Any ideas on how to keep the clock going when I disconnect the car battery?

[sujitroy]

I mainly use my Stag on weekends. I've observed as the car battery ages, It seems to drains without use. I use a quick disconnect and this seems to work

I'm working on Stag no. 2 and plan to add a disconnect to this one, but I'd like to keep the clock running.

I'm thinking of making a 12 volt battery pack out of a bunch of AA size rechargeable batteries and rigging up a charger for it. Are there off the shelf products available for such things?

Sujit

[mole42]

I use a screw type disconnector with a small fuse across it to run the clock. The only disadvantage is that the fuse blows if I try to start the car without remembering to screw the disconnect back in.

[bonnietiler750]

I seem to recall a kit that you could buy to allow the radio to retain its code whilst you removed the battery..It involved placing a car battery in the footwell and plugging a connector onto it and into the Cigar lighter..it kept the clock going as well...Just a thought

[Kithmo]

There are battery keepers that plug into the cig lighter. As said above, just put a small 12v in the foot well to save flattening your main battery.

[Kithmo]

Or one of these if you have light coming in to the garage:

[StagJonno]

I sometimes leave my car in the garage for up to 4 weeks without putting it on charge. This is with both the clock and radio memory still connected. If your battery is draining with these types of loads, then it's got to be either something is remaining on (eg boot or glovebox light) or your battery is approaching end of life. Suggest you address these and save the complexity and hassle of extra bits. A sensitive dc clamp-style ammeter can be very handy to measure current flows and identify circuits which may unknowingly be consuming current. Cost in the UK is ~£30.

I understand a tracker might consume ~1Ah per day, though this is only 7Ah per week (approx 10% of a newish 70Ah battery). Don't know if you've got one fitted. Also, as you may be aware, the cigar lighter remains live with the ignition off, so a SatNav or dashcam left plugged in will cause a drain.

Good luck

Jonno

[sujitroy]

For almost the 19 years of Stag ownership, I've been off and on trying to figure out what drains the battery. As mentioned as the battery ages, this gets worse. The only thing I haven't been able to check that someone mentioned - he diodes in the alternator (Mk1 could be leaky ) and that could be a cause for a drain. I have no clock. but do have a radio with a digital clock.

Now you mention it, maybe I should get my kid in the boot and see if the light comes back on when fully closed. ( hope I wont get arrested by a cop for going that)

The battery disconnect works for me.

I have no light in the garage. I do have a trickle charger but I still disconnect the battery. I do know that the quality of batteries in California has changed over the years. 20 years back you could get a battery with an 84 month warranty. Now 36 months at most .

Sujit

[barkerwilliams]

If I leave my battery connected when I return to the car a few days later the clock will be several hours out anyway. I have left the battery connected and the car unattended for over a month and it does not suffer from a drained battery. So I would agree check on the cigar lighter accessories /chargers / tracker, perhaps a modern radio draws some power when "off".

If car has had headlamp relays fitted it is possible that they have been fitted and it is possible to have the relays energised but the lights off depending on how they have been wired.

And of course old batteries have problems retaining charge over extended periods but if disconnected it would still discharge.

If you have a mobile phone with camera set it recording a video and place it in the boot and glovebox. The playback will show it the lights go out as they close.

Alan

[wilf]

It is a very sensible thing to disconnect the battery on a car that is infrequently used.

I know of two houses burned down because the car in the attached garage caught fire (alternator faults), and ISTR a Stag on this forum doing the same thing.

With an old car, I would always disconnect the battery after use, and use a "discarnect" device to do so. (good anti theft device too). My smart charger stays connected.

It might be a rare occurrence, but I like to stack the odds in my favour, especially when it costs little or nothing.

[Phil S]

get a battery isolator switch that allows a 3A feed to the clock/radio
the car can't be started but keeps the low amp feed with the key removed
Phil

[DJT]

https://www.demon-tweeks.com/uk/richbrook-discarnect-immobiliser-r-b1000-01/

also available on ebay. Type “discarnect” into the search field.