superhawk996 Posted March 11, 2021 Share Posted March 11, 2021 One of the environmental negatives people talk about with the Prius is discarding the traction battery when it goes to shit. I've been babying this one along for quite a while by replacing modules as they fail. The skinny grey things are called modules, a six cell NiMh battery pack, and there's 28 of them in series to make a nominal 202V. In the photo they've been rearranged so I could easily put them in parallel for experimental conditioning. The typical failure is one cell in the module goes bad and that's enough to piss the car off and it becomes super shitty. After several rounds of module whack-a-mole I decided I was giving up and was about to go buy a new battery, but then I decided to give it one last shot. New modules aren't available other than buying a whole battery so every time one takes a shit I buy a used one on ebay and just stick it in. The 'proper' way is to balance all the modules when one is replaced but that takes special equipment or a fuck load of time with minimally specialized equipment. Ideally the modules would all be cycled a few times, charge and drain at least three times. With what I have available that would take about a month of vigilant work to keep from killing them so I've decided to just hold them all in parallel with a mild charge to possibly balance them. In theory holding them at a fairly high voltage for a long time will let the weaker cells get a better charge and even out to the stronger ones. In normal use they're constantly charging and discharging and are never fully charged or discharged to make them last longer. When one cell gets weak it gets less charge making it weaker and eventually it's just fucked forcing a module replacement or some kind of reconditioning to possibly resurrect it. When the first one went bad I looked into buying a new factory battery and they were close to $3k. There's a bunch of cheaper options from new aftermarket modules to professionally reconditioned old modules. I re-checked prices a couple days ago and found I can get a new OE battery for $1560, that's what really had me close to pulling the trigger. This is going to be my last effort with this battery. If it works I'll be getting a proper NiMh charger so I can recondition them as maintenance and hopefully keep them alive. The charger is an old NiCad RC car charger. It's designed to charge for 15 minutes at a time and extended charging makes it overheat, that's what the little fan propped up by the light blue thing is for. Because it has no smarts I'm monitoring the voltage, if it starts dropping it's an indication to stop charging. I'm also checking the module temperatures every 13 minutes before resetting the charger's timer back to 15. The only convenient thing I had around to connect all the modules was some thin stainless rods which aren't great conductors so I rigged a few jumper wires to balance out the current/voltage to the modules, it's quite the mess of wires but it's working. Worst case scen Here's the most recent dead module, you can make out the division of the 6 cells. During charging/discharging they can swell up which is why I have them clamped in the battery case. You can see two black rods and there's two more on the bottom. They're internally threaded and there's bolts at both ends to squeeze the whole pack and keep them from bulging. Despite the bolts being pretty big (10mm) if the batteries are stressed hard enough their expansion force can snap the bolts. Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted March 11, 2021 Share Posted March 11, 2021 I got the conditioner kit from Hybrid Automotive when I got the Prius. Charge, discharge, charge once every 6 months. Best insurance against module failure. Quote Link to comment Share on other sites More sharing options...
lordzarkon Posted March 11, 2021 Share Posted March 11, 2021 8 hours ago, superhawk996 said: One of the environmental negatives people talk about with the Prius is discarding the traction battery when it goes to shit. I've been babying this one along for quite a while by replacing modules as they fail. The skinny grey things are called modules, a six cell NiMh battery pack, and there's 28 of them in series to make a nominal 202V. In the photo they've been rearranged so I could easily put them in parallel for experimental conditioning. The typical failure is one cell in the module goes bad and that's enough to piss the car off and it becomes super shitty. After several rounds of module whack-a-mole I decided I was giving up and was about to go buy a new battery, but then I decided to give it one last shot. New modules aren't available other than buying a whole battery so every time one takes a shit I buy a used one on ebay and just stick it in. The 'proper' way is to balance all the modules when one is replaced but that takes special equipment or a fuck load of time with minimally specialized equipment. Ideally the modules would all be cycled a few times, charge and drain at least three times. With what I have available that would take about a month of vigilant work to keep from killing them so I've decided to just hold them all in parallel with a mild charge to possibly balance them. In theory holding them at a fairly high voltage for a long time will let the weaker cells get a better charge and even out to the stronger ones. In normal use they're constantly charging and discharging and are never fully charged or discharged to make them last longer. When one cell gets weak it gets less charge making it weaker and eventually it's just fucked forcing a module replacement or some kind of reconditioning to possibly resurrect it. When the first one went bad I looked into buying a new factory battery and they were close to $3k. There's a bunch of cheaper options from new aftermarket modules to professionally reconditioned old modules. I re-checked prices a couple days ago and found I can get a new OE battery for $1560, that's what really had me close to pulling the trigger. This is going to be my last effort with this battery. If it works I'll be getting a proper NiMh charger so I can recondition them as maintenance and hopefully keep them alive. The charger is an old NiCad RC car charger. It's designed to charge for 15 minutes at a time and extended charging makes it overheat, that's what the little fan propped up by the light blue thing is for. Because it has no smarts I'm monitoring the voltage, if it starts dropping it's an indication to stop charging. I'm also checking the module temperatures every 13 minutes before resetting the charger's timer back to 15. The only convenient thing I had around to connect all the modules was some thin stainless rods which aren't great conductors so I rigged a few jumper wires to balance out the current/voltage to the modules, it's quite the mess of wires but it's working. Worst case scen Here's the most recent dead module, you can make out the division of the 6 cells. During charging/discharging they can swell up which is why I have them clamped in the battery case. You can see two black rods and there's two more on the bottom. They're internally threaded and there's bolts at both ends to squeeze the whole pack and keep them from bulging. Despite the bolts being pretty big (10mm) if the batteries are stressed hard enough their expansion force can snap the bolts. That is quite the science experiment you got going there Had no idea all the that was in there, and the sensitivity of those battery packs Thanks for sharing some cool info Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 11, 2021 Author Share Posted March 11, 2021 4 hours ago, Zero Knievel said: I got the conditioner kit from Hybrid Automotive when I got the Prius. Charge, discharge, charge once every 6 months. Best insurance against module failure. They have a few different kits from just charger to charger/discharger combos; which one did you get and how much $? Do you have to open the case every time or does it plug in externally? According to them and some tests I've seen you'll only get great results if you do a few charge/discharge cycles, but charging alone helps. Quote Link to comment Share on other sites More sharing options...
tomek Posted March 11, 2021 Share Posted March 11, 2021 How old and how many miles on Prius ? Quote Link to comment Share on other sites More sharing options...
SwampNut Posted March 11, 2021 Share Posted March 11, 2021 What's it like reaching that battery? I've never thought about where it is in the car and how it gets removed. Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted March 11, 2021 Share Posted March 11, 2021 4 hours ago, superhawk996 said: They have a few different kits from just charger to charger/discharger combos; which one did you get and how much $? Do you have to open the case every time or does it plug in externally? According to them and some tests I've seen you'll only get great results if you do a few charge/discharge cycles, but charging alone helps. I got both. The discharger makes it idiot proof. Hit a button and let it drain until the alarm sounds. Otherwise you're fooling around with bulbs of various wattages to manually drain down the battery. You have to access the battery ONCE to attach the harness. Basically on + on one end and - on the opposite end of the series. From then, you just plug it into the device you're using because it leaves a pigtail that you fiddle with. It also powers the cooling fan during these times so no overheat happens. I believe it was a tad over $600 at the time I got mine, and they claim it can rehabilitate a bad battery since the "failure" is more one of the battery cell losing its memory over time as the Prius never lets it charge to 100% long enough to equalize all the cells and the system never lets it go down to near zero. So, the limit of, let's say, 95% to 20% gets embedded and then the cell is going only to 95% and 20% of the new upper and lower limits until the cells can't hold a charge. Forcing the whole series to near zero charge and then trickle charging until all cells get to 100% keeps this from happening. Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 11, 2021 Author Share Posted March 11, 2021 2 hours ago, Zero Knievel said: So, the limit of, let's say, 95% to 20% gets embedded Worse than that, it's more like 30%-75%. But if the car allowed 1-100% the battery wouldn't last for shit so it's a good trade-off. It would be nice if the car would cycle them once in a while. Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 11, 2021 Author Share Posted March 11, 2021 4 hours ago, tomek said: How old and how many miles on Prius ? 2005 with about 220k. The first module failed on the previous owner about 2 years and 20k ago. Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 11, 2021 Author Share Posted March 11, 2021 4 hours ago, SwampNut said: What's it like reaching that battery? I've never thought about where it is in the car and how it gets removed. It's behind the back seat forward of the spare tire. In factory condition it takes about an hour to get it out. After the second module swap I omitted a couple couple braces which eliminates removing some interior panels, now it's out and onto the healing bench in about 10 minutes. It weighs around 80-90lbs and is a bit awkward to move/carry. From factory, to remove the modules from the case is also a bit time consuming, now it's about 10-15 minutes to open it and get them out. Quote Link to comment Share on other sites More sharing options...
tomek Posted March 12, 2021 Share Posted March 12, 2021 3 hours ago, superhawk996 said: 2005 with about 220k. The first module failed on the previous owner about 2 years and 20k ago. Well, that is actually pretty good reliability record. Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 12, 2021 Author Share Posted March 12, 2021 22 minutes ago, tomek said: Well, that is actually pretty good reliability record. Overall the car's been fuckin great. My friend bought it used in about 2012 with 89k miles. I went with him to check it out and while I didn't know fuck all about hybrids everything seemed fine. I didn't have much faith in the thing but he wanted it so he did it...and I got his 5 Spd. high pressure turbo convertible Volvo at dealer trade price. I have done all the maintenance other than some oil changes because he lives kinda far and isn't worth his drive for simple shit. Stuff I remember replacing when he had it: the headlights and engine water pump (normal belt driven pump and it was super easy) about 4-6 years ago, also changed the coolant and trans. fluid at the same time. The pump seal was weeping for quite a while before changing it. At one point it developed a problem in the throttle control that was kinda random. We took a gamble and I replaced the pedal assy. since it was cheap and a 50% chance of curing it, but I think it turned out to be the throttle body, he dropped it at the dealer to fix. He also had to replace the 12v battery once, guessing 6-7 years ago. I tested it a few months ago and it was still good. I probably did some other stuff on it, but nothing memorable. After getting it with just over 200k I replaced what appeared to be the factory spark plugs and front brake pads, and later the inverter coolant pump. Suspension and steering feel great and I assume it's all factory which is amazing. The cruise control works sporadically, pretty sure it's the clock spring. The hybrid battery has been the biggest issue, hard to bitch with the age & miles. Some owners bitch about being hit with a $3k bill from the dealer because the battery 'only' lasts 180-220k miles. They don't realize that if they'd bought a normal car they might already be on their second transmission along with a lot of other stuff. I guess it's the idea that a battery is a simple thing and shouldn't cost that much but a transmission costing that is ok. Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 12, 2021 Author Share Posted March 12, 2021 I was initially only going to charge the pack up once, then I decided to go ahead and cycle it. I ditched the crappy stainless rods as 'buss bars' and installed two 10ga. solid copper wires on each side, now the maximum voltage deviation under load is .02v. After several attempts of finding good ways to discharge I found a use for the stainless rods, I'm using one as the load. I was sure it would be too much but no. I'll probably measure the current later, but it's surprisingly less than I expected for a 'short circuit' with a metal rod. The second charge took more juice to get through the bulk of the charge but it was able to reach a higher voltage with less amperage, I think that's a win. It also held the voltage better through the over night rest. Quote Link to comment Share on other sites More sharing options...
SwampNut Posted March 12, 2021 Share Posted March 12, 2021 Well, that tells us what a shitty conductor SS is. I looked it up, the resistivity of SS is 44x (fourty-four, not a typo) that of copper. Also learned brass is a better conductor than copper. Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 12, 2021 Author Share Posted March 12, 2021 44...makes sense. The piece I'm using is about 12ga wire diameter and around 2' long. The spark when putting it on told me it was probably under 20amps, but 'logic' said it's gotta be a lot more. Nope, 15. 15 measly amps with a piece of metal directly shorted out. The target discharge is 43.3 amps so I'm using two plus some headlight bulbs. I'm modeling my charging/discharging on what the Prolong battery rejuvenator system does which many say works wonders. Theirs runs in series and I'm in parallel so I just gotta do a little math. In my theory cycling them paralleled should be better, series makes it easier for the user to balance their battery since it can be done without removal. Quote Link to comment Share on other sites More sharing options...
SwampNut Posted March 13, 2021 Share Posted March 13, 2021 That means that they are also resisting the charge current. That could be intentional, and could be a good thing. Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 14, 2021 Author Share Posted March 14, 2021 18 hours ago, SwampNut said: That means that they are also resisting the charge current. That could be intentional, and could be a good thing. ? Quote Link to comment Share on other sites More sharing options...
SwampNut Posted March 15, 2021 Share Posted March 15, 2021 The resistance could be a "buffer" or fuse of sorts. It may be part of the calculations on how the batteries charge and discharge. Having less resistance isn't necessarily a good thing. Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 15, 2021 Author Share Posted March 15, 2021 If you're referring to the stainless wire, that was something I dug out of my metals collection. The battery uses pretty hefty copper buss bars and heavy gauge wiring. Watching live data while driving I see 60+ amps in and out during hard acceleration/braking. Seems like a ludicrous amount of juice for little 6.5AH batteries, but I guess being fairly short bursts and never too close to max/min charge levels lets them live. The battery revival attempt was somewhat of a bust. The module I installed in place of the bad one was also bad, just not as obviously bad so I didn't notice. I'll replace it and see what happens, if it's still a bust I'll probably buy a new pack. Quote Link to comment Share on other sites More sharing options...
SwampNut Posted March 16, 2021 Share Posted March 16, 2021 I misunderstood the part about that, and thought you removed stainless that they used to replace with copper. Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 16, 2021 Author Share Posted March 16, 2021 The factory set up being series, the modules are arranged left/right with short buss bars connecting every other pair of modules + and -. For the conditioning I turned the modules all in the same direction and ran continuous 'buss bars' I made. First with the SS then copper when I discovered how shitty the SS conducts. With the SS I divided up the charging with several leads to spread the load along the 'SS buss bars' and the voltage variation between modules was pretty big. With copper I was able to put all the charge into one end and never saw more than .02, usually .01v., variation. Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted March 16, 2021 Share Posted March 16, 2021 On 3/12/2021 at 10:16 AM, superhawk996 said: [snip] EVERYTHING posted after this is why it was worth the money to buy the system fromHybrid Automotive. I even held off until after they completed work on the automatic discharger system because fucking with timers, multimeters and bulbs to control the drain rate was a headache I didn’t want. Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 16, 2021 Author Share Posted March 16, 2021 3 hours ago, Zero Knievel said: EVERYTHING posted after this is why it was worth the money to buy the system fromHybrid Automotive. I even held off until after they completed work on the automatic discharger system because fucking with timers, multimeters and bulbs to control the drain rate was a headache I didn’t want. A $700 maintainer vs. a new $1500 battery at 150k-200k miles, tough call. Had I known I was going to keep the car up front and had known about the effects of battery conditioning I would have set it up for that the first time I was in the battery case. I probably wouldn't spend the $700 on something I can do with under $50 worth of stuff, but I would have started conditioning it. Actually, had I known up front I was going to keep it and that I could buy a new battery for $1500 I would have done that the moment I bought the car, and I would have set it up for conditioning. Quote Link to comment Share on other sites More sharing options...
Zero Knievel Posted March 16, 2021 Share Posted March 16, 2021 1 hour ago, superhawk996 said: A $700 maintainer vs. a new $1500 battery at 150k-200k miles, tough call. Had I known I was going to keep the car up front and had known about the effects of battery conditioning I would have set it up for that the first time I was in the battery case. I probably wouldn't spend the $700 on something I can do with under $50 worth of stuff, but I would have started conditioning it. Actually, had I known up front I was going to keep it and that I could buy a new battery for $1500 I would have done that the moment I bought the car, and I would have set it up for conditioning. See if someone in your area has the kit? You'd have to buy and install the harness part, but you can give it a try without owning the whole kit. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.