I'm a fairly new owner of a 2006 HCH2 with ~175k and absolutely no known service history. I know, I know, but I got it for next to nothing. It's been running great for ~1500 miles, but I just had to replace the 100A fuse inside the IMA and I took the time to check my subpack voltages while I was at it. They look great to me, but I'm also not all that familiar with the HCH2 so I thought I'd see if anyone else could take a look. I pulled the IMA out and it sat inside for ~60 hours before measuring voltage the first time, and then I measured again around ~20 hours later when I replaced the fuse.

~60 hours sitting:
6 - 14: 15.81
14 - 5: 15.80
5 - 13: 15.80
13 - 4: 15.81
4 - 12: 15.79
12 - 11: 15.80
7 - 1: 15.83
1 - 8: 15.78
8 - 2: 15.79
2 - 9: 15.78
9 - 3: 15.79

~80 hours sitting:
6 - 14: 15.76
14 - 5: 15.75
5 - 13: 15.76
13 - 4: 15.77
4 - 12: 15.75
12 - 11: 15.76
7 - 1: 15.79
1 - 8: 15.74
8 - 2: 15.74
2 - 9: 15.73
9 - 3: 15.76

It looks like a spread of 0.05v to 0.06v, and they all seem to be discharging at approximately the same rate. It doesn't seem excessive to me, so I'm hoping I lucked out. Any thoughts?

 

I don't think anybody but a battery chemist could tell you what's normal for your situation after asking for more input data, but as someone who has owned two of these sh!tboxes and 15 of their batteries, your battery appears to be in great condition based solely on those voltage numbers.

Even though you don't appear to have any problems, you should consider preventative maintenance via grid charging.

 

It's on the list of things to do, for sure. Since I have no idea how well the previous owner(s) kept up on maintenance, I've been replacing all of the usual things and browsing through the forum to keep an eye on common issues. I've been following your suggestions in your post on maintenance/grid charging, I've already replaced the coil packs and spark plugs. MM says 80% oil life and it didn't look particularly bad on the dipstick so I'm skipping the oil change for now, but I'll be doing my first CVT fluid change on Thursday with plans for a 3 change flush if the fluid looks remotely bad. After that I'll be assembling my own grid charger and discharger, and I planned to do a charge/discharge/charge cycle to establish a routine. From there, I was planning on checking subpack voltages every month or so and grid charging once a year if no battery issues start showing up, or more frequently as needed. Does that sound about right, or would you suggest a different plan?

A bit off-topic, but since you're the resident expert I might as well ask... I live in a warm climate, and since high temperatures are never good for batteries I was looking into additional cooling for the IMA pack. I saw this thread on the subject and took a look at the OEM cooling setup. It looked to me like there's plenty of clearance below the pack to put fans here without changing the airflow path, and mounting extra fans would make cooling the pack while grid charging inside my house a bit easier. I was planning to throw some high CFM server fans there, is there any reason I shouldn't?

 

Warm? I live in Phoenix. How does your climate compare?

IMA fan is PWM controlled, so you either need to get a controller or get something like a 10A/12V power supply and ground the PWM wire to run it full blast.

I know it's comparatively expensive, but it's done right. The HA reconditioning packages are easy mode. If you haven't read elsewhere, yes, I'm an authorized installer. No, I don't get squat from recommending them. I do so because they are the best value out there. It's also EASY mode. No pulling pack, etc.

The most important thing to keep your battery cool is to drive it conservatively and use the A/C all the time. Keep the center vents pointed so they blow cold air onto the rear deck where the inlet is. Do everything you can to keep the interior temperature lower when parked in the sun. Use shade, covered parking, sunshade, windows cracked 1/4", etc. When you drive away with a super-hot interior, lower all windows for the first few minutes to flush out the hot air as the A/C cools off. I left mine on Auto, 75 deg F and recirc with the center vents dumping air on the rear deck.

Fans on the bottom of the pack will do more to inhibit airflow than enhance when installed. The IMA fan is a freaking leaf blower. The issue with these packs is the complete lack of baffling that was present in prior generations. They staggered the cells. Airflow around a cylinder is atrocious, and all they accomplished is to create a bunch of hot spots on every cell.

As far as a routine goes, 8-12 hour grid charges every 90 days with a 1/year soak charge and discharge to 106V. If your climate is like Phoenix, I recommend TWO soak/discharges per year - one before the hot season and one after - 6 months apart.

EDIT: Peter Perkins at Insight Central has a device that costs about $200 that will pull the 11 tap voltages from the OBDII port to XX.X accuracy (that's all the car tracks).

 

SoCal at the edge of the Mojave, so not quite Phoenix-hot but it's up there with highs in the summer over 110F fairly regularly. I know the OEM fan is a monster, that's why I was planning to use some monster server fans as well, to try for similar CFM levels. Do you know if the car complains if you bypass the PWM control for full speed while the car is running? I don't mind the extra noise and it would accomplish the same extra cooling while driving, and should be fairly easy to undo if/when I sell the car.

I've got sunshades for the front and back, but parking in the shade is out of the question for me. Thanks to all the sand, leaving a window cracked isn't very practical either, I end up with sand coating everything inside. Because of the high temps and parking situation, I was planning to pull the pack every time I grid charge anyway. I'm generally very comfortable working with electronics/wiring/etc so building everything myself isn't an issue, but I'll take another look at the HA kit and see if the cost is worth it for saving my time and effort. It sounds like I should go ahead and plan to soak/discharge twice yearly.

Considering my subpacks were all within ~0.05v of each other already, I don't know how much use I'd get out of that ODBII addon. It seems like my packs would have to get pretty far out of balance before that would tell me anything useful. It's annoying to pull the seat to check, but I think I'd rather have the extra precision. If they start to get further out of balance, I might look into it for more frequent monitoring.

Thanks a ton for all of the info, btw. I think I've got a pretty good handle on where to go from here.

 

Hot enough.

You won't get anything even remotely close to the IMA fan with anything that will fit in the space - even 3 of them. It is an electric leaf blower. The presence of the fans will restrict airflow through the pack when the IMA fan is operating.

I don't know if the car will code. I've played around and shorted it in-car with no ill effects. Running it ***** out will probably substantially reduce its life.

Phx is pretty sandy/dusty. I even have weatherguards on my front windows, which are the most amazing dust/dirt funnels you can imagine. I mean if you WANT as much dirt in your car as possible, they can't be beat.

Even with that down-side, I ALWAYS crack my windows. I can get dirt out of the car. I put my battery health at the top.

When you factor the repetitive pack removals/installs, etc., the ability to simply open the trunk and plug in pays for itself if your time has any value. The unit powers the fan for you, so you never have to worry about it. An effective cooling solution outside of the car is difficult to do unless you construct some sort of duct and channel the bulk of a box fan output on high through the pack.

Full charge/discharge April and October with a topping charge in Jan.

The OBDII unit has the added advantage of displaying real time tap voltages while driving meaning you can see if any of them are going out of whack with discharge/charge. That ability vastly outweighs the extra digit of accuracy with a manual VM check. All to often, resting voltages look fine, but one or more of them starts lagging due to imbalance, and you can actually see when you need to address it with a grid charge.

 

I'm going to skip adding fans and poke around with the OEM fan. Delta makes some pretty ridiculous fans, coming in a little over 500 CFM for a trio and sounding like a jet engine. Judging by the size of the squirrel cage in the OEM fan, I'd be surprised if it does over 300 CFM, but the 38mm thickness on the Deltas would put them rather close to the bottom of the chamber and that's too much restriction for sure. I plan to see if I can get some manufacturer stats on the OEM fan to check the MTBF, but I assume it's similar to other industrial fans. It'll definitely shorten the life, but I'd much rather replace a fan than a battery and it's a part that can actually be sourced used.

Being able to grid charge in-place would save a ton of effort, but I don't have anywhere secure to park and I don't like the idea of leaving the trunk open and an extension cord ran to the car for how long the process takes. The HA kit would be a no-brainer if I had a garage.

I hadn't even considered real-time monitoring the voltages, which seems pretty obvious in hindsight. That does seem like it'd be worth the cost. I assume Torque can be used to log it?

 

I've never been able to find any specs on the blower.

The OBDII reader is custom, and the tap voltages are not reported under a standard protocol, so it doesn't work with Torque.

 

I vaguely recall seeing a post where somebody put a small solar panel on the back deck and used it to power a fan, I think at the air outlets in the trunk, to force air out. That in turn pulled air in and eventually through the IMA, cooling it.

A simpler solution might be to make some sort of filter/shim thingy that could sit between the top of the window and the frame. Just keep a pair in the back seat and place them after parking. The filter material could keep the sand out while still able to release hot air from the cabin.

 

Yep, I've had the same thought, though I was just going to build one for a single side. I tried keeping the two back windows cracked about half an inch, and it went about as well as I expected. The next morning I had a thin coating of sand on the inside of all of my windows, and small piles in tons of places. Most of the yards here are a mix of dirt and sand, there's not much escape from it.

My current plan is to get a piece of black acrylic laser cut to match the window shape with holes cut to mount a filter and a pair of solar fans. It's not quite as secure as a window, but it should be good enough to leave in front of my house. The pair of fans should let me do both intake and exhaust, and if it turns out to not be enough I can assemble a second one for the other side, switching one side to intake and the other exhaust. I'm hoping a black acrylic will be close enough to the tinted windows to not draw much attention, but worst-case they break my fan contraption instead of a window.