.2008 at 12:50 PM.
   
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kostaktinos_mt
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05.11.2008, 01:31 PM

clutches do a really good work at eliminating cogging and smooth-ening out current 'spikes'... with a 'conservative' pinion, you would see a bit higher temps and a lot higher current peaks...

just my 0.02...
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cdis
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05.11.2008, 06:42 PM

I could run 2p as I've got 2 5S packs. Problem is, with 2 packs the revo is PHAT lol.

Also, its way unbalanced in the air with almost .5kg of batteries on one side lol.

I guess I'm just trying to avoid running 5s2p to keep the weight off, but I guess I will run 2p if I have to. I've tried a run with 5s2p and there was only a marginal increase in amp draw, which I put down to the motor having to push the extra weight around.

I'm using the DPRII-150, 150 amp version.
   
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Buzzsaw46
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05.11.2008, 10:06 PM

What do you have your LVC set at, maybe it's clipping the power? I run 5s A123 and rutinely see amp draws of 70-90amps.
   
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cdis
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05.11.2008, 11:00 PM

I got the LVC set to 2v/cell, so 10v.

What motor and vehicle you running Buzzsaw46?
   
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big greg
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05.12.2008, 12:06 AM

wow 2v per cell are you crazy? i dont like to go below 3v per cell
   
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bdebde
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05.12.2008, 12:13 AM

Quote:
Originally Posted by big greg View Post
wow 2v per cell are you crazy? i dont like to go below 3v per cell
The A123's have lower cut off than standard lipo.
   
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big greg
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05.12.2008, 12:14 AM

oh duh! didnt really relize that
   
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Buzzsaw46
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05.12.2008, 12:22 AM

We are using A123's dont really need a LVC but I set mine for 2v/cell also.

cdis, I have a 3905 E-maxx, and a brushless HPI NMT both will pull upwards of 90a from the 1p A123's.

The E-maxx was on a Medusa 36-50-3300 but I just moved a Neu 1512/2.5D into it, amp draws are about the same for both motors geared for the same top speed(33mph) on 5s A123's. Here is an Eagle tree log from a run today with the Neu.

http://i287.photobucket.com/albums/l...irstrunFDR.jpg

The NMT is running a Hacker C40-8L on 4s A123's.
   
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