Tuesday, January 21, 2014

Fast Charging Revisited

We are revisiting the Fast Charge abilities of the Synkromotive controller. I have had my project on hold for a long time but its time to restart. I took my Bug apart last year in order to sell the body. I took all my components apart except the Demo Board with the controller and components. I did however forget to write down the issues I had to go through to figure out the fast charge with the Synkromotive controller. It was actually a minor issue but an issue none the less that would render the setup non functional because of a couple simple errors on the diagrams. The first issue is to have the proper firmware. I have copies of them all so no issue there. If you want DC charging, I have it. If you want AC charging I have that. I also have Regen setup but still need a bit more information. It does work and yes it is for Series motors. The age old issue of arcing an advanced Series DC motor still exists. So you should have a neutral timed motor and if possible, one with inter-poles. Just like you find in the larger GE Series motors and the larger Kostov motors. I suspect that this function will be a bit less desired because it is not as elegant as the AC motor regen abilities. But I do suspect that the charging function of the controller will be very much one that will be desired. We now have 3 including myself that are totally interested in DC source charging through the controller. I am working with a couple others with the Synkromotive controllers and we will do a rewrite so those interested will have the ability to do DC charging. It really is easy. It was originally intended for those who were totally off grid and wanted to use Solar directly or from a bank of batteries to charge from. A lot of effort was put into this function. It is not open source. Now that the issues have be revisited again we have two more working charging Synkromotive controllers.

I wanted to charge from 240 but the way the controller works it is required to use 110 because 240 volts is higher than the controller can use. Its max is 192 volt nominal pack voltage. The setup requires a DC source that is lower than the discharged voltage of your pack. You must be sure that the DC source is not higher than the lowest voltage your pack will ever see. It uses an inductor in the system to boost the voltage to the desired voltage you set in the software. So I can charge from a high amperage low voltage DC source. Since I wanted to utilize my 240 I would need to find a way to step down the voltage to a level I can use for the controller to charge with. Mmmmmmm. What could I use. A bank of batteries? Yes. An old Lester type charger that step-downs the 110 voltage to a usable voltage for like a 96 volt system. I could use in that case an old 72 volt golf cart charger that charges at 30 amps. That would work but would be slow. So what to do. How about an old arc welder. Mmmm. Maybe it would work. Yes if you have the right one, it will work. I have one. It can take my 240 and step it down to any desired voltage I want. When you step down the voltage the amperage rises. This is what is needed for arc welding. So I take my welder and dial in a voltage that will give me as much as possible without going over the lowest possible voltage of my pack and then just plug it in. I will be doing a demo very shortly on this process. Last time I used a bank of 48 volt Solar Batteries. It works but limited. Since my home is solar powered I can claim my electric cars are all solar powered and solar charged.

So be on the watch for another video in a couple days.

Pete :)

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