Ideas for better cooling the IMA battery in 2003 Honda civic hybrid.

[S Keith]

Originally Posted by Matt04

I have tried that, but blasting the A/C makes the car use the battery more, thus shortening the battery life.

I believe where you love is hotter. However, I just put in new Bee max sticks 2 years ago and 9 already went bad. All the sticks in the center of the pack went bad. I believe it is because they get hotter then the sticks on the edges.

The bolded portion is about 99% wrong. The A/C compressor is strictly pulley driven. It has no electric motor like the 2006-2011 Civic Hybrids. You will get lower mileage because you are using the gas engine more, but it doesn't use the battery more to any significant degree.

Rule #1 with Hybrids: If you aren't cool and comfortable, your hybrid battery is potentially sustaining damage. NEVER spare the A/C.

I cooked the **** out of an HCH2 battery driving in AZ summer heat without A/C. Went from working very well to completely crapping out in a couple months.

Heat is the #1 killer of these things. The Honda "D" cell form factor is highly susceptible because they have the worst cooling characteristics. Run your A/C as much as is needed to keep you cool and comfortable. That's all you need to do concerning your fan speed. Blowing hot air over a hotter battery is not beneficial.

Pursue all recommendations that serve to minimize interior heat.

You are driving a car with a poor design. I've owned 2X HCH2, and I currently own 2X G1 Insights. Honda dropped the ball. Toyota figured it out after the Gen0 Prius in Japan used the same "bamboo sticks" the Hondas used... they sucked. Toyota moved to the prismatic module that everybody but Honda uses. Honda stuck with it and it only got worse.

Since you've mucked about with your battery, make 100% certain you installed it correctly. You need to have a good seal between the battery and the inlet, and you can't have any leaks around the IPU cover. Without a reasonably air tight seal around the IPU cover, you're going to suck air in through it and the cooling air won't enter through the battery.

Lastly, the HCH1 fan is PWM controlled. The ECU monitors the signal. If you alter it, you will need to spoof the ECU to provide the expected signal.

[Matt04]

I will make sure to run the A/C an appropriate amount. I understand that the compressor is belt driven, but the IMA kicks in to help the car accelerate went the gas engine is under the extra load from the compressor. I understand what everyone is saying about keeping the cabin cool though. I think I'm going to get the windows tinted as well as run the A/C to keep it cool.

Thank you for all the advice.

[S Keith]

You'd be surprised how little extra the IMA battery gets used with A/C use.

If you don't have one, get a sunshade for the front window and park to maximize how much sun it blocks for a given period (typically park facing west, so it will block the afternoon sun.

Crack the windows 1/4".

[roflwaffle]

Heat will without a doubt kill batteries faster, but too much current and heat plus high state of charge is what you really, really want to avoid. That's what was behind Honda's recall of the 2000-2004 Insight BMS/etc.

http://www.driveaccord.net/forums/at...3&d=1214150325

What is the problem?
The integrated motor assist (IMA) system in your
vehicle assists the gasoline engine for better
acceleration. Over time, excessive overcharging cycles
of the battery that powers the IMA system can cause
early deterioration. These cycles are typically created
by operation of the vehicle in unique topographical and
local conditions where the IMA battery typically
remains fully charged.

[Matt04]

Originally Posted by roflwaffle

Heat will without a doubt kill batteries faster, but too much current and heat plus high state of charge is what you really, really want to avoid. That's what was behind Honda's recall of the 2000-2004 Insight BMS/etc.

http://www.driveaccord.net/forums/at...3&d=1214150325

Ill keep that in mind. I live on top of a small hill, so my battery is usually under 50% when I turn it off for the night. I was think this was bad for the battery, but from what your saying that is good.

[S Keith]

The SoC gauge is a rough approximation of the state of the battery. It's not really a good indicator of 50%. IIRC, it's highly skewed. Where you're sitting is likely a lower state of charge than 50% due to the climb home.

To give you an idea of what batteries like, the Prius aggressively maintains a 60% SoC. If you go higher due to regenerative braking, it will favor a little more EV assist. If it's lower than 60%, it will lower EV assist and favor background charging to bring it up.

In short, the less your battery SoC gauge moves, the better.

[Matt04]

Originally Posted by S Keith

The SoC gauge is a rough approximation of the state of the battery. It's not really a good indicator of 50%. IIRC, it's highly skewed. Where you're sitting is likely a lower state of charge than 50% due to the climb home.

To give you an idea of what batteries like, the Prius aggressively maintains a 60% SoC. If you go higher due to regenerative braking, it will favor a little more EV assist. If it's lower than 60%, it will lower EV assist and favor background charging to bring it up.

In short, the less your battery SoC gauge moves, the better.

I did not realize the SoC gauge was inaccurate. It is such a bummer that I live on a hill. I should be moving soon and hopefully Ill be more on level ground.

[S Keith]

The problem with NiMH chemistry is that voltage is a poor indicator of SoC, and it's also temperature dependent. Can't remember if the hCH1 does, but the Insight actually counts current in and out to try and further refine the estimate.

The car is reasonably smart. A long sustained climb that pulls the SoC down is going to have the car decreasing the EV assist until it reaches 0 to protect the battery.

[samwichse]

Originally Posted by S Keith

The bolded portion is about 99% wrong. The A/C compressor is strictly pulley driven. It has no electric motor like the 2006-2011 Civic Hybrids. You will get lower mileage because you are using the gas engine more, but it doesn't use the battery more to any significant degree.

I 100% disagree. Not about the pulley-driven thing, but about the IMA use. Using your HCH1 with the A/C will flog your battery hard. It's almost impossible to keep the damn thing from assisting without A/C, with it on it's hard to keep it even from forced background charging.

As for keeping it cooler... you can always pull a Mike Dabrowski and run a duct from your rear A/C footwell outlet(s) directly to the IMA fan intake:
http://99mpg.com/mikestips/insightbatterypack/

Pictured is a gen1 insight, but you get the general idea.

[Matt04]

Originally Posted by samwichse

I 100% disagree. Not about the pulley-driven thing, but about the IMA use. Using your HCH1 with the A/C will flog your battery hard. It's almost impossible to keep the damn thing from assisting without A/C, with it on it's hard to keep it even from forced background charging.

As for keeping it cooler... you can always pull a Mike Dabrowski and run a duct from your rear A/C footwell outlet(s) directly to the IMA fan intake:
http://99mpg.com/mikestips/insightbatterypack/

Pictured is a gen1 insight, but you get the general idea.

I agree, running the A/C causes the IMA to give more assist.

That idea from Mike is a great idea. Not sure if my wife will go for it though... I am hoping that getting the rear windows tinted and running the A/C an appropriate amount will help keep the batteries cooler then last summer. I'll also probably use the HCH less in the summer an opt to driving my other car more.