[RFI] RFI issues in electric (or hybrid) vehicles

[W0MU Mike Fatchett]

My son's Honda like I said is 2004, I think, The noise on 20m with a 
Yaesu 857 and atas 120 is 20 over 9 when the car is on.  We did not 
spend much time trying to figure out the issue.  The batteries were 
recently replaced and are under the passenger seat.    The antenna is a 
mag mount on the trunk lid.    The battery for the accessories is very 
small.  If he was more interested in working mobile hf I would spend 
some time trying to isolate the noise maker.  I should check if I can 
hear his noise on my truck when parked close by.

I can't say that I have ever heard another hybrid on the road and like 
W0QE I have tons of mobile miles on my truck and the semi's are by far 
the worst.

Mike W0MU

W0MU-1 CC Cluster w0mu.net


On 4/10/2012 10:26 PM, Roger (K8RI) wrote:
> On 4/10/2012 11:27 PM, Dale Svetanoff wrote:
>> Roger,
>>
>> First, my thanks to you and the other responders to the post.  The replies
>> have certainly been interesting, as well as somewhat varied.
>>
>> I have a comment and a question for you.  First, the comment regards use of
>> the term "insulation", as you note in your reply remarks.  That word did
>> raise some questions in my mind when I first read the article.  My
>> conclusion then, and now, is that the author chose that word poorly.
> I wrote the author and asked, but have not heard back, but that's only
> been about 7 hours.
>
>>    I
>> think a better word would have been "isolation", since I think the idea was
>> to isolate motor drive currents (both "hot" and "return") from the
>> vehicle's chassis.  While it certainly does mean that the motor is
>> insulated from the chassis, the key element (from an RFI perspective) is
>> that the motor be isolated from the chassis.  Does that help?
>>
>> Now, the question: I do not own a Prius Hybrid or any other brand or model
>> of hybrid or all-electric drive vehicle.  What I am not certain about is
>> whether the gas engine in the Prius runs at all times,
> As I said in the previous post, we own an "older" Prius. It's unlikely
> we'll ever break even with the extra cost Vs the cost of gas saved. Our
> original goal was just to save gas. Now that there are cars that get
> comparable mileage that are not hybrids it's unlikely we'll get another
> and sales of all hybrids are dropping off substantially.  OTOH if they
> get to $5 and $6 a gallon there may be a resurgence.
>
> The gas engine runs part time.  Usually we can back out of the garage
> and be about half way to the road before the engine starts.  IE we can
> get about 50 feet before it starts.  When you stop at a stop light the
> engine will also shut down. It will also stop if you get stuck in
> traffic. In Europe the same cars have a button on the dash that lets you
> switch to all electric.
>
>>    or are there
>> instances in which the car is all-electric?  My thinking (could be wrong)
>> is that there might be differing levels of RFI present in these vehicles,
>> depending upon whether the gas engine was operating or not.
> In general I believe the speed control is "pulse width" which is
> notoriously noisy. Back in the old days I build a number of power
> controls about the time they came out with the diac and triac.  I used
> them as well as SCRs.  I remember one particular 3 phase furnace that
> turned into a nightmare that I never did tame. It was like the different
> heaters were interconnected, but the results were unexpected and
> unpredictable.  Turn up one set of heaters and it was just fine. Turn up
> the second set and the first set might not do anything, or they might
> get hotter, or cool down. Add the third set and the other two sets might
> both go up, both go down, or one go up while the other went down.  The
> problem was the trigger pulses getting back into the lines and
> triggering the other phases and with a purely resistive load the pulses
> could be strong enough to actually turn off the other SCRs at most any
> part of the cycle.
>
>>     Your comments
>> about the battery in the Prius are quite a surprise to me, as I had
>> imagined some fairly hefty batteries electrically stacked in series to do
>> the main job of moving the car.
> Those are not the same battery they use for the electronics, lights, and
> starter.  I think that battery with all cells charged runs close to
> 500V. The one for the starter, lights, and "other stuff" is similar to a
> "small" motorcycle battery and runs 12V.
>
>>
>> No matter what, it is good to know that at least in some cases, operation
>> of HF mobile radios is possible in these cars.  Thanks.
> With the different reports I've read, I'd want to actually try out any
> particular Hybrid or Electric and go over it with a spectrum analyzer
> before committing cash.
> BTW "I believe" the other two cars I mentioned both use Icom 7000's on HF.
>
> Monday night I saw a segment of a program that told how many miles or
> typically how long you'd have to keep a hybrid to break even for the
> extra cost.  I think the shortest was 5 1/2 years  and that was with
> today's gas prices. and driving a lot. For the Volt it was something
> like 20 years.
>
> 73
>
> Roger (K8RI)
>
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