Disconnecting The Battery Frequently

[MasterDon]

I'm having to borrow the battery of my honda(1.5 Vtec EFI) to start another car these days...,this means disconnecting and reconnecting the battery regularly,sometimes as much as twice a day.

I'd like to know if this is harmful to the car and would I be better off just leaving the car without a battery for about two weeks?

thank you.

[Sylvi]

I'm having to borrow the battery of my honda(1.5 Vtec EFI) to start another car these days...,this means disconnecting and reconnecting the battery regularly,sometimes as much as twice a day.

I'd like to know if this is harmful to the car and would I be better off just leaving the car without a battery for about two weeks?

thank you.

'MasterDon

To my Knowledge disconnecting and reconnecting the battery regularly that is nothing wrong sure you can get jumper cables to start the other car.

I have a master switch 160 amps fitted to my Vehicle every day I off same in the night.

Wijesinghe.

[MasterDon]

'MasterDon

To my Knowledge disconnecting and reconnecting the battery regularly that is nothing wrong sure you can get jumper cables to start the other car.

I have a master switch 160 amps fitted to my Vehicle every day I off same in the night.

Wijesinghe.

silvy,

the reason i'm asking is that i've heard EFI car's ECU resets itself after reconnecting the battery and that it goes through a "learning process" afterwards...i was wondering if that happens twice everyday will it be harmful.

and no,jumper cables will not do because I have to run the other car for trials and such...

i too have master switches fitted to the oldies but for new cars i'm not sure if its advisable.

[Sylvi]

silvy,

the reason i'm asking is that i've heard EFI car's ECU resets itself after reconnecting the battery and that it goes through a "learning process" afterwards...i was wondering if that happens twice everyday will it be harmful.

and no,jumper cables will not do because I have to run the other car for trials and such...

i too have master switches fitted to the oldies but for new cars i'm not sure if its advisable.

Sir,

I understand your point . You have one battery for both cars.

Yes I know ECU resets every time you remove battery terminals I have not had any problems for last 3 1/2 Years in this Chinese Vehicle has Bosch ECU and sensors 12 Volts DC electrical system once in 5000 Kms I do clean sensors.

Wijesinghe.

[hyacc]

silvy,

the reason i'm asking is that i've heard EFI car's ECU resets itself after reconnecting the battery and that it goes through a "learning process" afterwards...i was wondering if that happens twice everyday will it be harmful.

I've noticed this in my hyundai accent 2000. ECU memory is erased after few seconds if you disconnect the battery. I scanned the ecu using my OBDII reader and found out that all the values related to I/M status monitors(Misfire, Fuel system, comp com, Catalyst, EVAP system, O2 Sensor, EGR) had been erased. Fuel efficiency goes down until ECU 'learns' new values. Several driving cycles are required for these values to get restored. One solution I tried and worked is to connect a 9V battery to battery connectors until you reconnect the vehicle battery. Then ECU keeps it's memory.

[mirage7777]

i too have master switches fitted to the oldies but for new cars i'm not sure if its advisable.

@ MasterDon & Sylvi --pardon my ignorance -- what is a 'master switch or switches'?? Please explain the functions. Thanks.

My 2 cents on the battery query -- i don't know whether this method is for the benefit of the ECU -- but it was advised on some forum - when connecting the battery --to fit the '-' line first & the '+' line to be fitted last. When removing - vice versa.

Edited July 18, 2010 by mirage7777

[hyacc]

My 2 cents on the battery query -- i don't whether this method is for the benefit of the ECU -- but it was advised on some forum - when connecting the battery --to fit the '+' line first & the '-' line to be fitted last. When removing - vice versa.

It is to prevent short circuiting the batt.

[mirage7777]

It is to prevent short circuiting the batt.

Thanks - didn't know that. However when I installed a new battery recently - even the main technician didn't do it the correct way & when I asked him - shouldn't it be done this way -- he gave me a look - which indicated that he thoughts i was bats Goes to show the lack of knowledge of some professionals!!

[topgear]

silvy,

the reason i'm asking is that i've heard EFI car's ECU resets itself after reconnecting the battery and that it goes through a "learning process" afterwards...i was wondering if that happens twice everyday will it be harmful.

and no,jumper cables will not do because I have to run the other car for trials and such...

i too have master switches fitted to the oldies but for new cars i'm not sure if its advisable.

MasterDon,

I haven't really heard of anyone's ECU going faulty because the battery was removed but neither have I heard of anyone removing and fixing the battery twice a day! :-)

Theoretically, nothing should happen except that the ECU gets reset and has to reprogram itself but then, since this is not a normal situation, you'd better not risk it. better get another battery.

[Sylvi]

@ MasterDon & Sylvi --pardon my ignorance -- what is a 'master switch or switches'?? Please explain the functions. Thanks.

My 2 cents on the battery query -- i don't know whether this method is for the benefit of the ECU -- but it was advised on some forum - when connecting the battery --to fit the '-' line first & the '+' line to be fitted last. When removing - vice versa.

Master switch some ting like house hold main switch which disconnect battery from the entire electrical system of your Vehicle.

they are available at Motoecrade colombo 00200 Bary brook place.

I have different type my own modified.

Old Isuzu lorries had electrically 24 volts DC operated switch it works on solenoid principle and very efficient

Wijesinghe.

[Sylvi]

I've noticed this in my hyundai accent 2000. ECU memory is erased after few seconds if you disconnect the battery. I scanned the ecu using my OBDII reader and found out that all the values related to I/M status monitors(Misfire, Fuel system, comp com, Catalyst, EVAP system, O2 Sensor, EGR) had been erased. Fuel efficiency goes down until ECU 'learns' new values. Several driving cycles are required for these values to get restored. One solution I tried and worked is to connect a 9V battery to battery connectors until you reconnect the vehicle battery. Then ECU keeps it's memory.

Sir,

Your connecting a 9 volt dc Battery method to your system is good not to loose memory of ECU It has to be done just before you remove one terminal if not small 9 volt DC battery can damage due to 12 volts high amps getting into 9 volt battery.

Your driving cycles can be over come several stop and start of the engine mine is maximum 3 times the memory comes back to normal I have seen in reputed work shops do this number of times for expensive Vehicles.

Wijesinghe

[mirage7777]

Master switch some ting like house hold main switch which disconnect battery from the entire electrical system of your Vehicle.

they are available at Motoecrade colombo 00200 Bary brook place.

I have different type my own modified.

Old Isuzu lorries had electrically 24 volts DC operated switch it works on solenoid principle and very efficient

Wijesinghe.

Thanks for the reply Mr. Wijesinghe.

i suppose this is to prolong the battery life - right?

I suppose all have their own reasons for installing a master switch.

I on the other hand finds it a bother to reset ALL the radio channels again & even the clock - when the battery is removed & installed.

[hyacc]

Thanks - didn't know that. However when I installed a new battery recently - even the main technician didn't do it the correct way & when I asked him - shouldn't it be done this way -- he gave me a look - which indicated that he thoughts i was bats Goes to show the lack of knowledge of some professionals!!

It's not a must. It's just a precaution or a good habit to prevent a short-circuit.

[hyacc]

Your connecting a 9 volt dc Battery method to your system is good not to loose memory of ECU It has to be done just before you remove one terminal if not small 9 volt DC battery can damage due to 12 volts high amps getting into 9 volt battery.

Wijesinghe

yes I do it within seconds after removing 12V battery terminals.

[MasterDon]

Thanks for the reply Mr. Wijesinghe.

i suppose this is to prolong the battery life - right?

I suppose all have their own reasons for installing a master switch.

I on the other hand finds it a bother to reset ALL the radio channels again & even the clock - when the battery is removed & installed.

installing a master switch in modern cars is piontless,and no,it does not increase battery life either...I use them only on our pre-1960 vehicles because these english and italian classics have a nasty habbit of suddenly bursting in to flame...haha...

[mirage7777]

I use them only on our pre-1960 vehicles because these english and italian classics have a nasty habbit of suddenly bursting in to flame...haha...

wow - really??

MasterDon - interested to see some photos of your pre-1960 vehicles-- have you put up any on this forum or elsewhere? I think i saw pictures of a restoration done - there were other photos of cars -dont know whether your whole collection was there.

[shanX]

I'm having to borrow the battery of my honda(1.5 Vtec EFI) to start another car these days...,this means disconnecting and reconnecting the battery regularly,sometimes as much as twice a day.

I'd like to know if this is harmful to the car and would I be better off just leaving the car without a battery for about two weeks?

thank you.

Have a similar car, which I don't get to take it out much since recently. Has a weak battery, so the battery is dead, like whenever am about to go out. But luckily have a battery charger. So anyway so far nothing went wrong for me, except for a high idle on the first start up, after that it runs fine. But am also wondering whether this is ok or not

[Sylvi]

Members of the forum,

You can attach a mini charger to your car battery it will prolong the battery only in the night as car battery will be full by morning

This method was good for Diesel cars.

Mini charger you can make by your self buying a small 230X12 volts 1or 2 amp transformer with a full wave rectifier to convert AC to DC will cost around Rs 750.00 if you like you can add a small amp meter.

Wijesinghe.

[Mani]

silvy,

the reason i'm asking is that i've heard EFI car's ECU resets itself after reconnecting the battery and that it goes through a "learning process" afterwards...i was wondering if that happens twice everyday will it be harmful.

Don,

You have it exactly right. However, it will only go into learning mode if you start the car. You may also notice the car running a bit rough for few minutes until it 'learns'. No damage to the ECU by doing this as far as I know.

[Sylvi]

Don,

You have it exactly right. However, it will only go into learning mode if you start the car. You may also notice the car running a bit rough for few minutes until it 'learns'. No damage to the ECU by doing this as far as I know.

Mr.Mani,

I too agree to your answer some days my Vehicle starts in the morning with little speed high then What I do is stop the engine and start three times at the third time it comes back to normal speed.I was advised to do this by a leading motor vehicle service adviser.

Wijesinghe.

[Watchman]

Mr.Mani,

I too agree to your answer some days my Vehicle starts in the morning with little speed high then What I do is stop the engine and start three times at the third time it comes back to normal speed.I was advised to do this by a leading motor vehicle service adviser.

Wijesinghe.

Dear Sir,

May we know the name of the advisor please?

[harshansenadhir]

Memory of ECU does not get erased the moment you disconnect the battery. It'll take some time, in-fact some people keep the battery disconnected overnight to reset the ECU. Reason is electronic components inside ECU holds some amount of electricity, hence 'memory' unless otherwise you forcefully drain it. Therefore, disconnecting the battery and reconnecting within minutes would not have any significant impact on the ECU but your battery terminals and terminal clips will get damaged due to excessive removal and re-fit.

[MasterDon]

Thanks guys for your valuable input...I was just worried the ecu or other parts going bust...seems I have nothing to worry about...and good thing too,I'll have to use the battery for a couple more weeks because the other car(a citroen) is not yet ready(and I cant afford to) to have its own dedicated battery.

thanks again.

Mr.Mani,

I too agree to your answer some days my Vehicle starts in the morning with little speed high then What I do is stop the engine and start three times at the third time it comes back to normal speed.I was advised to do this by a leading motor vehicle service adviser.

Wijesinghe.

pardon me but,multiple starts while the engine is cold may be inviting breakdowns I would assume...

wow - really??

MasterDon - interested to see some photos of your pre-1960 vehicles-- have you put up any on this forum or elsewhere? I think i saw pictures of a restoration done - there were other photos of cars -dont know whether your whole collection was there.

yeah,their wire harnesses are pretty unstable and also they are prone to random petrol leaks...a fire extinguisher is a must!

I have a humble little collection mate,and i'm just one of the many classic owners at AL... http://www.facebook.com/album.php?aid=2001...mp;l=cc67960c0d

[mirage7777]

I have a humble little collection mate

Impressive collection - hardly 'humble'.

[MasterDon]

Impressive collection - hardly 'humble'.

thx

[Sylvi]

Dear Sir,

May we know the name of the advisor please?

Sir,

He is one Mr. Adikari from early German tec pass outs now service adviser for a leading importer.I had to get his permission to this post.

Wijesinghe.