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Crazy phantom battery drain ?

Hi both.

Been monitoring battery voltage for a while now.
After reconnecting the battery it dropped 0.2 volts in the first 24 hours. ( Would that be the residual charge coming off ? )12.99 to 12.73v
Over the last 7 hours it's only dropped 0.01volts. (Hopefully it will stay like that )
From the service records the car had a new alternator fitted at Honda Bristol in Jan 2013 and the drive belt was re-routed. I'm guessing that's not related and was probably due to a bearing problem.
Will continue to monitor the volts, but have ordered a fuse probe lead as I'm determined to find that elusive 20ma (if it's off a fused circuit ).
 
geoffdragon said:
Hi both.

Been monitoring battery voltage for a while now.
After reconnecting the battery it dropped 0.2 volts in the first 24 hours. ( Would that be the residual charge coming off ? )12.99 to 12.73v
Over the last 7 hours it's only dropped 0.01volts. (Hopefully it will stay like that )
From the service records the car had a new alternator fitted at Honda Bristol in Jan 2013 and the drive belt was re-routed. I'm guessing that's not related and was probably due to a bearing problem.
Will continue to monitor the volts, but have ordered a fuse probe lead as I'm determined to find that elusive 20ma (if it's off a fused circuit ).
Click to expand...
yes that volts drop is normal

New alternator and re-routed belt would not be an issue, but don't ***ume that a new alternator is not over-charging.


For checking to see if there really is a mysterious drain, this is what you really need
http://www.ebay.co.uk/itm/171527746839


£15 + free delivery + uk seller ....I'm tempted myself :eek:
In fact, if you buy it and use it, I'll buy it from you afterwards for £10, providing it does what it says (before buying, you'd need to message the seller stating what you want it for, and if it doesn't do it when you get it, you can send it back free post).


Easy-to-use DC power ****yser 4 - 60V 0 - 100A for measuring power flow in a low voltage circuit, such as the flow - in Watts - and the cumulative rate of flow - in Watt-hours - from a solar panel or a DC wind generator into a battery.

Simple +positive/-negative (GND) two-wire input (‘Source’) and two-wire output (‘Load’) for series insertion into circuit.

Two-line LCD - updated every 0.4 seconds - displays eight different values:

• Power 0 - 6554 Watts to 0.1W resolution
• Current 0 - 100 Amps (max), 50A continuous, to 0.01A resolution
• Voltage 4 - 60 Volts to 0.01V resolution
• Power flow rate 0 - 6554 Watt-hours (Wh) to 0.1Wh resolution
• Current flow rate 0 - 65 Amp-hours (Ah) to 0.001Ah resolution
• Peak current in Amps
• Peak power in Watts
• Voltage minimum (dip) over monitoring period

Low in-circuit resistance just 0.001 Ohms – negligible 7mA circuit load.

Dimensions 84 x 50 x 20mm (L x W x D)

Package Includes:

1 x Watt Meter
1 x User Manual
 
Here is a very useful FAQ on batteries http://www.dcbattery.com/faq.html
Wikipedia also has some good info, but it's a bit TLDR http://en.wikipedia.org/wiki/Automotive_battery
I like this (Peukert's Law) LOL http://en.wikipedia.org/wiki/Peukert%27s_law

Note that a standard car battery is not a deep-cycle battery

Bear in mind that, even though the battery is not very old, there could be an issue such as overcharging. In fact overcharging may even have occurred and ceased, yet it will have reduced the battery's life.

Best way to check a car battery is actually to use a hydrometer to check the specific gravity of the electrolyte in each cell.
But failing that, if you get that Amp-hour meter and it shows little Ah over several days, the battery must be faulty (maybe the lead plates were sub-standard, even a Varta)
 
That little meter looks interesting wish the manual was available Duh !
Read a lot about batteries on the net and that "Peukerts Law" nearly did the old brain in.
Will keep volt monitoring and may try that meter, but am definitely going to probe the fuses when the lead gets here.
It was interesting to hear that changing a battery that had tested good, cured a similar problem. If I go down that road, I am leaning towards a Yuasa 80amp 760cca.
If I can't solve the 20ma issue then maybe the extra 6 amp capacity will buy me a couple of days extra time.
 
I'm beginning to think it's the battery tbh, and if the car is over-charging, it will keep on happening with any battery.

If the battery is faulty and there is not much current drain in the car, you'll never find anything, and only an Ah meter will show the actual current drain.

To carry on checking volts only, you need to put a load across the battery each time, such as a high wattage bulb, when checking the volts.

Peukert's Law is interesting, but no real use LOL. In fact one of the problems with that formula is that Ah of car batteries is not well defined, which is a problem anyway i.e. Ah does not really mean a lot, other than more Ah is better than less Ah. CCA is better defined, and is related to plate surface area. The CCA of the 2.4 is quite big, but only 45 Ah, so the battery in the 2.4 is not good for several weeks with the alarm connected. For that reason, I recommend disconnecting the negative lead on the 2.4 if leaving the car locked for a long time.
 
geoffdragon said:
Thats a curve ball !!!
Why would the car be overcharging ?
Don't know of any way to check short of putting a proper ammeter in line with the battery positive lead.
It would have to be a high reading one as I think the alternator is rated at around 120A.
By the way that meter is also on the bay for £12.54.
http://www.ebay.co.uk/itm/111483996597?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Click to expand...
many reasons for overcharging, but it does happen, and I don't think it has to be by much. You don't measure charging current, you measure charging voltage. I'll have a look on the Honda e-manual (DVD) what it should be.;

If I were you I'd get one of those meters, it should easily prove one way or the other.
 
Some very long testing procedures on the DVD, but IMO that A-h meter would be a much simpler diagnosis took than a lot of the complex crud on the DVD


For the charging voltage, basically it says

  • Start the engine. Hold the engine at 3,000 rpm with no load (shift lever in Park or Neutral), until the radiator fan comes on then let it idle.
  • Raise the engine speed to 2,000 rpm and hold it there.
  • Turn the headlights (high beam) on, and measure voltage at the alternator terminal.
  • Is the voltage between 13.9 and 15.1 V?
 
Interesting. The car always shows 14.2 to 14.4 volts on the voltmeter when driving.
Will try it with the headlights on tomorrow.
 
geoffdragon said:
Interesting. The car always shows 14.2 to 14.4 volts on the voltmeter when driving.
Will try it with the headlights on tomorrow.
Click to expand...
Not sure whether voltage should be higher or lower with headlights on, one could argue it either way. Note also that it says 2000 rpm with engine fully warmed up.

IMO 15.2 volts would definitely be too much, IMO that will cream-cracker a lead-acid battery over time.
And you never know, it might even be under-charging at say 13.8 volts.

You'd really need a calibrated voltmeter to be sure.
 
Have you checked the battery in the wife's car? Just on the off chance it's the same you could swap them over to see if this solves your problems
 
Thanks for the suggestion. No besides being a higher capacity it's physically bigger. But I could get one the same 80ah rating in the right size case if push comes to shove.
 
even if the batteries were the same, I wouldn't recommend beggering up the battery in her car too :lol:
 
Haha I don't think it's the car buggering the battery up.

Would be nice to disconnect the battery and check how much it drops when not connected to the car.
 
Thing is...if the draw is only 24 mA...then that is normal surely?...i.e. there isn't anything wrong.
 
I would have thought that but it flattened my battery in 10 days. Only thing could be that the battery wasn't full when the car was left. Want to be belt and braces not to get problem when airport parking. Will check alternator output later.
 
So ask hotel to let you disconnect battery otherwise put wife's battery plus jump leads in boot.

Job done without spending any more time or money :)
 
If I were you, I would have bought that little meter and fitted it by now. Don't forget that "distance selling laws" apply to ebay "Buy-It-Now", so if it's not up to expectations you can send it back. Indeed, if you don't like the look of it, you can send it back.

Anyway, there are 4 possibilities
1. there is sufficient "drain" to flatten the battery over several weeks
2. charging system is over-charging
3. charging system is under-charging
4. old battery went faulty, and new battery was not "perfect" when you bought it

By buying that meter, you can then easily evaluate point 1.
By using that info in #38 you can evaluate (though you may not be 100% sure of) points 2 & 3

I actually do not believe it is point 1. Let's work it out at 24 mA ....

24mA is 0.5 Ah per day, which is 3.5 Ah per week.

By Peukert's Law, one would expect that a battery will live up to its full Ah spec, so the 45 Ah battery on the 2.4 car would take 12 weeks to go totally flat !!! But I can say from personal experience that the 45 Ah battery in the 2.4 car goes flat enough to not be able to start the engine in under 4 weeks, which means that the overall Ah drain on the battery from the alarm is more than 3.5 Ah per week. But what the drain is, is difficult to know, because I doubt if there is any formula that says how much Ah should be left in a battery for it to be able to give the CCA to start the engine in the car !!

Do checks 1 to 3 and you'll know what's going on. IMO it's number 4.
 
Does make you wonder if there is any underlying electrical issues with Hondas in general for instance my old man had a 2003 Civic and if left for 10 days whilst away on holiday the battery would be flat and he has the same thing with his 2010 Jazz, neither of which Honda could find any issues, Haven't had this yet with my accord as it gets used daily but afraid to leave it for any length of time due to this issue!! also I seem to remember you had an issue with the oil level sensor @Geoffdragon I wonder if this is not effectively switching off and causing rapid drain.
Cheers Pete
 
old cruiser said:
Does make you wonder if there is any underlying electrical issues with Hondas in general for instance my old man had a 2003 Civic and if left for 10 days whilst away on holiday the battery would be flat and he has the same thing with his 2010 Jazz, neither of which Honda could find any issues, Haven't had this yet with my accord as it gets used daily but afraid to leave it for any length of time due to this issue!!
Click to expand...
This "Honda" thing is a very curious issue indeed.

If the OP hasn't bought one of those A-h meters by this afternoon and taken me up on my offer in post #32, I'll get one myself as my car is SORN and parked up round the back of my house, locked, with the -ve lead disconnected. I would like to lock it with the alarm set, and that A-h meter would be great to monitor the battery drain (lift the bonnet once per week and look).

Now that I have discovered the existence of A-h meters for low-voltage DC, I want one, especially at < £15 !!! (incredible value for money IMO).
 
A few guys on the Isuzu Trooper forum have fitted solar panels to the roof of their trucks in order to keep the battery conditioned whilst not in use, maybe you guys could do the same :p

I'm quite interested in one of those amp hour meters, my Isuzu was slowly draining it's battery over the course of the week and would fail to start one morning after about 6 days on average (being used each day for my short commute), I've fitted a new battery but I'd definitely like to see if I've got anything draining the battery whilst the truck is locked up over night.
 
LOL. Anyway done some tests this afternoon, some easy to explain others not.
Alternator tested - as instructed. 2000rpm, hot, Dipped beam - 14.32v, Main beam - 14.27v.
That sounds OK to me.
Fuse pulling excersise.
Fuse 7 Underbonnet - 6ma. I think thats the control block.
Fuse 15 Underbonnet - 20ma. That controls fuses 5,6,7,8 and 9 Under dash.
Fuse 7 Under dash - 16ma. That took a but of finding because the current didn't drop until 5 seconds after pulling fuse.
From the list I have ( which may or may not be for the diesel model ) That fuse controls Combination switch control unit, Guage control module, Immobilizer control receiver, Immoes control unit,
Navigation control unit, Navigation unit, Power tailgate (which I dont have ), Ultrasonic alarm, Alarm control siren, Multiplex integrate control unit.
Maybe someone can confirm these fuse listings.
If they are correct, I guess they are all supposed to be powered up when car standing.
I know I'm missing a couple of milliamps but there you go.
And it's time for a bigger battery.

I did ask the seller if the meters are suitable for our purpose but they haven't come back to me yet.

As an aside, I had a Trooper 3.1 and that had twin batteries fitted. never any issue no matter how long it stood.
I guess if yours is the later 3.0 it will have lots of electronic gizmos that the earlier one didn't have.
 
geoffdragon said:
Btw freddofrog I just bought on of the meters. It will come in handy for a lot of things.
Click to expand...
Charging voltages in #54 sound good.

I'll get one of those meters as well, I presume you got the £12.54 one that you found, I'm ordering the same one now.

I'm not sure if a bigger battery would help, it might, but not by much. That A-h meter will tell us everything we need to know about these Honda battery-drain issues.
 
It may tell us everything we need to know, including the fact that Honda squezed too small a battery in when there's probably toom for a tray for a type 100 there, but can we do anything about it. LOL
Thats the one I ordered.
 
I love threads like this, it makes one think "outside the box".

I've always wondered if such a device existed but never even tried to find out .....until now. As I say, the 45 Ah in the 2.4 does go flat over a few weeks if you don't disconnect, now I intend to find out why.

I just hope that these meters are up to the job :eek:
 
Just had a look in the handbook - for what thats worth and it recons Fuse 7 under the dash is for "back up lights".
Thats confusing.
Can anyone confirm the diesel fuse uses please.
 
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