Open Source 12kW PFC Smart EV Charger - from $999

[valerun]

Hi All -

The same thread on DIYelectriccar.com got ~200,000 views and ~1,300 replies to date so I figured I would start a similar one here to make sure as many people as possible know about this product.

Over the last couple of years, my team has developed a 12kW / 70A charger design that exceeds all known chargers available on the market today (that you can put into a vehicle, anyway) - both in power and features. We just hated to pay $4000 to be able to charge our conversions in less than 5 hours...

An incomplete run-down of the capabilities:
* 12kW rated power - tested to 15kW continuous with liquid cooling
* 100 - 260VAC, up to 400VDC input
* up to 350VDC battery voltage (up to 425V with very minor modifications)
* fully PF corrected option available
* 144x144 color screen for controls & readout
* Fully digital control by built-in Arduino system
* All battery types supported with micro-processor controlled charging regimes
* Integration features - BMS cut-off, End-of-charge signal
* Thermal protections
* Timer shutoff
* Compact design - latest units are packed into a 10x10x8-inch box (air cooled) or 10x8x7" for liquid-cooled
* User-programmable through a USB cable

We have made design fully open-source and available to all (for non-commercial use). So if you are so inclined, you can make it yourself for less than ~$1,000 all-in (including all the heatsinks, enclosure, etc, etc.).

We have improved the design over the last few months, with beefier PCBs, better drive circuits etc. We also now have an option for 100A output! Finally, a custom enclosure is now an option - professionally machined and powder-coated in awesome black matte finish to show off your charger. As always, you can get more info on the latest specs / build videos / etc at http://www.emotorwerks.com/tech/electronics.

There are over 100 of these units in various conversions out there today.

If you like, we can help you with PCBs, parts kits, assembled / tested boards, and fully assembled units. Again, details are at http://emotorwerks.com/tech/electronics.

I hope that this effort will make EV conversions a bit more affordable to people and we will have a modest contribution to getting more EVs on the roads! Please consider supporting it by letting us help you with building out your units.

As always, we welcome feedback / suggestions / questions.

Thanks,
Valery.

 

[megacycle]

This is awesome, did you have a 25kW charger on the go too?

 

[flexy]

Hi Valerun, thanks for sharing.

I couldn't find the actual dimensions but it looks quite large for my application (7kwh pack in a scooter) although it would juice me up in under an hour

Is there a way to scale it down to around 5kw and hence making the case more compact so it could be built into a scooter or motorcycle conversion?

 

[valerun]

This is awesome, did you have a 25kW charger on the go too?

thx. yes, but only for high-voltage batteries at the moment (>340V CV point).

note that you can always parallel multiple 12kW units. In fact, check out this recent video where we demo 3 units in parallel delivering 36kW into one of our conversions: http://www.youtube.com/watch?v=hn0Bqsaiugo

V

 

[valerun]

Hi Valerun, thanks for sharing.

I couldn't find the actual dimensions but it looks quite large for my application (7kwh pack in a scooter) although it would juice me up in under an hour

Is there a way to scale it down to around 5kw and hence making the case more compact so it could be built into a scooter or motorcycle conversion?

10x10x8 for air cooled, 10x8x7 liquid.

Theoretically the design can be scaled but we don't produce kits or built units at lower power. The design is open source so you can derive from it... Docs at http://www.emotorwerks.com/VMcharger_V12P/

 

[bigmoose]

Interesting project. Quick look, I couldn't find a schematic of it. Do you guys publish one?

 

[megacycle]

This is awesome, did you have a 25kW charger on the go too?

thx. yes, but only for high-voltage batteries at the moment (>340V CV point).

note that you can always parallel multiple 12kW units. In fact, check out this recent video where we demo 3 units in parallel delivering 36kW into one of our conversions: http://www.youtube.com/watch?v=hn0Bqsaiugo

V

Thanks Valerun.
I expect ev enthusiasts in Europe and 415V countries, have been through with you, regarding connecting 3 units in a 3 phase 415V star configuration, as the current draw must be high, up around 45-50A per phase @415V.
Can you advise, if this works, parallel output, thanks.
Also can the controlling/ interface boards just be in 1 unit, with 2 kind of bolt on slave sections, reducing size and cost for those bigger charging jobs.
Sorry if i'm asking for previously posted info on other sites, links might help in this regard.

 

[valerun]

Interesting project. Quick look, I couldn't find a schematic of it. Do you guys publish one?

yes but newest not available yet. just uploaded the previous version - take a look

 

[valerun]

This is awesome, did you have a 25kW charger on the go too?

thx. yes, but only for high-voltage batteries at the moment (>340V CV point).

note that you can always parallel multiple 12kW units. In fact, check out this recent video where we demo 3 units in parallel delivering 36kW into one of our conversions: http://www.youtube.com/watch?v=hn0Bqsaiugo

V

Thanks Valerun.
I expect ev enthusiasts in Europe and 415V countries, have been through with you, regarding connecting 3 units in a 3 phase 415V star configuration, as the current draw must be high, up around 45-50A per phase @415V.
Can you advise, if this works, parallel output, thanks.
Also can the controlling/ interface boards just be in 1 unit, with 2 kind of bolt on slave sections, reducing size and cost for those bigger charging jobs.
Sorry if i'm asking for previously posted info on other sites, links might help in this regard.

Yes, it's possible to run 3 units in parallel - each off a phase's hot and common neutral. Most of the controls will need to be individual per phase due to different timing of phases. Overall high-level config can be aggregated, yes. We have not yet done that aggregation but it should be trivial. If there is a real interest in such a 3-phase 36kW unit (as in, someone is ready to pre-order), we will definitely make all necessary changes.

 

[jonescg]

Damn. I need a 700 V DC charger. I was hoping to not have to go to a dual-350 V system. Any thoughts on making such a device?

 

[megacycle]

You might have competion here from this offering, when it's in stock and looks like it may be capable of 20kW, though the actual output kW spec's are not listed and it's voltage range is limiting, though it does say up to 30A/ph, which is around 20kW@415V.
http://www.evworks.com.au/index.php?product=257

 

[jonescg]

If you install ^^ this charger into a car with a grounded 12 V system, you will get a shock from a battery terminal and the chassis. Not an isolated system apparently.

 

[j3tch1u]

val, love the EMW logo!

 

[Nuts&Volts]

Damn. I need a 700 V DC charger. I was hoping to not have to go to a dual-350 V system. Any thoughts on making such a device?

I'm pretty sure it can be modded to do close to 700Vdc (yea see halfway down this page http://www.emotorwerks.com/tech/electronics)

 

[valerun]

If you install ^^ this charger into a car with a grounded 12 V system, you will get a shock from a battery terminal and the chassis. Not an isolated system apparently.

no you won't. Term isolation in this case doesn't mean what you think it means. In this case, it means that the AC input is not galvanically isolated from the DC output. If your HV DC lines (i.e. the battery) is isolated from your chassis (as it should), you can't get shocked.

 

[valerun]

You might have competion here from this offering, when it's in stock and looks like it may be capable of 20kW, though the actual output kW spec's are not listed and it's voltage range is limiting, though it does say up to 30A/ph, which is around 20kW@415V.
http://www.evworks.com.au/index.php?product=257

Thanks for a reference. Would be great to have more offerings like that on the market. It's all about driving innovation forward. We are very good at that

 

[valerun]

Damn. I need a 700 V DC charger. I was hoping to not have to go to a dual-350 V system. Any thoughts on making such a device?

I'm pretty sure it can be modded to do close to 700Vdc (yea see halfway down this page http://www.emotorwerks.com/tech/electronics)

Yes, can be done but is a significant mod... Design is the same but components will have to be swapped. Therefore, power PCB cannot be used as-is

 

[heathyoung]

Is there a scaled down version?

I'm working on a 2Kw unisolated buck at the moment but time pressures are making it rather a difficult task to complete (I've done quite a few cheats to allow a lowside switch and differential voltage sensing via a transistor level shift) This brings down both the complexity and price. A simple two transistor totem pole could drive the IGBT or Mosfet directly from the microprocessor, or there are a heap of cheap lowside drivers that could do the job.

 

[valerun]

Is there a scaled down version?

I'm working on a 2Kw unisolated buck at the moment but time pressures are making it rather a difficult task to complete (I've done quite a few cheats to allow a lowside switch and differential voltage sensing via a transistor level shift) This brings down both the complexity and price. A simple two transistor totem pole could drive the IGBT or Mosfet directly from the microprocessor, or there are a heap of cheap lowside drivers that could do the job.

could be done but unlikely to be a commercially viable project. With the number of $700 Chinese chargers at 2-3kW power levels, it will be very hard to compete. Hence our 12kW and up approach

 

[grindz145]

Thanks for sharing your project on ES. What is the weight of the fully-assembled unit?

 

[heathyoung]

Is there a scaled down version?

I'm working on a 2Kw unisolated buck at the moment but time pressures are making it rather a difficult task to complete (I've done quite a few cheats to allow a lowside switch and differential voltage sensing via a transistor level shift) This brings down both the complexity and price. A simple two transistor totem pole could drive the IGBT or Mosfet directly from the microprocessor, or there are a heap of cheap lowside drivers that could do the job.

could be done but unlikely to be a commercially viable project. With the number of $700 Chinese chargers at 2-3kW power levels, it will be very hard to compete. Hence our 12kW and up approach

Completely understandable. It would be nice to use the smarts of this charger to run a dumb power stage - do you sell just the control section? (although the details of the current / voltage sensors if they are on the power board) would be nice to know.

 

[jonescg]

If you install ^^ this charger into a car with a grounded 12 V system, you will get a shock from a battery terminal and the chassis. Not an isolated system apparently.

No, what I meant was, if the battery is permanently connected to the charger and the charger is connected to the BMS (for HVC shut-down) there is a high impedance circuit between chassis ground and the HV terminals. You will get a shock between battery positive and the chassis. I found on with a 150 V system in a converted car. It's not going to hurt you but it can give you a fright.

 

[valerun]

If you install ^^ this charger into a car with a grounded 12 V system, you will get a shock from a battery terminal and the chassis. Not an isolated system apparently.

No, what I meant was, if the battery is permanently connected to the charger and the charger is connected to the BMS (for HVC shut-down) there is a high impedance circuit between chassis ground and the HV terminals. You will get a shock between battery positive and the chassis. I found on with a 150 V system in a converted car. It's not going to hurt you but it can give you a fright.

That BMS is badly designed. The resistance between HV and signal side in a properly designed BMS should measure in 100s of Megaohms. This is easily achievable by using proper opto-isolated signaling. This is how we isolate control stage of our charger from the power stage.

 

[circuit]

Could not find an overall schematic... It s essential to understand if it is worth a shot.

Is there a CAN bus control on your roadmap? I would like to be able to control output voltage and current on the fly over CAN bus. And I don't need any displays or buttons or algorithms on it

 

[valerun]

Could not find an overall schematic... It s essential to understand if it is worth a shot.

Is there a CAN bus control on your roadmap? I would like to be able to control output voltage and current on the fly over CAN bus. And I don't need any displays or buttons or algorithms on it

The previous version schematics is at http://www.emotorwerks.com/VMcharger_V12P/. We are refactoring the newest version files and will post soon but the prev version should give you a good idea - it's 90% the same.

Serial control just been implemented - see post 1302 on this page: http://www.diyelectriccar.com/forums/showthread.php/10kw-60a-diy-charger-open-source-59210p66.html. This already can be used to do what you want (albeit over serial, not CAN - yet). CAN is on the roadmap and will require control board swap. Or you can just wire the charge up to something like AVR-CAN https://www.olimex.com/Products/AVR/Development/AVR-CAN/ and write a simple sketch for command translation.

V