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Discussion Starter · #1 ·
A detailed walkthrough on how to charge/discharge and cycle your old lazy CRZ Nimh IMA battery to restore some performance?

It's a well established relatively inexpensive maintenance technique used successfully for many years on the other Honda Nimh IMA cars.

I'll do a text/video guide for the process/equipment/connections if there is enough interest.

Note. The IMA battery does not have to be removed from the car to carry out this process.

Have a safe Christmas. Peter UK

PS If something already exists along these lines please let me know.
 

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Sure why not.
I'm guessing it's similar to maintenance for smaller packs in consumer items where an occasional full discharge/recharge cycle is good for them, just on a larger scale. Maybe a few good blasts in Sport mode to run the pack down followed by allowing it to recharge?
Waiting to see if I'm close or way off base.
 

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Discussion Starter · #3 ·
Pretty much.

Doing what you suggest certainly won't harm the pack and it will work better when it gets warmer.
But you won't recover lost capacity or properly rebalance the pack.

To get the rejuvenating effects from balancing and cycling you have to gently push the battery way outside the limits the car will allow during driving.
I'll detail it all in due course.
 

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Discussion Starter · #4 ·
I could do with some decent pictures of the rear inside of the boot/trunk in particular over the IPU fan area in the rear right hand side back of a complete car.
Mine is all in bits with the trim out so I don't know what is accessible etc when the car is intact. Can anyone oblige? Thanks.
 

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Ok well at least I was partially right. ;)
Waiting to see the rest, probably not doing anything much here until warmer weather and currently I don't have reason to suspect any serious battery issues.
For those of us who have access to an HDS, can you post some numbers from the IMA section that might help determine what shape the pack is in before diving into this process?
 

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Ok I'll take a look at that next time I'm in there. So far I only had it connected once after I got it working and now it's too cold to be out there playing with it.
 

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Discussion Starter · #8 · (Edited)
Some preliminary work...


Testing a full pack grid charge on the bench.


I'm using two of the 12-18w model with the outputs in series for about 130V peak.

 

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Discussion Starter · #9 ·
Some IMA battery 250ma grid charging test results.

1) With the blocked battery case vents and an ambient temp of about 10-15C the internal pack temp rose to around 42C after 24hrs.
There was also a 10C temperature variation between upper and lower sticks in the pack.
IMO This would not be acceptable in higher ambient temperatures as the temperature would certainly rise further.

2) With the battery vents unblocked and relying on natural convection the temperature stabilised about 6C lower at 34C.
Again there was some temperature variation between upper and lower sticks.
IMO this is slightly marginal for use in higher ambient temperatures so not recommended.

3) With a 12V 1A fan pushing air into the exhaust vent the temperature rapidly went down and was well within acceptable limits.
So in the interests of cell life and peace of mind a low current fan gently moving air through the ducts will be needed.

As has been mentioned a fan can be temporarily duct taped or cable tied to the exhaust vent behind the passenger seat for the charging period.
Suitable 12V computer fans are ten a penny and can be run from wall wart power adaptors very simply.

If you have an HDS you can temporarily stop charging, plug in and check the battery temperature after say 12hrs if you are at all concerned.
 

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I'd post a pic of my boot area, but I have a 2013 with the OEM Lithium pack, so i would be slightly different layout.
BTW, I'm using a grid charger and deep discharger on my 1st Gen Insight to keep its IMA in good shape, but wish there was a similar set up to use for the Li Ion pack of my CR-Z. :)
Nice work, and I appreciate your contributions!
 

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I agree with what litz says. Nice work. Makes me want to give this a shot also. Would you recommend going to the next lower wattage power supply to reduce heat buildup? What was the final resting voltage of your battery pack? Good stuff for those of us with older CRZ's that may need some unknown maintenance.
 

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Discussion Starter · #12 · (Edited)
The final voltage depends a little on the battery temperature, a hot Nimh battery will have a slightly lower temperature than a cold one.
Mine was at about 118V. I need to check the tap voltages to see how well balanced the pack is.

The cheap led power supplies don't come in less than 250ma or so constant current output.
CC (Constant current) is the important bit.
If you have a posh CC power supply that can deliver less current then cooling will be less of an issue, but balancing will take longer.

Whatever CC power supply you get it must also have sufficient voltage capability to charge the pack.
About 130V or so is fine for the Nimh CRZ.

When the pack is completely full the cells burn off the energy as heat.
That equates to about 36W of power with the supplies I used that has to be absorbed/dissipated in the confined battery space.
The little fan is the simple solution to stop heat buildup. Especially if the ambient temperature is higher than the chilly UK.
 

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A detailed walkthrough on how to charge/discharge and cycle your old lazy CRZ Nimh IMA battery to restore some performance?

It's a well established relatively inexpensive maintenance technique used successfully for many years on the other Honda Nimh IMA cars.

I'll do a text/video guide for the process/equipment/connections if there is enough interest.

Note. The IMA battery does not have to be removed from the car to carry out this process.

Have a safe Christmas. Peter UK

PS If something already exists along these lines please let me know.
Absolutely! Count me in!
 

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I would also be very interested in this write up, as it appears I have a tired NiMH pack on my 2011, complicated by a previous owner that rarely drove the car and installed lots of aftermarket battery draining accessories (just finished pulling most of them out and installing a new, larger 12V battery). What I'm seeing now is 0 or 1 battery bar on cold startups that sticks around for a minute or two. Within a few minutes of driving the car the bars will be back at 75% or more. I'm hoping this regen process will help with this issue.

I'm new to the IMA system but if you still need some photos of the battery in the hatch area let me know and I'll snap some. Thanks!
 

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Discussion Starter · #15 ·
I'm new to the IMA system but if you still need some photos of the battery in the hatch area let me know and I'll snap some. Thanks!
I am interested in if you can get access to the IMA battery (Remove the cover etc) without taking out the side trim.
If you want to investigate that it would be useful. You will have to ease up the trim behind the seats/bulkhead to get the cover out.
There is a bolt down in the main switch area as well. Please take pics as you go. Thanks
 

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Discussion Starter · #16 · (Edited)
Hopefully this video when viewed in conjunction with the others in this thread and the accompanying notes
will be detailed enough for people to charge or cycle their own CRZ Nimh packs.


Basic requirements.

1) Rubber gloves. (To be worn at all times.)
2) Tools inc trim clip remover.
3) Dry & cool working environment with access to mains power.
4) E-Bay constant current LED Drivers with combined 130-140V output at a ~200-300ma
5) 12V 0.5A minimum cooling fan or equivalent for mounting on IMA air vent.
5) 60W 120V minimum incandescent bulb mounted on a secure insulated support. (Bulb only required for discharging)
6) Insulated miniature crocodile clips and wire.
7) Time and care.

Process. (Simple Charging)

1) Remove sufficient trim and carpet to gain access to IMA battery.
2) Turn main switch off.
3) Remove IMA battery metal cover.
4) Mount 12V cooling Fan to IMA exhaust vent and block off the rest of the grille.
5) Attach grid charger to IMA battery.
6) Turn on main IMA switch.
7) Turn on mains power.
8) Leave to charge for 24hrs ensuring cooling fan is running at all times.
9) Turn off mains power.
10) Turn off main IIMA switch.
11) Disconnect charger
12) Reassemble IMA and turn on main switch.

13) Reset IMA system by disconnecting 12V battery lead under bonnet for about 20 seconds.

Note. If you have an HDS or OBDIIC&C you can set the SOC to 75% (High) using that instead of disconnecting the 12v battery.
You should also reset the usable battery capacity to the maximum using the HDS or OBDIIC&C to restore lost capacity.

14) Start car and allow to idle for a few minutes, then drive as normally.

If you battery has not recovered or still performs poorly then you can try cycling using the discharging process below.

Process. (Simple Discharging using the bulb)

1) Charge frist for 24hrs (See above, unless you have just already done that.)
2) Turn IMA switch off and disconnect charger.
3) Attach 60w bulb.
4) Turn IMA switch on bulb should light up!
5) Leave until it goes out. (The longer it takes to go out the better)
6) Turn IMA switch off, disconnect bulb and leave for 1hr.
7) Do charge process as previously described for 24-30hrs.

If the IMA battery does not recover after cycling as above then it requires much closer inspection and may be beyond help.

Good luck.

Please post questions in this thread and not on YT.
 

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I am totally intrigued by this as I think my 170k mile, 2011, battery back probably could use a little help. I like this idea. Thanks for the plans!!
 

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Discussion Starter · #18 ·
Something I forgot to add/mention today but will do tomorrow, is demo install a charger socket so you don't have to remove the ipu cover etc the next time you want to charge the car.
 

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Discussion Starter · #19 ·
Lets only take the IMA apart once! (y)

Adding a power cable connector for future easy IMA battery access.


Notes.

Rubber gloves. (To be worn at all times.)


Switch the IMA battery off before installing.
Use a proper 150-200V rated connector with shrouded pins etc. I use the Sp13 series connectors.
Use decent double insulated cable and heat shrink the connections.
Switch the IMA battery off before plugging or unplugging the charger or discharging bulb.

SP13-2 2 pin waterproof connector Power Cable Connectors IP68 Plug Socket WH W2 | eBay

62955
 

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Any idea on what it would take to power the actual IMA fan from the mains? I feel like having a 12v transformer with a pwm would be the optimal setup, but at the same time I don't really know how to work with the fan's four pins, and I'm kind of afraid of actually damaging it.
Also, thanks for posting this thread! I've been looking for something like this for some time now.
 
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