Max voltage on Cellman 12 fet 4110

S

Spicerack

10 kW
Joined
Jan 27, 2011
Messages
602
Location
Perth, Western Oz
So... I'm thinking about trying out a slightly higher voltage on my setup.. At the moment I'm running a vented, temp probed 9C 8x8, 15S (62V) 35A through a Cellman 12 fet 4110 controller (originally from my MAC).

I've opened up the controller and it has the 100V caps in it.

Question is, what is a max safe voltage to run? I've got enough batteries for 100V but don't necessarily need to go quite that high... or do I? :twisted:

Oh and yes I'm aware of dangers, have precharge circuit, temp probe so can monitor winding temp, good brakes/suspension to deal with speed etc so naysayers need not comment... :wink:
 
If it won't take 100V, then it's crap anyway. I've been running my $35 15 4410 fets controller with 100V caps for almost 2 years on 24s lipo, and ran it on 18s the year before.
 
Thanks for the advice.... I'll see how I go.... a mushroom cloud over Western Australia means I pushed it too far! :wink:
 
always run 10% lower than the lowest rated component to be on the safe side.. so 90v absolute max. people running more voltage have just been lucky.
 
If I buy 100V caps, I expect them to take up to 105V minimum. If they fail at 100V, they're defective. That simple.
 
yes you buy a 100v cap it should be fine at 100v but this is in ideal conditions, depending on current draw and other factors this 100v may have 5 or maybe even 10v of ripple . Some may get away with it and others may not, there are also manufacture tolerances that need to be taken into account which also may be as much as +-10% . If you were making something electroinc that a life depended on it would you run everything at its printed spec ? .. medical and military electronics are normally derated by 20% and home consumer electronics by 10%. And this can be the difference between something being reliable and something just packing up for no apparent reason.
 
Yes, you do want to go that High. :twisted:

That said, A rating of 100 volts doesn't mean 100.1 is also safe. You may be able to push the componants a little further. Or you may fry them. Plenty of people here have run 24s Lipo on 4110 FETs and 100v caps. a few have also blown something trying it. And just because the battery is 100 volts, doesn't mean the componant sees 100 volts. You may have ripple voltage that is causing spikes in the system, or get feedback from the motor causing surges over the battery voltage.

Running a componant at it's rated max voltage is a lot like running a car at redline all the time. Or a 200 pound man deciding to hang off a cliff on a rope designed for 200 pounds. There is no safety margin. There is no buffer. No margin of error.

I do it. I run my 63V rated 48V controller on 15S, 63 volts. Been doing it for years just fine. I also run my 4110FET controller on 24S, a little over 100 volts. So far it's also fine.

If you try it, be prepared to have your parts go boom. If you're on a budget, this may not be worth the risk. But if you can afford the risk, the reward is worth it :mrgreen:
 
Drunkskunk said:
Yes, you do want to go that High. :twisted:

That said, A rating of 100 volts doesn't mean 100.1 is also safe. You may be able to push the componants a little further. Or you may fry them. Plenty of people here have run 24s Lipo on 4110 FETs and 100v caps. a few have also blown something trying it. And just because the battery is 100 volts, doesn't mean the componant sees 100 volts. You may have ripple voltage that is causing spikes in the system, or get feedback from the motor causing surges over the battery voltage.

Running a componant at it's rated max voltage is a lot like running a car at redline all the time. Or a 200 pound man deciding to hang off a cliff on a rope designed for 200 pounds. There is no safety margin. There is no buffer. No margin of error.

I do it. I run my 63V rated 48V controller on 15S, 63 volts. Been doing it for years just fine. I also run my 4110FET controller on 24S, a little over 100 volts. So far it's also fine.

If you try it, be prepared to have your parts go boom. If you're on a budget, this may not be worth the risk. But if you can afford the risk, the reward is worth it :mrgreen:
Click to expand...

^This!

It also seems partly luck (unless you source your own components). Those FETs, if genuine, will survive 100V. But you need enough of them to spread the load around. Try running a 6FET with 100V FETs at 100V and you'll most likely run into issue before doing that on an 18FET (pretty obvious though, right?)

Then the other part of sensitivity is the caps. Good quality caps rated at 100V will work at 100V. But some just won't.
 
Plus, there's an enourmous trade in counterfeit electronics components in China. Getting components that are fully up to their claimed spec is likely more of an exception than a rule...
 
I thought the main capacitors were there to absorb the large voltage spikes caused by the rapid switching of inductive loads.



Inductive voltage spikes are waaaay higher than battery voltage so de-rating seems necessary.

Especially if we are using no-name or dubious spec’d components.



Drunkskunk said:
I do it. I run my 63V rated 48V controller on 15S, 63 volts. Been doing it for years just fine.
Click to expand...

Same here. But just last week changed out the caps for low ESR 100V ones.
 
From what I've gathered there are many people that are running 24S successfully on 12 and 18 FET controllers with 100V caps.

I haven't heard of much of other mods beyond that such as higher voltage caps and/or FETs. Does anyone here have a link to a controller expressly made to handle 100V with a safety margin on the component ratings?
 
Ah this again.
Wesnewell I'm going to respectfully suggest you're talking crap. Someone who's been around for as long and amassed as many posts as you have should know better by now. You're spreading misinformation to the noobs!
Expecting or demanding a product to work beyond it's rating is just silly. As drunkskunk said it's like the redline in an engine and the other analogy about the tensile strength rating of a rope and comments about voltage spikes etc are also spot on.

As the wise ones above have said there is no safety margin. 100v max rated components do not make it a "100v" controller. 24S lipo is 100.8v hot off the charge and even if it was 99.999v you're still pushing your luck. Many people are lucky but others have been less lucky. You've been lucky SO FAR running parts beyond their rating but no one has any grounds to complain if things go pop. If I'm building a kit for someone I won't exceed 22S, which is just over 90v HOC. As I tell others if you really want to get every last drop of speed then run 23S if you absolutely must. I don't know about you guys but I hate pedalling or pushing my heavy offroad ebikes home when they break!
 
Spicerack said:
I've opened up the controller and it has the 100V caps in it.

Question is, what is a max safe voltage to run?
Click to expand...
Not to state the obvious, but why not just do what the vendor recommends?

He sets a spec that will give the best possible input range to compete in the marketplace but still gives reliable long service to minimize his Support issues. This isn't rocket science -- exceed the recommended working voltage for the unit and reliability will suffer. Paul is a respected vendor who knows his products through long experience. Believe what he says.

em3ev-12fet-4110.png
 
teklektik said:
Spicerack said:
I've opened up the controller and it has the 100V caps in it.

Question is, what is a max safe voltage to run?
Click to expand...
Not to state the obvious, but why not just do what the vendor recommends?

He sets a spec that will give the best possible input range to compete in the marketplace but still gives reliable long service to minimize his Support issues. This isn't rocket science -- exceed the recommended working voltage for the unit and reliability will suffer. Paul is a respected vendor who knows his products through long experience. Believe what he says.
Click to expand...

Why? Because sometimes the vendors err on the side of safety to minimise their risk. Fair enough too, but like many others in this game I like to push things a bit and by asking what others have experienced before can show what can be done if you're willing to take a punt. I'm not out to destroy the motor or controller but at the same time want as much speed and power as I can get with this setup before I move on to something much bigger/powerful.

Yes I'll probably end up running it at 21/22S but may test another spare/repaired controller of mine at 24S and see how it goes for fun. If you're not living on the edge, you're taking up too much room, dude. That's how we roll. :wink:
 
I'm sure my $35 Hua Tong 72V 1500W 40A 15 4410 fet controller is made from the most expensive parts made and that's why at 3 years old and running fully charge 24s lipo on it at 100.8V for the last 21 months is why it hasn't blow a cap or fet which are all rated at 100V. You think the companies that make electronic components rate them at the max they can take. Of course not. They can't keep tolerances that close. Most will be manufactured to 10% more than specs to keep returns down. Anyone here ever overclock a cpu?
 
It isn't a question of "it will fail" or "it won't fail", but a case of probability. If a manufacturer rates a capacitor at 100V then (IMO) that implies a certain percentage (however many standard deviations) will be able to be able to stand that.

You will always have a few examples from the extreme ends of the bell-curve. E.g. ones that will stand 110V and ones that will fail at 90V. This is where commercial or millitary derating makes sense.

So I guess it comes down to "are you feeling lucky, punk?"
 
Ok, so a person buys a 4110 controller with 100V caps and runs it at 24S knowing the risks of component failure.

What are the components that are most at risk and can/should be upgraded for headroom? Say a person buys a cellman 18FET 4115, which he states is only recommended for 90V (presumably due to caps), What other things should be changed to support the 24S voltage with a margin of error? higher rated Caps and beefed up traces?
 
cal3thousand said:
Ok, so a person buys a 4110 controller with 100V caps and runs it at 24S knowing the risks of component failure.

What are the components that are most at risk and can/should be upgraded for headroom? Say a person buys a cellman 18FET 4115, which he states is only recommended for 90V (presumably due to caps), What other things should be changed to support the 24S voltage with a margin of error? higher rated Caps and beefed up traces?
Click to expand...

Its hard to say, but you will need to look at all the components at the input to the psu side of the controller .. the fets and bus bar caps are easy to see and know that they are going to see the higher battery voltage but but a bit more delving will be needed to make sure that nothing is underrated on psu input.

Edit:.. but to be honest I would not run 100v+ on a bike, once to get up to these sort of voltages it can kill if you get a shock.
 
Spicerack said:
Question is, what is a max safe voltage to run?
teklektik said:
Not to state the obvious, but why not just do what the vendor recommends?

He sets a spec that will give the best possible input range to compete in the marketplace but still gives reliable long service to minimize his Support issues. This isn't rocket science -- exceed the recommended working voltage for the unit and reliability will suffer. Paul is a respected vendor who knows his products through long experience. Believe what he says.
Click to expand...
Why? Because sometimes the vendors err on the side of safety to minimise their risk.
Click to expand...
Gee - it seems that's exactly what I said....

The point is - Paul's recommendation is exactly what you heard here - a very modest 10% de-rating. Paul has put remarkable time and effort into modding these controllers for us over the years and is certainly not just another ignorant reseller. You asked for 'safe voltage' in the OP - there it is.

I'll probably end up running it at 21/22S ... If you're not living on the edge, you're taking up too much room, dude. That's how we roll.
Click to expand...
People with creds are worth listening to - that's how WE roll.

And it seems that in the end you're following Paul's 'safe' recommendation (that's 'rolling' straight to the head of the 'taking up room' line... in spite of the Bad Boy posturing :mrgreen: )
 
cal3thousand said:
Say a person buys a cellman 18FET 4115, which he states is only recommended for 90V (presumably due to caps),
What other things should be changed to support the 24S voltage with a margin of error?
Click to expand...
No need to upgrade - you have misquoted the spec:

em3ev-18fet-4115.png
 
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