Prius Battery rebalance thread

I would like to learn to do it as if I were doing it for a living and warrantying the battery, so what would these details / that process look like. Thanks in advance.

 

First buy some good equipment
- High Voltage safety gloves Cementex IGK0-14-10 High Voltage Gloves Kit, Class 0, Sz-10 Cert
- Leather covers for gloves (see above)
- Toyota techstream https://techinfo.toyota.com
- Accurate voltmeter Fluke 115 multimeter
- Internal resistance tester
- High voltage dc charger (Up to 500v)
- Solid state variable load (1000 watt)
- Programmable multi-stage charger (different charge amperage at each step)
- Data Acquisition hardware and software Data Acquisition (DAQ) - National Instruments

Using the equipment you purchased
Charge the modules.
Discharge the modules
Charge the modules
Measure Capacity (AH)
Put them briefly under heavy load confirm ability to maintain voltage
Measure Internal resistance (IR)

If you don't purchase the necessary equipment, you are not going to get to the point where you can warranty the batteries. Basically you'll end up crossing your fingers and hoping it works good enough.

 

Does anyone who purchased a charger balancer to perform a rebuild have their unit for sale, now that they've completed the process? I'd prefer a multichannel unit, but will need to get something. All the 4 channel units I've found online appear to be out of stock.

 

The grid charger from Hybrid Automotive is pretty simple 1 unit device. Charges the entire pack at once.....and it's in stock

 

Thanks, I'll keep this in mind, but I'm going to hold out a bit in case someone has a used multi-channel available. I still have a lot to read/learn in the mean time.

 

Do some more reading. Better single channel chargers available for less that can do it in less time. Without an extremely disciplined system for secondary checks and confirmations, a 5-10W unit - single, dual or quad, is effectively worthless in comparison.

In most cases, the HA system JC mentioned is superior in results and requires FAR less time/attention. If your battery hasn't actually coded, you can't beat it from a time-saving/value perspective.

check out the "Quantitative" and "discharge" test links in my signatures for before and after results.

 

Where are you located? I have one I'd sell, a Hitec x4.

 

Thanks for your reply, S Keith

I have a 2005 Prius purchased in Dec 2004. Currently it's at 220,000 mi. Prior to this the only battery problem I've had so far is with the 12V battery. I replaced it in 2014.

1. The HA system JC mentioned seems kind of pricy. Unfortunately, my current 'free cash flow' situation is a significant constraint right now.
2. By "disciplined system for secondary checks and confirmations", do you mean something beyond analysis of voltage and current vs time to establish SoH baselines?
3. I noticed your use of Techstream in your links. Cnet has it available for download, buy I'm currently on a tablet with limited capability, so I wasn't able to try. Am I correct in my belief that once I download, I'll also need to subcribe, or does the subscription buy me functionality or databases that I don't really need for the task at hand.
4. I actually do have codes and have experienced battery failure. What I've been looking for in the forum is if says anywhere that P0A80 is just a polite way of saying "You're hosed, sucker. Just buy a replacement battery." But the only other battery code is P3020, which indicts block 10, but leaves the SoH of the rest of the battery up in the air.
5. I also have issues with the coolant flow control valve and temperature sensor, which in turn affected my A/C performance. Last summer, I was stuck in 95-100 F (in the shade) traffic on I-65 for an hour and a half, with a non-functioning A/C. Even though it was out of warranty, Toyota had replaced my coolant flow control valve once already. It appears that there is an old, expired service bulletin that they agreed to honor. I had the work performed, but within 3 months, the codes reappeared. I figured that I could live without A/C, and just didn't have the gumption to call them back after the first repair failed. I didn't realize that the car needed the A/C more than I did. (I mention this for others that read this post so they understand if they don't bother to find and address root cause, they are wasting their time rebuilding their battery. I worked in manufacturing QA for 30 years in management and in quality testing and engineering capacities for the automotive, steel, and glass container industries. It may turn out to be a combination of age and bad luck with your spot on the manufacturer's failure rate bell curve, but it pays to be sure. In case it's not clear by now, I'll point out that my root cause was my own stupidity.)
6. Can I assume when you reference the white plug in the 12V, in your 'how to test thread' you mean the aux battery, and not some jack at the ECU? Also, what is 'ICE?'
7. My plan is evolving into

a) measure each module to identify cells with poor relative SoH i.e. - document 'as found' condition,
b) replace modules as needed, then balance the entire series, and
c) remeasure the entire series to confirm 'as left' condition. Unless someone tells me that P0A80 means "don't bother", I'll begin step a) this weekend.​

I'm assuming that the ability to program charge rates and cutoff parameters of a 4 channel unit will take 25% of the time of a single channel unit.​

Thanks, in advance. I hadn't started this post with the intent of asking/saying so much.

Thanks for the response.

I'm in Munster, Indiana. (20 minutes SE of Chicago, Illinois)

Which model? How much? If not ac/dc, also power supply?

 

Is 'Conversation' actually a PM function in the forum. I looked for PM before I had replied, and didn't see one.

 

Conversation is PM.
Just be careful not to click on the options below the conversation "post"
"Allow anyone in the conversation to invite others"
"Lock conversation (no responses will be allowed)"

 

Okay, so your battery has coded.

Techstr

1. sorry to hear it.
2. The 5-10W discharges the hitec chargers use is pathetic when you consider the modules can be subjected to 800W+ Light acceleration can easily pull 140W. Can you see how capacity testing at 5-10W (0.8-1.6A) may not tell you much about how it will perform in the car?
3. You need to purchase a MiniVCI cable and provide a Win-32bit laptop.
4. No. It leaves the entire battery SoC in the air. If the P3020 is the SOLE reason for the P0A80, then you may not need replacement modules. With Techstream, you can look at the block voltages in the car and determine a few things. If your resting voltage spread between min and max is relatively tight at or under 0.2V, there's a good chance the issue is due to imbalance, and a grid charge/discharge/recondition may correct it. If Techstream reports a big delta between the min/max, you have a failed cell in the low block. You can also verify by opening the case and checking all 28 voltages.
5. Yep
6. yes, on the 12V. ICE = internal combustion engine.
7. Good plan but the devil is in the details. Also, if you've subjected your battery to high inlet temps for a very long period of time, your potential capacity recovery is compromised. Sustained heat kills these things.Your assumption concerning a quad charger is only correct if you fail to look at the details. Let's say you have the higher end X4 with 10W discharge capability. You have that on each channel, so 40W total. What if you get a charger capable of 20A discharges? 20A * 7.2V = 144W. Which charger do you think will discharge modules faster? What if you get the 5W X4 with only 20W total discharge power?

144/40 = 3.6; meaning a 20A discharge will discharge 3.6X faster than a 10W/channel quad charger. This considers that you're running all 4 channels of the quad charger.

144/20 = 7.2; meaning a 20A discharge will dishcarge 7.2X faster than a 5W/channel quad charger.

Additionally, 20A has much more utility in identifying a module's performance in-car.

 

Thanks Steve,

Though I am anxious to get the car on the road as soon as possible, the overriding factor is that I have more time than money. Once I complete this task, I still also have the root cause to address too. (Though I can't fix stupid, I should be able to address my a/c problem.) Since my background is in chemistry and I'm not an EE I have more assumptions than knowledge in this case. Your thoughts on these continue to be helpful.

• The Prolong site says that it is for a battery that hasn't already failed. Once I've successfully reconditioned it, this purchase make more sense to me, in order to protect the previous investment(s). Techstream with the USB cable makes sense after the battery recondition in order to help diagnose the coolant flow valve/air conditioner problem. (Hot weather is coming.) Since the dealer repair failed, there is probably a hidden root cause here, too.
• At minimum, block 10 is damaged, and likely adjacent modules. So I'll probably (testing will tell) need to replace at least 4 modules.
• I'll be doing this on the bench, not in the car. Since I'm able to secure block codes, though risky, I'm assuming that I've not damaged. Some of the risk is that my root cause analysis could still be wrong and there is some other component contribution to the failure that I missed. Otherwise, if I'm thorough and methodical, if the battery is sound when I'm done it will work. Noted, there is some risk in this assumption.
• Though tedius, I can test using a pair of VOM's and a resistor (not clear on what resistance to use yet) in parallel, and record the values over time. I can test by blocks (14) at roughly 10 - 15 minutes per block, then test at the module level when I see a problem.
• If enough other blocks wind up being bad, I'll have to weigh the $1600 trade-in value of the car vs how many modules I'm willing to buy. At ~$800, a commercially refurbished battery is probably not something I'll want to do, considering I still have other problems to solve. More than $200-300 in modules is probably the limit I'm willing to go to.
• The Hytech 44167 has 50 watts per channel, assuming I can find one or it's competitive equivalent at a reasonable price. I suspect that the one Greasemonkey offers in not this model, and will require a DC power supply and provide less than 50 watts per channel. But I'll cross that bridge when I come to it.

I may not be understanding your 20A example. If each module is rated 7.2V x 6.5A, then a module has ~47 Watts, not 144. I'm believing that if discharge rate should be kept to less than 1 A, I would have thought that this point would be moot. This is my gap in understanding.

Again, thanks in advance,

Mike​

 

Mike,

Mike,

6.5 amps is the 1C rating of our modules. In use they are charged/discharged at up to 100 amps (130 amps in 206+Prii which is why Steve said that discharging at 20 amps is a better test. Just be certain not to overheat the modules ( have a good supply of cooling air flow ) and keep them clamped to avoid swelling due to internal pressure buildup.

JeffD

 

You have misinterpreted the specs. Do not confuse charge power with discharge power. One is about filling a battery via input. The other is solely about converting battery energy into heat. They work of two completely different mechanisms.

from:

http://hitecrcd.com/images/products/pdf/208_Hitec_X4_Manual_US.pdf

50W CHARGE power. It won't even be able to charge at 1C.
5W DISCHARGE power (0.7A at nominal)

The more powerful version is 80W charge/10W discharge.

The prolong is useful IN PLACE of a cycle charger.

No. Block 10 has been identified as weak. This can simply be from imbalance, not failure. And there is NO reason to arbitrarily replace both modules in a block. My experience has shown that blockmates to failed modules are strong because the "failed" module voltage swings reduce the cycle depth of the "good" module slowing its deterioration.

Proximity to a "weak" block has no bearing on failure. Modules in the center of the pack can be weaker than those towards the ends, and that's not consistent.

Time limited at the moment. more later.

 

so called 'paired' modules are a result of toyota using qty 14 volt meters instead of 28. all of the modules are in series.

watts = volts * amps
6.5 Ah, amp hours rating means the battery can discharge at 6.5 amps constantly over a one hour time period. 7.2 volts * 6.5amp = 47 watts during that 1 hour.

watts are a measure of how fast energy is used/moved. Amp hours is how much total stored energy is available.

this explanation is simplified but mostly accurate i think

 

Please do not test by blocks. Multiple issues can be masked by 12 cells vs. 6.

It's like you haven't even been listening. Let's fill the gap.

20A * 7.2V = 144W (discharge)
6.5A * 7.2V = 47W, BUT when you charge a module, you will be well above 7.2V; likely has high as 9.2-9.6V. A 50W charger will be limited to 5.4A as the module approaches full. IIRC, the X4 may also be limited to 5A.

Your belief is misplaced. How does 1A (actually 0.8A because of the limits of the X4) tell you what is going to happen in the car at 120A? I thought I'd made that point already.




























Merged.

To further explain (complicate)...

Typically ratings are based on a 5 hour discharge, so it's actually rated to deliver 1.3A for 5 hr. A 6.5Ah battery typically won't deliver 6.5A for 1hr as it will fall a little short. The exception is if the rating is a minimum and batteries typically exceed rating.

I can't remember the name for this effect (somebody that coined it), but it has to do with the voltage drop due to IR and higher current. With 12mR total module resistance a 6.5A discharge produces a voltage drop ((6.5-1.3)*.012) .06V higher, so the termination voltage will be reached sooner and less capacity will be extracted. Taking it up to 20A vs. 1.3A it's pretty common that capacity will be cut by 500-1000mAh.

 

My mother in law has a 2007 Camry hybrid with 75,000 miles. It is coding P0A80 and P3021. She had taken it to her mech. who said "You need a new battery, it will be $2k+". Dealer was $4k+. Is battery failure more from age or use? It only has 75k miles, not 175k!?

I bought two modules off ebay, hv gloves and have been shopping for balance chargers. I had intended to do a voltage test, swap the bad modules, connect them in parallel to equalize and then reinstall and then come back and do a capacity balance in a few weeks. I got the battery out and chickend out in the battery dissambly because it was looking like a lot more time than I had for the weekend and I did not want to leave the car in parts.

Am I wrong in thinking I could end up with a worse overall battery from a remanufacture than one where I swap out a bad module?