Gen II Prius Individual Battery Module Replacement

Do you remember that I do not sell tools to general public? They are not the Garage and they want to DIY. Let's them try and let us help them not to waste time on something others had already done before ....

 

I've used my HiTec "Toy Charger" now to discharge/charge all modules in that battery from a minimum for 3, to a maximum of 5 cycles..
Most of these modules are tired, but functional, and most improved a lot. Using the last cycle discharge rates, I have some in the 5000+ MAhr range, some in the 4000+ MAhr category, and a couple in the 3000MAhr range . I have also identified 2 modules to be replaced in addition to the 3 I have already replaced.

The interesting fact is that I replaced this battery because of a single "Block" DTC 3015. Apparently the hybrid computer was happy with the performance of the other 13 blocks/ 26 modules, although when I worked with them individually, most weren't very strong. This then leads me to 2 questions. Remember, although I am an engineer, I am a novice in this hybrid battery area:

1. Does the Hybrid ECU generate DTC faults based on absolute block voltages, or on some block(s) being below the average block voltages by some nominal voltage.

2. If the answer to 1 above is yes, and given the fact that when the process is all over you can re-arrange modules as you see fit (observing correct polarities of course) to match a strong with a weaker module to arrive at nominally the same combined voltage under load. Mine would
average at about 15.7 volts. Is that acceptable ??

I the answer(s) to the above is No, then I might as well remove the 5 best modules, replace them with the 5 bad modules I have, and then turn the whole thing in as a core.

 

1 and 2 are essentially correct. If one replaces dead modules and exchanges weak modules with decent ones an HV battery has an excellent chance to last another year or more. It is worth the effort if one has the time and another vehicle to drive while the HV battery is undergoing repair. That's one of the goals of DIY - saving money.

So don't let Kiwi (or any other Priuschat naysayer) persuade you that you're wasting your time and money. It will work.

 

That is what eBay sellers of modules try to incept into people's minds. Thousands of dodgy second hand remixed untested packs are already out there in second hand Prius for sale or at wreckers.

Ruudh is asking smart question about aiming at having all voltages in the rearranged mix to be the same under load. Aim for voltages to be the same under the same load on all pairs measured simultaneously down to 14V. See if that is over 1Ah. Aim for 3AH or more. Perfectly matched modules in two test packs with URC ~ 1AH lasted only 6 months. So when someone says year or more - I would say pure luck...
I've got a pack in front of me where 2007, 2008 and 2010 modules (all good by the way) were put together by DIY-er with no tools apart from voltmeter. Deviation in voltages on pairs was above threshold during load test after only few minutes (less than 1AH discharged). Good modules but not working in conformance with each other. 28 modules out of that mix of 38 were showing perfectly matching curves - but not the rest of the donor modules.

In another test fresh 4 modules were put as two pairs at the end of 28 module pack and resulting Delta V under load was too high. URC < 1AH. When they were mixed with existing ones - URC had increased more than twice. Pairing "weak and strong" is what Ruudh is asking about. That could work - just depends on condition of all modules and what the Delta V under load looks like (within the working range of the pack - down to 14v).

 

lol hihy most here are actually trying to help people,

My "home rebuild" pack is also still going strong 6 months and about 10k later, im sure it will still be going strong in another 6 months!

I use 10+ year old "toy chargers" with 20a discharge, a cheap (dangerous) home made grid charger and a selection of various AU 240v household globes for grid discharge, I can build an excellent pack with these few simple tools pen & some paper in a few days! proven results. kiwi just wants to sell stuff, I actually get that but what I don't get is how he dismisses our hobby level rebuild practice as useless when the results are at least as publically proven as are his, if not more ...

 

To the best of my knowledge the hybrid ECU does look at a rolling nominal block (pair) voltage and then compares it to each actual pair voltage. If any of the blocks stray too far from that voltage you then get one of those famous weak block codes triggered. This was why even though I checked all the capacities and they all tested above 6000 mAh, the load test quickly showed which one was bad. So when you are rebuilding you want to ensure both capacity and load tests are similar or it can trigger a code and/or cause you to have a significantly reduced overall battery capacity.

Yes, your idea of matching the weak with the strong modules would work as discussed way back on page 11 ( Gen II Prius Individual Battery Module Replacement | Page 11 | PriusChat ) but again if the capacities are too far from the nominal then you still won't get a very good end result. I would keep them within 1000 mAh (ideally around 500) from highest to lowest capacity and then load test them all to ensure all have very similar voltage drops under load. Once you have them all within range then use your idea of matching the weak and strong to create your new pack. Alternatively the ones in the middle tend to degrade fastest from heat so you may want to actually put the strongest ones together in the middle and the weaker ones towards the ends with the idea they will even out over time. This is especially important given you are located in one of those hot southern states and heat is a killer for these batteries and you can also see how your worst ones came from the center of the pack.

 

Thanx for your detailed and sensible advice. Yes, the weaker modules did come from the center of the pack. The other point is that I'm playing around/learning at this point. We have 6 Prii in our immediate family (wife and I, kids, grandkids) (see picture) 3 of which are 2005 Gen 2, 2 are Gen 3 including my wife's 2012 plug-in, and my granddaughter has a 2012 PriusC. Therefore this is a spare "learning" battery pack, as I want to be in a position to support/repair for sure the Gen 2 ones, the mileages are 178K, 189K (The Prius pickup truck conversion), and one over 205K showing no signs of battery troubles yet.

As outlined in my thread in the main Gen 2 forum, controlling the battery temperature of the Pickup truck conversion (Pruck) has been a problem as the battery lies just below the black coated truckbed. I am working various solutions to this, but am not quite there yet, as it is brutally hot this time of year in Florida. One of those solutions is to duct A/C air from the outlets under the driver and passenger seats into the blower manifold.

The nice thing is that this is a spare battery, and I can test it out in the Pruck since the truck bed is easily removed and the battery is right there - no need to remove rear seatbacks and all sorts of trim which takes a lot longer than just removing and re-installing a battery....RH

 

With that many Prius in the family you might consider getting a grid charger setup from Hybrid Automotive then go ahead and install the harness in all of them and share the grid charger and discharge setup around as needed. This would be very cost effective and should keep your batteries running at maximum efficiency. I don't have mine in yet but others have been very pleased with how their battery responded to the cycling.

 

First off, thanks to all who have shared their knowledge in this thread, just finished a full read through.

Background: I have a 2nd gen that started throwing traction battery codes recently. Found this thread and some others. Pulled the battery and bought a Turnigy QuadKore. Hooked it to 2 12v car batteries in parallel with a 2A trickle. Cycled my modules with 2A charge and 2A and 6A discharge(2A to see how my numbers compared to others' at the beginning of this thread. 6A for speed). Most of my pack sits between 4700mAh and about 5600mAh. One module was at 6.7v and another after cycling only had about 3600mAh capacity. Bought ebay replacements for both of those from hybridsource (since S Keith asked). After cycling both came in between 5Ah and 6Ah capacity. My pack modules drop about .2v under 6A load over 60 secs. The new modules about .1v.

My question(s): It seems nobody has mentioned self-discharge testing for awhile. Way back in the thread jdenenberg said that any modules that exhibit more than .1v self-discharge per week should be replaced. Is this still the consensus? Is there a specific SOC or voltage where this applies since this isn't uniform over the discharge? Are people not self-discharge testing anymore because(as I understand it from this thread) both self-discharge rates and voltage drop under high load are both related to IR. So high IR will show up as fast self-discharge and higher than normal voltage drop under say a 20A load. Is the stand alone self-discharge test not necessary with the turnigy regen 20A and 30A discharge or has self discharge testing just not come up?

Also, for those of you using higher charge rates(1C), I noticed S Keith said it was fine as long as your modules were clamped and you had adequate cooling. What are your opinions on what is considered adequate? Also what do you think should I be keeping the external module temps under? I only have an Infrared thermometer to measure. My work room isn't air conditioned and it has gotten up to 100 lately in SoCal.

Thanks in advance...

 

Welcome back ryou!

Your repair was a big success. Lasted much longer than a lot of "professsional" rebuilds in the market.

I'm curious about the brake actuator assy recall. How did the stealership verify that the assy was faulty?
Was there a DTC for it ?

My 05 has been making a lot of unusual noises that might be the brake actuator
but I've never had any issue with braking or warning lights. If that isn't a requirement to do the recall
I'm taking my Prius to the closest dealer and getting the work done before it fails.

 

Threw that code AT the dealership?

Makes me wonder!

 

Deleted double post

 

What will most likely happen if I put 11 gen 3 modules from a 2014 Prius with 9k in my gen 2 pack for a couple weeks til I can get 17 more gen 3 modules with 4k from a 2014 Prius?

Also, no matter how bad of an idea anyone tells me this idea is or not, I was wondering how I should put them in.

One gen 3 with one gen 2 x 11 or 11 gen 3 in middle of pack etc?

LOL, can't wait to read responses to this one!

Posted via the PriusChat mobile app.

 

Use 2 modules from the 2015, use 26 modules from failed pack

 

Putting the Gen3 modules in pairs with the Gen2 ones has the benefit of equalizing the series resistance of the pairs, so it is not a bad idea. Put the pairs with the highest capacity in the center of the stack. You should re-balance all of the modules to maximize each module capacity as well as equalizing the voltages of all of the modules.

DoctorD

 

What's the easiest way to equalize voltages?

Does wiring in parallel work or not?
I read one place that it does, then someone like kiwi comes along and say it's pointless. So confusing, I don't know what to believe.

What all does that Hybrid Automotive thing do? Will it do all I need without buying rc chargers and supplies for them?

I don't have any chargers. I really can't afford to buy chargers and power supplies etc.

One last thing...if wiring in parallel works, is there an easy way to make one? It seems super time consuming and dangerous and a giant aggravation the trying to make one.


Posted via the PriusChat mobile app.

 

Do not wire in parallel, it is pointless.

From what I think you're trying to do (grouping a bunch of gen3 modules together), you would just need to do a single grid charge to the pack to equalize all the voltages. You don't need to do any discharges.

You may just luck out and have all your voltages quite similar already

 

That is precisely what I am trying to do and what is I had figured myself.

All modules I am getting are manufactured in 2014 (4th digit serial digit "P") from a 2015 prius with supposedly 9k and a 4k mileage 2014 Prius with modules manufactured in 2013 with 4th serial digit "O"

So, the Prolong 'Standard' Battery Charger from Hybrid Automotive for $359.00 will do?


Posted via the PriusChat mobile app.