Quark ESC Power Board Comparisons/Mods

[GriffinRU]

Originally Posted by sikeston34m

Here's the Data sheet on the Big Mosfets that I intend to use for the new powerboard.

http://www.fairchildsemi.com/ds/HU%2FHUF75545P3.pdf

Here's the datasheet for the Quark 80 Power Mosfets.

http://www.ortodoxism.ro/datasheets/...3S_Rev1.11.pdf

Griffin, could you take a look at these and tell me if they are capatible with each other?

I'm going to research the driver fet's in the Quark 80 now.
Thanks.

Well, it is hard to give you straight answer, because more info requires about application, like in your case what are the current ratings of fet's driver current and power ratings of system providing power to fets' driver IC's? Do they use bootstrap technique in Quark 80 if yes then what capacity bootstrap cap has and what are diode ratings?
Then what exactly you would like to accomplish, stock configuration or higher voltage/current one. How many Fets you would like to use...

As far Rg for "Big" Fet - check on page 6 inside PSPICE model RGATE value 0.87

And, I tend to agree with lutach there are plenty fets, what so special about this one?
I mean both MGM, Quark, Castle... are using probably the best fets for the price and ease of assembly, when you shooting to do something custom you want to get the best (regardless of price and assembly pain) and deal with tuning and tweaking until "green light".

[sikeston34m]

These "Big" Mosfets are ones that I have on hand. Just wanted to do some comparisons and learn more about compatibility.

Correct me if I'm wrong, but Mosfets with a lower on resistence value translates into more voltage at the motor leads with less heat buildup in the ESC.

I took my Quark 80 back out of the case to investigate the driver fets and their ratings. They are sandwiched between the power board and the brain board. I can't get a good look at them. I'm hoping to catch Zeropointbug and ask him for a closeup view of the brain board that he has already disassembled.

"I mean both MGM, Quark, Castle... are using probably the best fets for the price and ease of assembly, when you shooting to do something custom you want to get the best (regardless of price and assembly pain) and deal with tuning and tweaking until "green light"."

In Business, I'm sure they are balancing the most profitable (cheapest) way to go and live up to the ratings of their ESC's.

On the Custom work, I can't aggree with you more. I'm not worried about the cheapest route.

Is it possible to use a Quark brain board from an ESC that's rated for 2 to 6 Lipo cells and adapt it to a larger capacity power board for a 10 or 12 lipo cell rating?

[GriffinRU]

These "Big" Mosfets are ones that I have on hand. Just wanted to do some comparisons and learn more about compatibility.

Correct me if I'm wrong, but Mosfets with a lower on resistence value translates into more voltage at the motor leads with less heat buildup in the ESC.

I see.
Rg and RDS(On) are not the same. RDS(On) directly related to voltage drop across FET.
You cannot tell how good FET is based on RDS(On) you need to check dynamic parameters the ones with "ns" units. Transition time from off/on will determine how efficient switching happen, less time better. Later we can cover why too fast is also not good.

I took my Quark 80 back out of the case to investigate the driver fets and their ratings. They are sandwiched between the power board and the brain board. I can't get a good look at them. I'm hoping to catch Zeropointbug and ask him for a closeup view of the brain board that he has already disassembled.

Unsoldering, unsoldering and picture might not be enough...probing and digging layout.

Is it possible to use a Quark brain board from an ESC that's rated for 2 to 6 Lipo cells and adapt it to a larger capacity power board for a 10 or 12 lipo cell rating?

Over 25V opto-coupling or other technique will require to isolate from high-voltage switching problems. So, probably won't work.

[sikeston34m]

It would be the high voltage back EMF sensing that would cause the problems in a HV setup?

[GriffinRU]

Originally Posted by sikeston34m

It would be the high voltage back EMF sensing that would cause the problems in a HV setup?

That is minor and must be solved at the same time when you figure out how to generate supply voltage for your ESC microprocessor and subsystems (It is complicated going from above 35V down to 5).
You still need to sample supply voltage, if you plan to monitor battery voltage to use LiPo cutoff.

-
As far high voltage problems, it is a complex to describe, but think of your ESC as a hammer. When it is small you can use it and neighbors won't even hear you, while if you start using pneumatic one then entire neighborhood will know that you mean business. :)

[lutach]

One thing I have to add. As you all know there are some delays with m ESC, but the engineer that is building it told me that it would be easier to make a 80 or 100 volts controller. I already told him I will do a few after I receive the one I'm waiting for. Just te thought of having a ESC capable of 18S and 22S lipos just makes me happy LOL. I think I like HV stuff mainly because I got electrocuted twice. First time was in Brasil with 220 volts, I was 7yrs old. The other time was in HS in Florida. It was from a nasty Hi Amp Audio Grade battery that knocked me a few feet back LOL.

[sikeston34m]

Originally Posted by lutach

One thing I have to add. As you all know there are some delays with m ESC, but the engineer that is building it told me that it would be easier to make a 80 or 100 volts controller. I already told him I will do a few after I receive the one I'm waiting for. Just te thought of having a ESC capable of 18S and 22S lipos just makes me happy LOL. I think I like HV stuff mainly because I got electrocuted twice. First time was in Brasil with 220 volts, I was 7yrs old. The other time was in HS in Florida. It was from a nasty Hi Amp Audio Grade battery that knocked me a few feet back LOL.

Please keep us updated Lutach. You sure have my interest in that. But please, be careful around all those flowing electrons. LOL