Wireing diagram of Battery Computer Plug.

Could you post some photos of your car showing the damage and battery areas?

Bob Wilson

 

Sorry but the photos are so out of focus, it is hard to tell what we are seeing. Also, perhaps you might do a little editing to reduce the volume? The files are so large and often photo editing software gives the ability to post the image without taking so much space. But these photos are so out of focus I can't really tell what we are looking at although I can make out smoke traces on the orange covers.

The battery is on a bench or still in the car? You've pulled the cover off? Could we get a whole traction battery photo?

I'm also interested in what the control electronics area looks like. My concern is there might have been damage in that area too.

Just to give some historical perspective, the first traction battery fire I've seen photos of was an Australian NHW11. It was parked in the driveway. By the time the owner found out, the fire had destroyed the rear seat and rear window.

So now I'm wondering if your climate might have a higher 'salt' or conductive dust that combined with saturating humidity might lead to the short? The reason I ask is I remember seeing coronal discharges on power line insulators near the sea shore. On foggy nights, I could hear and see the faint, bluish hues from the ocean mists on the insulators. Any problems with high tension line losses in that area?

I suspect the first step will be to strip out all of the cables in the pack and throughly inspect. It is very likely you may have to replace them. We also need to survey all of the modules numbered from 1 closest to the control electronics to 38 at the far end. Your earlier posting on voltages means all of the modules need to be 'surveyed.'

• initial voltage by module
• smart RC charger designed to handle NiMH battery and put a known charge and discharge on each module (6 NiMH cells) with a record of the Ahr capacity
  • RC hobby chargers know how to deal with the dV and temperature signature of a fully charged module. Anything less is going to fail, it has to be automated!
• get all modules to the same voltage . . . assuming they have no evidence of a failed cell in the module(s)

What I can not tell from the photo is if the connector is part of the vehicle wiring . . . a problem . . . or internal to the battery pack. Internal to the pack is a lot easier to deal with. But part of the vehicle wiring can be a problem.

Bob Wilson

 

* * * Comments Inserted * * *
Sorry the bad photo I havent got a good camera this might be better.

I get the impression the camera has limited, close-up. Holding it further from the object being photographed will usually solve the focus problem. We can always then crop and expand the area of interest. Focus first and the rest can be dealt with. <grins>

It is the plug that goes into the Battery computer from the 20 sense wires

Ahhh, good! This is a lot easier problem to solve than if the car wiring is bad. Still, it may give us insights if there are other problems to resolve. BTW, there was a nice Japanese lady who had a similar problem in this area only it was corrosion that 'ate' a pin in the connector.

this car was in a very salty area near the beach maybe the humidity ect has contributed to the problem.

Ok, so this problem might have been developing over time. It means the modules might not be fubar, yet.

I would have thought they would have put isolating resistors at the connection to the cells each point goes to a 100k surface mount resistor on the computer board and to an opto in the computer board so it looks like the computer was isolated from any HT.
But a very poor design bringing in HV into the PC where all that electronics are and a path to the rest of the car via control wires and the 12v supply.
Maybe they changed all that in the newer ones.

When this car was designed, there were not many 'off the shelf' designs. My understanding is the sense wires are 'switched' into a sample-hold cap and this cap is read to measure each module pair. If so, increasing the resistance would significantly increase the RC time and lead to low values.

There are weak aspects of the NHW11 design and many were corrected in the next version. In the Prius family, this was their second release and yet it did so many things right.

The battery is on the bench and I have taken the loom off and will have a look tomorrow how i can reconnect it into the control module if i cant get another 20 way plug and socket ill hard wire it in just worked out how they numbered the pins so will be easy dont need a circuit.

Exactly, it can be done, not fun but doable. I'll check my electrical manual after work but I do not remember this being in the manual. The electrical manual covers the vehicle wiring, not wiring within the traction battery . . . IF I remember correctly.

I see some battery testers on ebay and the local electronics place here has one as well so ill go there tomorrow and see if i can get one do they usually give you an indication of Ah or just go thew a discharge charge cycle.

Take time to read the specs. Remember these are NiMH modules and you really need one that understands the chemistry. Look for both dV detection (the drop that happens right after peak V) as well as a temperature sensor for thermal run-away. The really cheap ones have just a temperature detector and are used by people who like to buy NiMH batteries . . . a lot of them.

I would like to get this battery going as the one in the car is of unknown quantity just came out of a wreck.

A lot of us are running traction batteries that were rebuilt using parts from crashed NHW20 and later models. The reason is their modules are much improved. Given the traction battery location, it is difficult to find them compromised in a wreck. You might find a much better connector and control electronics in the other one.

The copper module terminals are green and a couple have leaked a green stuff i have cleaned with some vinegar and are soaking the copper links in vinegar i might have to get something stronger ill see how they go overnight.

Leaking KOH electrolyte 'eats' copper and one risk are the sense wires.

* * * End original * * *

Sounds like you're well on the way.

Bob Wilson

 

I had a feeling back when I posted this that someday it might be useful to somebody.

-Chap

 

* * * Russell Walker, * * *
Last night I swapped the 12v battery for the original i had on charge tester showed it ok but this morning it was flat so i put a good one in and now 12.5v OK.

Anything less than 11.5V and all bets are off. Did it go up to 13.8-13.9 when running? This is the normal charge level.

I went for a run up the road and the triangle and check engine light was on.
Also the motor dosent run if i turn aircon on or floor it, looking at the battery voltage its 280v when the engine starts at ready, the voltage still is around 278 280 i would have thought that it would have been getting charged it shows low on the battery indicator and if i go for a drive it only runs on battery and the engine dosent start.
I have inverter fluid moving. I will know more when I get my scanner.

This is why trying to diagnose on overt symptoms is a no-show. Three primary control computers, engine, hybrid, and battery, have their three error and multiple INFO codes and are just waiting to report them. BTW, swapping the 12V battery would have cleared the 'legacy' codes so you'll be working on the current, active list . . . a good thing.

But this is what happened when i put the recycled HV battery in first and after driving for a few minutes the lights went out and all was fine.

Not to worry, the computers retain the codes. <grins>

Have i got it right that if the cells are 0.3 volts out between banks then this is what it does. Has anyone disabled the voltage sense in the banks at the battery computer would this make the engine run the car.

You get a different code, "snapped sense line" or something like it. Monitoring the 19 module pairs is a key reasons why our Prius work and don't sit by the side of the road smoking . . . and I don't mean tobacco. <grins>

I have made a HV charger that will limit at 300MA and have put that on the battery will that help to equalize the banks ?? I hope low current will not get any good banks hot. Im working through the original battery and so far most are coming up 3500AH some of the 0.3 volt banks come up on the charger DRY i gather there no good the book I got with the charger is a bit verge. Its ebay 5 amp charge 1 amp discharge Is a charge rate of 5 Amps OK they dont get warm to touch. Has anyone got a idea of the normal current drain when driving and a average charge rate.

Everything you are doing is well within limits. I tend to use 1-1.5A but then I have more time. But don't think "normal current drain" as this is not how our hybrid really works.

The primary purpose of the battery is part of the transmission to even out state transitions and handle short-term, energy needs as the engine starts and begins providing power. These are typically unit seconds long. It also provides power when in reverse, there is no engine-to-wheel reverse gear.

The maximum currents are: ~70A in one direction and ~50A the other way. Having a senior moment, I think it is 70A on charge, stopping while descending a hill at high speed, and 50A maximum hill climb.

* * * end * * *

You are making good progress,
Bob Wilson

 

The control computers are sensitive to low voltage and can go into 'strange states' with a weak battery. Always remember our cars have seven control computers and we are 'driving the computers'.

Bob Wilson

 

Hi Russell,

I did a little bit of editing, did I get it right?

That works. This is high enough to give a reasonable approximation of the AHr capacity. But looking at the spreadsheet, it looks like the lower limit voltage was not close to 6V, the nominal discharge voltage of a six-cell, NiMH module. Still, a reasonable approach.

That has been my experience. The voltage drop for ones with dead cells is even faster.

The scanner will also let you read out the three temperature probes.

Bob Wilson