Sabvoton 72xxx 21S regen

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Sattva Ram   10 W

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Sabvoton 72xxx 21S regen

Post by Sattva Ram » Dec 11 2020 2:10am

Does anyone know if this controller will work properly with a 21S ion pack? It's supposed to work up to 90 volts so I am sure it will work forward no problem what I am curious about tho is whether the regen will work all across the operating voltage range?

Thanks

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amberwolf   100 GW

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Re: Sabvoton 72xxx 21S regen

Post by amberwolf » Dec 12 2020 12:47am

I'd say it will depend on which "sabvoton" you actually end up with. There appear to be a number of companies making and/or selling controllers branded with the "sabvoton" name, but sabvoton themselves haven't existed for a few years now, based on what I have read around the forums, and none of the controllers carrying their name made since then are actually the same controllers they made, nor are they all the same as each other despite using the same model nomenclature. Some of them are pretty poor quality; I don't know if any of them are really good quality or not.

So, if you have one that's actually well-designed and well-built (which I wouldn't assume) for a 21s system, it should work fine in any mode.

But if you have one that's designed for a lower voltage, even if its' well-designed and well-built (which I wouldn't assume), then it may or may not have the margin to work in any mode at voltages above what it was designed for. Any part within it could be on the ragged edge of it's capabilities, with no margin, and any random spike of voltage or electrical noise in the system could cause failure of that part.


Most likely, you'd simply have to try it, and accept the loss when it blows something up, or have fun if it doesn't. :/

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Re: Sabvoton 72xxx 21S regen

Post by john61ct » Dec 12 2020 3:25am

Personally I'm willing to believe the controllers that QS sells that it calls by that name, are still decent quality

at least for the purpose of driving their motors it sells them with, presumably pre-programmed for.

I don't know who actually makes those controllers, if they can be bought as separate items from QS, nor how easy they are to program for the other various non-QS motors.

All of which I would love to learn more about from those who know

hias9   100 W

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Re: Sabvoton 72xxx 21S regen

Post by hias9 » Dec 12 2020 4:38am

I have used an unlocked Sabvoton 72150 a few years ago with a 22S battery.
It worked fine, but there was one problem: Regen was not possible before battery voltage was down to somewhere around 84V. I did not find a solution, this is probably a firmware limitation.
So with 21S you would not have regen available for the first part of your ride.

Sattva Ram   10 W

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Re: Sabvoton 72xxx 21S regen

Post by Sattva Ram » Dec 12 2020 3:18pm

Really??? Ohh fuuuck. I just ordered the batteries for the 21S pack, anyway maybe I can still cancel some of it.

Okay I have a 24s lifepo pack first thing in the morning will be to test the controller.

Shiet this build is getting worse and worse by the day. I just figured that the qs 4000w mid motor cant handle 180 degrees only 150, but I thought that it can handle 180 when I ordered it. Had I known it i probably would have told them to make it from the better wire. Disappointment upon disappointment this is a 💩tty day...This build seems to be nuisance at this point I swear to everything that is sacred that this is my last.

Hope you are not right tho. We will see tomorrow keep the fingers crossed... Well this bike wont be as badass as I initially thought...anyway it seems there is no magic. Cheap meat has a thin stew as we say in my country. Anyway thanks for the great advice.
Last edited by Sattva Ram on Dec 12 2020 3:24pm, edited 1 time in total.

Sattva Ram   10 W

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Re: Sabvoton 72xxx 21S regen

Post by Sattva Ram » Dec 12 2020 3:22pm

With the greentime it's definitely the lvc and it can be fixed. All you gotta do is to have an exclusionary switch - like the blinker switch on the handlebar - and you switch between the higher and lower lvc whenever needed. All you gotta to is to wire it to the respective resistor inside the controller that sets the lvc. I guess it's the same issue here anyway I test it tomorrow and let you know if you are interested...
Last edited by Sattva Ram on Dec 12 2020 3:28pm, edited 1 time in total.

Sattva Ram   10 W

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Re: Sabvoton 72xxx 21S regen

Post by Sattva Ram » Dec 12 2020 3:26pm

john61ct wrote:
Dec 12 2020 3:25am
Personally I'm willing to believe the controllers that QS sells that it calls by that name, are still decent quality

at least for the purpose of driving their motors it sells them with, presumably pre-programmed for.

I don't know who actually makes those controllers, if they can be bought as separate items from QS, nor how easy they are to program for the other various non-QS motors.

All of which I would love to learn more about from those who know

I think the sabvoton is fine I also hear these urban legends everywhere here that it's a knockoff counterfeit but I dont really believe it. It seems pretty decent to me.

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Re: Sabvoton 72xxx 21S regen

Post by john61ct » Dec 12 2020 4:05pm


Sattva Ram wrote:I think the sabvoton is fine I also hear these urban legends everywhere here that it's a knockoff counterfeit but I dont really believe it. It seems pretty decent to me.
Then there should be a single company that owns the brand

there isn't.

And plenty of members with decade's experience state that there never was, right from the beginning there were multiple makers of varying quality.

I'm not saying "the sabvoton" is not good

I'm saying that which the phrase refers to cannot even be objectively defined.

Like "smart bluetooth" BMS, just a general descriptor, dozens of products of widely varying quality fit the category, impossible to nail down a particular model as being good or not.

Other than people recommending a specific URL to buy from, and hoping that vendor is consistent in what they are selling from there.

hias9   100 W

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Re: Sabvoton 72xxx 21S regen

Post by hias9 » Dec 13 2020 5:00am

I can only speak for the Sabvoton I had.
It was an unlocked 72150 without the display. At the same time there were 72150 with displays available which are locked to 150A/350A and have a different firmware. I don't know if these units also have this 84V or 85V regen limitation.

Sattva Ram   10 W

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Re: Sabvoton 72xxx 21S regen

Post by Sattva Ram » Dec 13 2020 6:10am

You are right. I just conducted the experiment. I made a sloppy 90volt pack from scrapped cells to test it. It only regens up to 84 volt and above it it releases the motor. I dont really know what to do tho. I ordered 714 cells for a 21S34P config. I hope I can cancel 34cells. Tooo baad that extra 200 rpm would have come useful. It would have been "free" power. 😔 The bright side tho is that I might not have to squeeze the pack so tightly this way...I might also be able to use a honeycomb holder this way so I dont have to glue the cells. However I want to make a water cooled pack and the gap of the honeycomb holder is too large it uses up too much water adding extra superfluous weight, so I might just stick to the gluing with a slight added heat shrink spacer between the cells. Also with the honeycomb I should also give up 2Ps too cause of space issues.

Anyway thanks for the great info had you not told it I might not have done the experiment...

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Re: Sabvoton 72xxx 21S regen

Post by hias9 » Dec 13 2020 11:16am

No problem. Unfortunately there is no real solution to this unless you can somehow convince MQCON to make a modified firmware which is very unlikely.
If you want to use a 21S battery, just live with the fact that you will not have regen for the first part of your ride or go for a different controller.

Why do you want to watercool the pack? If it‘s 34P and the Sabvoton draws 150A max from the battery, cells should not get hot at all. Or do you want to heat the pack before riding on a cold winter day?

Santacruz   100 W

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Re: Sabvoton 72xxx 21S regen

Post by Santacruz » Dec 13 2020 11:31am

Sattva Ram wrote:
Dec 13 2020 6:10am
You are right. I just conducted the experiment. I made a sloppy 90volt pack from scrapped cells to test it. It only regens up to 84 volt and above it it releases the motor. I dont really know what to do tho. I ordered 714 cells for a 21S34P config. I hope I can cancel 34cells. Tooo baad that extra 200 rpm would have come useful. It would have been "free" power. 😔 The bright side tho is that I might not have to squeeze the pack so tightly this way...I might also be able to use a honeycomb holder this way so I dont have to glue the cells. However I want to make a water cooled pack and the gap of the honeycomb holder is too large it uses up too much water adding extra superfluous weight, so I might just stick to the gluing with a slight added heat shrink spacer between the cells. Also with the honeycomb I should also give up 2Ps too cause of space issues.

Anyway thanks for the great info had you not told it I might not have done the experiment...
You could always just charge the 21s pack to 4v per cell. Within limits and a battery pack with a much extended life.

Sattva Ram   10 W

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Re: Sabvoton 72xxx 21S regen

Post by Sattva Ram » Dec 13 2020 11:44am

Well yeah but 84 resting voltage is maybe 70ish percent with a pack like this. I find it kinda low. I guess I stick to the 20S it's better for the capacitors as well...😔

hias9   100 W

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Re: Sabvoton 72xxx 21S regen

Post by hias9 » Dec 13 2020 12:35pm

84V should be about 80% for a 21S pack. But my Sabvoton measured 2-2.5V more voltage than real which makes the regen issue worse.
I used the Sabvoton for over a year at 22S and had no problems besides the regen issue.
Regen on lower speeds is quite weak with the Sabvoton by the way.
But of course it’s much more likely to blow a FET at 22S than at 20S.

Sattva Ram   10 W

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Re: Sabvoton 72xxx 21S regen

Post by Sattva Ram » Dec 13 2020 3:27pm

I think 84 resting is closer to 70% actually. Anyway I dont mind it oh so much the bright side is that my pack can be narrower giving more space for winterizing the pack with Styrofoam, also I might not have to modify the kickstand awfully. True the controller measures 2 volts more. When I did the test I was like "ohhh at 86 it still does regen 21S seems fine then. Then I put on the multi cause I suspected that it's inaccurate and indeed it was".

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