# Final Drive



## winzeracer (Apr 3, 2012)

Nice Video Pete. Looking forward to seeing more detail on charging with the Synkromotive, I am seriously considering running this controller instead of the Soliton Jr, due to size and weight issues on my kart. I contacted Synkro and they said there should not be any problems running my Agni with it, even said that it can do regen with some extra contactors, not sure if I will end up going regen as it is a bit harder on the motor, which will already see plenty of abuse. It really seems as if this controller is packed with features!

*EDIT:* I just watched your DC charging Vid( very informative), do you think it would be possible to demonstrate the AC fast charge with the Synkro?


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## Wolfswagen (Jul 2, 2012)

Great video, Pete. Congrats on the sale, although it's too bad they're not keeping it an EV... It's a great looking car.


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## onegreenev (May 18, 2012)

Wolfswagen said:


> Great video, Pete. Congrats on the sale, although it's too bad they're not keeping it an EV... It's a great looking car.


The car was a nice dry rust free California car but it still had issues and for sure needed painting. My son ruined the pain by painting perfectly good gloss black with some matt finish black in a can to coverup some graphics on the doors. Looked like crap up close and he did not paint the whole whole thing matt black which would have looked better than just painting part matt finish. But I never did intend to keep the car and got what I wanted for the car. It was just an extra project we did not need to keep around. Worked perfect for our test bed and we got to have some fun with it too. I still have the performance engine my son built. That is a piece of work and a very well built machine. So when I am ready to sell that I will be able to get about $1200 for the turn key engine. That will be sweet. More batteries will be purchased with those funds. 

Pete


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## onegreenev (May 18, 2012)

winzeracer said:


> Nice Video Pete. Looking forward to seeing more detail on charging with the Synkromotive, I am seriously considering running this controller instead of the Soliton Jr, due to size and weight issues on my kart. I contacted Synkro and they said there should not be any problems running my Agni with it, even said that it can do regen with some extra contactors, not sure if I will end up going regen as it is a bit harder on the motor, which will already see plenty of abuse. It really seems as if this controller is packed with features!
> 
> *EDIT:* I just watched your DC charging Vid( very informative), do you think it would be possible to demonstrate the AC fast charge with the Synkro?


The controller has lots of features. I will be doing more with the DC and yes I will demonstrate the AC Fast Charging function on video. I am waiting for my high power rectifier to come in so I can finish the high power version of the AC charging. I still need to finish up the dedicated 110 200 amp circuit for charging at high current rates. I expect to be able to get 150 amps into the battery from this setup. That will be 1.5C for my cells. That will be fast. I am hoping that the AC will be smoother than the DC to setup but the DC does work great. You just need to remember to keep the stationary bank of batteries charged up. With AC you don't have to worry about that.


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## winzeracer (Apr 3, 2012)

onegreenev said:


> The controller has lots of features. I will be doing more with the DC and yes I will demonstrate the AC Fast Charging function on video. I am waiting for my high power rectifier to come in so I can finish the high power version of the AC charging. I still need to finish up the dedicated 110 200 amp circuit for charging at high current rates. I expect to be able to get 150 amps into the battery from this setup. That will be 1.5C for my cells. That will be fast. I am hoping that the AC will be smoother than the DC to setup but the DC does work great. You just need to remember to keep the stationary bank of batteries charged up. With AC you don't have to worry about that.


Pete,

Could you elaborate on the rectifier, specs, source, cost?

Thanks,


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## onegreenev (May 18, 2012)

MDS200A 3-Phase Diode Bridge Rectifier 200A Amp 1600V $66.14 for two and free slow boat from China shipping. This sucker needs a good heat sink and fan to keep its cool.


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## winzeracer (Apr 3, 2012)

onegreenev said:


> MDS200A 3-Phase Diode Bridge Rectifier 200A Amp 1600V $66.14 for two and free slow boat from China shipping. This sucker needs a good heat sink and fan to keep its cool.


Ahh, very nice, so you can feed single phase 110v into this 3-phase rectifier? I am in my E&M class this semester by we are still on Coulomb's law


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## onegreenev (May 18, 2012)

This is what was recommended to me so I am assuming that you can use 110 into. So what I am going to do is parallel two 110 circuits to make a high amperage circuit so I can pull good amperage from the wall to the car. I will be pulling high current as AC up to the car then run it through the rectifier and inductor to boost the voltage to pack voltage. It it is not recommended to have the lowest voltage of the pack be less than 120 volts. So it is recommended that you have a pack voltage of at least 185 volts. I will be at 192 volts. I will limit my pack voltage to something like 156 volts or even 120 volts and the remaining will be just a sag pad. At 156 volts and having my pack limited to 120 volts it showed no real difference when I put it back to full pack voltage. The sag was quite a bit. I preferred the car set to 120 volts out of 156 volt pack. That way I knew I was getting 120 volts or nearly so when I accelerated. 

So when we do the charge I will limit my current at first but we fully intend to have at least a 1C charge rate for my 100ah cells. If I can squeeze out 1.5C that will be exceptional. From a generator the circuit breaker will be limited in its output so you'd need to change the parameters on the charge functions to limit current to keep the circuit breaker from tripping. 

I want to see how well it does off the wall and off a high current 110 circuit and off a 60 amp generator.


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## dladd (Jun 1, 2011)

who's shooting the cannon? 

I look forward to your video showing the AC charging, I'd love to do that with my Synkro but haven't really looked into it yet. I gather at a minimum it's a couple of contactors in the motor loop, yes? Then the big rectifier takes the AC and gives DC? I've briefly looked into the option of picking up a used AC/DC power supply, but they are quite pricey at the wattage needed.

I'm at a crossroads of moving forward with the Synkromotive controlled charging or going with the EMW 10k unit.


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## onegreenev (May 18, 2012)

The cannon is actually our neighbors air cannon to scare the birds off his pistachio trees. It is harvest time and the birds come and try to strip the trees. The cannon keeps them away and it works but is very very annoying. Thankfully it is only during the harvest season. Once harvest is over they turn it off. Does not keep the jay birds off my pecan tree. They strip it clean every year. We usually get enough to make a few pies. They don't bother our walnuts. 

Yes. AC to the Rectifier then through a set of contactors then through an inductor. The inductor can be a combination of the field windings and another external one but you do need cooling for them. If you use high current through the field windings of your motor you WILL need good cooling. Like any HIGH CURRENT charger you will encounter lots of heat that you need to remove. Since the motor will not be running it will build heat without any cooling. If you do lower current you can get away with an external inductor and bypass the field windings if you like but you do need cooling. Yes the rectifier accepts AC then outputs DC. Need cooling on that rectifier too. Nothing difficult mind you. A simple fan will provide enough cooling. And an external fan for the motor if you use it for the inductor. 

Pete


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## winzeracer (Apr 3, 2012)

onegreenev said:


> The cannon is actually our neighbors air cannon to scare the birds off his pistachio trees. It is harvest time and the birds come and try to strip the trees. The cannon keeps them away and it works but is very very annoying. Thankfully it is only during the harvest season. Once harvest is over they turn it off. Does not keep the jay birds off my pecan tree. They strip it clean every year. We usually get enough to make a few pies. They don't bother our walnuts.
> 
> Yes. AC to the Rectifier then through a set of contactors then through an inductor. The inductor can be a combination of the field windings and another external one but you do need cooling for them. If you use high current through the field windings of your motor you WILL need good cooling. Like any HIGH CURRENT charger you will encounter lots of heat that you need to remove. Since the motor will not be running it will build heat without any cooling. If you do lower current you can get away with an external inductor and bypass the field windings if you like but you do need cooling. Yes the rectifier accepts AC then outputs DC. Need cooling on that rectifier too. Nothing difficult mind you. A simple fan will provide enough cooling. And an external fan for the motor if you use it for the inductor.
> 
> Pete


Hmm, sounds dangerous to use my PM motor as the inductor, the heat could destroy the magnets, and then i would be down a motor, not sure if it is worth the risk. I assume you still need to do this for the DC charging as well. I was getting excited about the prospect of charging with the Syncro at the track off a AGM supply pack, but the heat just sitting there in my motor worries me as it is only a 26lb motor not much thermal mass to shed heat. Even with fans I think it would make me nervous.


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## onegreenev (May 18, 2012)

What I was going to do was to take an old motor and remove the armature and just leave the field windings in place and connect a fan to the opening and use that for my inductor. It could be used for an AC setup as well. No need to have it installed in the car either. There are many ways to configure this so you don't ruin a motor. I think using a motor like an old 6in motor with no armature would work great. An old 6" motor should handle a couple hundred amps in the field with no problem if you intend to charge at that high of current. A good fan with an open hole. Heck you could even strip out the field windings of a motor and install them onto an aluminum heat sink and connect a fan to that sink. I have some extra field windings and will be testing the abilities of different motor windings. I even have a large toroid transformer we will try as an inductor. We will only use one side of the transformer and see how well and how much current it can handle. But if you have a FAN on your motor and keep the current lower you should be just fine. But getting an external inductor would be best. I even took a large 40ft coil of 1/0 cable and used that as an inductor. 

I understand your concern. I will pass this information along to Synkromotive and will see what they say about your concern. 

I will get back with you tomorrow. 

Pete


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## Tesseract (Sep 27, 2008)

winzeracer said:


> Hmm, sounds dangerous to use my PM motor as the inductor...


PM motors don't have a field winding so you can't use them as the inductor in a high current charger. This stunt is only possible with a series DC motor.

I tinkered around with running a Soliton Jr and the field in a WarP-9 as a rapid charger and while it worked ok, it was kind of kludgy. The field winding does tend to run hot, mainly because the solid steel field structure is a rather lossy inductor.

A much simpler way to rapidly charge a battery pack is "dump charging". This is when you use a stationary lead-acid pack that is 12V-36V higher than your vehicle's battery pack and just connect the two together directly through a massive contactor or IGBT or the like. A small 1-2kW generator (and charger) can recharge the lead-acid "dump pack" in between races.


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## Ziggythewiz (May 16, 2010)

Tesseract said:


> This is when you use a stationary lead-acid pack that is 12V-36V higher than your vehicle's battery pack and just connect the two together directly through a massive contactor or IGBT or the like.


What kind of amps do you get charging like that? I would expect hundreds-thousands.


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## winzeracer (Apr 3, 2012)

Pete: Thanks for the help in figuring this out, I do have a email trail going with Synkro about this and a few other questions.

As for charging with the controller, ideally I would like to be able to charge at 15kw (125v 120amps). However if Synkro says that lower pack limit should be greater than 120v, I would have to add one more parallel module( in series) to my pack to bring up the pack voltage or rearrange it to 36s5p not 30s6p which would pull higher C rates... Anyway sorry about all the detail, feels like I jacked you thread. I would clearly have to have an external inductor of some kind.

So since you are going to try charging at 28.8kw, I would assume( though i will verify) that 15kw is within the controllers ability for charging.

Tesseract: Thank you for that clarification, I had planned on using the Sjr on my kart but looks like size will be an issue for my ideal mass distribution and mounting. I will also look into "Dump Charging".


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## onegreenev (May 18, 2012)

Brock,

Setting up the charging with a lower voltage stationary pack and an inductor is the best way and the way it works for the Synkromotive. 

So lets say you want to do DC charging from a stationary pack of batteries. Your pack voltage is 96 volts nominal and your lowest voltage is 72 volts or 2.4 volts per cell static. Your Stationary pack needs to be lower than 72 volts. You could use a fully charged 60 volt pack of 10 deep cycle 6 volt batteries. If those batteries have enough amp hours you could charge your 96 volt pack in your car or kart. You may have a small AH pack in your kart and at 96 volts so your 60 volt fully charged charging pack could charge your small high voltage lithium with no trouble. As long as your source pack can handle HIGH output currents the controller can handle up to 800 input amps. That would be well above any C rate for any of our cells. Yes, the Synkromotive controller can handle high currents in as well as out. 

So I had 156 volts in my Bug and charged the pack with a 48 volt stationary pack. Output current from the pack was high and the input was higher than my current charger. Being that my stationary pack was only 48 volts the input current into the batteries was lower than I wanted but still quite good. The inductor bumps up the voltage while the controller controls the on/off to regulate the magnetic field and current. As you bump up the voltage your input current goes down. So the closer in voltage your stationary pack is to the one in your vehicle as long as the vehicles low voltage is higher than the high voltage of the stationary pack you will be just fine. 

With the AC you are using 110 which is lower than my 192 volts I will be using. My low voltage will be about 150 volts if I let my low voltage be 2.5 volts per cell. Best if I can have a bit lower. So like 2.3 volts per cell lowest. And at 110 volts which is still lower than 138 volts the charge will work. Change 110 to DC then run it through the inductor to bring it up to high pack voltage and being close to voltage the current in will be decent.


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## onegreenev (May 18, 2012)

The fast charge setups that will be public will be setup like this. Just that they will have higher current abilities and some cars will be needing to charge well over 200 volts so you will need high voltage and current available. Bump the voltage and reduce the current and you will have a very fast charge. So lets say your station can charge a 192 volt pack and you have on tap 800 amps. Bumping the 110 to 192 will be easy and keep a very high current ability to charge into your vehicle. 

You will need cooling. They all will need cooling. Even the 10kW chargers need extra cooling. Air or water which ever you may have or build into your system. 

I will be demonstrating air cooling. Should be enough to demonstrate good charge times. Maybe not the 10 minute goal but if I can recharge in 1 hour or less I am doing exceptional. 

Pete


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## winzeracer (Apr 3, 2012)

Pete,

Great info... My LV point would be 102v and HV point 126v ( running my Li-poly from 4.15 to 3.55 with some give) thus my stationary pack would be 84v of AGMs like these (http://rebirthauto.com/dekaagm12vdc95ahbatterygroup49-9agm49secondquality.aspx ). To get enough AH and kwh, I would run 7s3p from the specs that should give me 90ah and thus 7.5kwh. This way I could fully charge my 3.3kwh pack at least 2 full charges before recharging the stationary pack. I will also be looking into better induction devices, since it will be off the kart anyway.

I will look around for different kinds of stationary packs, but for now at least this gives me some idea of what I will be getting into with this setup. I think this just might solidify the Synkro for my build, just need to get back an email to them that had a few other questions.

Also looking forward to the new donor for this setup of yours. I saw the vid of rebirth's crazy dual warp 9 bug!! That thing looks like a good time with 600 ft/lbs

Thanks again Pete


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