When I contact Castle about my concerns, they said it should be fine but I would be using it out of spec - so basically "at your own risk". However, they did say they could make me a special version with an additional FET layer to make a "HV-160". That would be crazy at 288A @ 25*C and 0.00042 ohms. At 75*C, it would still be 172A continuous.

IMO, they could conservatively rate the 3-layer HV-110 for 120A, and a 4-layer version for 160A. And that's at almost 170*F! Man, they should just slap a brains board with car software on it and call it the HV-MMM!

I wonder if thats possible...to put an MM brain board on otherwise an HV-110, maybe even double stack the HV-110 to make an HV-220. :lol:

150mph Truggy anyone?

HmmmmMM.... I wonder where they (and/or we) could get a board with car software to use?

EDIT: BP-Revo you scallywag!

Well, it would take a little work. I found that when I removed the heatshrink, that the brains board is just held on with a special connector (no soldering). So, it's just held on via heatshrink. Makes removal easy (the FET boards have this same connector, but also have soldered heavy power and motor bridges). Figuring out the pinout shouldn't be too hard either (GriffinRU, are you listening? :wink:). There are a few other things to work out (like gate drive, using the Opto instead of a BEC, etc), but a worthwhile goal IMO...

I have some MOSFETs to run by Patrick and if he gives the OK, I'll buy them to put in my HV110 that I still have to send to them. My options for the MOSFETs looks like this: (75V, 45.8A cont. and 0.0133ohms), (60V, 30A cont. and 0.0092ohms)and (100V, 34A cont. and 0.023ohms). I might go with the 100V unit as they are in stock. I just have to see if Patrick can use them.

I'll take option 2 (60v, 30A, 0.0092). Makes a solid 10-12 ESC with low rdson and high current. Higher voltage would be nice, but then we'll start needing electrican's licenses for the high voltages! :lol: What's the switching speed like on those options? The voltage drop X current during pulse ramp-up/down when switching on/off is a big culprit for heat, not only Rds on...

I've been trying or should I say begging for something like that to be done. Patrick has mentioned something about hardware not being compatible. I'm going to see if he can do something real simple to atleast have my HV110 working with forward/brake only, but be able to use a pistol radio.

You can use a pistol radio with the existing setup - with a bit of tweaking. But I wouldn't want to use electrical brakes with voltages that high...

It wouldn't have to be an MM brainboard. The fet boards are passive, after all, so you could use a Quark brainboard and have the nice smooth power without the heat!

I'm going through my datasheet database and I basically know the good stuff (volts, amps and rds). When looking at the datasheet, where can I find the switching speed? Man I hate just knowing how to sell this things, when it comes to anything else I stink at it :lol:.

Switching speed would be the sum of the on-state current rise/fall times.

IE: Rise = 4uS, Fall = 3uS. Total = 7uS so 1S/7uS = 142857.blah blah blah which is about 142 kHz.

I did make it work with my pistol radio, but my vehicle has no option for mechanical brake. I like the brake that a car ESC have and if my brake system doesn't come to reality then the controller will have to offer me some braking to slow the car to a safe speed. Is this
(Resistive Switching Characteristics) where I look for the Switching Speed in the datasheet?

It should be listed under the "dynamic characteristics" table.

Let me see the FDS5672 has a Rise Time of 20ns and a Fall Time of 14ns. The 60V MOSFET that I would like has a Rise Time of 15ns and a Fall Time of 5.5ns.

Oo nS! I like it! That would be ~29 MHz for the first one and ~48 MHz for the second.

Me too! Get it done man! :smile:

Is that good? If so I might just ask the MFG for enough samples to make 2 HV110 and extra if some fail.

Billionths of a second is good. It means you could run higher-pole motors at higher speeds without cogging like the BK controllers. :wink:

You guys are going to turn me into an :diablo: genius :lol:, but I do have to go with what Patrick says. If he gives the OK, then I'll try and get some stock on them. The 100V one I know there's stock of it, and the Tr is 15ns and the Tf is 9.3ns and will 0.01ohm make much difference?

I love learning new things. Too bad I can't make ESC and just thinking if I could, this hobby would get dangerous very quick. I hate to be the reason the government ban our R/C goodies.

What is the current rating on the 100V? It's hard to say if the 0.01 ohm will matter, since there is usually less current flowing in a HV system the losses would be about the same as a LV but HC system with a lower resistance FET. Although 0.01 is about 5 times higher than average Rds for a FET.

The 100V has the following specs: 100V, 34A cont., 0.023ohms, Tr is 15ns and the Tf is 9.3ns. The FDS5672 has a Rds of 0.01. SO would 0.013 make a lot of differance?

Compared to the 0.01ohm that 0.013ohm would be 30% higher resistance and so 30% higher losses at a set current. A 10W loss would become a 13W loss and so forth. Since you would have a bunch of them in parallel to handle motor current it wont matter too much. I take it you would get a smokin' deal on these FETs- is that why you're so interested in them a not one with a lower Rds?

I won't buy them from the MFG just yet because it's really low QTY. When I do buy for my clients, it's really large QTYs and my prices are incredible. I'll buy them from whoever has stock and only the 100V one is showing in stock. I will have to check a couple more distributors to see if they have them. I'm going to see if I can get samples of the 60V one ASAP, if not the 100V will have to do.

Well a 23s controller would be pretty awesome...with 8p per phase you could easily put 10KW through that thing!

While it would be nice to have 100v capability, I wonder if it would be needed. Sure, the higher resistance won't matter much if using >50v, but most won't and companies have to manufacture for the majority, not the extreme monority.

OTOH, an ESC for portable transport (like bikes) would make good use of 100v FETs. It's all about target audience. I don't see someone placing a 27s pack in their R/C anytime soon! Just the wiring of the balancer plug(s) alone would be a nightmare! Maybe if someone came out with 10v cells...

The 100V can be used for only 12S lipos. My controllers are having 75V FETs in them, but they are rated for only 14S (15S max).

Like this? :mdr:

http://www.recumbents.com/wisil/shumaker

Matt

Yeah, like that. :smile:

Lutach, why only 12s on a 100v FET? Even generously allowing for back-EMF pulses, that is still at least 20s. I wonder if the limiting factor of your 75v FETs is the other components (caps, etc)?

At any rate, for your typical 12s setup, the 60v FETs are fine IMO. And the ones you have access to seem quite a bit better than the ones currently in the HV-110 as far as the current, on resistance, and switching time goes. You'd only need one or two layers instead of 3 (of course, more won't hurt :smile:).

Don't the controllers have a watchdog that knows if a voltage is higher then what they can actually take? I know my Schulze 40.160 will arm at exactly 60 volts and nothing more and they use a MOSFET of the same voltage as the ones my controllers will have. If Patrick can change the MOSFETs for the 100V units and I can use higher voltage, then it will be a plus. I wish they could've done the HV like the MGM with the brainboard in the middle and if you wanted more power just stack the powerboards. Kind of like a hot swap set up.

Depending on the ESC, it might have some type of voltage monitoring, but that would most likely be in firmware or some dedicated IC. Even then, this watchdog thing will only prevent the ESC from functioning, but the full battery voltage will still be at the drain and source terminals of the FETs.

Using higher voltage FETs would keep them further away from the actual voltage being used (best not to run anything at their max values). But if the current, slew rate, and rds-on are not equal (or better) as the lower-voltage FETs, you're not gaining anything. I would rather have FETs that are rated around 10-15% higher voltage than what you plan to use, but use ones that have higher current, lower rds-on, and faster slew rate for thermal reasons.

As far as construction, the method Castle uses to stack the power boards is pretty good. The brains are on top where they (hopefully) won't get as hot from the FET boards, and stacking is simple even with the heatsinks. With the MGM, the brains board might be heated beyond what I would like. Oh, and the heatsinks on the HV are nice since they contact BOTH sides of the PCB so ALL the FETs are cooled. The only layer that isn't cooled is the top one, but Castle puts an Al heatspreader on there. I might contact them to see if I can get an extra heatsink piece for that. The more I look at this ESC, the more I like it! If only they would make it work with pistol grip radios a little better.

I found the problem about voltage with the Traxxas VXL controller which could be a nice 4S controller, but the thing won't do nothing if you plug 4S to it. I also like the HV110 design. The MMM could've looked like it.

Well, I ordered the ThunderPower TP-210 balancer and a HV UBEC.

I know I could have simply gotten another LBA10 and networked them, but didn't like having to use the network cable, not to mention the added mess from the input/output Y adaptors for the main charge current.

The choice between balancers was between the DimensionEngineering HVBEC and Western Robotics. The WR BEC was kinda pricey, but is capable of higher current (3.5A vs 2.5A for the DimEng one), and the components on the WR looks beefier. Once the BEC comes in, I'll perform a test on it like I did with the other BECs. The other option I was tossing around was to daisy-chain 8 diodes in series to drop ~5v to bring the 10s battery voltage down from a max of 42v to ~37v. This would have allowed me to use the KoolFlight UBEC (which tests out and performs quite well). The KF BEC has a max input of 40v - actually, the switching IC is rated for an absolute max voltage of 45v but that's pushing it.

Now I'm looking for connectors. I was going to use Deans, but they don't handle the current I'm expecting. I don't want to use bullet connectors because they are a PITA to connect/disconnect IMO. What is available that is polarized/keyed, rated for 100A+, connects both poles at the same time (like Deans), yet is still small/light?

Two sets of deans?

Have you taken a look at the Power Pole connectors that are offered at the Mega Motor site?? www.megamotorusa.com, under connectors in the shop.

Arctic: Maybe, if nothing else works like I want. 50A X 2 would be sufficient I think. Kind of a PITA, but oh well I guess. Deans really outta make a higher-current version...

Speedracer: The 75A version of those powerpoles is probably what I will have to go with. They're big, but I don't want something that won't handle the current I anticipate without voltage drops. I ckecked out powerpoles before, but all I saw was the 30A version. Thanks for the tip!

It is good to focus on connectors. I run Deans without issues, But, I am pushing them beyond what I really trust them for.

One thing to consider too is minimizing wire length. You are much more knowledgeable in electronics than I. But, I have seen huge voltage losses in my wiring. Make EVERY effort to shorten the wires from cells to ESC and ESC to motor as much as possible. It may seem like "Ya, ya, ya, I know that......" But, it is easy to overlook when dealing with the more involved aspects of the project.

I strive for NO wire heat after a run. Heck, if you are running an Eagle Tree, I would suggest running a temp probe on the main power wire to the ESC at the center point to read wire temp.

Just a thought.

Matt

Oh yes, I'll be keeping wires short as possible. The HV-110 uses 10GA wires, so that will help. If you look at the pictures, you can see I tried to position the ESC so all connections are made with the shortest wire length, but it had to be "pretty" too. :smile:

I don't have an eagletree, but a finger check of the wires after a run for warmth should give me a decent clue.

I know it is a pain but with this kind of one off setup I'd go for 5.5 or 6.5mm castle connections...

Hi

I havent read all of this thread but am wondering how is the build coming along? Are you entering the speed event in October?

Cheers