Battery loses charge too quickly...
Discussion
Something of a "101" question, but I'm afraid it's an area I come up a bit short on...
I had a few starting problems and the battery was past its best, so after a shiney new repacement, I was happy for a couple of weeks. With the recent rain, the car has been tucked up more than usual, so gets run once a week at best.
The result has been that the battery isn't holding its charge long enough, soa jump is required. After a drive, everything comes back together, so its chargng OK.
I've found a few posts, but either they don't explain at 101 level, or are slightly O/T.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
I'm really looking for a basic idea of what can be checked to try and help/improve/fix this.
From reading I'm seeing some recurring themes:
- Big Fuse erosion
- Earth to chassis connections
- Battery connections
Without sounding too much of a numpty
any "abc,123" help would be much appreciated.
I'd be happy to take it to an indie and pay for half/an hour of time to have someone go over her thoroughly, but I really think it's something I should be able to sort - in the initial steps at least.
Thanks in advance for any pointers...
I had a few starting problems and the battery was past its best, so after a shiney new repacement, I was happy for a couple of weeks. With the recent rain, the car has been tucked up more than usual, so gets run once a week at best.
The result has been that the battery isn't holding its charge long enough, soa jump is required. After a drive, everything comes back together, so its chargng OK.
I've found a few posts, but either they don't explain at 101 level, or are slightly O/T.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
I'm really looking for a basic idea of what can be checked to try and help/improve/fix this.
From reading I'm seeing some recurring themes:
- Big Fuse erosion
- Earth to chassis connections
- Battery connections
Without sounding too much of a numpty
any "abc,123" help would be much appreciated.I'd be happy to take it to an indie and pay for half/an hour of time to have someone go over her thoroughly, but I really think it's something I should be able to sort - in the initial steps at least.
Thanks in advance for any pointers...
Phil, do you have a test meter? I'd be checking the charging voltage with the engine running. One lead from the meter on battery positive, the other on the engine as earth - for instance the lug on the air con compressor. If it's not sufficient, you battery will only partially charge and hence will die faster. I'm sure this point was mentioned before, just not by who.
Steve.
Steve.
Thanks for the responses - looks like we're still in the dark, but at least now I'm not alone in the dark 
Few points to try and progress things...
1. Sounds like the same problem - I get the impression that grounds are an issue, but I don't have enough knowledge to do much about it.
2. I have an integrated accumulate, but that tends to hide the problem. I'd rather get it resolved at source.
3. I have tested with the meter, and the charging isn't the problem. It's perfectly healthy, except when left for a week or so, whereby the charge dissipates somehow to the extent that a booster or jump is required.
... any more thoughts...
Few points to try and progress things...1. Sounds like the same problem - I get the impression that grounds are an issue, but I don't have enough knowledge to do much about it.
2. I have an integrated accumulate, but that tends to hide the problem. I'd rather get it resolved at source.
3. I have tested with the meter, and the charging isn't the problem. It's perfectly healthy, except when left for a week or so, whereby the charge dissipates somehow to the extent that a booster or jump is required.
... any more thoughts...
If it's charging properly then that points to your battery being the issue. As you've mentioned it being changed, this shouldn't be the case. What voltage do you seen when the battery is being charged, it may not be enough. You may need someone to hold the engine at a typical driving rpm - say 3k to see what you're really getting, since when the engine is at idle, the output from the alternator can be too low.
My bad earth problem wasn't bad enough that the multimeter showed it up, but it was bad enough that the starter wasn't getting enough juice and the alternator not charging the battery properly.
In the end I traced it to internal corrosion in the chassis-earth strap, but I recommend buying an earth strap and connecting it directly from battery negative to the bracket for the airbox and see if your problem goes away.
If only I'd done it sooner, I wouldn't have ended up melting a clutch cable, or spending £300 on an unnecessary starter refurb.
(Always a good idea to make sure the big fuse is in tip-top health as well though)
In the end I traced it to internal corrosion in the chassis-earth strap, but I recommend buying an earth strap and connecting it directly from battery negative to the bracket for the airbox and see if your problem goes away.
If only I'd done it sooner, I wouldn't have ended up melting a clutch cable, or spending £300 on an unnecessary starter refurb.
(Always a good idea to make sure the big fuse is in tip-top health as well though)
Check that the boot light is really going off when the lid is closed. Digital camera with a time delay setting or a small child work well for this!
If your battery is charging ok, then something must be draining it while it is idle. Take the bulb out of the boot light, then connect a meter on the amps setting in between the battery and the lead. That let's you measure the current draw. Ideally this should be no more than 200mA with thbe alarm on.
If it is more you can start pulling fuses one by one untill you see what is drawing the current.
If your battery is charging ok, then something must be draining it while it is idle. Take the bulb out of the boot light, then connect a meter on the amps setting in between the battery and the lead. That let's you measure the current draw. Ideally this should be no more than 200mA with thbe alarm on.
If it is more you can start pulling fuses one by one untill you see what is drawing the current.
Edited by Tanguero on Tuesday 27th November 09:48
Edited by Tanguero on Wednesday 28th November 07:01
Check the drain on the alarm. I used to get a lot more time before needing to jump if I had a secure place to leave the car without needing to have the alarm on.
For reference I used to be able to go a couple of weeks without needing to jump her if I left the alarm on, and extra week or so with the alarm off.
For reference I used to be able to go a couple of weeks without needing to jump her if I left the alarm on, and extra week or so with the alarm off.
A) Go to an auto electrician and get them to test the alternator as it could be starting to fail.
B) I have been told that at idle the alternator does not output enough juice, so if you are spending alot of time in traffic with loads of electrics on, that could also be a problem.
C) Battery could be dead again if it has repeatedly been run down.
D) Check that none of the interior lights are staying on as it could be dodgy door sensors. ie: not sensing the door closing. The intoerior lights could have even been switched on accidentally.
B) I have been told that at idle the alternator does not output enough juice, so if you are spending alot of time in traffic with loads of electrics on, that could also be a problem.
C) Battery could be dead again if it has repeatedly been run down.
D) Check that none of the interior lights are staying on as it could be dodgy door sensors. ie: not sensing the door closing. The intoerior lights could have even been switched on accidentally.
Thought I should give a little update just in case it helps someone else with similar pains... 
Firstly, I've not had the opportunity to get an electrical whizz to go over some of the obvious possible draws on the battery.
Secondly however, I've found massive improvement, back to where we were previously. Now, I find this atrange myself, but, the only thing I've changed, is the internal cabin light's setting. I turned it to "permanently OFF", and was experiencing the problem of the battery losing charge quickly. However, I have switched it back to "ON when the doors open", and as far as I can fathom, its the only variable which has changed, and the problem has improved, been fixed. Left her tucked up for 2 weeks, and came back, thought I'd check, and she started first time, no trouble!
I'm not sure that I understand how changing the light setting in this instance could actually impace the battery like this, as the light DOES remain off all the time. Perhaps someone with more elctrical know-how might want to venture a theory? Maybe a short on that particular switch setting somewhere which wouldn't affect the actual bulb? Can this feasibly be the root cause???
I'll be a very happy man if it is!
Firstly, I've not had the opportunity to get an electrical whizz to go over some of the obvious possible draws on the battery.
Secondly however, I've found massive improvement, back to where we were previously. Now, I find this atrange myself, but, the only thing I've changed, is the internal cabin light's setting. I turned it to "permanently OFF", and was experiencing the problem of the battery losing charge quickly. However, I have switched it back to "ON when the doors open", and as far as I can fathom, its the only variable which has changed, and the problem has improved, been fixed. Left her tucked up for 2 weeks, and came back, thought I'd check, and she started first time, no trouble!
I'm not sure that I understand how changing the light setting in this instance could actually impace the battery like this, as the light DOES remain off all the time. Perhaps someone with more elctrical know-how might want to venture a theory? Maybe a short on that particular switch setting somewhere which wouldn't affect the actual bulb? Can this feasibly be the root cause???
I'll be a very happy man if it is!
The changes in temperature recently have left my battery in better condition.
I'm disconnecting the battery pos on saturday, in a bid to clear my fuel pump problem. I'll let you know what the current draw is, when I've finished.
P.s. when checking for amps, dont forget to put your multi meter leads back in the right slot, when you've finished. I'm forever shorting things out at work
My favourite for anyone suffering excessive current draw whilst parked up, would be a duff battery in the self contained alarm/sounder.
Mines been took out of the 4.2, and I've left that car for over a month, and it's always started.
I'm disconnecting the battery pos on saturday, in a bid to clear my fuel pump problem. I'll let you know what the current draw is, when I've finished.
P.s. when checking for amps, dont forget to put your multi meter leads back in the right slot, when you've finished. I'm forever shorting things out at work
My favourite for anyone suffering excessive current draw whilst parked up, would be a duff battery in the self contained alarm/sounder.
Mines been took out of the 4.2, and I've left that car for over a month, and it's always started.
RUSSELLM said:
The changes in temperature recently have left my battery in better condition.
I'm disconnecting the battery pos on saturday, in a bid to clear my fuel pump problem. I'll let you know what the current draw is, when I've finished.
P.s. when checking for amps, dont forget to put your multi meter leads back in the right slot, when you've finished. I'm forever shorting things out at work
My favourite for anyone suffering excessive current draw whilst parked up, would be a duff battery in the self contained alarm/sounder.
Mines been took out of the 4.2, and I've left that car for over a month, and it's always started.
Interesting about the alarm battery, where is it and can it be replaced?I'm disconnecting the battery pos on saturday, in a bid to clear my fuel pump problem. I'll let you know what the current draw is, when I've finished.
P.s. when checking for amps, dont forget to put your multi meter leads back in the right slot, when you've finished. I'm forever shorting things out at work
My favourite for anyone suffering excessive current draw whilst parked up, would be a duff battery in the self contained alarm/sounder.
Mines been took out of the 4.2, and I've left that car for over a month, and it's always started.
Tanguero said:
Check that the boot light is really going off when the lid is closed. Digital camera with a time delay setting or a small child work well for this!
If your battery is charging ok, then something must be draining it while it is idle. Take the bulb out of the boot light, then connect a meter on the amps setting in between the battery and the lead. That let's you measure the current draw. Ideally this should be no more than 200mA with thbe alarm on.
If it is more you can start pulling fuses one by one untill you see what is drawing the current.
When you know how much current is being used you can work out roughly how long the battery can sustain this from fully charged. At 200ma (0.2A) with a 60 A/H battery you get 60/0.2 hours ie 300 hours, so 200ma is too much I would say as a faily well charged battery will be flat in 10 days. Its a rough and ready calculation but will be within +or- 25%If your battery is charging ok, then something must be draining it while it is idle. Take the bulb out of the boot light, then connect a meter on the amps setting in between the battery and the lead. That let's you measure the current draw. Ideally this should be no more than 200mA with thbe alarm on.
If it is more you can start pulling fuses one by one untill you see what is drawing the current.
Edited by Tanguero on Tuesday 27th November 09:48
Edited by Tanguero on Wednesday 28th November 07:01
I would expect to see less than 50ma.
Then as someone else mentioned you can pull fuses till you know whats gobbling the power.
Jon
I looked at doing this the other day, as I'm having similar problems. However, the problem I found staight away is that the sub-systems are grouped, quite randomly, per fuse. For example, the alarm and immobiliser are paired with the injectors and so on which makes it difficult to pin-point the source of a leak.
I have decided to go down a seperate route which seems to have worked very well for one owner so far. I'm going to fit a kill switch in the engine bay which will be wired into the feed from the battery to the fusebox in the boot, i.e. NOT across the battery to starter cable. This way, I can get out of the car, close the door, turn the switch off in the engine bay and drop the bonnet (without locking it obviously) and then leave indefinitely without worrying about any drain on the battery. The only way the battery can flatten then is if there is an internal fault with the alternator. Also, this completely disables all electrics and so renders the car completely imobile so long as the kill switch is not found.
Seems like a good and very simple fix to me to solve this problem, unless there is something I'm missing?
I have decided to go down a seperate route which seems to have worked very well for one owner so far. I'm going to fit a kill switch in the engine bay which will be wired into the feed from the battery to the fusebox in the boot, i.e. NOT across the battery to starter cable. This way, I can get out of the car, close the door, turn the switch off in the engine bay and drop the bonnet (without locking it obviously) and then leave indefinitely without worrying about any drain on the battery. The only way the battery can flatten then is if there is an internal fault with the alternator. Also, this completely disables all electrics and so renders the car completely imobile so long as the kill switch is not found.
Seems like a good and very simple fix to me to solve this problem, unless there is something I'm missing?
Edited by longbow on Thursday 17th January 17:43
Ah, you see I already thought of this and it wouldn't make it any easier for a would-be thief. When the battery power is reconnected the alarm/immobiliser immediately resets itself, locking all doors and arming the alarm/immobiliser etc. Hence you would simply be back to square one although with access to the bonnet. There isn't anything in the engine bay that can gain access to the car or boot. I'm not doing it to make the car more secure, simply to stop the battery draining. The fact that it acts as an additional barrier to a would-be thief is a bonus. Besides the Cerbera is not really the sort of car thieves are interested in these days - how many have actually been stolen over the years? Far too unique and rare to shift on easily. Besides my car is parked in a locked garage on a secure military base, so its pretty safe where it is.
Also, the kill switch I'm buying isn't like an ordinary on/off switch - it uses a red plastic key which is removed when the switch is off. In order to power-up the car, you'd need the exact same key which is pretty unlikely.
If anyone can think of a better solution I'm all ears..........
Also, the kill switch I'm buying isn't like an ordinary on/off switch - it uses a red plastic key which is removed when the switch is off. In order to power-up the car, you'd need the exact same key which is pretty unlikely.
If anyone can think of a better solution I'm all ears..........
Edited by longbow on Thursday 17th January 21:25
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