Howard, I have no direct knowledge of what voltage the system operates on, but its likely its much higher than the desired voltage for a charger,,
One suggestion would be to befriend a technition from the service department and pick his brain?
I will see if I can gather any intel for you ,, what version of Hybrid is this?

Erik Rogers and I were wondering whether one could get electricity out of a hybrid car for field charging electric stunter batteries. One could tap into the 12V car system, but the car would probably need to be turned on, which wouldn't necessarily be desirable.  Those cars are full of electricity, but I don't know how to get at the high-voltage stuff, let alone a good way of getting it into a form acceptable to a stunter battery.  I have put zero effort into finding out.  I am hoping somebody will hand me a solution.

The easiest way would be to put a 12V battery in the trunk - then at the field set it on the ground and connect your charger to it.   

(I don't know about others usual procedures, but I almost never charge anything at the field anyway. I do most charging at home.)

If the hybrid car has an alternator, then it likely has a 12 VDC system that is separate from the propulsion battery. If it does not have an alternator, then the 12 VDC may come from a DC-DC converter that is part of the hybrid controls package. In that case the battery charge may be maintained by the propulsion battery, which you could then access by hooking to the 12V battery.

When I was building pure electric vehicles, we used a DC-DC converter to charge the 12V battery, which was there as a buffer for the 12 electrical systems. The converter was permanently hooked into the system, so the 12V battery didn't have to be very big. The propulsion battery was 148 VDC nominal.

Check the 12V battery voltage with the car turned off, then put a load like the headlights on for a little while and see if the voltage drops off. If that happens, the battery charging circuit may disconnect the 12V battery to prevent residual loads from damaging the propulsion battery. The car people have some severe liability constraints on how to handle high voltage systems that are sold to consumers, so there is no guessing as to what the control system might do about this issue. My design info is now about 10 years old, so I'm sure some things have changed.

John

I would thnk that the car comes with a 12V cigar lighter outlet.  Probably 10A max.

The above is a pretty good idea.

I was going to suggest a gasoline generator placed a safe distance from the vehicle (hybrid or regular), based on the high penalty cost of failure.

The big question here, is, why is Howard worrying about charger power sources?

John

Hi Howard,

Eric and I talked about this at lunch during the GS contest after seeing your Hybrid Prius. Thank you for helping to save the planet and lesson our involvement in the Middle East by using such a fuel efficient car!  :)After watching you pack, I almost went and got my saw to make your beautiful plane a TAKE-A-PART so that your lovely wife could bring more than her handbag on your flying/vacation!   

After talking with you and Phil, I was very glad to hear that both of your talented engineering brains are looking into the possible use of E power for your next designs. We would all be proud to have the world famous JST join our growing family of E Stunt. With your team, Paul W., Bob H., Igor, maybe Dave F. and others, we would have a strong example of the world's top flyer's using E power. 

(To our readers) ..... BTW, the Prius has plenty of room in it for TWO take-a-part planes, all their equipment, two people and plenty of luggage. But it gets a little crowded with a .60 size one piece plane! 

RE the "where to plug in" question:

1. There will be NO help from Toyota. They are an excellent car maker, with outstanding customer service, but they will not touch the electrical system after it is made. My Toyota Sienna has 5 12V outlets and two 115V outlets. I asked if they would change the wiring so one outlet could be "hot" without the key on (GPS and other stuff all comes on and runs down the car bat) so I could plug my charger in at the field (with the lipos OUTSIDE the Van for safety). They said they are not allowed to make ANY changes or mods to the wiring system. ...... My guess is that they would be even LESS likely to touch one of their Hybrids, or give you any info about their systems wiring! 

2. With the above said, my EE friend showed me how to use a shunt in my fuse box to bypass the key between my 12V outlet and the van's battery. He uses this method all the time in his, it works.

3. (As others have suggested) We both agree that the ideal (and safest) method is getting a 12V car battery inside a safe box, along with it's own dedicated charger,  in the back of the vehicle, and plugging a 12V charger into one of the Van's 12V outlets to keep the 12V battery always charged up, trickle mode after charge. 

4. But, Lifting a 40 lb car battery in and out of the Van is not my idea of fun, and less than ideal for a healthy back. ...... I have been using two 12V/20Amp Wheelchair batteries. They are sealed, relatively light, and have built in carry handles. Each one gives two charges for my 5S 4,000 mAh Lipos. This plus having 6 batteries allows me to do more flying than I can do in one day! ........ After 5 flights, training slows waaaay down! 

5. My guess is that the more Electronic gadgets (portable TVs, computers, E games, etc. etc.) we use in/and outside the car in the future, the car mfg. will wake up and give us more access to our powerfull (easily charged) Hybrid batteries.    ............... until then, I am afraid they will be "locked up" and out of our reach. 

THE GOOD NEWS: ....... Now that the new Hyperion batteries are able to be charged at a 5C rate, and the price has come down to almost 1/2 of the TP batteries, and their quality is still at the top of the heap, we can easily have the 4 or 6 batteries we need for a "field charge free" day's practice or for a full 2 event contest. 

Good luck Howard ..... Please keep us all informed on your progress with your Hybrid to E Stunt cycle. 

PS: At Next years contest party entrance for the JST we will get you the smoke you wanted this year, and we will have you and Phil leap out of a big cake wearing your Rio style bathing suits! ......... The crowd will go wild! 

Warm Regards,