RC-Monster Forums - BL Revo conversion almost finished!

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- - BL Revo conversion almost finished! (https://www.rc-monster.com/forum/showthread.php?t=7658)

Finnster

09.10.2007 09:06 PM

Quote:

Originally Posted by zeropointbug (Post 117667)

thanks again,

I am trying just a 7s1p pack for starters, it will definitely be able to power it, but with how much voltage drop.

With the Maxx truck (good remembering Finnster :yes: ) I had 2p yes, and there was very little voltage drop with the max amperage of around 70 amps, sometimes 80, the lowest I saw the voltage go down to was ~21 volts (from 23v nom.), so 70 amps should be easy for 1p. I am guessing the V-Droop will be around 19.5v with this truck at 70-80 amps, as I geared it a little lower (13T from 15T), and it is lighter than the Maxx truck as well, so taking that into consideration. The runtime should be around 15 mins, as it was at least 30 mins with 2p pack, and geared higher, and heavier.

I will get it finished tomorrow (when heatshrink arrives for pack), I will post some pics for sure! :rofl:

Aqwut, unfortunately I don't have my Sony Cybershot anymore! (video capable) :no: I traded my sister for a Canon Rebel SLR, which is what these pics were taken from.

Yeah I'd like to see what it does, tho I thought the A123s were rated for 70A max discharge according to the spec sheet. I draw 120A+ from mine (2P), and they get to ~110F as the pack dumps, so we should see. That's fairly close to max and they are not getting too warm. Truck looks great tho

zeropointbug

09.14.2007 12:24 AM

3 Attachment(s)

Hey guys, here are some pics of my finished E-Revo 3.3 conversion.

My computer has not been working for the last few days so I could not post the pics... but anyways here they are! :yipi:

zeropointbug

09.14.2007 12:25 AM

2 Attachment(s)

Some more...

zeropointbug

09.14.2007 12:31 AM

Anyways, I ran it for the first time today because of cold rainy weather and it performs great! It feels very light and agile compared to the maxx truck with 7s2p... I was running 7s1p this run. I used the eagletree in there as well and found the voltage drop at ~70 amps is around 19 volts (from 23v nom.) so right around where I thought it would be, but obviously lower than what a guy would like. :oops:

With the 7s1p, it looks to have about 1200 - 1300 watts of power, and the pack weights a tad over 500 grams which is very light.

One thing that is very different about the Revo is the suspension feel, it's just so much different from Maxx trucks, both the feel and adjusting.

It was geared for 40mph top speed today. Sorry, no video for now! :no:

MetalMan

09.14.2007 12:32 AM

That is one CLEAN Revo conversion. Looks like it should stay that way :angel.

If you haven't tried out those tires yet, you're gonna love them.

Finnster

09.14.2007 11:51 AM

Excellent conversion bro. Nice to see all the radio/bec gear fit into the stock servo box. If I ever ditch the manual brakes I may rearrange mine like this. (I looked at putting the futaba fasst rx in the micro servo slot, and still looks like it a bit too big.)

Good to hear about the A123s performance as well, nice at 500g too. 2.7v/cell@70A isn't bad at all. I was getting 2.8v @60A. These things are discharge monsters. Could you put some some ET data when you get a chance as well?

Last Q: How removeable is the Q125 over the shocks? The MGM I bought is quite a bit bigger than the MM I have, so I may need to move it above the shocks, but haven't thought of a secure mount that's ez to remove for diff and shock service.

suicideneil

09.14.2007 02:45 PM

I like. Not to repeat the same question already asked, but how exactly is that esc mounted- looks great & very low profile.

What's_nitro?

09.14.2007 07:00 PM

Nice job man, very clean.

Only one problem: You need more capacitors on that Quark. :tongue:

BrianG

09.14.2007 07:36 PM

That's not a Quark, that's a capacitor with a Quark attached to it. :smile:

zeropointbug

09.15.2007 01:02 AM

Quote:

Originally Posted by Finnster (Post 118290)

Thanks guys! I am very happy it turned out, it looks killer! :intello:

-Yeah, 70 amps on only 2300mah in a truck cannot be used with lipos, they simply would fail, presumably. I am still impressed by them in that respect, in their current 'handling'.

-My Quark125 is mounted on top of the screws of the shocks and a little lip on the tranny, and is held down by a reusable zip-tie. I am thinking up something different to do with the controller however, as it is a little 'rigged' at the moment.

What's Nitro, I am glad you like my Quark mod... :wink:

zeropointbug

09.15.2007 01:02 AM

1 Attachment(s)

Here is an Eagletree of part of the run.

I looks like the voltage will be at roughly 22 volts at top speed, maybe higher, so top speed should be right around 40mph, can anyone confirm this?

zeropointbug

09.15.2007 12:39 PM

I just did another run on the truck, and took the temps this time.

Runtime was very good, a solid 15mins with only 7 M1 cells, not bad at all! :oh:

Temps:

motor: 108F
esc: 80F
pack: 102F

The temps are very good, but, also it was not hot out today, so that helps.

BrianG

09.15.2007 01:14 PM

15 minutes on 1p - wow, that's pretty darn good! That means you are averaging 9.2A current draw with peaks somewhere around 60-70A. So, that means 212w average and an estimated 1500w burst power.

zeropointbug

09.15.2007 02:58 PM

Yeah, I am as impressed as you are, I was waiting for it to dump... just kept going, all I was doing was runs back and forth in the yard, just shy of hitting top speed. But the temps I was getting, amazing! I thought the batts would have got warmer than that! :oh: This was with low 'power' setting, and softest torque setting.

The average current is right around 9.2 amps like you said, but the peak power is somewhere around 1300 watts more like, that's what the eagletree shows.

So now I am going to finish up my 2p pack for more power and runtime... so I will have two packs, one for racing if I ever get a chance to... I am 2 hours away from the nearest one, and they are only in a couple months of the year.

BrianG

09.15.2007 04:14 PM

Well, that 1500w estimate was generous. I typically use between a 6x-7x multiplier and it usually works out very close. 9.2A x 7 = 64.4A burst. That makes 1487w, but that's assuming the voltage is 3.3v/cell, which I'm sure is not the case. Assuming the 7x multiplier is right, 1300w would equate to about 2.8v/cell under that load. Is that about right?

I'm curious because I still want to make that runtime calculator/lipo selector page for my site and need all the sample data I can get. BTW: Could you post your eagletree results in that thread? It would help a lot.

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