"SuperCharged 5 Cell" SPEC2 SKYLINE GTR - Page 3

e_lm_70 · #31 11-29-2002, 08:15 AM

I have added a pic on the 6 cell mod thread:
http://tinyrc.com/forums/showthread....2583#post32583

I have used the Subaru WRC body.
But it look the same space available also on my Mitsubishi WRC (but it till has 4 cell only ... need to order oder two 120mAh from Conrad)

Here is a crappy photo of my two mod Epoch compared with the similar version on iRacer and Bit.

e_lm_70 · #32 12-19-2002, 02:45 AM

Quote:

Originally posted by natedogg4674
i was just about to do the 5 cell mod, im not now, i dont know the first thing about how to upgrade the electronics to be able to handle the increased voltage

I got up to 6 cell ... no Electronic update !

The only proble so far ... since I have lost the Cap around the motor I have a little interference with the steering ... going to fix it soon since I have a new Cap now !

The Electronic of the Epoch is so good that can handle 6 cell with no problem ... I have tested evily , even on carpet ... no problem at all . The PCB has never get hot ... the motor has just get Warm !

6 cell compared to 4 cell make a big difference !

The big PCB protection I guess it come out of the smal cell, they are not capable to provide too much Amp ... so they can't damage the PCB ... since they are limited in Amp ... it doesn't really metter how many cell you put in serie ... the maximum Amp will be always the same ... it just change the Volt !

And for my opinon is far better to put the two cell inside the body then make a cut on the front for put some additional one !

e_lm_70

P.S: It could be that you need electronic update only if you re-wind the motor ! Thing that I don't raccomend if you are not an expert !

MicroRCracer · #33 12-23-2002, 12:13 AM

natedogg4674,

To be honest, ive tried 5 cells before and fried my electronics on the EPOCH SPEC 2 racer.. Im not sure if it was just me having a defective bad luck ESC or what.. Just letting you know the other posibility through my experience...

ClockwOrk · #34 12-30-2002, 12:52 AM

lol a little belated, but the charger look is classic!! Great work!

chelboed · #35 03-07-2003, 02:47 PM

Has anyone else fried their Epoch by running 5 cells? I don't want to buy more than 1, so I will probably just stick with 4 unless y'all tell me otherwise. I have been modding bits/frying bits too long, now. I just want to race and enjoy it. I'm tired of having to fix my cars.

e_lm_70 · #36 03-10-2003, 04:43 AM

Quote:

Originally posted by chelboed
Has anyone else fried their Epoch by running 5 cells? I don't want to buy more than 1, so I will probably just stick with 4 unless y'all tell me otherwise. I have been modding bits/frying bits too long, now. I just want to race and enjoy it. I'm tired of having to fix my cars.

So far I'm was too lazy to update my 2nd Epoch to 6 cells (I got the cells, but not the mood for use my solder).
BTW my 1st Epoch with 6 cell is till well alive, and ultra fast, compare to my 4cell it is really 50% faster !

The best protection in the Epoch is due to the type of Cell.
The 1/3 AAA NiMh isn't able to provide enough Amp for make the ESC in trouble. 2nd the 6cell 120mAh will not last more then 10minutes, so it will be not too long for over heat the PCB ... BTW I have tested my Epoch and the PCB don't get even hot.

The only draw back of 6cell is some instability on the stearing, it is not a meter of Cap around motor, it is probably too much power given to the servo, cousing it to be little bit instable... I guess it need a new resistance between PCB and servo motor for make it more soft. BTW the car is allways very drivable only in some rare case like TX off or switch on can couse some epilettich attach on stearing.

BR

e_lm_70

P.S: Also my Mini-Z have been succesfully upgraded with 6 cell (top speed over 40km/h)

fastboy · #37 03-11-2003, 05:14 AM

ahem....you think its just amps that will kill your epochs circuit board??..WRONG WRONG WRONG.

please dont say that because you are using small cells that the circuit wont get damaged,too much voltage regardless of the cell type can and will destroy it,however the only way to find out what the limit of voltage it will take is an expensive trial and error
situation

dave

e_lm_70 · #38 03-11-2003, 08:33 AM

Quote:

Originally posted by fastboy
ahem....you think its just amps that will kill your epochs circuit board??..WRONG WRONG WRONG.

:-)))))))

There are two type of possible damage in a PCB when the Volt get increased:
1 - Immediate damege since some component can't handle high voltage, causing a short and cousing an irreversible damege ... so you try if work fine for 2 second the PCB is safe for this damage.
2 - Power dissipation damage, due to a continous usage with an increasing temperature in a component.

So my Epoch clearly have no problem on handlying 1

What can scare is point 2 ... let see more in detail:
Power dissipation : W=V*I
Where is critical the power dissipation on the Epoch: On the Main Motor ESC.
How much power is dissipated in the ESC ?
- It is W=V*I where V = R * I (The R in the ESC can be assumed costant and based on the ESC type)
So W= I*I*R

1 cell can provide the same maximum ammount of Amp like 6 in sequence.

What is critical it is during a transiction like an accelleration or changin from forward to backward, in teory this situation will generate a Amp peak ... this peak will be short (an this is safe for use) and as well limited in Amp since the cell can't provide too much amps ... so in this situation the Volt around the 6 cell will be dropped since the 6 cells are not able to provide the adequate power.

So using 6 cell will not make big improvment in acceleration but will provide a very good top speed.

e_lm_70

chelboed · #39 04-08-2003, 02:38 AM

Do you think that the reason your steering is fritzing out is because you didn't do the FET upgrade? Maybe the added FET transfers more power to the motor and doesn't overpower the servo.

Did you guy's stop posting on this thread to cool off or what? I am still interested in how the 6cell car w/o FET stack is performing.

And MRCracer... why not show how to do the FET upgrade? Everyone else here on the forum is ready and willing to help other people to learn to make their cars better and faster. Look at Gertman's 4cell mod. Pretty tedious, but the step by step instructions has brought so much joy to the lives of every 4cell Epoch owner.

Don't be so stingy, man. Share a little. If the Mini-z guy's had never shown anyone how to do their's, everyone would be in the Mini'z "dark ages", right? Now look how much has opened up. Sign your name to it and demand credit if you want, who really cares who came up with it as long as people love it.

e_lm_70 · #40 04-10-2003, 08:49 AM

Quote:

Originally posted by chelboed
Do you think that the reason your steering is fritzing out is because you didn't do the FET upgrade? Maybe the added FET transfers more power to the motor and doesn't overpower the servo.

No ... I have the same steering problem with my Mini-Z with 6 cells.
So far, I till have to find the time for make some experiment in order to fix/minimize the problem. But my best guess it is that adding a/some Diodes or Resistence in series with the servo motor will solve the problem !
But the noise effect on the Epoch due to the 6cells is not critiacal ... it is just for have a cool clean mod !

Quote:

Did you guy's stop posting on this thread to cool off or what? I am still interested in how the 6cell car w/o FET stack is performing.

Few posting it is because the Epoch scene is lmited !
Only very few people are hiding information, and this is true both in the Mini-Z scene and as well in Epoch.

If you want to go for a 6cell on epoch this step is trivial:

Just go first for the 4cell as documented.
Somewhere there is a pic of my 6cell car, but basically you just have to take 2 cells, make a linear serie of these two, position this "long" 2.4V NiMh cell in the rear axe, just behing the PCB, add wires for connect to the 4cell that is connected inside the lower part of the car ... and that's it.

Only issue, you just need a different charger, since the stock one can at best charge 4 cell !

Good luck

e_lm_70

chelboed · #41 04-10-2003, 11:04 AM

Yeah, I don't think I would have a problem figuring out how to do the added cells. I have been doing that with bit's and Zip's for a long time. I was just talking about letting others know how to stack the FET's like the other guy did. I think that would be a killer mod to protect your electronics and get great speed. If you haven't had any problems with your electronics w/o upgrading the FET's, then I may just have to try it.

Thanks.