Just as an update, the IMA light went off. The engine light stayed on, so I disconnected the 12V battery and reconnected, that is gone too. The autostop came back this morning. Seems like everything works fine.

I thought may be I let it work for a while and see if it comes back on, then change it.

I am still not sure if I can drive it without the IMA battery. I just read somewhere that these cars don't have any alternator, so not sure what happens if I lose the IMA battery altogether.

I am thinking of changing the 12V batter just in case, althogh not sure what brand to buy for HAH 2005. Any suggestions?

 

This reprieve is temporary. You will get another IMA light.

If your 12V is marginal, replacing it will reduce the load on the IMA battery. Personally, I buy the cheapest batteries I can find and have no recommendation besides that... cheap. According to parts stores, it's a group size 35.

The HCH1 & 2 don't have alternators, so I would assume the Accord is the same. The DC-DC converter will still pull 12V off a weak IMA battery up to a point, so as long as the IMA doesn't go very dead, you will still likely have 12V power. You can buy something like this to plug into your cigarette lighter to monitor voltage:


Good luck,

Steve

 

Thanks again, Keith.

I am getting ready for it!

 

Back to the grid charger, I was reading the instructions for HAH 2005 and since there is no pictures of the steps available, I am not sure I understood what the site says about having the fan on and not cooking the battery etc.

Could you please briefly explain what the charging actually entails? I connect it to the batter and leave it there to charge or need to keep the battery cool somehow during the process?

 

I recommend you contact hybrid automotive directly. I am not familiar enough with the details of the Accord to confidently address your question.

The accepted best-practice of grid charging with the IMA battery installed entails running the IMA system cooling fan to ensure there are no heat issues. I believe the Hybrid Automotive grid chargers do this.

If you have the pack out and can monitor it or setup a box fan to blow through it, heat won't be an issue. Personally, with the pack HCH mounted horizontal, where there is a stagnation area at the top, cells at the top were 127°F when the cells at the bottom were 102°F at the end of a soak charge. This is too high for comfort. I addressed it by setting up a box fan to blow through it.

With the IMA in the installed orientation (mostly vertical airflow path), there is less concern because there is no stagnation point and convection can help cool the cells. Again, best practice dictates use of IMA cooling fan if possible. Use of the fan guarantees you will have no heat issues and eliminates the need/worry associated with monitoring temps. You simply check the charging voltage periodically to note when it peaks. Continue charging for about 8 hours past that, and you're done.

Steve

 

Many thanks, Steve!

 

Yes before replacing the hybrid battery, I will check the 12V battery to see the health first. I have this issue before too and I finally pin down to the 12V battery being the issue. Changed it and no lights ever since and the hybrid system worked perfectly.

 

Thanks, Tedson.

Just as an update, I replaced the 12V battery but nothing changed the voltmeter did not show any difference. Then I proceeded to install the grid charger. I charged the battery once and I felt the gas mileage went up by 5 miles. I am planning to charge it again one more time in two weeks.

So thanks for all the advice!

 

Again in two weeks? Obviously, you should go with whatever Hybrid Automotive suggested, but frequent grid charging can actually reduce capacity. NiMH batteries actually develop a condition due to over charging that reduces capacity. In many cases that capacity can be recovered by very deep discharging and recharging. The best way to avoid it is to not subject it to frequent over charge by grid charging.

For me and my DIY grid charger, 24-32 hours is an optimal charge cycle. I don't do it anymore frequently than is necessary or quarterly, whichever comes first. The pack in my HCH2 has started doing multiple recals and threw an IMA light recently when my wife drove it for a couple weeks. Her drive is very hilly and is very hard on the battery. My normal commute is level with mostly surface street driving where I can fairly easily get 50mpg. I suspect that if she hadn't driven it, I wouldn't need a grid charge right now and would have made it to my quarterly target.

Since I have the sticks from two spare packs sitting waiting for post-self-discharge testing, I'll probably just swap the pack out and try to refurb at the stick level.

But I digress... follow Hybrid Automotive's recommendations, or do it quarterly, or do it no more frequently than is needed to maintain reasonable performance.

Steve

 

Thanks, Steve. Good to know.

I did not specifically ask them about the frequency of charging but the website says even weekly or more frequent. I will then wait until a quarter is past since even before charging, as I mentioned before, it went back to normal and the IMA light turned off.

But your comment about the driving conditions/habits is very interesting. Up to this recent issue with the battery I did not realize that can affect battery life. I have had this car since 2005. The first battery lasted until 2012. And it was changed under warranty so it did not think about the cost of changing it. Also I always thought the car will run without the hybrid battery so I thought if it cost to much to replace it I will not do it and my car will be a non-hybrid. Not true I later found out, a lot of hydraulic components work with the hybrid battery in addition to the fact that it does not have an alternator!

Anyway, I never drove this car because of the savings per se. It is as you know a 6 cylinder car, very powerful engine, super high acceleration, I always like the agility and superfast drive. The hybrid version is more powerful than non-Hybrid Accord and I guess that is why they stopped making them after 2007.

I have to read more about best driving habits now that I know all those effects on battery! Any advice?