Changing the LVC in a 72v generic controller

[Zenid]

So I ended up installing a 2.2k resistor rather than the SMD resistors. Some napkin math calculation says it should hit LVC near 37v (or 2.3v per cell for 16s).

Your piccy isn't showing properly. Could you post another or explain where you put the resistor. Great to hear you figured this out, nice work!

[auraslip]

Ok. It doesn't help that none of the parts are labeled in this section of the board.

Basically, from VCC there are SMD two resistors in series. After them, there is one SMD resistor that leads to the MCU and another SMD resistor that leads to ground. This last resistor is the one you need to remove and raise the value of. You can do this by replacing it with the appropriate SMD resistor, or by drilling a hole in the trace and attaching a regular resistor to it and to ground. In the pic above the hole is drilled on the left, and the resistor connects to a random pre-drilled hole that connects to ground on the right.

Drilling a hole in the trace is a bit of a pain though. Need a real small drill bit.

[wesnewell]

So what do we use when we don't have a 12V converter? All I've got is 100V coming from the 24s lipo battery pack. If I understand you correctly, Brake-Hi just turns the controller off when pulled high? I assume that will shut off cruise control too?

Yes, brake-hi switches off the controller when you send 12V into it, and it cuts off cruise control too..

Are you telling me you don't have a 12V system at all? If so, then what's powering your headlights and indicators, and - more importantly - your brake light?

All vehicles as I know them have a 12V system for this purpose...

I'm using this on a bicycle, not a scooter. It doesn't have a lighting system of any kind because it doesn't have an electrical system at all other than the 100V battery pack I installed to power the controller/motor. I use self contained headlights and tail lights that use AA and AAA batteries

[Zenid]

Related: you can see by my finger where I tried to drill a hole through the trace to run a resistor to ground. The drill bit was too big, and ate through all of the trace so I had to make a little jumper to the otherside.

Could you clarify where you planted the leg of that resistor by these SMCs and their tracks? Is it that hole top left of the left SMC resistor or one of those two(or is it one?) on the right? The picture isn't very clear. The right leg I can see you just put down into one of those four holes in that square section to the left of M2 (shown here):
http://zenid10.files.wordpress.com/2011/07/p1000967-1600x1200.jpg

I notice in the second picture where you've installed the resistor, that yellow wire in "M4" had gone. What happened to it?

One problem I had was the meanwells kept shutting down if I drew too much power. I don't know what that's about?

I don't want to be a buzzkill, but have you actually tried running the controller live off a 48V bank, attached to a scooter to make sure it does all actually work?

[auraslip]

No need to be a buzz kill, the problem was I was tripping the over current protection. It works fine and the motor spins up.

Ok. I removed the yellow wire because I didn't need it. I removed all the wires I didn't need actually. Lots of stuff on this controller I can't use!



There is probably a better way to do this because you need a real small drill bit. The nice way to do it would be to replace the original SMC resistors with ones of a higher value.

[auraslip]

Don't mean at all to be rude, but research voltage dividers and how they work to understand what's going on here.

[Zenid]

Don't mean at all to be rude, but research voltage dividers and how they work to understand what's going on here.

I understand how voltage dividers work, but don't have a controller board to hand to follow how you changed the layout here (I only have one left, and that's packed away ready to ship). I was hoping you could clarify where you planted the left leg of that resistor so I could follow what you did once I've got one of these apart again (I'm getting another order in shortly). The detail on that picture makes it hard to see what's going on on that left side, and my own photos don't cover that section in close-up.

Well done on figuring this out. I ran all over the place with a continuity tester trying to find the equivalent of that R12 divider but just couldn't locate it. Layout is evidently slightly different and I didn't find what I expected.

[EDIT] I just saw that picture of yours clearly labelling everything. Thanks a lot! I'll give this mod a go when I get in more of these. Did you think of maybe routing the extra resistor via an external self-connector (like the 60/120 degree plug) to make the controller dual mode? Might be handy for 48V users who are planning to upgrade...

[Zenid]

Ok. It doesn't help that none of the parts are labeled in this section of the board.

Basically, from VCC there are SMD two resistors in series. After them, there is one SMD resistor that leads to the MCU and another SMD resistor that leads to ground. This last resistor is the one you need to remove and raise the value of.

This is the bit that confused me. If you were adding a resistor in parallel, why not just add one that modifies the existing resistor value? That way, if you want to revert back to the 72V arrangement, you just snip the new resistor. Doing it this way also allows you to make your controller dual-mode, by looping it through an external self connector (like I suggested in my last post).

Drilling a hole in the trace is a bit of a pain though. Need a real small drill bit.

Yes, tell me about it. Very fiddly work, and not easy to do with a great big drill...

[amberwolf]

To drill tiny holes in PCBs, take the blade out of an Xacto knife, loosen the blade holder all the way, insert the very small drill bit into the center of the X-cut in the holder, then tighten it down as much as you can.

Now you have a pen-drill that can be used to hand-drill small holes such as those to cut traces, or drill new holes in PCBs for components taht are too wide a leg spacing for the existing holes.

If the pen diameter does not give enough torque, wrap it tightly with thick tape or similar, or cut a strip from an old mousepad and wrap it very tightly around the pen, grippy-side in, then tape that down. It'll increase it's diameter enough to give you much better torque on the bit.

I use a larger 1"-diameter-handled Xacto for this purpose (well, I did, but now it's somewhere in one of my boxes of stuff packed away, who knows where).

[auraslip]

So stupid question, but does anyone know the original value of the SMD r12 resistor?

[Ultraman]

I've bought one of these controllers from DHgate. Arrived today, but it turns out that it lacks the connector to switch from 120 to 60 degree phase angle. It's the yellow "H" connectors from this photo that I don't have.

http://zenid10.wordpress.com/category/3 ... ontroller/

This is unfortunate as both the motors I want to use with this are 60 degree. And someone mentioned in another thread that the stock 120 degree controllers are the same board as the ones with this jumper. If someone (Zenid?) has any info on where I could solder to the board to make this switch, I'd appreciate it.

[auraslip]

I've looked at the board and tried to figure out what is what WRT to switching the phase. One yellow wire goes to ground, and the other goes to a pad near the output side of the board. I cant' for the life of me figure out which it is though! Dammit. Gonna have to get pictures, or experiment

Anyways, rather than just fixing the LVC with a resistor, I installed a 5k pot inside the controller and set it to run 72v. This way you can adjust the LVC with ease if need be. I finally shipped today btw.

[Zenid]

I've looked at the board and tried to figure out what is what WRT to switching the phase. One yellow wire goes to ground, and the other goes to a pad near the output side of the board. I cant' for the life of me figure out which it is though! Dammit. Gonna have to get pictures, or experiment

This any use to you
http://zenid10.files.wordpress.com/2011/07/htr-1600x12001.jpg

But, um, isn't that the wire you just took out because you "didn't need it"?
http://endless-sphere.com/forums/viewtopic.php?f=2&t=26306&p=437500#p433487

[auraslip]

There we go! Thanks zen! I took it out because I assumed just about every hub motor had the same degree.

BTW, have you figured out regen or 3 speeds on these? I'm assuming ds, sl, ybs, xs, and ybk are the ones to ground.

[Zenid]

BTW, have you figured out regen or 3 speeds on these? I'm assuming ds, sl, ybs, xs, and ybk are the ones to ground.

No. I still have to test out your LVC mod on my bike with my old SLA bank. I haven't had time to tinker any more with these just yet...

[Ultraman]

This any use to you
http://zenid10.files.wordpress.com/2011 ... x12001.jpg

That's the photo I was looking for, thanks a heap Zenid. And thanks for shipping the controller out auraslip, looking forward to giving it a go.

[Reactor]

Hi everyone,
I have been following this closely and would like to change the LVC for 12S Lipo 3.3v per cell 12x 3.3 = 39.6v.

I have bought the controller and am just clarifying that all I need to do is put the correct SMD resistor value here http://min.us/lbz86GlV9

So I ended up installing a 2.2k resistor rather than the SMD resistors. Some napkin math calculation says it should hit LVC near 37v (or 2.3v per cell for 16s).

Some help in working this LVC calculation or the formula involved would be appreciated . I am guessing something around 2k.

[auraslip]

Sorry. I haven't been checking this thread.

I forget the math... IIRC LVC for 72v SLA is... I don't know

but figure that out and then find the ratio between it and the LVC you want (39.6v)

and then use that ratio to figure out what resistor value you need. FYI, you may need to alter or remove the voltage divider resistor to get the value you need.

Sorry can't help more. Hung over as shit.

[Zenid]

Anyways, rather than just fixing the LVC with a resistor, I installed a 5k pot inside the controller and set it to run 72v. This way you can adjust the LVC with ease if need be. I finally shipped today btw.

I don't quite understand why they put that extra SMD slot on the board: Adding a resistor in parallel will only raise the value of the LVC, so why did they include a blank space in parallel as part of the voltage divider? I know for a fact that these controllers don't take kindly to overvolting...
http://zenid10.wordpress.com/2011/09/03/meltdown/
I've finally got round to opening one of my new batch of controllers up and can see exactly what you're talking about. But I've found alternative mounting points that might make things a little easier, and think I'll go with a 1.8KΩ setting for the 48V LVC, and a 1.5KΩ setting for a 60V LVC. I'll use a pot for this like yourself. Congrats again on nailing this.

[auraslip]

extra smd slot just gives them more options. this board could probably be used with voltages from 24v-100v depending on the build.

Good to know that the fets are only rated at 75v. I honestly don't know why these controllers are so popular. For the amount of work you have to put into them, and for the quality of them.... better to just spend twice as much and get a programmable controller.

I need to look into importing some generic infenions.

[The Mighty Volt]

extra smd slot just gives them more options. this board could probably be used with voltages from 24v-100v depending on the build.

Good to know that the fets are only rated at 75v. I honestly don't know why these controllers are so popular. For the amount of work you have to put into them, and for the quality of them.... better to just spend twice as much and get a programmable controller.

I need to look into importing some generic infenions.

I'd be more than interested in that.

[wesnewell]

You people are really screwed up. The fets in the Hua Tong 72V 1500W controller are not 75V, but 100V fets. Zenids meltdown link showing the controller is not even a Hua Tong 72V 1500W controller. The Hua Tong 72V 1500W controller does not use P75NF75 75V fets. If it did, I would have smoked them the first time I used a 100V pack. It uses 100V fets, 15 of them.

[bobale]

The fets in the Hua Tong 72V 1500W controller are not 75V, but 100V fets. Zenids meltdown link showing the controller is not even a Hua Tong 72V 1500W controller.

I second that. Older HuaTongs had 4410, and newer have 4710, so both 100V rated. Caps also.

BTW, he said this about controller he blown with overvolting:

The LiFePO4 bank also spends for more of its discharge at above nominal voltage, so I was seldom going below 80V, and running the bike typically at 81-84V. The fact that it survived two weeks running at about 115% of its rated value – continuing to work even after it began melting – is a testament to how rugged these units are…

[auraslip]

You people are really screwed up. The fets in the Hua Tong 72V 1500W controller are not 75V, but 100V fets.

extra smd slot just gives them more options. this board could probably be used with voltages from 24v-100v depending on the build.

The controllers are probably just built with what ever they can get the cheapest that day. This is china.

[wesnewell]

Even so, they wouldn't use 75V fets in a 72V controller. Even an SLA 72V battery pack has more than 75V output. Closer to 81V.