Simons 1999 Toyota Prius

Website · Post by **Simon** » Sun, 12 Sep 2010, 22:56

Got a new project to play with yesterday!

It's a 1999 NHW10 Toyota Prius. The battery needs some attention.
The 288V warning light was coming on and it would not start. I tried using the 12V NiMh charger that is built into these first gen Prius and got a little charge into the pack before the charger fault light came on. I waited a while and tried again a few times until it got enough charge to fire up the ICE.
The ICE is making lots of noise when it idles but goes quiet after 10-20kph. The park gear doesnt work but seemed fine the other day.
Heres some photos.

Post by **coulomb** » Sun, 12 Sep 2010, 23:27

So what's your plan? Patch up the battery and continue as a hybrid, make it a plug-in hybrid, possibly with extra or replacement lithium, or full electric, with or without the motor it has now?

Website · Post by **Simon** » Sun, 12 Sep 2010, 23:50

Undecided what to do at the moment.. First things first though, fix up the battery and any other problems and get it licensed.
It wont stay a stock hybrid for long if I can help it!

So yeah possibly plugin hybrid with an Enginer kit or full electric with or without the stock electric motors.
The noise the ICE is making has me worried there is a problem in the transaxle.. Hope not.
We shall see.

Website · Post by **Simon** » Sun, 19 Sep 2010, 04:15

I got the battery pack out of the car now.

Measured voltage of the passenger side half pack 147.6V
And individual 6 cell sticks.
1. 7.50
2. 7.54
3. 7.54
4. 7.51
5. 7.44
6. 7.57
7. 7.53
8. 6.19 **
9. 7.53
10. 7.56
11. 7.49
12. 7.57
13. 7.55
14. 7.42
15. 6.21 **
16. 7.56
17. 7.60
18. 7.44
19. 7.49
20. 7.61
Pulled out stick number 8 & 15 so far. Here is number 15 with one cell that has got hot & leaked. Number 8 has 2 cells that have leaked but the heatshrink is intact.

Post by **Johny** » Sun, 19 Sep 2010, 22:15

Interesting stuff Simon. Thanks for documenting it. Can you include a longer shot sometime. Not having a Prius in bits I'm not sure what I'm looking at some of the time.

Website · Post by **Simon** » Mon, 20 Sep 2010, 00:13

No worries Johny
What would you like a longer shot of? Battery sticks? Battery box?
Heres a shot of the 2 sticks from the passenger side half pack next to a lighter.

Measured the voltage of the drivers side half pack: 149.3V
1. 7.43
2. 7.44
3. 7.51
4. 7.51
5. 7.42
6. 7.57
7. 7.49
8. 7.36
9. 7.41
10. 7.50
11. 7.49
12. 7.39
13. 7.55
14. 7.50
15. 7.40
16. 7.52
17. 7.56
18. 7.41
19. 7.50
20. 7.59

Put a load of 5A on battery number 8 from the passenger side half pack and it dropped straight away to 4V. So trying to charge it up now using a 7.2V NiMH charger set to 0.6A.
Been doing some research on NiMH charging/discharging on the net and now Im unsure what is the best way to charge. Fast? / slow? / or trickle charge?

Post by **coulomb** » Mon, 20 Sep 2010, 00:53

You should probably read posts like Prius NHW10 (MK1) Hybrids - How to test and resurrect them. In particular, don't charge with too much current, unless you have adequate cooling in place. These batteries are very susceptible to thermal runaway and fire. 600 mA is probably at the very high end, and needs very good cooling. 300 mA is probably a lot safer (from memory, please check the thread above).

Website · Post by **Simon** » Mon, 20 Sep 2010, 01:17

Thanks coulomb. I found that thread already and have also been reading the Mk1 Prius yahoo forums. The yahoo forums are such a pain to read and to search.
Does anyone know how the BMS works in the Prius? Just wondering if it would be better to replace the weak sticks and let the BMS do the majority of the balancing. Or cycle all the sticks first and charge to 100%?

Post by **GRMarks** » Mon, 20 Sep 2010, 02:15

A 1999 prius and problems already ! I have a 1997 RAV 4 (with after market turbo - can put out over 200 KW) and have had no problems with any of the Toyota parts. The only thing to go wrong (several times) are oil hoses to the turbo (non Toyota).
Thats over 2 time original power and yet no engin or drive train problems at all, amazing!. Its only done 140,000 km (I've had it from new).
Was originaly impressed by the prius but then realised that fuel consumption on a long trip was not all that good. Economic desiels have better economy.
Maybe get a standard font wheel drive gearbox (and transaxels) and convert to full electric - should be ultra reliable then.
Just for the record - I am amazed at the reliability of my RAV 4 - most reliable car I have ever owned. I traded my first RAV4 2 door in on a RAV4 4 door.

Post by **antiscab** » Mon, 20 Sep 2010, 04:45

the mk1 prius battery had a design flaw, the sticks were thermally is parrallel.
a big no-no on nimh, must be series or you run into balance issues.

anyway - simon,
replacing the whole stick is faster.
you can't revive damaged nimh, only memory affected ones.

the prius BMS monitors voltage at the stick level.
when one goes out of bounds its is noted, and power cut back.
it happens to many times, you get a turtle.

full cycling the pack 1 stick at time would be a good idea though, just to sort out the memory effect issues aswell.

memory effect is where the cell is cycled over a narrow SOC range over a long period of time. the voltage under discharge below the usual minimum SOC is 1v rather than ~1.2v.

Matt

Post by **7circle** » Mon, 20 Sep 2010, 07:54

I've got a cheapish NiMH charger with LCD that tells me Ah reached when charged. If you have one of those it would be worth cycling each of them at least twice and record the results. The Cells are Panasonic HHR650D (from ESPrius NHW10 (MK1) Hybrids - How to test and resurrect th

So a 6.5Ah NiMH cell (D size) is often fast charged with a burping action to absorb the gassing action at the electrodes.

So if you can only charge them with a constant current then charging them at the 10 hour rate of 650mA with some extra would be on the safe side but slow.

You may find more cells with low capacity after you have done the 2 charge/discharge cycles.

As you may have noticed when there is a dead cell in the string when you have current passing through the string the faulty cell is a resistor and has a negative voltage drop (V=I.R).

(If you just want to get it going for RWC and rego I wonder if you shorted the dead cells with links, and cleared the error codes that the BMS system may not detect the missing cell +voltage.)

If you can't get a hold of Prius Spec battery would you consider another brand of NiMh cell with a capacity of at least 6.5Ah?

As the cells are 33mm to 36mm Dia and 60mm long two of them are 120mm and nominally 2.4V but when charging their voltage raises to 1.6V. So two would be 3.2V. You might get where I'm heading. Has any one replaced the all the cells with Headway 38120P 8Ahr cells. If the cells could fit. I Noticed Coulombs post in How to Convert a Hybrid other cells like LifeBat may fit too.

Refd: from above link: Battery capacity in the 1997-2000 Japan Prius is 6,0Ah @ 288V (25-30 mOhm) NHW10 Not released into US market

The heating issues of NiMH during charge and discharge may be negligible with LiFePO4 chemistry.

But the per Cell BMS issue is there so until they include a magical 3.9V Zener that can cope with 10A bypass during recharge.
Or a smart BMS for $1 per cell.

I must check on what causes the venting and crystal growth on the dud cells. Is it Heat during overcharge or heat during forced current when discharged.

It would be very helpful to know what the MAX charge voltage is in the NWH10 Prius Mk1before it detects fault.

Website · Post by **Simon** » Wed, 22 Sep 2010, 03:51

Well I have found the reason for the noisy transaxle.. Decided to change the oil and when I took out the sump plug there was no oil!!

Its a bit of a mystery as to why there is no oil though. There is a big dent in the transaxle sump but no signs of holes or leaks. The only evidence of oil leaks is on the inspection bolt hole.
So now the plan is to not spend any time on the batteries just replace the 2 bad sticks. Refill the transaxle with oil, start the engine and run it for a while then drain the oil then inspect and replace it.

Post by **GRMarks** » Wed, 22 Sep 2010, 05:21

If there was no oil in it then who knows how much damage has been done up to now. Does it have rubber boots on the ends of the trans axle where it connects to the drive shafts ? If so one may have a crack in it.

Post by **EV2Go** » Wed, 22 Sep 2010, 05:29

I very much doubt that fresh oil is going to help from a noise perspective because the wear will already be there. I do however agree that to help flush out the metal particals it would be well worth doing at least once.

Following that I would suggest you look at a product like Morey's to help give it a fighting chance.

Website · Post by **Simon** » Mon, 04 Oct 2010, 23:35

Well I have filled the transaxle with toyota type 4 atf fluid. Started the Prius up and it has helped reduce the noise a bit but still noisy until 20kph.
Found some oil leaks but they dont look real bad. But probably enough to not pass the pits.
The drivers side axle seal is the worst of the leaks.
So think I will have to pull the engine/transaxle out to fix the leaks.

Website · Post by **Simon** » Tue, 19 Oct 2010, 03:24

Well I have ran it for a bit to flush out the crap and then drained the transaxle. Took the sump off and the magnet was full of metal and also lots of fine metal the size of fine sand in the sump mostly aluminium I think but also some that looked like brass?
So anyway trying to avoid pulling out the transaxle I added some Nulon Auto Transmission treatment to help with the leaks and filled it up with more oil.
But after running it with the new oil and auto treatment I think the transaxle is really dead now because it was making a noise that sounded like a loose chain grinding metal away!

Post by **Electrocycle** » Tue, 19 Oct 2010, 22:07

hmm doesn't sound healthy!

Post by **EV2Go** » Fri, 22 Oct 2010, 19:18

Was the Nulon product a flush or a coating treatment?

sounds like it was a flush and has dislodged a lot of the loose particals that were keeping it quieter.

Brass particals aren't too bad as anything brass is probably replacable.

Alloy on the other hand is not good news

Website · Post by **Simon** » Sat, 23 Oct 2010, 03:43

The Nulon product I used is an oil additive : http://www.nulon.com.au/products/Auto_T ... Treatment/
The Prius had been parked on the verge for a couple of days and I decided to move it back to the driveway.. well I made it half way there and no further!
When I got to the edge of the driveway and tried to mount the small curb it just stopped. So I turned the key off and tried to reboot the car and it just repeatedly tried to start the ICE without success. The "ready" light did however light up for a bit but nothing happened with electric motor power either.
Oh well there is no avoiding pulling the transaxle/ICE now!!

Post by **EV2Go** » Sat, 23 Oct 2010, 03:58

There comes a point where singing really loudly to avoid hearing the obvious just can't be ignored any more. Sounds like you have reached that point. Good luck with it.

Post by **naitsirk17** » Tue, 01 Feb 2011, 17:50

I also have a 1999 Prius and it won't start on me. The normal car battery is new but I don't why it won't start on me. The "READY" sign will not appear so it doesn't start.
What do you think is the problem? By the way, I live in Kalgoorlie, WA and temperature here for the past 5 days has a max of 45 degrees. Does the high heat have something to do with the problem?
I know nothing about fixing mechanical issues for it is my first car.
I hope you could tell me what might be the problem.

Post by **coulomb** » Tue, 01 Feb 2011, 18:50

naitsirk17 wrote: The "READY" sign will not appear so it doesn't start.
What do you think is the problem?

95% chance that it is the hybrid pack gone too low voltage to run the show. You may be able to resurrect it by externally charging the pack.

Do it slowly! 600 mA max. There have been experienced people burn their Prius by charging without adequate cooling or monitoring.

Carefully read the DIYelectriccar thread I referenced above.

Website · Post by **Simon** » Sat, 05 Feb 2011, 02:05

Hi naitsirk17
How long has it been since it ran last?
Is it showing any warning lights? Like the 288V warning light?
High temperatures increase the rate of self discharge of the Nimh cells.
So it is likely the traction pack could be too low state of charge to run.
If that is the problem it is easy enough to use the inbuilt charger to bring up the SOC enough to start the ICE.
Feel free to ask any other questions and let us know how you get on with your Prius..

Post by **naitsirk17** » Sun, 06 Feb 2011, 05:42

I clicked on the link you said from your previous post but the thing is, I have no idea what you were saying there because I know nothing about engines etc. Would you be able to explain it to me in layman's term?

Post by **naitsirk17** » Sun, 06 Feb 2011, 05:49

Hi Simon
It's last run was on the 28th of January. The only warning light it is showing is the car. And the turtle always come up when I had the luck to start the engine. I try to give it a go everyday but I had no luck starting it.
I tried to recharge it using the inbuilt charger but it always come up as "FAULT".
What else can I do then? It seems that the TOYOTA dealer here have no experienced mechanic to fix my car.
Is there still a chance to revive the car? Or should I just sell it to the junk shop?