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I have a 2003 Civic Hybrid. I am the original owner. I have wrung the electronic assist battery out. The battery is the original, and is done for. I understand what's involved - money and labor - in replacing that battery. I'm not interested in replacing the battery. Period.

I have only one question:

Is it possible/safe to disconnect the electronic assist system and still drive the vehicle as if it were just a 'plain', gas-only, vehicle?

If the answer is "No", I would appreciate a brief explanation as to why.

Thank you for your time to answer my question.
Paul

 
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Yes, you can.

You will have two orange lights always on the dash. Your 12v battery will only charge at high rpm. Auto start/stop won't work. When idling, you'll get the red battery light on the dashboard too.

Its just about usable - but I'd suggest upgrading the 12v battery to a bigger deep cycle one. Even then, power hungry things like heated seats or the mirror or rear defroster I'd only use when driving on the freeway. I suggest buying a $30 emergency jumpstart battery and/or a battery voltage monitor so you don't accidentally get stranded (the petrol engine continues to run down to about 9 volts).


To try this mode out, remove the back seat cushion (bolts down by the seatbelts), and then flip the big switch in the middle off.


If you're happy, you can remove the big high voltage battery behind the back seat, making the car lighter (and therefore slightly less sluggish).

 
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Thank you!

Paul

 
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I thought the big hybrid battery did the charging for the 12V battery. Which would mean your 12V battery would go dead after a while, leaving you stranded. I could be wrong.

 
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Thanks again to CivicGuy04 for the comprehensive answer. Bropotatochip's response has me thinking that I may have been in this "gas-only" mode for the last 6 months or so. For the sake of completion and in case there is anyone 'out there' that might be experiencing the same circumstances, I will elaborate on my situation.

As I said, I'm the original owner, therefore I know that this is the original battery. Therefore it is on its 20th year. I think I got my money's worth out if it. The car has been through a family of four, taught two daughters how to drive, (with associated bumps and bruises), all of which render it in an unsellable state. Its a working car, that I can use as second (or even third) vehicle when necessary. I seriously doubt that I could get $500 for it in its current condition. Money into it for a new 144 volt battery, or cosmetic repairs would be wasted. In fact insurance costs have to be considered in terms of the cost to continue to use it. Its redeeming values are that it runs, and it gets better mileage than my newer cars. In Alaska, we call these 'a beater with a heater'.

All of that said, the following are the symptoms I have been experiencing for the last six months or so.

1) If I don't run the engine/drive it almost every day, the car won't start because "the battery" is run down.
2) When I drive it, if I have to do a lot of hill climbing, the number of "battery bars" goes down rapidly.
3) If I can get flat road for a while, the battery indicator "recharges" about as rapidly as it discharges.
4) Once, while stopped at a traffic light, the car wouldn't restart. I had to use the battery charger I keep in the car, to jumpstart it at the light. (A socially unpleasant experience.) I attribute that inability to restart to the IMA system turning the gas engine off at idle, and the 12 volt battery being too depleted to restart the engine once the light turned green. Correct?

Based on what I've read, and the age of the 144 volt battery, (the car has probably it's third 12 battery in it), it sounds to me like I've been running in "gas-only" mode for a while. HOWEVER, with the 144 volt battery still "attached", am I unnecessarily over-loading the 12 volt battery as it tries to do the job of both batteries by running the IMA motor, turning the gas engine off at idle, and the having to supply restart cranking amps to restart the gas engine?

Thanks again for your help.
Paul

 
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The 12V battery would not be doing any of the IMA work, that is strictly the 144V battery. However, if my above assumption is correct, the failing 144V battery could be failing to charge the 12V battery. There is no alternator, so no other way to charge it. This would explain why it fails to restart sometimes.

 
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CivicGuy said that it only recharges when in high RPM, might be the case.

Now, 20 years in the IMA battery in Alaska?!?
Yer lucky dog, I hear they last in average 10 year!

 
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sdaidoji - I agree. That's why I said I had "wring it out". There's nothing left that battery I'm sure.

I'd like to not have it run with the "nature" it currently has. Hence my original question. I'd like to reduce the load on the 12V battery as much as possible without having the "computer" constantly messing with me.

I will be following CivicGuy04's instructions, and "seeing how it goes".

Paul

 
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Good info here.

https://www.bumblebeebatteries.com/i...al/bypass.html