Hybrid battery No. 2 Frame wire voltage sensor HACK

In my opinion, being critical keeps people honest.

Being critical is not a negative thing – unless there is something that one is not being open and transparent about.

FWIW, in post #18, VZvrtny responded transparently and openly and did not come across (at least to me) as being threatened by the questions.

The responses from Camper and Azusa, on the other hand ...

 

Glad I commented. I had no idea there were the ACENBAY aftermarket products and as always I am glad to read the detailed dialog regarding what would not be commonly discussed or as readily found with my search queries.

Nitpicking is great, even if not dissed or cussed.

In my situation, I wound up using another harness from a parts battery. So will be one down as the one found in the 04 pack I was attempting to get back into service was bad. Was reported the vehicle ran fine until what appears the P3030 code happened due the something causing corrosion and or an open circuit on the og harness. Found a low block 3 module measuring 6.3V and also labelled 6.8V. Had a few 7.40V measuring modules that have sat for months and ghetto replaced since was instructed to only do that. I guessed would be OK as all the pack modules were reading 7.60 to 7.61 beside the 6.3V module in block 3.

Little awkward not testing each more thoroughly and doing the balancing shuffle where I think I can make a algorithm to optimize the placement via iterating through all the combinations to find the least voltage, current capacity and/or internal resistance difference. Seems like an app or excel or calc open source spreadsheet would be handy.

Here's after an hour drive and sitting for a few hours. Seems OK, good enough and made them happy.

 

To be sure, I am happy that someone has undertaken to supply these harnesses, given that Toyota stopped offering them for sale for gen 3, so aftermarket is the only game in town. I thank you for working on it. My only technical reservation about the product itself is about the insulation.

True enough, but all of those wires get bundled together toward the multipole-connector end, and, for obvious reasons, the nominal-voltage spec for electrical wire is not applied by considering the two wires in the bundle with the smallest voltage between them. It's applied by considering the two with the largest voltage between them.

That's the U spec, the maximum voltage between any two insulated wires running together, which in this harness is around 270 volts during charging conditions. There is also a Uₒ spec, the maximum voltage between any of the wires and the surrounding structure.

In this battery, Uₒ should normally not be an issue, because the sheet metal is at body ground and supposed to be isolated from both ends of the battery. But Uₒ can be up to 270 volts in a P0AA6 situation[*], and those situations do happen.

I can't say yet that I know that to be true for the OEM wires. It was claimed in the earlier discussion that the OEM wires "are like AVS automotive wires", and your aftermarket wires are FLRY-B.

I assume I can rely on that latter claim, as you surely know what wire you selected to build your own harness. As far as what the OEM wires are, I did ask in July,

but I don't remember seeing that question answered.

I question whether Toyota would have chosen a wire with nominal Uₒ/U of 60/60 V for this application, but it may be possible they could have done so, relying on their own extra testing and analysis convincing them that the wire they are using is up to the job. They might have to repeat that process even if they just switched to a different supplier of nominal 60/60 V wire. The simplest way to be sure of the design would be to use a wire rated, say, 300/300.

Likewise, the simplest way to show your product up to the job would be to show a spec sheet for the wire you're using that shows a nominal Uₒ/U of 300/300 V or better.

I'm totally on board with that goal; it just surprised me that your list of selling points for the quality did not include any discussion of the insulation rating, which is the primary difficult engineering constraint for this particular harness.

For the question "what makes this wire harness different from all other wire harnesses?", the answer is "it needs to be very thin wires with very thin insulation but still suitable for 270/270 volt Uₒ/U." That's the one thing that makes the material selection important and hard. Nothing else about it is all that special as auto wiring goes. Plus, the fact that it is used only for voltage sensing, carrying practically no current, makes all the other usual design considerations easy.

Anyway, the insulation rating was my only technical reservation about the product itself. My other comments are not any criticism of the product, but more about the promotional language, which so far hasn't included anything about the voltage rating (the chief difficult constraint), but seems to emphasize other things of less importance or even no importance given the application. A couple things mentioned may be genuine benefits:

The mechanical robustness can be a real improvement, if it has been an issue with the OEM harnesses. And maybe someone could think of a circumstance where the extended temperature range would turn out useful.

On the other hand,

It's less clear why those points are even mentioned, for a wire harness that is used only for voltage sensing, which involves practically no current. Between 10A and 13A is no meaningful difference when both are at least three orders of magnitude higher than the currents involved. When a wire is carrying practically no current, it is simply the same voltage at both ends, and that is the only "signal" the ECU needs, and you don't get better "quality" than that.

No need to belabor that here, as nothing has changed about the physics since the earlier discussion (which also got into why "internal resistance" is a misapplied concept here).

Certainly having higher ampacity and lower resistance doesn't make these wires any worse than OEM for this application, so I would never say it's any problem with the product. It just seems odd to push those things so high up the list of promotional points when they're of no importance to what the harness does.

Of course it's not up to me how you want to write your promotional copy. So the only reason I take the trouble to mention this is, whenever I am giving other people advice on how to be informed consumers in the caveat emptor world, one pattern I definitely encourage people to watch for is when promotional copy leaves some actual important specification unmentioned, and then is padded out by touting other points of less or no importance.

And that means there might be people who will read your promotional copy as it now stands, and feel that it matches that pattern, and therefore be put off, and that's something you could probably avoid if you revised the copy to give more space to the important specifications (starting with insulation rating, the key thing that makes this harness special), and less space or even no space to less important things like the ampacity of a harness that isn't used for current.

I offer this in a spirit meant to be constructive.

[*] Edit: I originally said P0AA6-612 there, but really it's any P0AA6 situation regardless of INF code.

 

Being critical while not being overbearing, as in being a decent person who wants to support the individual efforts of doers in our community, rather then discouraging them is all I'm asking for... Of course if you're a former Mirai zealot in the farthest away by distance from technology innovation in New Zealand, that whole concept of supporting others probably makes no sense.

 

You're probably not aware of it, but you're being a straight up jerk with this response! There's lots of NiMH battery rebuilders who are grateful for ACENbay's product and clearly you're not a rebuilder who helps keep Prius on the road.

In other words, please show just one single instance with a link on PriusChat where insulation on pathetic little wires designed to sense voltage would cause an issue/concern if their insulation rating were in doubt? If you can't provide a real life example of why that matters then please apologize to ACENbay for your disrespect.

And if you want to know my personal agenda in all this, I spent several years trying to find someone to help with an upgrade to the OEM voltage sensor system to address corrosion problems caused by NiMH chemistry in the voltage sensor circuit and ACENbay finally did that... Thank you ACENbay!

 

Hearing all sides of the story especially when there are safety concerns is always useful.

Like proper engineering? Or simply asking questions that typically are brushed aside?

Yes. Exactly.

It seems that promotions and sales are against the forum rules.

Why not start your own sales oriented forum?

 

There you go again, indeed.

I have no idea what you mean by this. All you do is come across as ad hominem, xenophobic, ill-informed, and ignorant. I couldn't care less what you think of me really, but come back to me when you know what you're talking about.

Chap does not come across as overbearing, unsupportive, or discouraging to me. The fact you sum up the post in those terms says more about you from where I'm standing.

Pot, kettle. For the record, I don't think the post sounds anything like that but rather sounds more like a failure to comprehend the material discussed.

 

I want to thank you for voicing your concern, you raised a valid point about the insulation of the wires, and after careful consideration, I admit that I overlooked a simple, yet important detail about how the wires acquire voltage signal from the battery because I was operating on a faulty assumption. Having said that, I did examine the insulation's electrical and physical properties, and I think there is a strong case to be made that the insulation of wires chosen for the aftermarket wireharness is in fact suitable for the application. If I understand correctly, the only real concern you have about the aftermarket wireharness has to do with the integrity of the FLRY-B wire insulation. I hope we don’t talk past each other, so I invite you to point out things you want me to expand on or to clarify what is not clear. Given the information available regarding Gen II and Gen III Prius traction battery and the data specs of FLRY-B wires, here are the facts and assumptions that govern my thought process, in no particular order:

• This is a signal-transmitting and not a power-transmitting application, hence very low current (estimated between 1 µA to 10 mA). It is important because due to low current, the wires can effectively handle the electrical, and thermal stresses and maintain their insulation properties even in a higher voltage application.
• The maximum potential difference in the wireharness is estimated to be 270V
• Insulation material used on FLRY-B wires is PVC with a dielectric strength of 20kV/mm (20,000 V/mm)
• Insulation thickness is 0.40mm (OEM wires thickness is actually thinner, measures at 0.31mm, but the material is different (I measured both, see photos below))

• Wire diameter: 1.6mm (also the minimum center distance between any two adjacent wires)
• Maximum current, on the conservative side, 10mA
• Wire internal resistance 37.1 mΩ/m

Here is the justification for the integrity of insulation in this particular application

Insulation breakdown due to maximum voltage stress at 270V in a single wire:
20kV/mm * 0.40mm = 8,000V. Compared to the strength of the insulation of 20kV/mm we get a very sizable SafetyMargin of close to 30 (8000V/270V=29.6). The insulation can comfortably handle the peak 270V, well below its threshold for breakdown

Insulation breakdown due to the maximum voltage delta between any two wires.
E= ΔV/d=270V/1.6mm=168.75V/mm. Comparing the maximum theoretical electric field of 168.75V/mm to the dielectric strength of 20,000V/mm, it is well within the safe limits. SafetyMargin=(20,000V/mm)/(168.75V/mm)= 119.

Just as a side note, the insulation breakdown due to heat generated in the FLRY-B wire is the following:
P=I^2*R, P=(0.01A)^2*0.037Ω= 0.0000037W=3.7μW which is almost nonexistent, completely negligible.

The FLRY-B wires are designed/rated for a continuous load of 13A at 60VDC, and tested at 1,000V to 3,000V. Considering the particular application of transmitting Voltage signal and not Power (with negligible current values), the wires deliver voltage signal effortlessly, as demonstrated above and the actual insulation is capable of withstanding significantly higher electric field than what is expected in this particular application, with a very generous margin of safety.

I hope this info was helpful addressing the suitability of FLRY-B wires for Gen II and Gen III wireharnesses.

 

@ChapmanF

 

Another example of Azusa posting a screenshot image from an unidentified source that presents dubious information, also seen here and here.

 

Thanks for the offer on the harness. Received a few days back. Thinking I'll stow away until I find that great priced low mileage gen 4 module (at least in the Prius world) HV battery and use those when I replace all the modules in one of my gen 2 HV batteries.