View Full Version : Question about battery pack depletion on steep inclines.
04-30-2008, 05:03 AM
I have a 2005 HCH MT with 73000 miles on it. There are at least two hills that I have to go up daily from a stop at the bottom, one with a 26% incline over .3 mile & the other at 35% incline over .1 mile and if I want to keep moving forward on the first I have to be using no more than 3 gear and deplete over 50% of the pack and on the second wind up going up in 2nd gear and deplete 75% of the pack. I try my best to feather back to stop using the assist but if I want to keep moving forward and not block traffic the assist is being used heavily.
I recently had the O2 sensors replaced after a check engine light and that did help some on mpg and the hills. The depletion use to be worse, like nearly 100% on the steepest grade. The pack does recharge back at a fairly decent pace but I am worried about it. It just seems like I am losing too much power both from the ICE and battery pack while traversing these hills.
I realize its only a 1.3 liter engine but I use to have a 1.1 liter engine that made it up these hills easier, but of course I wasn't monitoring an IMA on the way up. Can any of you mechanical and/or Honda knowledgeable people tell me if this is normal or should I be going after my dealership for help before my 100k extended warranty gets any older? Or will they just look at me like I am crazy.
Right Lane Cruiser
04-30-2008, 07:34 AM
The battery usage you see is unfortunately normal. Gearing in your car is relatively high and the engine really doesn't have a lot of torque (hence the electric motor to help out at times). I'll be looking at Laurie's car this month (same make and model as yours) to see if I can use the clutch mod IMA drop out feature in it. If so I can help you get one installed in your car so you can just turn off that side of the mechanism and get up the hill on gas alone.
In the mean time, I know it is a bit extreme but your car will not use assist if you can get the RPMS up in the neighborhood of 3.2K or so. To do this, you may need to attack the hills at a higher speed than you normally do, but it can be done. We discovered this on our cross country run in Laurie's car. Try getting up to a bit over 60mph and drop to 3rd to see if that will do it for you.
Ooh... I just noticed you have to start from a stop. :( Is there a shoulder you can use?
04-30-2008, 08:32 AM
I agree with what Sean has said. If we go any direction other than east, we have to climb out of the valley. It is pretty much impossible to keep off the pack. If you get slow enough you might need to get down into 2nd to keep the RPMs up.
I have just recently put in the Calpod clutch switch in the Insight. Insight Central has a very good article on this mod for the Insight with some good pictures. In a nutshell the switch fools the computer in thinking that the clutch is in resulting in no assist. On the Insight it is in a very inaccessible place for anyone other than a midget.
I will try to determine tonight if the HCHI seems to be the same. Like your HCHI, we also have to be careful with screwing up the warranty.
From what you say, the pack is probably fine. Usually Honda will not consider a replacement if the IMA light is not on.
Right Lane Cruiser
04-30-2008, 08:42 AM
I look forward to hearing what you find out about the clutch switch in the HCH, Wayne! I forgot you also have one. :o
I know what you mean about inaccessible. I'm 6'5" and it wasn't easy to get both hands up where I could work on that area. :eek: I did get a temporary install done but it took me way longer than I had anticipated. :p
04-30-2008, 10:00 AM
I tried looking under the dash for that switch but being 6'3" with a bad shoulder the pain was more than I could bear in that position for more than a few moments. Should be having surgery for that sometime this summer, but still might be an impediment to crawling around upside-down under dashboards for awhile. :) The switch sounds to be a good solution to the assist as long as it is easily removable for at least the remainder of my 25k miles worth of warranty.
Ok well you guys have answered the question that there is probably nothing wrong with the pack or engine. To answer you Sean, most shoulders in PA are a dangerous place to be, hell the roads are barely passable at times. We are known for our lousy road maintenance. The 25% hill does have a decent shoulder but the 35% is more like off road driving on the shoulder. Unfortunately there is no run up to either because of stop signs and one is actually a right turn from the very bottom.
Now what is the long term implications of just continuing what I am doing and using the pack? Is it going to die sooner? And is there any evidence that using the pack for what it seems now, it was designed to do, that it will cause its premature demise?
I will try the high rpms going up to see if that cuts out the assist. Shouldn't be that difficult as I always feel like I should be down-shifting again depending on my speed.
Right Lane Cruiser
04-30-2008, 10:08 AM
The less you use your battery, the longer it will last. Avoiding using the battery also tends to maximize mileage as you don't have to deal with the hit on efficiency to charge it back up later.
I know that the HCH-I with stick has had a few failures of packs reported but I suspect those vehicles had the packs hit harder (as in more often) than you are subjecting yours to.
Try the higher RPM and see if you can't at least get out of assist quicker so the SOC stays higher. Hopefully either Wayne or I can determine if it is possible to do the clutch mod for the HCH-I in the near future.
For reversibility, I'm working on a solution for the Insight that is going to be basically plug and play. I'd imagine the same methods would work in your car if this turns out to be a viable modification.
04-30-2008, 08:24 PM
I looked at the HCHI. There are (2) similar looking switches activated by the clutch petal that are virtually identical to the (1) Insight switch. So hopefully through the process of elimination, we should be able to determine the right one. And the best part they both are much more accessible than on the Insight.
Perhaps we should start a new thread on the Calpod switches even though they are old hat for some.
On the Insight, I did not have a momentary switch so I did not do the brake/boost switch. I’m not sure I will. I’m not sure I would normally use it. I ended up removing one of plastic switch covers on the left in the lower dash to mount the switch. It looks like it belongs there and is easily reachable.
Other than overcharging, I think that the most damage to a pack occurs when it is cycled to complete discharge. So keeping it as full as possible seems to be a rational approach. I wonder what kind of MTBF data Honda has on those packs. I bet that info is not public knowledge. And also it seems that high temps like might occur during the summer climbing hills will also shorten pack life. Perhaps a temp probe with a read out would help determine when the pack is starting to heat up. Can the SGII be programmed to provide that?
05-01-2008, 06:14 AM
In thinking some more, I think the other switch de-activates the CC.
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