# Kostov 11



## ElectriCar (Jun 15, 2008)

I had a DC9 that averaged about 400w/mile on a 165V Calb 200ah battery pack. Ran it around 2500rpm or higher on average to keep it cool. Never ran hot, no blower. Finally blew it, my fault, great motor with good torque. After replacing the armature and blowing it again, I went with the Kostov. 

Decided to convert it to auto at the same time, reinstalled the alternator and connected the AC back. Now after maybe 500 miles I'm averaging 6-700 watts. If I drive it at 60-70mph for more than 5 minutes or so, it's so hot you can smell it and this one has a probably 5" squirrel cage 150CFM blower with a 3" duct on it running anytime the Soliton is energized. It also seems to have much less power than I expected going from a 9 to an 11. Totally disappointed. Lots of $$$ invested and though this would be the cats meow and final motor. It's rated at 46KW, more than the 9 rating and I'm running it probably around 30-35kw most of these trips. 

I have no idea why this is happening. The wiring is per the drawing, SERIES. Checked it a few times to be sure before even starting it the first time. Unlike the DC9 this one has interpoles, also at higher RPM it uses considerably more power. I'd be over 1000 watts/mile if I ran it at the RPM I ran the 9 at! I know a larger motor is supposed to produce more power at a given amp vs a smaller motor but this one seems to be less powerful using 50% more power. It's sluggish at highway speeds, even dumping lots of amps into it. 

If any of you have any thoughts on it I'd love to hear it. I feel it's not long for this world if I can't figure out why it's running so dang hot even with that blower. I've worked with electric motors since the 80's but not a motor with interpoles. Is it possible the thing would even run is the interpoles were wired backwards? It's a 6 lead motor. 

Thanks in advance!


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## ElectriCar (Jun 15, 2008)

One note, at idle with the trans in park, it's pulling about 2.5 or so KW driving the tranny input shaft and alternator only. In drive but stopped it jumps to around 3kw.


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## ElectriCar (Jun 15, 2008)

Just drove about 9 miles, city traffic and made some notes on the power usage. 
30mph level road, draws about 10kw. 35mph up a slight grade, jumps to 20kw. 
Measured the temp of the armature, 168°F, housing was around 130F


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## MattsAwesomeStuff (Aug 10, 2017)

Sounds like you've got something funky with your setup.

You changed multiple variables and are blaming it on the motor, but might not be the motor.

Ideally you'd have the luxury of doing apples to apples.


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## brian_ (Feb 7, 2017)

ElectriCar said:


> I had a DC9 that averaged about 400w/mile on a 165V Calb 200ah battery pack. Ran it around 2500rpm or higher on average to keep it cool. Never ran hot, no blower. Finally blew it, my fault, great motor with good torque. After replacing the armature and blowing it again, I went with the Kostov.
> 
> Decided to convert it to auto at the same time, reinstalled the alternator and connected the AC back. Now after maybe 500 miles I'm averaging 6-700 watts.


If I understand this correctly, you replaced a manual transmission with an obsolete automatic transmission. If this is true, the wasted energy is not surprising.


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## ElectriCar (Jun 15, 2008)

brian_ said:


> If I understand this correctly, you replaced a manual transmission with an obsolete automatic transmission. If this is true, the wasted energy is not surprising.


It's a racing transmission. I bought it because of the expected asphalt ripping torque I was going to have with a 1000A controller... 🙄


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## brian_ (Feb 7, 2017)

ElectriCar said:


> It's a racing transmission.


Okay... but it still has a torque converter. If it doesn't have a torque converter lock-up clutch it's obsolete (and more importantly inefficient), no matter how rugged it might be.


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## ElectriCar (Jun 15, 2008)

It has a lockup.


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## ElectriCar (Jun 15, 2008)

The losses though regrettable aren't a huge concern. The motor overheating even with a 150 cfm blower is the issue..


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## piotrsko (Dec 9, 2007)

Well, 165 v is kinda bit low for a kostov, in my case that is the low voltage cutoff and when it's there it is a current pig. I run 196, should go to 250 but that's another story. Interpoles are counter wound coils that reduce back emf which leads to zorching the commutation at voltages above 150v

Two comments, your idle load seems excessive and at 30 mph youre making 13 ish hp which is twice what im seeing in my ranger but not that excessive when running a slush box. It is consistant with adding the higher idle load. The other comment is that kostovs are eastern European design which isn't performance oriented but brutal conditions longevity. A warp 9 is rated higher hp and torque but doesn't play well with voltages above 144. Kostovs aren't a good choice for drag racing, but incredible in a taxi or box truck. I suggest yanking it and going back to the 9.


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## ElectriCar (Jun 15, 2008)

piotrsko said:


> Well, 165 v is kinda bit low for a kostov, in my case that is the low voltage cutoff and when it's there it is a current pig. I run 196, should go to 250 but that's another story. Interpoles are counter wound coils that reduce back emf which leads to zorching the commutation at voltages above 150v
> 
> Two comments, your idle load seems excessive and at 30 mph youre making 13 ish hp which is twice what im seeing in my ranger but not that excessive when running a slush box. It is consistant with adding the higher idle load. The other comment is that kostovs are eastern European design which isn't performance oriented but brutal conditions longevity. A warp 9 is rated higher hp and torque but doesn't play well with voltages above 144. Kostovs aren't a good choice for drag racing, but incredible in a taxi or box truck. I suggest yanking it and going back to the 9.


Hey guy, thanks for the post. Didn't know if you were still around. Well I'm an electrician and studies motors, generators etc and would love for you to help me figure out a solution. Reconfiguring it to parallel field seemed to help it and haven't noticed a reduction in performance. So 3 questions.

1. "Interpoles are counter wound coils that reduce back emf which leads to zorching the commutation at voltages above 150v" Did you mean "BELOW" 150v?
2. Can you explain why the voltage needs to go up? I could add some but I'd have to reconfigure the battery box and charger. 
3. Anything else that you can suggest other than a motor swap?

If I need to boost the voltage, I certainly can. However the (200AH cells) Calb pack I run has lost some capacity, has about 15K miles on it. Not sure how much but a recent replacement battery voltage holds steady while the others have dropped a bit and it throws my balance meter out somewhere around 150AH of use. Where I once got about 90-100 miles on a charge, yesterday I ran it about 45 miles and the voltage was dropping fairly fast, down to 148V at 149AH depleted. So it would def help my range to go higher pack V.


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## piotrsko (Dec 9, 2007)

Yup still here every once in a blue moon. Hate the google educated bunch that comment but haven't built anything.

Reconfiguring it to parallel field seemed to help it and haven't noticed a reduction in performance. 

Ooooh I like that concept, except that it might increase current significantly.

1. "Interpoles are counter wound coils that reduce back emf which leads to zorching the commutation at voltages above 150v" Did you mean "BELOW" 150v?
Nope above 150 the carbon in the brush gaps conducts or the air gap becomes inadequate and you get uncontrolled flashover. Two things: arcs erode the comm, and huge braking effect as the powered poles no longer align.
2. Can you explain why the voltage needs to go up? I could add some but I'd have to reconfigure the battery box and charger.

Doesn't need to go up, but the motor charts show as you increase voltage you conquer back emf , current requirements go down, possibly more battery capacity.........
3. Anything else that you can suggest other than a motor swap?

On a kostov, just go in there and disconnect the interpoles and make sure it it's neutrally timed, since they all seem to be retarded from the factory. Kennybobby did a how to maybe 10 years ago, but it's a common industrial maintenance.

If I need to boost the voltage, I certainly can. However the (200AH cells) Calb pack I run has lost some capacity, has about 15K miles on it. Not sure how much but a recent replacement battery voltage holds steady while the others have dropped a bit and it throws my balance meter out somewhere around 150AH of use. Where I once got about 90-100 miles on a charge, yesterday I ran it about 45 miles and the voltage was dropping fairly fast, down to 148V at 149AH depleted. So it would def help my range to go higher pack V.
[/QUOTE]

Well not sure if it warmed up where you are, but it hit 86 here in reno last week and my pack got to its happy place. Almost forgot how nice it was. Go look for low cells. Your calb cells seem to die of old age


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## ElectriCar (Jun 15, 2008)

Thanks! I'm gathering data now. Re batteries aging, yea idk but they definitely have lost a chunk of capacity. Otherwise they're performing well. I may sell them and do a new lower AH pack with more cells or may build a new vehicle altogether. Not something I'm eager to do for sure!


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## ElectriCar (Jun 15, 2008)

piotrsko said:


> Yup still here every once in a blue moon. Hate the google educated bunch that comment but haven't built anything.
> 
> Reconfiguring it to parallel field seemed to help it and haven't noticed a reduction in performance.
> 
> ...


Well not sure if it warmed up where you are, but it hit 86 here in reno last week and my pack got to its happy place. Almost forgot how nice it was. Go look for low cells. Your calb cells seem to die of old age
[/QUOTE]
Ok I've been driving a bit and using around 690wh/mile. At my cost for electric and diesel im saving only about 12 cents/mile. Driven over 200 miles for $30 energy savings.

In considering adding 10 more cells I find it a waste of money at this level of power consumption. 

So, have you any data of what power consumption at 192V might be vs my 160? Ive thought about adding 24v of lead battery in series for a bit to see what changes at 184v.


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## piotrsko (Dec 9, 2007)

The ranger is about 430-450 wh per mile average, less at 25 mph, typical for a ranger electric conversion, better than the factory with Fla but not by much and only because it's lighter. Your split motor with parallel field is probably more efficient than mine at the lower voltage you have. 690+ wh/mile says something wrong somewhere or you're running heat/cooling or hilly-freeway driving or both. What does it weigh?

When I was working, it was a buck a day for charging, vs $5 for the diesel F250, $2 for the tdi golf , fuel only.


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## ElectriCar (Jun 15, 2008)

Wednesday I put two weak but charged 12V lead batts in and drove it around a bit. I did a comparison of the kilowatt load from a point a to point B at the same speed and it was the same. However the wh per mile was in the 550 range vs 650-690 range so it seems better but the batteries were sagging badly after 4-5 miles so I couldn't continue my testing. 

I have it set up to his idle at lights etc and that adds to it. Thinking about eliminating that but not sure how the transmission would hold up doing that. Any thoughts?

Regarding hills, I am in the foothills of the Appalachian mountains so it is hilly around here but thats the same as with the old 9" motor.

I'm thinking of buying some batteries on Alibaba. Ten SE 200ah Calb like I have they want $1300 for it. But it's hard to justify that only saving $.10-$.12 per mile. Insurance cost me $61 a month and midway through May I have not even saved enough to pay half of that. I might just take the plunge, at least it will give me more range and allow me to make more and longer trips.


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## Electric Land Cruiser (Dec 30, 2020)

A couple thoughts that come to mind:

1. Idling at traffic lights with an automatic transmission = no wonder your motor is overheating. Get rid of the idle. You say it is pulling 2.5kw in Park and 3kw in Drive. That's crazy!!! You are burning through your batteries for no reason.

2. Ditch the alternator and get a real DC-DC converter. Electrical>mechanical>mechanical>electrical. You are probably losing 50% efficiency or more!

3. Generally speaking, the higher the voltage the more efficient the motor will be.

4. Have you adjusted the motor timing to neutral as @piotrsko recommended? If the motor has retarded timing you will have poor performance.


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## piotrsko (Dec 9, 2007)

Well the tranny should take a while to pump up after it's stopped but Mizlplix eventually ran a external pump and a T&C flat track converterless kit. If it was a powerglide you'll wear the low bands out, I won't claim to be qualified on anything modern. 

I run an alternator, back when I converted, dc-dc boxes were too low power and unreliable and I'm too lazy to redo, besides that's where the ac gets driven from. Figure 2hp at idle about the same as the power steering so 3-5hp don't sound all that wasteful even if it's 3kw.

Only thing I can think of is run it like a chevy small block and keep it in gear until 4,000 then shift up if you have the battery headroom to go that high. That should put you at 2500 max power but cooler. I have a 5 speed, so any time I'm below 2500, it goes down a gear even on the freeway. Kostov told me they tested them to 6000, mine has been to 5500 once (oops)


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## piotrsko (Dec 9, 2007)

While I'm thinking..... you know they are only max rated for 165 hp @ 200 volts? Not gobs of torque either.


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## ElectriCar (Jun 15, 2008)

A couple thoughts that come to mind:

1. Idling at traffic lights with an automatic transmission = no wonder your motor is overheating. Get rid of the idle. You say it is pulling 2.5kw in Park and 3kw in Drive. That's crazy!!! You are burning through your batteries for no reason. I have some concerns about this. Don't want to burn anything else up!

2. Ditch the alternator and get a real DC-DC converter. Electrical>mechanical>mechanical>electrical. You are probably losing 50% efficiency or more! There's pros and cons to this. Being I don't have regen, the alt gives me regen, or at least free power to run the AC and fan while coasting. I also have a DC-DC I removed but installed it again temporarily a while back. Didn't make much difference. 

3. Generally speaking, the higher the voltage the more efficient the motor will be. I've studied motors and worked with them for decades in plants but I don't understand this in a DC motor, AC absolutely. 

4. Have you adjusted the motor timing to neutral as @piotrsko recommended? If the motor has retarded timing you will have poor performance. It is timed like it came from the factory. And to change that is not something I'm interested in at the moment. That may happen later but it's a PIB to work in that area. 

I have some concerns


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## ElectriCar (Jun 15, 2008)

piotrsko said:


> Well the tranny should take a while to pump up after it's stopped but Mizlplix eventually ran a external pump and a T&C flat track converterless kit. If it was a powerglide you'll wear the low bands out, I won't claim to be qualified on anything modern.
> 
> I run an alternator, back when I converted, dc-dc boxes were too low power and unreliable and I'm too lazy to redo, besides that's where the ac gets driven from. Figure 2hp at idle about the same as the power steering so 3-5hp don't sound all that wasteful even if it's 3kw.
> 
> Only thing I can think of is run it like a chevy small block and keep it in gear until 4,000 then shift up if you have the battery headroom to go that high. That should put you at 2500 max power but cooler. I have a 5 speed, so any time I'm below 2500, it goes down a gear even on the freeway. Kostov told me they tested them to 6000, mine has been to 5500 once (oops)


The external pump is an idea. Wouldn't take much for that.


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## Electric Land Cruiser (Dec 30, 2020)

ElectriCar said:


> 1. I have some concerns about this. Don't want to burn anything else up!
> 
> 2. There's pros and cons to this. Being I don't have regen, the alt gives me regen, or at least free power to run the AC and fan while coasting. I also have a DC-DC I removed but installed it again temporarily a while back. Didn't make much difference.
> 
> ...


1. Electric motors are not designed to idle, and idling at a low RPM there is not much airflow to keep the motor cool. = It's going to start getting hot even before you start putting a load on it. DC Motors are huge heatsinks that will absorb the heat but don't like getting rid of it. Once you get "behind the curve" then thermal runaway is inevitable.

2. Yes, the pro is that your truck drives. The con is that it isn't very efficient and you need to spend a bunch more money than you originally calculated on more batteries. If that's fine, then great. If you want to make your truck more efficient, then it's not great.

3. More voltage = less current for the same power. Less current = less heat, less wasted energy. More voltage = more RPM with less current, more speed with less current.

4. The timing is probably why it feels sluggish compared to your 9" motor. If you advanced the timing it will drive better. If you don't want it to drive better, don't adjust it. That simple.


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## ElectriCar (Jun 15, 2008)

Electric Land Cruiser said:


> 1. Electric motors are not designed to idle, and idling at a low RPM there is not much airflow to keep the motor cool. = It's going to start getting hot even before you start putting a load on it. DC Motors are huge heatsinks that will absorb the heat but don't like getting rid of it. Once you get "behind the curve" then thermal runaway is inevitable.
> 
> 2. Yes, the pro is that your truck drives. The con is that it isn't very efficient and you need to spend a bunch more money than you originally calculated on more batteries. If that's fine, then great. If you want to make your truck more efficient, then it's not great.
> 
> ...


As an electrician of 40 years working with motors, I just don't see in a DC motor that "more voltage = less current". With an AC motor, lower supply voltage leads to higher current BECAUSE at lower voltage the armature is slower. More current is allowed because lower speed = lower back EMF but it's designed to run at X rpm. As more current speeds the armature rotation, the back EMF increases reducing current. The back EMF will almost = input voltage at it's design speed where current becomes steady due to the voltage and EMF almost being equal. In my mind it doesn't matter if the voltage is 10 or 100 so long as it can push the current to reach the rotation speed desired. I'm not so stubborn as to think I can't be missing something however. If I truly need more voltage, I need to understand why to justify spending the money. However a DC motor doesn't run at a fixed design speed, it's a totally different animal.

Also you know that the pack voltage isn't the same as the motor voltage due to the controller right? That said, if the pack is 160V and the controller is putting out 50, 80 or 100 volts to the motor and easily pumps more amps than the motor is rated, why do I need more pack voltage? That's the quandary I'm in now. Hopefully you or someone can clue me in.


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## ElectriCar (Jun 15, 2008)

Just to be clear, I don't have an acceleration problem. It's more than I need in most cases. I did however see a substantial increase in torque when I added two golf cart 12V batteries in series with the pack. However since they died quickly I didn't finish my testing. They are being replaced in a few days so I may try it again with the new batteries and note any change in power use and heat.


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## ElectriCar (Jun 15, 2008)

piotrsko said:


> Yup still here every once in a blue moon. Hate the google educated bunch that comment but haven't built anything.
> 
> Reconfiguring it to parallel field seemed to help it and haven't noticed a reduction in performance.
> 
> ...



Ok the timing. Maybe that's it. I'll have a look and go to neutral if that's where I need to go. I generally run the rpm low like a gasser would normally run thus the blower install. An recommendation on the timing with the rpm I use in mind?

Thanks a ton! Hope I can figure it out and that helps.


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## ElectriCar (Jun 15, 2008)

One more note. Went to the Kostov site and ended up leaving a message about this. They say with interpoles the timing is different than standard motors and they are FACTORY SET at the right place. Moving them can result in motor destruction. Well IDK how they're supposed to be so I asked them. Don't want MORE issues!


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## piotrsko (Dec 9, 2007)

You want at least 2500 rpm when making power. I will keep on sayng that. 
Retarding timing increases the high voltage tolerance so they do that. 4 degrees. They didn't admit the retard back 5 years ago until you asked what it was while replacing the brush plate.

Didn't know they were still in business, as I know they were purchased outright by some company in a neighbor place. I do know they weren't supplying parts last year when I needed brushes and definitely didnt answer the phone, fax, email.


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## ElectriCar (Jun 15, 2008)

piotrsko said:


> You want at least 2500 rpm when making power. I will keep on sayng that.
> Retarding timing increases the high voltage tolerance so they do that. 4 degrees. They didn't admit the retard back 5 years ago until you asked what it was while replacing the brush plate.
> 
> Didn't know they were still in business, as I know they were purchased outright by some company in a neighbor place. I do know they weren't supplying parts last year when I needed brushes and definitely didnt answer the phone, fax, email.


I hear ya. However on their site it says the timing is retarded for interpole motors and set at the factory for that and that moving it risks damage to the motor. Didn't give any details or say how far it could move before damage would be likely. In that light I don't want to change it but if someone could explain it in a logical manner how moving it back to Zero wouldn't pose an unacceptable risk, I'll yank it and crank it!
Thanks btw!


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## ElectriCar (Jun 15, 2008)

piotrsko said:


> While I'm thinking..... you know they are only max rated for 165 hp @ 200 volts? Not gobs of torque either.


Well guy due to your comments I gave up and ordered 8 more batteries which will get me up to 185.6 nominal. My brief testing, adding 2 12v lead batteries to the pack indicated a drop in wh/mile to around 550, which is better but lead of course sags. Hope with the new Calb 200s there won't be much sag and hopefully it will drop closer to 500. I would love that but don't really expect it. 

I know it's less than your pack but not much. If that does well I'll probably get two more would get me to 192! Wonder how it would hold up with 4 more making a 62 cel pack? I know I ran my 9" at 160 for a while with no problems other than destroying the motor easier!🤣


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## piotrsko (Dec 9, 2007)

Should be fine to 250v since I don't know what if anything Kostov changed on their new motors. Definitely fine to 198, btdt freaked out about my lipos and backed off .2v ea.


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