Hey guys. So a little background, I build hybrid battery packs for a large company out here in California, I will remain anonymous for the time being...anywho, I’ve probably done about 20 packs for the Yukon/Cadillac/Tahoe models, and I haven’t had any problems, since I did my first 2.

Last night, I assembled an entire battery pack Out of a core that we keep at the shop, did a voltage test on the pack after completion and it read 298 volts. All the modules I put in the pack average roughly 7.9 volts across the board. 7.9x40 totals 315 volts, which shows me that somewhere that 1 cell block (2 modules worth of voltage) is being lost somewhere. Nonetheless, I rechecked EVERYTHING. Every busbar is present. Every busbar nut is torqued to 50 inch pounds, per protocol on every battery I do. All modules are balanced between 5.8A-6A between the pack of 40 as per my equipment readings. All modules are tested with a megohmmeter grounded to the case to weed out high voltage leaks.

Against my better judgement, I let the pack go this morning with my installer to go do about 5 jobs in Southern California, thinking I was just tired and delirious.

He does the install, pops the hood to reattach the 12v ground, and it fires up, engine idles. Then, as soon as he closes the hood, the vehicle sounds like it’s misfiring, then the gauge goes to autostop and the vehicle dies.

ZERO CEL, no warning lights, nothing. As long as the hood is open, the car runs and idles.

Battery was not bad before replacement, but customer wanted it done as preventative maintenance because the dealer told him it would be done soon.

any ideas would be helpful. I am starting to think there may be something wrong with the HV power leads that go to the Orange plug, for why the pack is not giving me 315 volt. Any input is appreciated. If I can’t figure it out, I may bring home the customer’s original pack and do a side by side comparison.

These packs are finicky. I absolutely hate doing them, although they seem to be very easy to install in vehicles and disassemble and reassemble.

 

Sure you didn't flip a single module around? You'd lose ~15V that way.

You read the 20 block voltages?

No idea on the hood.

 

I’m gonna peak again tonight and if I did that I’m going to feel like a complete jackass. But all the bottom module bolts went in properly if I remember correctly so I think i did it right. My tech of course forgot his scan tool so he couldn’t see voltages. Customer was nice enough to let his car sit for a few days so we could take his old battery to compare as well.

 

I've only done a handful. Hate them more than a big fat hatey thing. My last one was a Yukon, and I boneheaded it by orienting the modules like the Prius. Fortunately, the fact that NONE of the bolts would go in was a quick clue.

If you had any modules that came out of Dorman cores, I don't know if you've seen this, but they have started moving the threaded insert to the other end and potting in the leaking hole. They could have tricked you!

When I see those, I don't care how good they test. I fantasize about punching a Dorman baby and then toss it in the core pile.

 

funny you should mention that. I just had to explain to my battery builders that they do that. I figured when I put the vent tube on that I would’ve noticed myself as well, how weird

Dorman sucks.

funny I actually learned a lot from you from your posts on PC, years ago when I was learning on my own. I owe you a beer.

I’ve got a room full with 15 stations of RC quad chargers and cooling tables. 15 x28 (quad is 4 individual channels per charger). And 3 prolong pro thunderbolt units. You wouldn’t believe it if you saw.

 

Congrats. Happy to "help." I keep it small, and I pretty much won't even attempt to recondition anything but a Gen2 Prius. I have NEVER found a GM, Lexus, Camry or 2010+ Prius that has more than 1-3 end modules even close to my minimum standard.

They seized my content. I removed a lot of the stuff after I decided to stop supporting the site owners/moderators financially, and they banned me and restored from backup. Oh well.

 

You’re pretty spot on about cores. GM’s are by far the worst. The closer to 2015 on the GEN 3’s the better they are. Older camrys can be good too, they just typically fail later. They suck.

And mixing gen 2/gen 3 packs are no good unless you can prove internal resistance is comparable.

curious as to see what your minimum amperage threshold to let modules go is. I’ve had packs on the road approaching 3 years now...if you do it right, they will last!

 

I have done ONE 2015 Prius, and it was actually in reasonable shape. IMHO, it was because it was a privately owned Discount Cab that had 170K miles on it in 2 years - A/C always running, and it never got hot, but it clearly had a hot "zone" due to the sh!te cooling system in the Gen3.

I have packs pushing 4.5 years, and I have some turds too. I've had a handful of "dumbs" where I made a clerical error and misidentified a module and didn't catch it until install or a month later, but that hasn't happened for a few years. My goal is to build a pack with a good potential to last 3 years. Warranty rate is about 5%, and I've only had a handful of return customers. For the last 3 years, every failure I've seen of one of my packs doesn't have an explanation. There is no clue in the data as to why they failed. I figure I'm at the "**** just happens" level of the process, so I stick with it.

I've started experimenting with how monumentally crappy I can build a pack and run it in my black Gen2 (black ones destroy their batteries here - never had a core yield a usable build). The current one I have in my car performs better than one of those horrifying cylindrical cell packs the Chinese are forcing on the builders. In 4 months, it lost 40% of its capacity, and at 2 years, it leaked like a "D" cell you leave in a flashlight too long.

P0AA6 is rampant here. I don't even try to put those back in service ever. Every single one came back before I realized what was happening. There was about 6 months where I was putting them back in service, and every one of them leaked again between 3 and 9 months.

I'm still shocked by a 200K mile 2004-2005 Phoenix core that kicks the **** out of anything else out there. I love seeing E, F and the occasional G in the 4th place.

Note that I haven't answered your question.

Good luck. Glad to see someone making a legitimate effort vs. the Craigslist module swappers.

 

04-05 are the best!!!! I bought myself a Megger that i use to test every pack before I leave...I am out in Phoenix to see my lady quite a bit. If you ever need a hand or want to take me up on that beer, let me know!

will updated your when I open these Tahoe packs tonight.

 

AZ isn't the best place to go out for a beer right now...

Maybe next year...