Synkromotive Update

Well I got some useful information back about the charging algorithm of the controller. It actually does do the CC/CV charge algorithm. What I saw the other day was that the voltage was at the level where it started the CV and the amperage was dropping. It was not that I had an empty battery but a full battery and the current was in the process of dropping before termination. So what I need to do is to lower the charge current due to the fact that the stationary pack is only 48 volts and we are trying to charge a 192 volt pack. So with that I will recharge the stationary pack and recharge the cars pack via the stationary pack at a lower current and monitor the charge and current so we have a graph of the charge. This is excellent. Much better than thought. The guys at Synkromotive do have other projects so this one takes some time to gather information for my needs.

Pete :)

I need to remove all my cells from my stationary pack and clean each battery. I need a piece of plywood on the base of the cart because if any acid leaks it is going to eat that metal of the cart. I need better covers for the cells. They leak out acid. Bummer.

A little on Synkromotive

Synkromotive Controller is also usable as a charger. It can use a stationary pack of batteries to charge from and routes that through the motors field windings to be used as an inductor. If you have like a 96 volt system you can use a 72 volt stationary pack to charge from. The controller will PWM the incoming power through the controller to keep the required voltage and current up so it will charge your pack. The closer the voltage of the stationary pack is to the cars pack the better but it must remain lower than the lowest voltage of your cars pack. So a 96 volt pack will be considered empty at 75 volts or 2.5 volts. So I can charge from a stationary pack that is 72 volts. If I charge from a lower voltage pack which it will do the amperage from the pack will be much higher as you go down in voltage size. So if you can match your stationary DC power as close to your pack requirements then your good to go. This is done with AC as well. AC works best like this too. Have a source like a dedicated 100 amp circuit and use that to charge from. Anyway by using the controller as a charger you gain an added benefit of not having to find a spot for a big heavy clunky charger to keep on board. It is huge to have that ability. This is how it will work for FAST charging which this controller is fully capable of doing.

It would be great to open up a charging station that offers both FAST Direct DC charging and fast AC charging. But with a large station the stationary pack will need to be huge. Remember some of the proposed vehicles that will be filled have huge kWh requirements and it needs to be pumped in fast. My  Leaf uses a 24 kWh pack. My Bug a 19.2 kWh pack. My solar panels put out a good 48 kWh daily. What would happen if I had a Tesla S with an 85 kWh pack. I could not charge that in a day with only solar panels unless I had a very large solar array. As it is I can charge not only my Leaf but my Bug as well. So if Tesla doe build some solar charge stations the size of the solar must be huge. It will require loads of space and it will create lots of shade.

Pete :)

Pack Size

Well I still need to put in the cells I charged up. Been busy. I found that my DC stationary pack is way to small to charge my pack in the car. It was a good demo for low voltage vehicles and a good demo of what the controller is able to do. Now that we are at a high voltage we need good AC source for charging. I can build a dedicated 100 amp AC circuit for charging and pump in a cool 50 or more amps into the pack. All through the controller. The best thing to do is to just setup like any normal charger and charge that way. Takes longer but runs cooler. If I were to build a good DC source for charging I'd need a huge bank of batteries. Since I am now at 192 volts I can have a stationary pack of at least 144 volts and as much AH as I can possibly get. This would be a great way to recycle lithium batteries. Run them in a cool ground box. You need energy not power for charging. At charging rates the batteries would not even breath hard while charging. That is good news. But for the mean time it would be good to have a good AC source set up to charge your car. It would eliminate the need to use the motor fields as an inductor and introduce heat and would allow a much cleaner install. Jack has proposed a way to use the CANbus setup for the Elcon chargers and to allow you to set your own settings for your own needs. It would give you a great charger that you can configure for a decent price. The chargers are good. I have two of them. But you still need to mount them in a good place in your conversion and that space is limited. You can't just stuff them anywhere. I like the idea of the controller being the charger too. Small light weight package and no extra charger. That is a huge deal. I am going to try to get my DC generator running to see how much power I can pull from that running off a gas engine. Mostly for portable power away from home. Need to make a mount and connection to the gas engine. A nice Joy coupler should do just fine. If I can pull 36 volts and 400 amps I should be able to charge my car at a pretty decent rate. I am thinking more like 3 hours rather than 8. This is just speculating but we will do a test.

Time to put all the components into the Red Roadster. Hunting for some nice seats right now. Looking to find some good ones that are leather. Leather holds up much better.

Cell Charging Complete

Well it took 5 hours at 15 amps to charge up 12 100 Ah cells to 3.5 volts per cell or 42 volts total for the pack. This resulted in a few cells in the 3.6 volt range and after resting all night I got a range of static voltages of 3.325 to 3.338 between the 12 cells. The highest voltage cell is my lowest capacity cell. I was unable to count AH's in because I do not have my meter for that hooked up yet on a test bench. I will connect it up in the car to check my total AH's of the pack. I am thinking that I will be at about 80 to 90 AH for the pack. The cells are not filled all the way and some I am sure will not hold a full 100 Ah anyway. These are used and abused Hi-Power 100 AH cells. But being such they are doing me just fine for what I am doing with them while testing the controllers and charging and such. I will have the Ah issue figured out soon. This afternoon we bump to 192 volts for a total of 60 cells.

Cell Charging

I am finishing up the last 11 cells so I can boost my pack to its final 192 volts. What I did was to discharge all the extra cells to 2.6 volts and then charge them up to 3.5 volts with no voltage holding. We are only charging to 3.5 volts each. Then I will insert them into the cars pack which is charged to 3.5 volts per cell. We are only doing CC charging. No CV charging. Once we max out the pack I will set the max voltage to the motor to 144 volts. That leaves a solid 48 volt Sag Pad. I will limit the amperage at first to 600 amps then slowly move that up as we find out how well the motor handles that voltage and amperage. I hope to soon find out how many usable AH's are available in my cells.

Pete :)

156 Volts

Well I can assure you that 156 Volts is way better than 72 volts. I now have 49 cells in the Bug but I limited the volts to 120 volts for now and limited the amperage to 600. I took the car out for a spin and found that it just jumps to speed as any good old car. It actually does better than a stock VW Bug. I did the limiting this way to allow a full 120 volts to the motor when asked for but leaves a SAG PAD when accelerating. This way the motor really gets a full 120 volts. I will find out what the sag is then boost my limit to that voltage. That way I give the motor a solid voltage with no sag. If I only put in 120 volts worth of cells the car would not have performed as well as it did with 156 volts and limit to 120 volts. With only 120 volts at full throttle the sag would be pretty great so the motor would not be seeing a true 120 volts but the sag voltage. Tomorrow I will increase the voltage to 144 just to see how well it runs at that voltage but I do expect enough sag to actually provide a bit less than 144 volts. Thats OK. I will then do a fast or as fast as possible DC charge. I will be charging from a 48 volt pack to charge a 156 volt pack. Pretty cool actually. Won't be as fast a charge as when it was lower voltage but it will be from a stationary DC source. Next will be the AC charge routine. And once again, no extra charger. The controller is the charger. No extra pre-charge box needed.

Ever want to have a super simple but powerful system? Consider the Synkromotive Controller.

DC Charging

I now have the DC battery bank set up better to eliminate any excess heating while charging. I have connectors from a welder to connect the DC battery source to the car. I tested the charging today and got no excess heating and every thing stayed cool even with the settings at 150 charging amps. The DC  power is routed through the motors field windings to act as a built in inductor. The motor is large enough to handle a healthy current with no ill effects and no overheating. Because the source DC pack is limited in size I need to install a cutoff circuit so if the main battery pack goes below a specified level it will shut off a contactor that is connected to the pack. Right now there is no such contactor as I am not leaving this connected unassisted. I did todays charging into a 72 volt pack from a 48 volt stationary pack. I can now configure the pack to charge at 150 amps vs the weenie amps of your normal plug in style chargers. The other nice thing is that you no longer need a separate charger. The Synkromotive Controller doubles as a charger. It only charges to a specific voltage then cuts off but you set the current  at a constant current until you reach your desired voltage. You can set the amperage to any level up to 255 charge amps. Charging at such high currents will sag the stationary pack by quite a bit. Just like driving when you sag a pack during the drive. More current draw equals more sag. So to combat that you need a large AH stationary pack to better handle the charge. What we are doing is small scale but no different than what one would do if they were to set up a large public fast charge station.

So to recap:

The Synkromotive Controller is also a Charger.
The Synkromotive Controller is Small and Light weight coming in at 7 lbs.
The Synkromotive Controller is forced air cooled, no need for complex water cooling.
The Synkromotive is a Power House of a controller.
The Synkromotive Controller will do 192 volts and 900 amps with the current high output fan.

No longer a need for an extra charger as the controller charges the batteries too.
You can Charge from ANY DC or AC source. For DC  you need to be sure the source power is less than the lowest voltage of your pack you will charge at. So if you have a 144 volt pack in your car you can have a stationary pack up to like 96 volts and not have any troubles.
Since most homes use either 24 or 48 volts a 48 volt high amp hour pack is ideal. If you can get a pack large enough to give you a few thousand AH's then you can have a real nice stationary pack. You can also charge off a DC generator and AC generator.

My Military Starter/Generator will output 36 volts and 400 amps. I am going to test charging with that generator running.

Pete :)


Tomorrow we test 156 volts (49 Cells). We upped the voltage and I hope the motor handles it. I have the voltage limited to 120 volts first. Then we will increase to see how it handles that. So a jump from 72 to 120/156 is huge. Time to fly. :)

Synkromotive in Action

Thought you guys might like to see the Synkromotive controller in action. They posted a link on youtube but did not make it known. It's a quickie but good video. These are excellent controllers. Enjoy the demo.

Pete :)

DC Pack and Plug

Got my DC pack set for 48 volts now and I also have the charge cables ready to go and have the plugs installed on the Bug ready for Fast DC charging of up to 100 amps and maybe even more. Hoping for 150 amps to stuff into the cars cells. There is enough to charge the pack once fully and fast. It is a demonstration of FAST DC charging at home with no extra charger on board. I have no AC charger on board either. Remember I said the Synkromotive controller is also the CHARGER. I can fast charge directly from any AC source or any DC source as long as the DC source voltage is less than the lowest voltage of the pack being charged. So with 48 volts I can charge a 156 volt pack. Nice. Testing and configuring with 72 volts first. It does work so my testing is only to get it up and running smoothly on my vehicle.

Pete :)

Photos and video soon. Work gets in the way some times. The price we pay for good full time work.

DC Charging

This afternoon I changed the profile of my stationary pack from 24 volts to 48 volts. This should allow lower current to do the same charge time. I connected and the PWM went from 93 PWM at 100 current amps at 24 volts to 52 PWM at 100 amps at 48 volts. I then had to lower the current as my tiny anderson connection could not handle 100 amps. The anderson connector got pretty hot to where you could not hold it. So I lowered the current to 50 charge amps. At 50 amps the car pumped in AH's at a pretty good clip and all the connections cooled down to where it was only warm to the touch. I will need heavier cables and an anderson or some other connector that can handle up to like 300 plus amps. The main connections can handle a bit of power. I do not think the inductor can handle that heat. I think I will need to increase the inductor to be able to handle 200 amps. I think that 200 amps will be plenty for fast DC charging. My stationary pack can handle that but my inductor is still getting warm.

So for now, 48 volts will charge up my 72 volt pack just fine at 50 amps. That is far better than my current charger and all that with no extra charger. Just a couple extra contractors and an inductor.

Cool, a small foot print controller and charger in one. Charge from multiple sources. DC stationary pack. AC directly from the wall. It may be possible to charge directly from a generator. Might need to convert it to DC then directly into the cars pack.

My setup testing is going well. It is a known way to charge. My testing is not new but its new for me. It will be new for all other users too but the ability has been built in from the beginning. Even the beta units could charge from a direct DC source. If you have a dumb charger you could connect directly from that DC source but you'd limit your amps to what that source can put out. But NO extra Charger. Just your Synkromotive controller and a couple contractors and inductors. Or you can use your motors field windings for your inductor. That will be tested once again with a bit higher voltage.

Pete :)

Time to let the cat out

Synkromotive Controllers Rock. What would you do if you could charge your car in a couple hours vs 8 or more hours? What would you do if you could charge your car directly from a stationary DC Battery Pack? What would you do if you could charge directly from a generator? What would you do if you could Fast charge directly from your homes AC.

What would you do if you could do all this with no extra charger?

Well, you can. Synkromotive Controller is also a Charger. One which you can do directly from a DC or AC source. If you charge from a DC source the source needs to be less than the lowest voltage of the  pack being charged. AC charging should be done if you have a large voltage pack of around 156 up. You can charge directly from your 240 and if you dedicate a line you can fast charge up to like 100 amps.

You can also do normal charging speeds too. When you Fast charge you need to have cables that can handle the current. With this kind of current things can get hot.

I have been charging my Bug now with a 24 volt Deep Cycle Solar Battery Bank at 100 amps. I will be changing the voltage to 48 volts and charge again at a higher rate. The higher voltage of the stationary pack will allow you to charge at higher current with less heat and better efficiency.

We are planing on using a DC generator to allow charging while on the go. Not sure how fast we will be able to charge but we should be able to do at least 100 amps or at minimum 50 amps.

So you can have a sweet controller that has yet to have any troubles and one that can double as a charger too. The controller is not a heavy hunk of aluminum. There in no need. No water cooling issues either. Small foot print and fully configurable. Computer monitoring and logging.

DC750 Specifications
Input Voltage Range (Nominal): 24 volts to 180 volts Peak Battery Voltage (During Charging): 195 volts Maximum Motor Current: 750 amps
Maximum Loss: 1.5 KW
Switching Frequency: 20 kHz
Operational Safe Temperature Range: -10°C to 40°C Minimum Supply Voltage (Turn On): 11.7 volts
Off State Supply Current: 25 milliamps 








Dynamite does come in small packages.