Disco 2 Battery drain

I’m fed up jump starting the disco every time I want to use it so decided today to do some investigation work.

The battery was changed end of July due to the same issue occurring which appeared to fix the issue howler it has manifested again in the last 4-5 weeks.

With the engine running the volts read 14.7. As soon as it stops this drops to 12.3 then slowly and steadily decreases.

I have disconnected the battery at the negative connection and put a meter across the lead and battery to show the pull on the battery (taken the lead from a google search so not sure this is the right thing to do?). The attached pictures show the result. 11.16 increasing to 11.18. Am I right in thinking this should only be about 0.03? The battery had dropped to around 10.36 after about 30minutes.

I have systematically one by one pulled each fuse to see the effect and there is none whatsoever. I am now at a loss.

I have disconnected any new items I have installed to take these out of the equation and again these have had nil effect.

The only other aspect I can think of is I do have a very leaky windscreen which is soaking into the headliner and I’m not sure if this could have any effect if it got into the electrics somewhere?

does anyone have any ideas or advice of next steps to find and fix this issue?

TIA!

Realised I had the meter on the wrong setting!!

I'll try again tomorrow on the right setting and see what we get then¡

SteJ said:

Realised I had the meter on the wrong setting!!

I'll try again tomorrow on the right setting and see what we get then¡

Click to expand...

A voltmeter in series will basically act as a large resistor and measures the voltage drop across its terminals. By applying Kirchhoff's Voltage Law and assuming that the battery voltage is higher than 11.18V when at rest, there is a voltage drop somewhere else of around battery voltage - 11.18V. It's not generally recommended to take voltage readings like this though especially on current sources as they could easily damage the measuring instrument.

You need your meter on its highest DC current range. Your meter will be will normally be fused for this setting, usually 10A.

How old is the battery, and have you had this tested. Does the battery hold charge if its disconnected overnight ?

would get battery checked if it's dropping below 11 volts may have damaged cell good old bosch have had several with cell failure , just because it has been replaced
does not mean it not the problem ,bring back the open cell battery's ,not the money spinning maintenance free ,if you had a good
hydrometer( specific gravity ) and a keen eye you could see the problem from discolouration to excessive bubbling on a individual a cell

Thanks for the responses. I think I've found the route of the problem and seeing as I find all the other posts useful thought I'd share my findings for others if they ever look like I do.

After my schoolboy error yesterday I have check the amps like I intended to and started with 0.19 pull. Reading around it is commonly fuse f12 which gets a response but this wasn't the case. Working through from there the sunroof fuse was removed and the reading dropped to 0.11. putting it back in it shot up to 0.40 before settling between 0.24.and 0.34. I know I've got a severe leak into the car from either the sunroofs or the windscreen so suspect this is the issue here. The job was high on the agenda to fix, it's not just shot up the list and the fuse is staying out. They're good in the summer the sunroofs but if the car don't move they're useless soni can live without them!

Following on I continued to check fuses one by one and got to the towing electrics and bingo, the reading dropped to 0.01. Obviously when I replaced the sockets I e connected something up incorrectly so will be looking at that in time. I only tow about twice a year so will leave the fuse out and replace when it's needed.

Lovely to hear you have found the two sources.
Personally I have never understood why my D2 has both sunroofs and aircon. My D1 only has aircon and it is just fine like that.
Lots of people just tape them up and forget them, but if you don't have aircon you may feel differently.
Amazing what you can do with an old skool cheapo electric meter, not that I have any idea of how "cheapo" your meter is!!

Right guys, I'm back again as it seems my solved problem has resurfaced! At first it was I thought due to not being used so my dad has had the car during lockdown to keep it running on his trips to work weekly however it seems it is parked up for a couple of days the battery needs a jump.
One comment above mentioned getting the battery tested. Can this be elaborated on i.e. can I do this myself?
Obviously as it's.less than 12months old I'll be contacting the company about it but would like to to keep my options open incase it is not the battery.

Cheers

Go to a Kwik Fit, and get it tested for free...

https://www.kwik-fit.com/batteries/information/free-battery-check

If you disconnect the battery, does it hold charge after a few days...