Tuesday, July 17, 2012

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. :)


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  2. I am also wanting to know if you can use 24 volt solar panels to get 192 volt as a charger also

  3. Sorry but I mucked up your post and accidentally deleted one of them. Here is a link on how to connect cells in parallel and series.


    Yes you can use 24 volt solar panels to charge a 192 volt battery pack but the charge amperage will be very low.

    So do you have a Synkromotive controller? How are you going to control the charge algorithm? How are you going to terminate the charge cycle?

  4. You can look a the pack I show. It consists of 6 volt batteries in series for a 48 volt pack. For 192 volt pack and 12 volt batteries you just need 16 of them wired in series.

  5. Hello,
    I'm a student at Topsail High Electric Vehicle and we have 2 synkromotive controllers as well. We saw that you are using yours as a charger and were hoping you could provide us with some information as to how you've done it. We have contacted Ives but have yet to here back. If you can send me an email at sessions.shelby@gmail.com