Battery rehydration thoughts

Update... After an extremely busy summer and the last battery build hanging in there til recently, I have great hopes of getting to do some battery hydration hacks. I put the majority of the cells Bob brought in the pack (best mah ones) after cycling for the data, and finally got my abs booster (passenger side unit) installed ,everything was working perfectly(had to also replace a right rear bearing and now maybe front left). That carried me through a heavy work schedule (approx 140 miles/day ) until I started getting an uneven battery voltages error. It was minor, (only about .35-.4 volt, but was evident on module 6,7,8,9 and 16. I was able to keep going by just firing up the mini notebook and reset it. usually happened first thing in morning a couple times and sometimes of the evening.

So ....now a finally clean and usable workbench/shop , most of the needed concrete pours completed around house and the need to fix the main a final time (get rid of worst modules) all came together today and I yanked the main out in less than an hour (yep I'm getting good at that part).

All those modules I had in the pack previously were sitting at really low voltages indicating they are really good candidates for the hydration experiment.

I could put together 5 modules that had good sitting voltages after maybe 6 months and cycled out well with at least 6000 AH capacities.
this should get the pack working for now... but having a bit of trouble presently seeing any low voltage modules . All but 2 read between 8.05 and 8.10 volts having driven the car this morning.
The 2 with less than 8 v were not the ones the computer identified. Maybe I'm identifying them incorrectly , but the module number is stamped in the bottom metal plate with #1 closest to Battery ECU and I have images of maybe 15-20 freeze frames of the pack voltages for the many resets.

No load was used to test, just my DVOM I am cycling the suspected bad ones to see if the data shows them bad.

Now ...while I have all the equipment out , am going to hydrate a few of them and see how they respond to cycling and if the data shows them better than the 5 I have for now decided to use.. This will allow me to experiment as well on the sealing method. I plan to cut a module open and visually check the hydration and look for best possible way to hydrate them.

I'm beginning to feel at first thought , that drilling the useless pressure vent may be the best route....but will experiment with other ways including some Bob and others brought up including the stainless screw and melt method that seems to work on another post.

Reality dictates that since the gen 1 modules (any that can be obtained) are now really old and with the car pushing 250000, I doubt that buying a gen2 replacement pack would be a smart investment, There are other things wearing out and it may be a better idea to move the car on (in working order) and get a gen2 or 3 car which I will be able to buy good modules for many years to come. I would personally love to see a conversion to 18650 liIon cells if anyone has done this. (should be doable)...but plan b (getting a newer gen) maybe smartest move.

...but for now , I get the wonderful opportunity to provide something possibly useful , and if successful , may allow old , cheap low voltage cells to be rejuvenated and keep a few of these old gen 1's on the road. They are a great car (a classic prius) wear well, were built well originally, and are like an old friend you don't ever want to be without. Mine's still in fine shape inside and out...so IMO is a great test bed for the experiment....something I had intended to do 6-9 months ago but heavy works schedules and projects didn't allow.

...let the project begin !....and Thanks once again Bob for the huge favor bringing those modules....such a great guy he is!

note....

....just cut the top off an really dead module... here is my observation.. Unless there are between cell chamber vents midway or at bottom, then drilling out the single useless vent is ...well useless...

Planning on cutting off the bottom tomorrow to verify... At this time looks like one would have to drill a hole per cell ...probably on top. I think a 1mm hole so a syringe needle fits loosely will be way to fill them. Loosely so the air will come out as the water is injected.

One thought would be use a drill press and drill vertically down the wall of the little square bubble that sits over the cell junction...one could fill it with thick CA , kick it , and then polish it off with a hot knife or soldering tool.. this should give the CA enough traction on the longer hole wall to make it stay put and the sealed melted plastic to make sure.Just not sure if the heat and hydration would possibly decompose the CA which may do weird things to the chemistry.

another thought is the hot water is probably a waste of time as the immediate contact with the mass of those cells would cool it very quickly. A better way would be to preheat the module with a heat gun or oven prior to injecting and follow up immediately with cycling to keep the heat on thereby wicking the water into the cells....or inject the water...seal and heat/cycle which may be best order.

 

Update.. 4-4-18
My mother in law (83) passed peacefully a couple months ago and is now in a much better place.
With intense care and then arrangements wound down, the 2002 Prius was again acting up with multiple alarms One being the detected abnormal voltage differences, catalytic converter, and the Power steering error (caused by worn out aux battery voltage ---in this case an aging lawnmower battery replacement)

I had reset the ecm so many times, maybe it got mad at me and now I cannot reset anything with the mini vci and pc program.. The dash display went from sometimes on its own coming back to normal but only after a lot of driving warming the main battery up. But by next day, there was enough battery voltage differences to kick another alarm ...with some days I might see the normal display for a little while , most days not.

I did discover that with the gen 1 , you will be able to reset via the 3 key on method to get it out of limp mode on the side of the road....and that was reliable to get me through the day/s til now.

Getting good at removing the main and onto the bench...2 hours tops now...maybe 3-4 to reinstall.

OK....now the results of the rehydration experiment..

Most all the ones I rehydrated were not originally reusable. The sealing method worked perfectly. ([2]-1/16" holes in top of interchamber vent hump using a syringe to put 3ml of distilled water in it and seal it with just a soldering iron tip by mashing the molten plastic to smear and seal it) (none were discovered to have leaked)

What I did mention earlier was I took the worse ones with maybe 5 v remaining to do the experiment on. That I believe was the problem.

I feel you MUST have at least a usable module (near 7 v sitting voltage) to create a 'better' or revived module with the rehydration method.

If it is down around 6v or less, its simply too far gone to revive and last.

The method did work for a near emergency get-by and was usable for a short while without alarms..

Now I am seeing a company hvhybridparts that I ordered(off ebay) a sample gen 1.5 (or so they seem to call it) module that is purported to have been manufactured after 2008 and is (and appears to be) a direct replacement for these gen 1 modules. The only difference in the modules is a silvery laminate on the sides of the module (where all the little tiny bumps are) for better heat sinking...and of course a much better chemistry.

What is a bit fishy is they are the only ones selling them I know of and suddenly they cannot seem to answer their emails or phone and are in the process of moving.. (maybe could not pay their rent...I do not know)...but I am now needing 7 modules(like the gen 1.5 they sent me) , am planning to use theirs as there is not many gen 1 modules on ebay that look like they would last very long.

I plan to get refurb the main (everything is fine but the 7 ) and then sell the car to get a later model Gen 2 or 3 that only has the 28 modules which I can easily get ...The gen 2 or 3 pack is only around 80 lbs and I can service it as needed. This makes for a better route car that is easily serviceable.

Other new of note was the 2003 Escape (which we rebuilt the tranny 3 years ago due to failure) blew the tranny yet again .Escapes have that known problem, a tranny from a Probe (4 cy) was utilized in the Escape as a 4cy... then a very powerful v6 was optioned...and then all the 4wd stuff put behind it makes for a imminent transmission failure.(Fords better idea...at least for them)

..... so I was so please with my hybrid experience (even though I've had to rebuild it a few times) I bought a 2011 Prius 3 for the wife..
She went from " I dont want a battery car" to I LOVE this car.. in 24 hours...although I had to replace the passenger side low beam (a real PITA unless you pull the coolant reservoir).. The car is definitely a keeper and I consistently get 50 mpg ave for the miles I drive it.

...so the rehydration works , and I highly recommend that you use only 7 volt or higher modules...but if this gen 1.5 is a legitimate module and is reliably available, I highly reccommend buying those rather than the rehydration method if only for the advertised better battery chemistry.Maybe someone knows if this company (www. falconhybrid.com )is legit and/or if they will be around for warranty purposes. If so, there gen 1.5 modules should be be the best answer to the 'very old module' situation perplexing gen 1 owners. This could very well make the gen 1 car a reliably serviceable car...and one you can easily get 300,000+ miles out of. Everything else can be fixed on this car.....but the ecm can be quite picky.

 

I found later I really didnt need to use the heat gun to preheat the case.... it you use a blunt and cleaned soldering iron tip with a high enough watt pencil iron, it will seal it well. (you will have to play with an dead module and seal a few and you will find the best way to move the plastic where you want it, then finally 'smear' over the tiny hole to seal)

 

As far as the companies office is concerned they are a ligit legal entity, but in any case, stay away from them, they do not have a very good reputation here.

That sounds like the MO of Falcon. Don't know if hvhybridparts is the same company under a different name, but what they call Gen 1.5 modules are probably just recycled modules from Gen 2 and Gen 3 cars. If you were really serious about rejuvenating the car, and you sound like the type that really enjoys this sort of thing, buy either 2 Prius c or Prius packs or a Camry Hy pack. Buy the newest you can find at a price you can afford. Transplant the modules into your Gen 1 pack. Do a complete balance and recondition cycle of charging/discharging. Sell off the excess good modules to offset some of the cost.

Next option, just buy a new pack from Toyota for about $2200, I think they go for.

 

My HV battery is still fine, but I see companies in Phoenix offering reconditioned Gen 1 batteries for $650 with a six month warranty. Installed. They take the old core. $50 extra for each cell in the old core that is not able to be reconditioned.

I also see a lot of totalled Gen 2 and 3 Prii that the batteries could be salvaged from. I don’t know how much the owners would want for just the battery, but I’ve seen whole cars offered on Craiglist with the front ends completely gone for $950. It also depends on how savvy the owner is about the value of their HV battery.

So, if you’re good with a wrench and safe with electricity, what’s the best low cost option for the Gen 1 owner needing a HV battery replacement? Get a reconditioned one with a short warranty? Salvage your own cells (or buy them on eBay, etc) and rebuild your pack? By a Dorman for around $1400. Go whole hog with a genuine Toyota battery with an excellent warranty and feel the pain in your wallet?

 

Definitely not.

Yes, as a cheaper option. At least you know what you are getting.

No.

Definitely not.

Best option.

The question you have to ask yourself, is how much are you willing to put into an old car?

The other question you have to ask yourself, would you continually buy used tires with 3/32" tread?

Batteries are the same. They are a consumable and best is to replace with new.

 

I think your question is extremely valid. Why would someone buy reconditioned - used or refurbished cells when they could just buy new? The answer is pretty obvious for Gen 1 cars. They're overall value does not support the installation of a $2200 battery. And this whole discussion started as one for reconditioning cells. By the way - the re-hydration method sounds like it works to a point, but it scares the hell out of me to drill holes in batteries.

My 2002 has 115,000 miles on it and I consider that low. There is no way that my car would ever be worth $2200 more with a new Toyota battery installed. Would I have greater piece of mind? Absolutely. Would I ever see the return on the investment - maybe if I drove it until 300,000 miles or so.

If I was totally in love with the car to a point where I could never see myself parting with it, I think I would be willing to pony up for an OEM battery. Maybe a stator replacement. But you'll never see the money again.

I restored a 1966 Triumph Spitfire out of love. I also have a 1998 Boxster gathering dust in my garage that I again am willing to spend my time and money on because I love the car and the fun of wrenching. And if you think driving an old hybrid has it's risks, look up Intermediate Shaft Bearing failures on google about the Boxster.

 

Hi all...and especially Bob ...
Yes, the 'method' of rehydration ...and the method I used to seal the cells works well and is very easy to do.. drilling into the top of the 'hump' is easy ...just take a dremel and cut a hump off one dead module (make sure it is sitting vertical so no battery chemicals get slung out of cut slot.--and please use goggles)...that way you get to see how thick the plastic is, and can put a little collar on the drill bit so it only just goes through the plastic , no further even though there is about 1/8" or more clearance to cells. If you have a drill press its even easier., you can set the depth. The 3 ml dist water is about right and once all are injected just use the higher wattage pencil iron (mine was about 40-60 watts) and smoothly blunt the tip on a grinding wheel or just sandpaper....then clean it with a wire brush.
When it gets good and hot , it will make it easy to mash around the little 1/16 hole to close it , then smear smoothly across the top of the hole and it seals it very well.... nothing scary at all. Maybe I can gets some pics of the process.

Now reality...

Bob was really , really nice in bringing me his old pack that had been sitting for about 10 years, and I was able to cycle enough modules to get the car going again and get us through the tough period of taking care of mom in law. Now wife can , and is working again and is why we was able to get her a nice 2011 Prius 3.

...but the 2002 is nearing 300,000 miles on it (has all new tires and replaced abs booster), but I get an occasional hv battery leakage detected alarm which can be coming from the MG1 which bothers me.. If that is so, the car is definately not worth restoring. It doesnt rate , at these miles, any rebuilt, new or even a high quality pack, but may make someone a good car for maybe another year or so if I can find 7 decent gen 1 modules.
This will only allow me to either trade up or sell this car and just get into a gen 2 or 3 so I can always buy much fresher modules as I need them to keep it alive. This old Prius, even though it has been somewhat a challenge, has made me to not want anything but a Prius...especially since I can fix batteries. It was a skill learned right here . I cant fix transmissions on Escapes, but if i can get decent modules, I darn sure can fix a main battery in a Prius....so since the ICE and surrounding car is well built, the main is the only really maintenance part of this car, which makes it perfect for my route work..and affordable to repair.

BTW, the Falcon and hvhybridparts are one and the same... It is their ebay and Amazon presence....but I have been trying for a week and a half to buy 7 modules from them . Got them (or whoever answers ebay messages) to quote $32 each for 7 cells shipping incl....and made them an ebay offer (as he suggested) , but in a day and a half, they have neither accepted nor replied....

The one module I did buy from them was exactly the size of the gen one....but had the silver inlays (I'll have to post a pic)
and was a quality module looking like new. This is why I hoped I could get the modules from them, but to be honest, with such a lack of communication, not answering phones, and not so hot reputation in this forum, I am getting cold feet with those guys.

Looks like I will have to just find what I can to patch up the pack as I cant drive the old Gas hog Explorer on this route for very long...waaaay too expensive .

ebay may be the only source to find 7 modules ...at least for now.

When I do get the 2002 back on the road, I''l either trade up or sell it outright and find me a gen 2 or 3 with a known battery problem (if one can be found) so when I yank the pack out, I can go through it thoroughly and end up with a really reliable and fixable car.

 

You could try @ericbecky or @jeff652 at Hybrid Automotive. They sell quality modules, but not sure if they have Gen 1 as they are so old, but they will have plenty with the silver inlays that I'm sure are 2004-2009 modules.

 

Hybrid Automotive only list 2004+ modules.

Replacement Toyota Prius Module - Hybrid Automotive

 

What about Greentec?

2001-2003 Toyota Prius Hybrid Battery,

Remanufactured with a one year warranty (the same as Toyota) $1050.

2001-2003 Toyota Prius Hybrid Battery,

New generation cells with a 36 month warranty $1950.

 

All remanufactured batteries are just failed batteries repaired with modules from other old or failed batteries. Companies rarely take the care to match modules. Some even mix module generations. Even fewer test for even charge and discharge curves.
For a 36 month warranty I would expect the battery would need replacing three times or more during that period, inconveniencing you each time. Some battery warranties do not cover installation charges.

 

If you want to pursue this direction, I suggest you start your own thread, or tack onto a more appropriate thread.

Discussion on this thread is about battery rehydration and your questions are off-topic.

 

Sorry I bothered.

 

I think I am going to try this, I have a whole bunch of bad batteries.
Should be fun to refurbish...

 

I have a 'good' battery (except the battery ECU burnt out) which I plan to refurbish. However it works fine without throwing codes or anything.

I also have two complete battery packs (also NWH20); one was 'I bought a good battery but it turned out it was the inverter so I put the original back in and sold it'. This battery cosmetically looks much better than my working one, but has four blocks which each have a dead cell somewhere (a 1.2v cell which has the ability to charge and discharge in approx 30 seconds under low load). I have another pack with Techstream readout done at Toyota; this has a definitive bad cell and was from a more trustworthy seller. I am going to swap this one into my car for initial diagnostics and see if it has just one bad cell, or worse (given the techstream snapshot showed voltages, and obviously not actual charge capacity.

I am going to see if I can fix modules which are considered a 'total loss' (e.g. with one cell in the module discharging in 10 seconds when connected to the car, and when the car is only consuming maybe 300W from the hybrid pack).

So... Does anyone know what specifications are needed for the potassium hydroxide? I have found 99.5% analytical grade KOH powder for sale; about $10 US for 1.5 kilograms. Have other people been using special 99.99% grade or is it possible that 99.5% grade is good enough?

 

Coming back to this thread; I see my reply doesn't make complete sense. I was reading another thread where a member put a hydroxide (sodium or potassium IIRC) solution into the cell. However, I like the idea of distilled water in the first instance. Of note, the truly good battery, with one failed cell, mentioned in my post above, gave off a 'hissing' sound after I did a forced charge. That battery is legit, from a low mileage car (90,000km). The hissing sound was interesting, because it 'started' and 'stopped' in stages, as if several modules were venting at the same time. The safety valve, while useless, may actually occasionally vent gases, and this may be why we have to rehydrate (because, literally, the hydrogen + oxygen periodically vents out, slowly draining the water.

I'm still using my original battery but I found that with full throttle up a mountain I could get 0.7 volt delta, and with hard regen, a 0.4 volt delta. So one of the modules in that one is 'going out'. Interestingly I get 0.07-0.12 volts delta during normal driving every day, commuting, including big hills that fully charge the battery (and more), meaning that my battery is likely to 'fail' for highway driving, but then last a lot longer for normal city driving. Work has been so busy that I've had little time to do anything, but I will look into rehydrating the one bad module in that good battery at some stage the next 3 weeks, and post back here with the results (good or otherwise!)