Electronic Rust Prevention systems - battery drain

[Lafia]

Hi All

I've read quite a few of the posts here relating to the electronic rust prevention systems and none of it is positive. My 130 had one fitted when I purchased it last year and although I was sceptical I didn't bother removing it. However now I'm wondering whether this unit could be the culprit in my slow but increasing discharge of the battery. Just lately I've noticed that I don't seem to have a full charge on starting up first thing in the morning, but during the day for work it has no problem with regular starts.
Last weekend I ended up with a nearly flat battery which I blamed on a rear door being left ajar overnight. After fully recharging and reconnecting the battery the engine started well and I had no problems during regular use for two days. I then left it in the carport for two days without use and it is now totally flat.
I think the light sequence has changed from the regular periodic flash on the rust unit to a sometimes continuous light or a more rapidly flashing sequence. It seems to be a bit erratic now.
So, my question is: Are these systems likely to fail like this and drain the battery in this way? If so, what is the best way to disable it? (I know I'll probably get the simple answer of "Just unplug it" but thought I'd best check to see if there are implications from the more knowledgeable out there).
Picture attached of the unit in question.

Cheers

[Bearman]

I don't think it will be the culprit. They do have a small discharge that will drain it over a couple of weeks if it is not run but not over a 2 day period.

[Leroy_Riding]

may as well toss it in the bin, my defender has surface rust in a fair few places, including front bar and rear mud flap brackets, and my car has been fitted with a electronic rust prevention uni from new. I don't see how they can actually work without having a real 'earth' but anyway.

I also doubt it will be the culprit, I doubt it has the ability to pull that much current from your battery to drain nearly overnight, as you yourself mentioned. the easiest test is to unplug it. this wont blow your car up or anything.

Leroy

[Mick_Marsh]

I'd say your battery is well past it's use by date. I'm tipping it's more than six years old. Buy a new one. If that drains after a week or so, you have a different problem. That's what I'd do.

[Lafia]

I'd say your battery is well past it's use by date. I'm tipping it's more than six years old. Buy a new one. If that drains after a week or so, you have a different problem. That's what I'd do.

That was my initial thought so I did in fact buy a new battery even though the old one didn't look too old (but without a date code there's no way to be sure), and it flattened that as well. So it looks like I have a different problem. I've had a spate of of wires chafing through recently so maybe it's just got to that age, but the slow drain has been there for ages.

I think I'll disconnect the rust unit though.
Thanks all for your thoughts.
Cheers

[manic]

Use a multimeter, measure current draw reading at the battery terminal and start pulling fuses till you see it drop.