Tekin RX8 first impression

[lutach]

Originally Posted by galaxy76

yes.

know exactly what it is (BSC079N10NS or BSC118N10), right?

Which of these two?

It should be this one: http://www.onsemi.com/pub/Collateral/NTMFS4833N.PDF. I'm not 100% sure if they are using a Infineon MOSFET, but I can be wrong. The part numbers you provided are not being used as the BSC079N10NS is a 100V MOSFET (Would make a nice 20S esc though) and the BSC118N10 is the same 100V, but less AMPs. Who knows they might be using a 40V MOSFET, but my best guess is the OnSemi one.

"snellemin" has opened. has done a photo of FET?
no one else has done a photo of FET?

[lutach]

Originally Posted by galaxy76

"snellemin" has opened. has done a photo of FET?
no one else has done a photo of FET?

He has, but the FETs were not shown. That MOSFET I mentioned and provided the datasheet is what most use. It's one of the best, but there's always new ones coming out. Giving the power level of the RX8, my best guess is that they use it or they are using a more powerful one.

you think the 210 Amper are continuous or peak?

thank's

[lutach]

Originally Posted by galaxy76

you think the 210 Amper are continuous or peak?

thank's

It's what I like to say a continuous burst which you might get in a very hard acceleration. Maximum burst will depend on the gearing, weight and the way people drive, but I don't know what the maximum burst of the RX8 is. None of the current car ESCs can handle 100A or 200A continuous, but they can average around 20A or so (Maybe more, but those were the numbers I got from my set ups). That number is much lower with higher voltage, correct Kv motor and gearing.

thanks, you were very helpful

I read in another forum that has 30 MOSFET (10xphase)

real?

[snellemin]

Here's another update.

I've been running the RX8 ESC on 4s2p A123 in the GTP geared 51/20 with the 4000kv hacker. Everything was okiedokie, but topspeed was not the same like the 6s1p A123 pack. So I ordered the 25T pinion from Mike and the GTP became an animal again...for like 2 minutes. I thought the RX8 smoked, but all was good and the motor plugs were all unsoldered. Soldered on 6.5 connectors instead and ESC kicked butt again. I need to datalog the sucker and see how many amps it's consuming.
Motor wires are 12awg, and battery input wires are 10awg.

[snellemin]

Here's a snipped of the datalogger. I pull about 159Amps @ 8.68V right before I brake.

[florianz]

hi,

I've got a question regarding those extra power caps you have there. Where did you get them, and what are the specs?

In the past, I have always equipped my esc's with extra power caps. I used to have some plane-esc's (well, the breaks are crap), and I soldered some extra power caps on (approx. 3000uf).

So I "pimped" my sae-brushless esc (http://www.rc-monster.com/forum/show...&highlight=sae) with some extra caps. I am not quite sure, but I think it ran cooler afterwards. But finally, one day it burned. I 'm pretty sure it was due to the hard cogging after a jump, and not my fault, or caused by the extra caps (low esr).

I have got a replacement-esc, so I now wonder, if I could add some extra caps. I've asked mr. constructor (lutach has his chassis) about that, and he thinks, that some more caps - probably - also could cause damage, if they have the wrong capacaty or volts.

regarding the replacement sae-esc, I will post some news as soon as I have tested it. Probably they have improved the software (other users of the new one report very smooth throttle), at least the wires/cables have a better quality.

There are power caps available for yge or etti esc's, so it can't be wrong I think.

I just want to be sure, if adding caps prevents the esc from damage.

and yes, those hands are just amazing....

thanks for any hint
florian

[snellemin]

Wow, I don't remember what size caps I used. I'm thinking they were 3 1000uF 35V ones and a pair of tvs's. On my other RX8 I used 2 1800uF 35V caps and a pair of TVS's as well. I've seen the Etti's cap banks and I think that is the most economical way to go. I would go with the etti-e035-lv cap bank.

[florianz]

Thanks for your reply. But tell me, what's the story about that "electronic board", where the caps are soldered on? Is it against sparks?

I am thinking of using one of those:


The ones in the back have been used as additional caps in the past. I am either taking the big fat one on the right, or the two 2200uf. I know it's better taking more small ones then one big power cap. I am using 5s Lipos in a truggy, with a delicious medusa 3680-1800.

So what do you think, using the caps without that "board" would cause problems?

Many thanks, it's hard to get solid information on that topic.

florian

[snellemin]

That "board" is to clamp the voltage down to a certain value, so I don't go over the ESC Voltage limit during hard braking when running at max rated ESC voltage. You can just add caps with out the "board", but use good quality batteries when running at max ESC voltage. This will aid in the reduction of the Voltage spike you get during braking.

[florianz]

Originally Posted by snellemin

That "board" is to clamp the voltage down to a certain value, so I don't go over the ESC Voltage limit during hard braking when running at max rated ESC voltage. You can just add caps with out the "board", but use good quality batteries when running at max ESC voltage. This will aid in the reduction of the Voltage spike you get during braking.

ok, thanks. If I understand that right, if I have eg. 36v caps and no "board", the spikes (up to 35) absorbed by the cap can hit the esc and damage the esc.

So adding two 25v 2200uf caps should be ok? I'm runing 5s lipos (esc max. 6s).