starting probs help!

[jonno]

hi
i am having trouble with my battery going flat:doh.after a full charge it will work fine for a week then one morn it will be flat as a fart. i have checked that the lights are off over night and i have had the battery tested at a couple of garages who both have said its in perfect working order but it still keeps going flat. if i get a jump start it will start spot on for the rest of the day.i was thinking either something is slowly draining the battery or the alternator is not charging right. does anyone know how to check if either of these are the case. any help would be much appreciated.:thumbs

 

[rustic]

If the alternator is faulty, the diodes can go down or the regulator and they can drain the battery at a few amps.
You need to find the cause of the drain, you can fit a 10 Amp multimeter in line with the battery lead, ie in series and monitor the current, if it's 100mA ie 0.1 Amp or less then that won't be cause for concern, the ECU, Radio, alarm all take some current.
Be aware by disconnecting the battery you will loose your radio code, the ECU will have to re-learn and the alarm, may need to be re-set, but from what I have read before, it should only be your radio that you will have to reset.... I'm not sure.

If you have a few amps, then remove the connector on the alternator.

If you are unsure about doing this test get the guy who inspected the battery to do it.

Also monitor the battery while charging should be 14.2-14.5 Volts when charging.
If you put your headlights on, rear heater etc, it shouldn't drop more than 0.2 volts if at all.

If it drops to less than 13 Volts, the Alternator is naff, or the belts are slipping, just try revving the engine as sometimes the alternators like a few revs.
Hope this helps, best regards, Rustic

Edit:-- just thought, it could be one of the battery cables, they have a habit of becomming open circuit...

 

[jonno]

thanks for the reply rustic the batt is out and on charge at the min but as soon as it is charged ill check the volts so it should be between 14.2 and 14.5 with engine running and not drop by more than .2 with lights etc.. on.

also how do iknow if the batt cable has become an open circuit :doh.
cheers

 

[rustic]

thanks for the reply rustic the batt is out and on charge at the min but as soon as it is charged ill check the volts so it should be between 14.2 and 14.5 with engine running and not drop by more than .2 with lights etc.. on.

also how do iknow if the batt cable has become an open circuit :doh.
cheers

Put a volt meter on the battery terminals direct ie the lead posts, after you have fitted the battery clamps,

Monitor the voltage as you start the car, if the battery appears dead, and you still have close to 12 volts on the meter it is one of the terminals/ cables , then check which one by putting the black lead of the probes on the chassis to check the earth.

 

[jims-terrano]

I had same symptons and it turned out to be the starter motor.

Jim

 

[rustic]

I had same symptons and it turned out to be the starter motor.

Jim

But jump starting helped..:nenau Could be the extra current capability helped to turn the motor, there may be just one part of the motor burnt out.:nenau
Never had a faulty starter as yet....

 

[jonno]

put the batt back on after 3 hours charge and it started ok.
when the engine is running it reads 14.5v when i turn on the lights and wipers it drops to 12.83v if i remember right the battery shows 12.66v when the engine is off so does this mean its the alternator thats fooked

 

[jims-terrano]

Pretty much the same readings as mine was too and 3 hours isn't enough to charge a flat battery unless it's one hell of a charger.
Try disconnecting the earth from the battery at nights to prove it's not draining. Sorry but the more I read it sounds more like Starter on mine, see if Clivvy has a read too.

Jim

 

[rustic]

Disconnect the earth on the battery, and put a meter set on 10Amp range and connect it between the -ve on the battery, and the -ve lead and measure the current with everything switched off.

Re: battery voltage, it should be higher than 12.66 volts, did you try increasing the revs?

Rustic

 

[jonno]

Disconnect the earth on the battery, and put a meter set on 10Amp range and connect it between the -ve on the battery, and the -ve lead and measure the current with everything switched off.

cheers rustic for putting it terms a dumdum like me can follow:augie

getting a reading of 0.20 so i guess i have something draining the batt

 

[rustic]

cheers rustic for putting it terms a dumdum like me can follow:augie

getting a reading of 0.20 so i guess i have something draining the batt

That's 200 mA or 0.2 amp, In 24 hours this will consume 4.8 AH, after a week, 7 x more so about 33Ah this will be about half of the capacity of a good battery.

How quickly it builds up. :doh

This cold weather the battery will not give out the full output so that explains why you have a flat battery after a week.

Well what could it be?, you could disconnect the alternator to see if it's this, but have you fitted a new radio ? I fitted a radio to the boat, and thought what is the drain when it is not switched on ? ie on standby, and it was 150 ma, but I leave the boat for weeks so I have to disconnect the memory feed every time we leave the boat longer than a few days. :doh

I have also installed some solar panels that charge at a reasonable rate.

When I park the mav in my garage, I have a battery charger that keeps it topped up without over charging it, I fitted a socket on the front bumper and plug it in most nights.

When my daughter had her fiesta, I did the same but as it was outside, the cable was tied off with string so it automatically disconnected... as she reversed out.. :thumb2


So I hope this explains the issue, I would be worried if I left my mav for more than a week while say I am on Holiday.

One solution, buy one of the battery disconnectors, one type fits on the -ve terminal, with a green knurled knob, unscrew 2-3 turns , battery isolated.

Something like this..

http://cgi.ebay.co.uk/Battery-Disco...arts_Vehicles_CarParts_SM&hash=item53e234aea1


But you will loose the alarm.

Hope this helps,
best regards,
Richard (Rustic)

 

[jonno]

Nothing new fitted so nothing obvious. I will pull out the radio and see how much power it is using with the multimeter. I have got a cb in and after Market Alarm so I will see if/how much they arre using too. Other than that Im not sure what else to check.

 

[jonno]

ok i removed the cb and it is still drawing 0.2 amp.
removed radio and reading 0.19/o.2 amp
removed what i thought was the alarm (black wire to +ve on batt with inline blade fuse) dropped to 0.03 amp:clap, put the wire back on and back up to 0.2 amps so this wire is drawing the power but it aint the alarm as it is still working(i am now deaf in one ear) so i followed the wire round the engine bay and into the bulkhead on the passenger side.
so i know where the drain is coming from but not what from untill i have a look tomorrow in the daylight.
thanks for the help so far:bow will post when i find out what its for.