Voltage regulator @ 50v

[209143]

Hello all,

Im looking for some way to regulate voltage to my motor controller to stay at a constant voltage. At about 52v is where my motor controller will not allow movement. So I want to connect say 70v worth of lipo batteries and have it regulated to a constant 50v where it does function. Varying voltage/current draw on the batteries to maintain that 50v. My commute is 4.4 miles total To and from. Any help is appreciated. Thanks

 

[okashira]

Hello all,

Im looking for some way to regulate voltage to my motor controller to stay at a constant voltage. At about 52v is where my motor controller will not allow movement. So I want to connect say 70v worth of lipo batteries and have it regulated to a constant 50v where it does function. Varying voltage/current draw on the batteries to maintain that 50v. My commute is 4.4 miles total To and from. Any help is appreciated. Thanks

Not a good idea for many reasons. If you are running too low you need to add another battery in series.

 

[cycborg]

There's been this odd rash of threads lately of people wanting to stick something between their battery and controller to regulate voltage. Let's consider the controller's two essential functions:

(1) A commutator, to switch power to the appropriate windings as the rotor rotates
(2) A switch-mode DC-DC converter, to regulate the motor voltage and therefore speed.

Adding another piece of equipment to do what the controller is already doing (function 2) just adds weight, complexity, and failure modes.

What is the problem that you're trying to solve? Are you finding that the top speed drops as your battery discharges? If so, get a controller that can accept a higher input voltage. This will almost certainly be less expensive than adding a regulator, and will definitely be less failure-prone.

 

[cycborg]

If you are running too low you need to add another battery in series.

Sounds like he has the opposite problem.

 

[amberwolf]

Im looking for some way to regulate voltage to my motor controller to stay at a constant voltage.

Your controller IS your regulator.

If your battery is too high a voltage for it, then you need to replace the controller with one suited to your battery, or you need to replace your battery with one suited to your controller.


If you REALLY want to put a regulator in there, you could, but in order to handle the power and surge requirements it will be large and heavy (probably much more so than your controller) and cost more than your controller (possibly more than your battery, controller, and motor!). Before you can find one you'll need to find out what the maximum surge and constant currents are that your controller pulls from the battery, and then search the web for a weather-sealed and vibration-proof (probably potted) DC-DC converter that can handle taht kind of power at the exact voltages you need. You may also need to heatsink or actively cool the converter, so you'll need to read the specifications for the ones you find to make sure or it could overheat in use.


If you have electronics design skills, you could modify a brushed motor controller to act as a DC-DC, adding teh appropriate inductors and capacitors on it's output to smooth the PWM output it uses to regulate the voltage into what your controller needs to operate.



Alternately you can read around the forums to find the many threads on modifying and/or programming controllers, to see if yours can be modified in some way to work at a higher voltage. This is not for the faint of heart or inexperienced, as you can damage it beyond repair with a mistake, depending on the methods used and controller design.

 

[bowlofsalad]

Im looking for some way to regulate voltage to my motor controller to stay at a constant voltage. At about 52v is where my motor controller will not allow movement. So I want to connect say 70v worth of lipo batteries and have it regulated to a constant 50v where it does function. Varying voltage/current draw on the batteries to maintain that 50v. My commute is 4.4 miles total To and from. Any help is appreciated. Thanks

I think You will be far better off either reconfiguring your pack or changing your controller in some way.

What I mean by reconfiguring your pack, change the amount of cells in series and parallel so that you still have the same total cells (capacity) but the voltage you desire.

What I mean by changing your controller is if your controller truly cannot handle the voltage you wish to use, you can buy a new one. Not only is replacing the controller going to be easier, it's probably going to be cheaper and more efficient(in terms of power consumption). If this is simply a matter of programming to which your controller has a voltage cutoff that you can change, maybe figure out how to change that?

 

[209143]

Wow with the quick and multiple responses! Thank you!
I purchased a "36v 800w" system from Amazon. Soon to learn that the 36v controller was really a 48v. It was written with a sharpie, so..... I dont have any heat issues. It gives max speed and torque at 50 v. I want to keep it there for the whole 2.1 miles. Upgrade the motor controller? After the voltage drops to about 41v it cant climb the hills. 26in bike 215lbs. Im fairly knowledgable in dc currents but not transistors or microprocessors. Thanks!

 

[amberwolf]

The problem you describe is not your controller, it is probably your battery simply not having enough power to do it once it's run down that far.

You don't specify your battery info but it sounds like it's simply nearly empty at that point.

Add more battery in parallel to your existing battery, or replace it with a better one sized for your controller.


Also, an HVC of 52V is not a 48V controller, becuase a 48V controller would have an HVC more like 60V+. So you do have a 36V controller.

 

[cycborg]

What are the specs on your battery (nominal V and Ah)? 41-50 V sounds like an odd range for either a 48 V or a 36 V nominal battery. And if it's running down after only 2.1 mi (or even 4.2 mi), something's wrong. You should only need something like 50-100 Wh to get that far - that's like power tool battery pack size.

 

[dnmun]

Hello all,

Im looking for some way to regulate voltage to my motor controller to stay at a constant voltage. At about 52v is where my motor controller will not allow movement. So I want to connect say 70v worth of lipo batteries and have it regulated to a constant 50v where it does function. Varying voltage/current draw on the batteries to maintain that 50v. My commute is 4.4 miles total To and from. Any help is appreciated. Thanks

why does your controller not allow movement? what is the actual DC voltage? what controller do you have and can you show a picture of the label? when you say "about 70V" what does that mean? what is the specific voltage that your battery reaches at full charge. the true DC voltage.

 

[alexis57]

One reason that it's not a good idea at all. THE EFFICIENCY ! It's really important for embedded system.

If you add a regulator, the maximum of efficiency you could find for this system is 90%. Then you will already loose 10% of the energy the battery will provide. Just with the regulator, I let you multiply other efficiencies (controller, motor etc).....

 

[209143]

Okay, so i am using 5Ah LiPO turnigy nanotech 50-100c discharge batteries. 9 of them. 4.2vx9=37.8v. i assumed for 36v motor and controller 37.8v would be sufficient to get me to work (2.1 ish miles) charge them at work and come back. i was wrong. at 36v it sucks. i also have 3 8Ah SLA's @ 12v a piece so used all 3 SLA's and 3 of the Lipos in series to get 50 some volts. WOW awesome. climbs hills crazy fast and acceleration is awesome. so I suppose I'm "overvolting" the motor which is giving me the awesomeness lol. but with lipos the voltage drop from 4.2v to 3.9v happens very quickly then has a smooth discharge curve the rest of the way. THATS my issue, nominal on lipo is 3.7v but fully charged is 4.2v thats a big difference in peformance 3.7vx9 = 33.3v. versus 4.2vx9 = 37.8v. I intend to purchase more of these lipo packs to get me to the full 50v BUT 14 of these packs at nominal vol would be 51.8v WHICH IS PERFECT, but that would mean i could never fully charge the batteries.


So what i gathered from the earlier replies is that i do in fact have a 36v controller b/c the HVC is 50v versus a 48v controller with a HVC of 60+V . makes sense. what had me thinking it was a 48v was the battery indicator. as soon as i hit the throttle the green indicator cuts off leaving only yellow and red. after i added the extra volts the meter works properly.(Chinese POS maybe...)

So an upgrade of the controller to 48v could possibly solve all my problems. it could handle the fully charged lipos. i just wouldnt have to press the throttle all the way. i would in turn also get a little bit longer run time too. can you recommend a 48v motor controller maybe? below are pictures of what i have. there is no label on the controller, only the writing.

 

[dnmun]

so you are saying that the controller is shutting off because the input voltage is too high because there is some sort of HVC similar to the HVC of a BMS to protect from overcharging a cell? is there any evidence that is part of the controller circuitry? is it mentioned in the owners manual or any literature about the controller?

i have never seen a controller with an HVC.

 

[cycborg]

Since it sounds like you'll need to invest in more batteries in any case, before upgrading the controller maybe you should try this and see how you like it:

Since you're not getting much energy out of the 3.9-4.2 V/cell range, how about getting 4 more cells for a total of 13, then charge them to 50 V total, or 3.85 V/cell. That way you start with the 50 V performance you like, and the decrease in performance won't be as dramatic.

On the other hand, 48 V controllers in the 750-1000 W range aren't terribly expensive - $100 from Grin Tech, $76 plus shipping from China from EM3ev.

 

[DAND214]

Just get 2 6s 8000mah packs and run 12s which charges to 50v. That alone will be better than all those single cells you are using.

37v is not 9 cells but 10 cells which also would give you what you might need. Rated voltage is not charged but nominal. Most of the kits voltage are based off of old tech LEAD which are 12v nominal. Not the charged voltage. You say your controller cuts out at 50v then don't charge all the way to 4.2v per cell. A 12s pack will do great at 4.15v per cell, I use it most of the time. Don't need 40mph anymore happy with 20 to 30 max. A good LiPo pack will give about 1 mile per Ah. You really don't want to trust that and never believe the throttle lights as they are more likely for LEAD which sags a lot.

Dan

 

[amberwolf]

i have never seen a controller with an HVC.

I don't think I've had one either, but:

A number of Currie products have them, from waht I've seen in various threads. Some other OEM controllers appear to, like some of what Prodeco uses. At least some Kellys have a programmable one, Addapto has one (but it is more than just a controller). I thought I'd seen a thread on an XC-series MPU type that did but can't find it now.

So it wouldn't surprise me to see this one might.

I have an XC-series type that I'd like to test for HVC at some point, once I have something else to replace it with if I blow it up trying.

 

[dnmun]

that looks like a generic controller so i doubt if it has more than LVC. it just may not have sufficient input power resistor so the voltage regulator is overvolted or the mosfets and input caps might be only 50V also.

 

[209143]

wouldnt short charging the lipos be bad for them?
does anyone know anything about the motor in the pics? i cant find any matches for the etched numbers on the motor.

I charge the batteries individually that is until my balance leads arrive. there is no bms. i have a voltmeter attached to the bike so i dont drop below 3v per cell under load .i like these batteries and probably wont change them until their cycles run out.

i found some sort of cuttoff by adding more batteries until the throttle did not cause movement. took one battery out and bam. the performance at that level is perfect.

even if i had enough batteries for 36v operation its too slow and barely climbs the hills. so some would call 48v operation on a 36v motor overvolting hot rodding or something. which is fine.
i dont have any issues with heat in the motor at this voltage

is there a cheaper motor controller out there for 48v? im on a tight budget. dont really care if its generic as long as it works.

you guys have been a great help and i appreciate you listening to my rambling. never posted in a forum before.

 

[cycborg]

wouldnt short charging the lipos be bad for them?

Partially charging a battery won't hurt it at all. You can damage a battery by overcharging, overdischarging, pulling too much current, overheating, and leaving it at a high state of charge for a long time. Oh, and poking it with sharp objects.

some would call 48v operation on a 36v motor overvolting hot rodding or something. which is fine.
i dont have any issues with heat in the motor at this voltage

Yeah, you'd have to be pushing that motor really hard to put it in the red zone over only 2.1 miles. I'm sure it would be fine at 48 V and say 15 A continuous, and higher current isn't a problem for pushing it up a hill for a few minutes.

is there a cheaper motor controller out there for 48v? im on a tight budget. dont really care if its generic as long as it works.

Cheap used controllers show up from time to time on the ES marketplace. You can also do some searching on AliExpress and EBay.

 

[dnmun]

wouldnt short charging the lipos be bad for them?
does anyone know anything about the motor in the pics? i cant find any matches for the etched numbers on the motor.

I charge the batteries individually that is until my balance leads arrive. there is no bms. i have a voltmeter attached to the bike so i dont drop below 3v per cell under load .i like these batteries and probably wont change them until their cycles run out.

i found some sort of cuttoff by adding more batteries until the throttle did not cause movement. took one battery out and bam. the performance at that level is perfect.

even if i had enough batteries for 36v operation its too slow and barely climbs the hills. so some would call 48v operation on a 36v motor overvolting hot rodding or something. which is fine.
i dont have any issues with heat in the motor at this voltage

is there a cheaper motor controller out there for 48v? im on a tight budget. dont really care if its generic as long as it works.

you guys have been a great help and i appreciate you listening to my rambling. never posted in a forum before.

overvolting the controllers is quite common. what is puzzling is that your controller shuts down when the voltage exceeds some voltage around 50V from what i interpret your statements to mean.

without looking at the controller circuitry it is impossible to guess what is causing the shut down. there may be some other device connected to the controller which monitors the voltage and shuts it down.

either one of these should capable of being hacked to work at higher voltage. the controller looks like it is a small controller so it may be limited by the mosfets and until we know it is hard to figure what has happened unless you can do more analysis which is pertinent to identifying the cause of this shut down.

 

[amberwolf]

is there a cheaper motor controller out there for 48v? im on a tight budget. dont really care if its generic as long as it works.

Cheap used controllers show up from time to time on the ES marketplace. You can also do some searching on AliExpress and EBay.

There's one similar to yours but at 48v in a review/tech thread by me, linked in my SB Cruiser thread. It's not a great controller, but it does work, albeit at only 32A peak though ti says it should be 40A. Dogman could say for sure but IIRC it was around $30 off Aliexpress. Might even be a link in teh thread.

 

[Eclectic]

Am I missing something or did he say he made a 9s1p battery. That's only 5Ah @ 33.3V (37.8 or 189Wh HOTC).

I have the same motor (but I use a Lyon 9 FET controller). 12s2p (10AH @ 44.4V) would get me close to 15mi. I would imagine he could be pulling 1kW+ every time he starts off the line. Wouldn't that eat up a little battery pretty quick?

 

[cycborg]

Am I missing something or did he say he made a 9s1p battery. That's only 5Ah @ 37V (37.8 or 189Wh HOTC).

You might have missed the 4.4 mi RT distance.

 

[209143]

To all,

I have ADHD and my thoughts are all over the place, maybe this isn't the right topic to be conversing about this....

so here's the insides of the controller.

the mosfets are soldered nicely, caps not so much.
I've got soldering skills, not so much on surface mount components though. I've been playing with electricity since i was 3 years old. but if i could mod the controller i already have that would be awesome.

side note: on the way home i consumed approx. 10,244 mAh spread across a theoretical *11* 5Ah lipos which is approx. 1136mAh per batt. with an end resting voltage of 3.97v. this is at full throttle on varied hills and flats. i'm assuming i'm doing about 30 mph. 2.2 miles. so my batts. arent really an issue i guess b/c of the short distance. when i say "theoretical" i mean 8 lipos and one 12v 8 Ah SLA. in 7 days i will order the rest of the batts. those SLA's are HEAVY! Currently at my disposal are 3 12v 8Ah SLA's and 9 5Ah 3.7v lipos.

for all intents and purposes, my setup is purely transportation to and from work 2.2 mi up and 2.2 mi back. The speed limit is 35mph at most, so i need to be able to keep up w/traffic.

In the middle of the night i can make a round trip in 18 minutes with no traffic.

The motor is great, with a few more volts I could hit 40mph easy. After all the replies and discussion i think i need to either mod or upgrade my motor controller.

okay so side-side note: spokes loosening/stretching... tic tic tic tic tic tic tic sounds riding home tonight. Tightened them twice so far B/C of the tic tic sound . maybe i need HQ spokes? cant risk an injury.
lol, you wouldn't believe what i found when my tire went flat last week. they crammed what looked to be a 30" inner tube into a 26" rim. no liner and lots of burrs on the aluminum rim.WTF!!! good thing i didn't get hurt.

thanks again!