Gen II Prius Individual Battery Module Replacement

Im using a reaktor 300W charger and trying to run discharge/charge cycles, but the cycle gets interrupted by hitting the 7500mah capacity limit. is there a setting to continue cycling even if this limit is reached, or should the capacity be increased higher? The way Im operating now, i have to manually initiate each run, and Im thinking I must be missing something??

 

I know it's a ways back...

Gen II Prius Individual Battery Module Replacement | Page 68 | PriusChat

"If the Reaktor hits a safety limit, it terminates at that point. It does not go on to the next program. You want your safeties to provide a means of preventing catastrophe, not to regulate your process."

I generally disable capacity limit or set it north of 9000.

 

Wow, I read that page a few times before but missed that detail. Thank you!!

 

LOTS of info in this thread. Easy to miss.

 

Hi Gents,

First off, Thank you. There's so much information here that I'm bordering on overwhelmed but most of it is making sense to me. I have a couple questions I'm hoping you all can set me straight on.

The Situation: I too have a 2005 Prius with 120K miles on it. The dash lit up a few days ago with the Christmas tree of death and the traction battery warning. My Bluetooth ODBII adapter, cell phone and Torque revealed the replace battery code. A few phone calls and some GoogleFu told me that the dealer wanted $3k for a remanufactured replacement, various vendors were willing to sell me a reman battery for between $1k and $1700 and e-bay sells individual battery modules sell for $35 to $50. PriusChat showed me that it was possible to refresh this battery on my own if I was patient, diligent and persnickety with details. The warning stickers on the battery are plenty scary but scared and ignorant (in the not knowing stuff sense of the word) have never stopped me from diving into projects that most folks think are best left to properly trained professionals. Somehow I’ve managed not to kill myself, blow up my house or burn down my cars in 48 years of diving in and tinkering.

Of the 28 modules in my battery pack, the vast majority of them read between 7.88V and 7.92V within half a day of the car’s last short drive. One module stuck out as obviously suspect at 6.67V, another one read at 7.65V and three more showed 7.85V, 7.86V and 7.87V respectively. All modules read about 0.1V less after a full day sitting on my work bench.

Ryousideways and Britprious et al. inspired me to pick up a Hitex X4 (the AC powered version) and give the task a whack. Reading through most of 72 pages gave me some confidence that I would not burst into flames but there’s so much information going in so many directions that I got the point of being unable to pick out what I really needed to know.

So here I am several modules into the process of discharging and charging following Ryousideways’ charger settings from his write up on page 2 post#35.

My questions:

#1 - Is there something magical about 3 discharge/charge cycles? So far I’ve had a few modules report hitting the chargers programmed capacity at 07250mAh on the second charge cycle and one that needed 4 cycles before reporting hitting said capacity.

#1A - Is there anything gained or lost by moving on to the next module if the current one charges to 07250mAh on the second or even first charge cycle?

#2 - Wherein I expose my expose some of my ignorance. Given that the modules are nominally 7.2V each, is it problematic or concerning that the charger reports 9 or more V at the end of a charge cycle and that my multimeter reads at 8.1V?

#2A – Is my inexpensive HomeDepot yellow multimeter going to cause me to blow up my car and burn down my house?

I’m still very early into the process so your help and guidance are most appreciated.

 

#1 No. The charge capacity has nothing to do with it. The mAh Discharge capacity is what you're looking for. Multiple cycles tends to restore capacity. Your termination criteria should be, "when I see the discharge capacity no longer increasing." Typically 3-5 cycles is the norm. You generally gain more with more cycles, but you rapidly get into the diminishing returns zone. Once you get improvements in the 5-10% range, you're probably done, but you may want to experiment to see what works best for your situation.

#1A. See response to #1.

#2 No. 1.2V is NOMINAL meaning it can go above and below. It's impossible to fully charge a module without supplying a little over 1.4V/cell (8.4V). A little higher is better. At higher currents, the voltage should go higher. Relating to the 9V/8.1V disparity between the charger and multimeter, the charger is also affected by voltage drop of the wiring, quality of the connection and internal resistance of the charger. 0.9V seems high. Are you saying you saw 9V on the charger while measuring 8.1V on the multimeter at the same time? If so, set charge current to 0.1A and compare. If you see the numbers get way closer, it's just the internal resistance of the charger.

#2A probalby not. I use the even cheaper harbor freight ones. Just use the same one for all measurements you intend to compare.

Perspective:

Car can demand 120A of load from these modules and can charge with as much as 80A.

This is 16X the charge current your charger can supply (assuming 50W version) and 150X the load (assuming 5W version). Your charger is just gently tickling it...

The biggest risk I see with the lower power chargers is charging at an intermediate rate. Charge at 0.6A or lower, and you're pretty much fine for about 16 hours. Charge at 6.5A or higher, and again, you're fine because the charger will detect the voltage drop when the module is full and cut the charge. It's the inbetween charges that can get you. 5A is close enough to 6.5A to reliably detect deltaV, but the 2-3A range may not terminate properly and without temperature, time or capacity safeties in place, severe overcharge can occur. I recommend charging at as close to 1C (6.5A) as possible.

good luck,

Steve

 

Got my mini VCI today. Here are the codes I received after running a health check on all systems:

P0A0D High Voltage System Inter-Lock Circuit High
P0AA6 Hybrid Battery Voltage System Isolation Fault
P3000 Battery Control System

C0215 Rear Speed Sensor LH Circuit
C1259 HV System Regenerative Malfunction -
C1310 HV System Malfunction

B1421 Solar Sensor Circuit (Passenger Side)

B2775 Interior Verification (to Theft Deterrent ECU / Smart Key ECU ) -

B1200 Body ECU communication stop -
B1207 Smart Key ECU Communication Stop -
B1271 Combination Meter ECU Communication Stop -

My interaction with the miniVCI has been purely intuitive as I haven't yet done any reading on operating Techstream software. I'll look into it some more tomorrow

 

this suggests safety plug ...

this suggests trans ..

not sure where you should go from here, will step aside so the experts can guide you!

 

Screen cap the health check and post it.

For any of the codes that have a little blue snowflake or splat next to them, click (double click?) that symbol, screen cap the results and post it.

Also, go into the HV Battery ECU and take a shot of that screen.

P0AA6 is the code that lets you drive it and then disables when you stop. If you replaced a module, it may be that you have a module with a path to the case through the lower mounting hole. It could be battery, transmission, inverter or A/C compressor.

 

maybe caused a leak trying to manipulate the pack back together

 

• P0A0D-350 is failure to properly install the service plug or an inverter cover installation issue. Make sure the safety plug is pushed in, levered up and then slide straight down as in the figure below.
• P0AA6-526/-612 HV leak most likely in the vicinity of the battery. If you over-torqued any of the bottom mounting screws, it's possible you damaged the module case and a leak has resulted. I had an extreme leak as you can see in the pictures below:
• P3000-123 HV battery system or Battery ECU - I suspect a connection issue.

The simultaneous issues with the interlock, an HV leak and the battery ECU makes me suspect something is wrong with the installation. Remove the driver side brace and remove the ECU cover.

Check ALL connections in the ECU bay as well as the external connections. Look for loose connectors, pinched or broken wires.

Good luck,

Steve

 

Pulled the battery and found that there is a leak. Luckily it's toward the end of the pack, only had to remove 5 modules. Now, how can I tell which one is leaking? It wasn't apparent which one is the culprit.

 

I'm almost done cycling the existing modules. Next job will be to swap in the ebay modules and cycle them once to verify capacity.

The plan is to replace two modules (8 & 10), unless anyone has some other suggestions?

 

you have some brilliant numbers there, you should get excellent results

 

Why the emphasis on the charge capacity? Charge capacity basically means nothing. Stop cycling when your discharge capacity stops improving.

IMHO, you should be running charge/discharge cycles, not discharge/charge. I have no idea why people do this except because they're using capacity cut-off to control charge limit - this requires the module start empty, thus discharge/charge.

You should cycle the eBay modules 2 times; chg/dchg, to confirm capacity or establish a trend. If there's a trend, you need to make an assessment of that trend.

EDIT: after taking a closer look at the numbers, at a minimum, you need to keep going on 1-4, 6, 8, 9, 19, 21, 27

 

some of Sanguis's DCHG capacities are above rated! what's with that?

 

IIRC, he's using a 30 minute wait following a charge. Since SD isn't coming into play, it's pretty easy to get at or above rated capacity if the modules are healthy. WA is also a very mild climate for NiMH.

I have two AMAZING Gen1 modules from 2002 that can squeak out 6850mAh using the same cycling program. It took 20 cycles to get them there, though. Fuggin' nuts.

 

I was keeping track of the final charges on each cell. I've noticed that when I can get a charge over 7700, the next discharge will generally be above 6000; I just skipped an extra discharge cycle that would have verified every module has discharge capability over 6000. When i've set the charger to run 2-3 cycles, I have used discharge/charge and charge/discharge interchangeably. I initially discharged all of the cells manually to measure initial capacity of each module (as it comes out of the car) for a reference point.

Yes, I set for 30 minutes between cycles, charging at 6.5A, discharging at 15A. I did have a few days pass for modules 1-10 after the second charge. The discharge capacity looks like it went down, probably due to SD. My car spent its first 4 years in the hot south, and the rest in mild WA.

Is a module that took 6 or 20 cycles to restore capacity equivalent to a module that only took 3 cycles? I'm a little hesitant about the overall health of modules 16 and 20 with 6 cycles compared to modules 27 & 28 that only needed a couple charges.

Module 8 read 6.6 volts after the initial discharge and did not recover to 7.4 V like the rest of the modules. I think that module is starting to go bad and decided to replace it. I did run some charge/discharge cycles on it for fun, but it's going to the recycle yard regardless.

 

I prefer data to "generally".

SD factors in very quickly. The initial drop from 100% SoC over just 24 hours is pretty significant.

It's relative. 3 vs 6, yes. 3 vs 20 maybe.

It means there was a pile of voltage depression. 20 cycles was the extreme. When the other 36 of 38 modules were complete garbage, what's the harm in running them through a bunch? My termination criteria for that exercise was >100mAh improvement from the prior discharge. In most cases, 3-5 cycles gets the vast majority of the goody back.

Subsequent testing has confirmed the 20 cycles results. They are monsters.