Converting 6FET 4110 to 6FET 4115

[Skedgy Sky]

Hi all! I decided on rebuilding my 4110 6FET into a high voltage backup controller.



Necessary changes I made for HV operation
R12 is 600 ohms (2x programmed regen multiplier)
R01 is 500 ohms.
4115 FETs added.
High voltage caps added

It worked at 90V, but 126V it took out the Lm317 which I replaced.. then accidntally killed the 2nd one (d'oh!!)

What other changes are required to make the controller operational at high voltage (I'm sure it's just something on the resistor network)? Thank you.

 

[Skedgy Sky]

Ok... 4 days later I've gotten somewhere.

1. Blew a lot of LM317 regulators.
2. Tried high R1 values, like 2k.
3. Blew more regulators and then FETs, maybe because MCU and other circuitry wasn't getting enough voltage?
4. Bought LM317AHV (good for 60V on input vs output of regulator).
5. Have R1 set to around 1.2K.
6. Packaged controller up.

Controller powered on for about 10 min so far. Back end gets warm to touch (that's where R1 sits). So far, no fire. LM317AHV component may have been the key (heard of its existence elsewhere on the forum).

Edit: After about an hour of being powered up, the case is now 45C. Either I need high watt resistors on R1 or don't think my R1 value is optimal. The 60V capable LM317AHV was getting warm without heatsink with current R1 value, so I think I was getting close to its limits, even with an R1 of around 1.2k... Higher wattage resistors might be required (right now I'm just using ones that usual come on these controllers.. 1-ish watt resistors?).

 

[cal3thousand]

Good info. Thanks for this

 

[Skedgy Sky]

It's doing 2kW into my cromotor (20 inch bmx rim) and gets pretty warm (feels like 50-60C) after a few minutes. 116V at 18 amps max. I'd be afraid to push it much higher.
Bike is 140lbs and I'm another 140lbs..

I think as a backup and temporary high voltage controller, it does okay. Not sure if it can push any more amps to get more speed.