Battery drain, help please!

[AlBundy]

Hi everyone, I have a 1986 1.6 Diesel that has a battery drain issue.

I have checked for parasitic draw and with the alternator disconnected I get 0.04. With the alternator connected i get 0.74. I cant post pictures unfortunately, says my region is blocked? I am in the UK.

Does this sound right, can an issue with the alternator cause this problem? I tested the other cables coming from the battery (battery tender cable, upgraded lights, and connection to Sargent EC155 and they don't seem to cause the same problem.

Due to go away in the van tomorrow with the family for 8 days, so its all a little last minute and I really don't want to cancel!

Thank you in advance.
Al

[Lillythefrenchie2026]

Long shot, but does your head unit have a contact live feed to it. I had this issue on mine when I fitted a new stereo.

[R0B]

If you type battery drain in the search box, there will be a few pointers there.

[AlBundy]

Thank you both, I had had a look through, and was mainly wondering whether it's worth working through all of the rest of the tests if my theory about the alternator is right, if it helps I can explain what I have done so far.

I removed all 'additional' cables that run either to or from the vehicle battery, and tested the drain by linking a multimeter between the -ive terminal on the battery and the -ive battery terminal cable, adding the cable connections one by one, and testing again. 

+ive attached to: Fuze box, lights, sargent ec155, battery tender
-ive wire attached to: engine block, battery tender

ampage when set to test 10amp, was 0.04.

+ive attached to: Fuze box, lights, sargent ec155, battery tender, and alternator
-ive wire attached to: engine block, battery tender

ampage when set to test 10amp was 0.55.

This to me suggests that testing the fuse board, upgraded lighting and Sargent system wouldn't result in finding anything as there wasn't significant draw from those systems (unless 0.04 is significant enough to completely flatten a battery in 5 days)

If this logic holds up, and there is a potential / probably fault with the alternator, then I can hopefully (if the wind blows in my direction) get a new one, fix that 'quickly', and my holiday is back on  

If this logic doesn't hold up, then I will likely need to send the van in to be fixed, and the holiday is off

E D I T: I also found that with the alternator attached to the battery the battery tender (that had been attached the whole week) wasn't getting the vehicle battery to go above 6.3v, when I removed the alternator cable and reattached the tender it had quickly gone up to 7.4v (and rising).
 

[firetrader]

From what I can gather its quite common unfortunately, someone put a post on here which was very helpful.It related to how the radio can cause the parasitic draw and steadily lower your battery reserve charge, they even put a remedy on, this entailed fitting an on/off with to the vehicle battery wired connection to the radio.I do think my van has this problem,(and maybe other ones) my radio can be turned on without the ignition being turned on, furthermore, if you disconnect the battery and reconnect it the radio comes on by itself, so one day will investigate how to fit the switch by reading the post again.In essence, every week I put a charge into the battery via a battery charger. Also as a classic car owner an experiencing many times a flat battery I have a vehicle jump starter power bank that I keep stowed away on board from Amazon. Maybe as your holiday is close you could take a small battery charger (Lidl do a good little cheap one around £15 that's small to stow away)and an Amazon power bank jump starter around £30 just to give you peace of mind?

[AlBundy]

Latest update.

The battery tender (which is supposed to be able to charge too) appears to have a fault of some kind. The vehicle battery had dropped to 6volts overnight from being around 8 volts when I last saw around 11pm, and the display on the tender had an error code. I have now removed that completely.

I got the van started using a booster, it started first time, and I tested the alternator at resting (12.6 volts) and at max revs and it only got to 13.4 volts.

I also tried to do the same parasitic battery test, and this time it came out 0.00? 

The lack of consistent results in testing is frustrating, and almost certainly down to use error although I am convinced I am doing the same thing for the parasitic battery test.

Where I am at the moment is that the battery tender was the primary cause of the rapid battery drain. This has been removed and will need to be replaced.

The alternator is not delivering a full charge at full revs, either due to poor connections (I can't remove and clean all connections, some are too stiff and will need some mechanical advantage I don't have at the moment), so the alternator is not firing on all cylinders, but should be enough to charge over a longer journey.

Should I risk it and just get going, or just take the tent and be done with it?

 

[Lillythefrenchie2026]

Can your radio be turned on without the ignition being switched on?

[AlBundy]

Yes, it does switch on, I have taken it out completely just in case.

Drove 4 hours and now set up, battery is full so alternator is working. Fingers crossed it works tomorrow morning!

[Alfredo]

While you are away, disconnect the battery overnight.

[Lillythefrenchie2026]

Can your radio be turned on without the ignition being switched on?

I would say theres a high chance your radio is pulling a feed even when it’s switched off. I had to fit an inline switch to mine as it kept flattening battery. Had no issue since.

[firetrader]

Searched high and low for the post showing how to fit an on off switch to the radio, can anyone point me in the right direction please?

[shepster]

Simple rocker switch on the live feed would do it surely?

[Lillythefrenchie2026]

Here you go.

This morning I also fitted a 12V inline switch to the head unit, as it has a permanent live and was draining the battery.

Any chance you could post some idiot proof instructions on how you did that please?

First off, disclaimer – I’m certainly no electrician!

So, what I did was buy a couple of inline switches from eBay, along with some terminal blocks and cable from Amazon.

On my stereo, the red wire is the main power (ACC), yellow is the memory feed, and black is the earth (yours may be different, so always check first).

I cut into the red wire and wired the inline switch into it. This interrupts the main power feed to the head unit, preventing it from having a constant supply. The yellow memory wire remains permanently connected, so the stereo keeps all of its settings, radio presets and paired devices.

Normally, the red wire would be connected to an ignition-switched feed, but my van doesn’t have one, so this was my workaround.

I mounted the switch next to the instrument cluster so it’s right in front of me and I remember to turn it off. I then extended the switch wires using two 2-foot lengths of cable, connected them to the switch, drilled the mounting hole, fitted the switch, and fed the cables through the dash to the back of the head unit.



I then cut into the red power cable and connected each cut end to one of the switch wires. Before permanently fixing everything in place, I reconnected the head unit and tested the switch. With the switch in the OFF position, the stereo wouldn’t power up. Flicking it to the ON position brought the head unit to life immediately, and all of my settings, radio presets and Bluetooth/CarPlay pairing were still saved thanks to the permanent memory feed.

Once I was happy everything was working as it should, I made sure all of the connections were secure and wrapped them well with electrical tape to keep them insulated and prevent any movement or vibration. Finally, I tucked the wiring away neatly behind the dash.

This modification worked for me.

[AlBundy]

I removed the radio completely last night, and the battery was full at the time. This morning we are down to 5 volts, completely flat. I will add that switch though, definitely helpful as the radio does draw from the vehicle battery.

Going back to my original theory that it is an alternator fault.

We're away in South Wales at the moment so if anyone happens to have a spare lying about that would be awesome. #longshot!

[hotpod]

5 volts sounds like your battery is knackered. 6v would give me an error code on my battery charger. In those situations I have to boost the voltage to 10 or 11 volts with an old fashioned charger before my smart charger will do anything. Also at that point I go any buy a new battery because the 5v one will be stuffed.
How old is it? I have in the past had batteries which would appear to take a full charge looking at the voltage but there really wasn't any Amps in them to do anything useful.
If your battery shows full charge but wont start the engine, then I would suggest a new one. If you get a new one, keep a close eye on it and disconnect it if it drops below 12v.

On a note re the stereo drain issue, I have noticed on many stereos in the past I have had to swap the red and yellow connections as they are sometimes the wrong way round for some reason. One of the wires from your van loom should have a permanent 12v  and one should have an ignition 12v. If the stereo can switch on without the key in the ignition then try swapping them. If both of your van ones are permanent live then something is miswired.