To be more explicit - The orange cables are actually bundled cables consisting of four smaller orange wires, with some of the cable bundles being covered by a coax shield. the construction is shown in a link on Alan's web pages in the Hybrid section. The orange coloured plastic cover serves to identify the cables as a potential source of HV for first responders.

One never disconnects the orange cables and never opens them up to splice them.

For a safety precaution, one also doesn't touch them while the Prius is 'powered on' however they are extremely well insulated so it really isn't an issue.

I also don't have a wooden broom stick that I can work with - my ex-wife took off with it :-))
 

I also used split beads on every large orange wire (as well as others). However you also need to improve shielding of the orange wrapped wires. When you pry off the outer plastic orange cover you see that there is, on some of the cables, an very loosely woven braid (like co-ax). There is a link on Alan's web site that shows the shielding characteristics of this shelded cable assembly. This braid lets a lot of noise through. That's why I covered it in 3M copper foil tape and then bonded it all to groung

Part of the problem I expereienced is that there is not much room to work under the hood of the Prius and simply trying to get torroids on the cables is difficult.

A bigger issue is that the DC-DC converter box 'leaks' huge amounts of noise, this is the primary issue I am trying to deal with, and the use of 3M 1181 tape is helping, but, again, it is hard to work on - and you simply can't take it out of the vehicle, this is way too complex a job! Disconnecting it sets of software alarms that only Toyota can re-set - beleive me I ran into this problem as I tried to get it out and it cost $80 to get the alarm code re-set.

I had also thought of buying a used DC-DC converter from a crashed Prius and then opening it up and bypassing/shielding the electronics inside 'properly' but at $1500 for a used one, I think that the 3M approach, while messy and difficult, is the cheaper alternative.

One thing I have not done is monitor for noise from the electric engine while the Prius is running in EV mode. My guess is that there will be noise from the electric motor, and I will hear it when I try mobile ops this weekend.

Hi

I've probably done the most research of anyone and I am glad to share my knowledge I can e-mail photos, but have no web site to post them to. The good news is - if you don't mind the extensive effort involved, you can reduce the noise. My efforts are still a work in progress, however they are providing results - I am at the point of being able to install my Icom 7000 this weekend. I will use a custom stainless steel bracket (being made) that will be bolted at the top left hand corner of the hatch, on the vehicle body side. I wanted to mount on the roof but the metal had too much flex. The antenna will be a mini-Tarheel, though I may upgrade it later to something bigger.

I also have an interface unti on order that will allow me to connect the ICOM 7000 video display and audio to the Prius in-dash LCD display and sound system. I'll let y'all know how it works.

I drive a Prius for 2 reasons: I care about the environment; and - my XYL has extensive sensitivity to environmental pollutants, including exhaust emmisssions, and the Prius is a car we can drive long distance in without getting ill (although there are others - we chose the Prius).  

Enough said.

Please note that Mr Toyota does not like what I have done to some of the cables in my car. As a result, I now go to an independant garage, who happens to service the Prius (mine is out of warranty - we bought a used vehicle as the new car 'offgassing' is dangerous to environmentally sensitive people like my XYL)

Please read Alan's web pages about bonding. The pages are important to read (and re-read) because you are going to put in a lot of bonding cables. I think I have 20 bonding cables, and I need more. Bond all the doors, hatch, hood, etc as described in Alan's web pages.

You will need to invest in at least 2 rolls of 3M 1181 copper foil shielding tape. Buy only 1181!

You will need to invest in some RF split beads, they will be used on 'some' of the Orange cables attached to the DC-Dc converter (this is the approx 12 inch by 12 inch box marked 'SynergyDrive' under the hood.

The biggest source of broadband 'hash'and noise is the DC-DC converter box. When you 'power on' the prius, but the engine is not running, you hear all kinds of noise and spurious CW signals on 80, 40 and 20. When the gas engine turns on you will hear ignition noise ( from the COP and spark plug wires) The various other computers in the car and the breaks and Air Conditioner fan also emit noise.

I have successfully reduced 'some' of the noise, but it is an extensive trial and error process and I use an Spectrum Analyzer and probe to probe for noise source, then I bond the sources to ground, add in a split bead, or cover/wrap the source in 3M 1181, then I go back and use the Spectrum analyzer again and test for residual noise.

You will end up covering all of the seams of the DC-DC converter in 3M 1181.

You will need to cover each bolt head on the bottom of the converter (all the way around) with 3M 1181 and this will be bonded to the converter and then ground.

The orange cables at the rear(near the firewall) of the converter need split beads and 3M 1181 and bonding.  Take off the orange plastic cable cover (it is split down the side), do your mods, then put the orange cover back on - this is a safety issue - you need to put the Orange cover back on as it identifies HV sources to first responders who may need to cut cables in an emergency and it protects their lives!

The large black cable on the RHS (as you look at it) if the DC-DC converter also needs tape and a bead

The COP and ignition need this. My advice - do not remove the COP units! Simply tape around each unit while it is on the chassis.

Be careful when using the tape, I have many cuts on my fingers as the tape is sharp

There are undoubtedly more cables that are noise radiators, I have not yet found them all. But the ones described were the noisiest. As I reduce the level of emissions of the major radiators of noise, I then go on to the smaller ones (using a Spectrum Analyzer really helps) I hope to get the majority of the noise sources covered and bonded before October and winter sets in.

Most of the noise is in the band from ~ 3 Mhz to abt 15 MHz.

Feel free to e-mail me direct, I  have some pictures I can share.

Oh - the Prius 12v battery is quite small, I will parallel in another battery, to give increased AH ratings for when I go camping (which is often)

I'd love to hear of anyone else's experiences.

73

John VE3XKD

I have had mine in Canada for over two weeks though I ordered it over two months ago from Burnaby Radio in Burnaby British Columbia.

Hi

My 2004 Prius (which is much different from the 2003 Prius) does exhibit noise from the DC-DC converter. This converter takes the output from the hybrid's NiMh battery pack and converts it to a higher DC voltage to run the electric motor that powers the hybrid. The converter seems to be well shielded (in a metal box) which I bonded to the chasis in two different points. ( I also followed the other excellent bonding guidelines on Allens's web site). I tried putting Mix 31 beads over the DC power cables, but there was little improvement. I did notice that the power cables going in and out of the DC - DC converter are bundled together in groups of 4, and that the bundle of 4 cables  is covered in a shielded braid and the whole is covered by a loose  orange plastic corrugated tube. I am going to try bonding that braid to ground, however have run out of nice weather, it being winter in Canada and my Prius is generally covered in snow and ice these days.

Try turning your HF radio on, then powering on your Highlander without the gas engine running. You should hear the noise go up by 3 S units or so on 20/40/80, with the gas engine off, then possibly go higher with the gas engine on.  Two different RFI engineers told me that, in general, DC - DC converters exhibit square wave on their outputs, and the harmonics of the square wave are what I am hearing. They beleicve I need to bypass the output of the converter with two capacatoatrs - a 0.1 Ufd and a .01 Ufd to ground out the harmonics. Unfortunately this requires opening the DC - DC converter which may void the Toyota warranty.  However I have undertaken to write Toyota Canada on this matter to see if they can help.

I hope this information helps hams with Hybrids.

 

I've just taken my 2005 Prius (base model) out for a test drive using my IC 703 and a 3 ft CB whip on a mag mount attached to the roof of the Prius to see what the noise levels are like.

There is lots of noise (but not S9)when the engine statrs up, when the electric motor kicks in, and when braking. Cruising at 35 MPH there is minimal noise.

The DSP Noise reduction unitl in the 703 helps - but does not eliminate the noise.

As I could definately copy signals, and the noise level was way down when crusing, I intend to repeat the tests with a screwdriver antenna using a mag mount in a few weeks to see how well my 706 MK2 works mobile in the Prius.

If anyone else has any insight, I'd appreciate hearing from them.

73's all