Flat battery for newbie
Moderators: Doone, westonwarrior
Re: Flat battery for newbie
Some good info so far but let me just to give some general info that may help.
A good battery at rest no engine running and no significant load should read around 12.4v to 12.6v anything less and either you have something loading the battery or its past its best.
Anything less than about 12.2 and your battery is past its best.
when the engine is running you should see between 13.8v and 14.2 but no higher than 14.6v as this can start to cook the battery.
When you were measuring with the jump leads on you should have been seeing around 14V so suspect you may not have had a good connection somewhere.
12.9v after charging is fine it will slowly drop to a natural level after a few hours.
The very low voltage of the leisure battery sounds like it may not be charging or is very knackered. being as low as it is it may not recover either but is worth a try.
Once you get the engine running again I would check the voltages and you should be seeing the above on both batteries.
See what happens when you check this and then i think it will help point us in the right direction. Charging fault ie Alternator, Batter fault, or something draining them
Cheers
Ian
A good battery at rest no engine running and no significant load should read around 12.4v to 12.6v anything less and either you have something loading the battery or its past its best.
Anything less than about 12.2 and your battery is past its best.
when the engine is running you should see between 13.8v and 14.2 but no higher than 14.6v as this can start to cook the battery.
When you were measuring with the jump leads on you should have been seeing around 14V so suspect you may not have had a good connection somewhere.
12.9v after charging is fine it will slowly drop to a natural level after a few hours.
The very low voltage of the leisure battery sounds like it may not be charging or is very knackered. being as low as it is it may not recover either but is worth a try.
Once you get the engine running again I would check the voltages and you should be seeing the above on both batteries.
See what happens when you check this and then i think it will help point us in the right direction. Charging fault ie Alternator, Batter fault, or something draining them
Cheers
Ian
- mikeonb4c
- Supreme Being
- Posts: 22877
- Joined: Sun Nov 05, 2006 10:49 pm
- Location: Living with Mango Bongo in the North West but with a tendency to roam
- Contact:
Re: Flat battery for newbie
Great post Ian 

Re: Flat battery for newbie
You need to let the battery "rest" for 30 minutes at least after charging before measuring the voltage, it shouldn't then exceed 12.8 at most more likely 12.6.
Geoff
2001 Aero V6, AFT, full side conversion.
2001 Aero V6, AFT, full side conversion.
-
- Junior Bongonaut
- Posts: 18
- Joined: Thu Aug 24, 2017 8:32 am
Re: Flat battery for newbie
So attached battery after a full nights chargenow reading at 12.8v with multimeter.
With key switched to on, air con works, alarm light and lights also work.
Hazzards work, but not the indicators!!!
I also hear a click from under bonnet.
If I turn key to start nothing happens.
There are now no lights on the dash.
There were yesterday.
Looks like we're not having a holiday:(
Any ideas?
With key switched to on, air con works, alarm light and lights also work.
Hazzards work, but not the indicators!!!
I also hear a click from under bonnet.
If I turn key to start nothing happens.
There are now no lights on the dash.
There were yesterday.
Looks like we're not having a holiday:(
Any ideas?
Re: Flat battery for newbie
It sounds like you may have more than a single problem.
Start by cleaning the battery terminals and checking the actual connections to them.
Then remove each fuse and check the state of the connectors (NOTE: The big left hand end 100Amp fuse is bolted in so that should be OK) of each fuse.
After that either the battery is damaged internally or there is a more serious problem. You can check the state of the battery by connecting the voltmeter to the tops of the lead posts while getting someone to turn on the headlights, if the voltage falls from 12.8v to below 11v then it indicates that the battery is damaged.
Start by cleaning the battery terminals and checking the actual connections to them.
Then remove each fuse and check the state of the connectors (NOTE: The big left hand end 100Amp fuse is bolted in so that should be OK) of each fuse.
After that either the battery is damaged internally or there is a more serious problem. You can check the state of the battery by connecting the voltmeter to the tops of the lead posts while getting someone to turn on the headlights, if the voltage falls from 12.8v to below 11v then it indicates that the battery is damaged.
Geoff
2001 Aero V6, AFT, full side conversion.
2001 Aero V6, AFT, full side conversion.
Re: Flat battery for newbie
Also check the Starter Motor if battery capable,is it not possible to have Mechanic have a wee look at your vehicle ,it might save you money in the long run and let you have your well deserved Holiday.
-
- Junior Bongonaut
- Posts: 18
- Joined: Thu Aug 24, 2017 8:32 am
Re: Flat battery for newbie
So proper noob.
The alarm wasn't disabled.
In other news the coil light is flashing.
Is this bad?
The alarm wasn't disabled.
In other news the coil light is flashing.
Is this bad?
Re: Flat battery for newbie
That is probably because you have been disconnecting the battery, there is a permanent backup supply to the ECU and if the battery is disconnected then the ECU error light flashes (Glowplug light flashing), it should clear if there is no other fault once you have it running and then restart it.
Geoff
2001 Aero V6, AFT, full side conversion.
2001 Aero V6, AFT, full side conversion.
-
- Junior Bongonaut
- Posts: 18
- Joined: Thu Aug 24, 2017 8:32 am
Re: Flat battery for newbie
TUrns out it flashes if the leisure battery is disconnected
Re: Flat battery for newbie
Hi.
Did you also try and charge the Leisure Battery? Did it take a charge ok as it was very low?
Some on on here will know better than me but I am sure I read that if one of the leisure battery looms have been fitted so that the interior lights, blinds, stereo ect are moved so they run from the leisure battery this includes some of the permanent power feeds to ECUs.
So if your still having trouble with the leisure battery charge voltage this could be causing an issue.
Not sure it would stop the engine turning over though it may stop it from starting.
Could you try jump leads between the 2 battery as some one else suggested and see if that helps.
I think i agree thought that we may be looking at more than one fault
Good luck.
Ian
Did you also try and charge the Leisure Battery? Did it take a charge ok as it was very low?
Some on on here will know better than me but I am sure I read that if one of the leisure battery looms have been fitted so that the interior lights, blinds, stereo ect are moved so they run from the leisure battery this includes some of the permanent power feeds to ECUs.
So if your still having trouble with the leisure battery charge voltage this could be causing an issue.
Not sure it would stop the engine turning over though it may stop it from starting.
Could you try jump leads between the 2 battery as some one else suggested and see if that helps.
I think i agree thought that we may be looking at more than one fault
Good luck.
Ian
Re: Flat battery for newbie
WestyK wrote:Hi.
Did you also try and charge the Leisure Battery? Did it take a charge ok as it was very low?
Some on on here will know better than me but I am sure I read that if one of the leisure battery looms have been fitted so that the interior lights, blinds, stereo ect are moved so they run from the leisure battery this includes some of the permanent power feeds to ECUs.
So if your still having trouble with the leisure battery charge voltage this could be causing an issue.
Not sure it would stop the engine turning over though it may stop it from starting.
Could you try jump leads between the 2 battery as some one else suggested and see if that helps.
I think i agree thought that we may be looking at more than one fault
Good luck.
Ian
Maybe this could explain the starting problem.
Quoted by BingaBonga
"So proper noob. The alarm wasn't disabled."
Re: Flat battery for newbie
Ah missed that bit
Thanks Rita

Thanks Rita