Clock backup battery?

[Nioreh]

I have a master battery switch which I turn off when not using the car, since I don't have access to a battery tender where I park it. This makes the clock in the center console forget the time. Is there any way to wire in a backup battery for it? What have you done in your cars?

[Rich]

I have a master battery switch which I turn off when not using the car, since I don't have access to a battery tender where I park it. This makes the clock in the center console forget the time. Is there any way to wire in a backup battery for it? What have you done in your cars?

This solved that problem for me:

I bought a reproduction clock for the car 2 years ago from a fabricator/seller in Germany. It has a dedicated internal backup battery as you request. Mine has been fantastic. Here's a thread about this clock. (https://dmctalk.org/showthread.php?14994-VFD-replacement-clocks) (VFD = vacuum fluorescent display, the technology the OE clock uses)

It looks and works the same as the factory clock except:

a. It normally on the car's voltage but also has a replaceable (3yr) coin cell battery in it so the clock won't lose the reference time if the car's battery is disconnected. The coil cell doesn't run the clock display - it only keeps the clock's time going in memory when 12VDC is off.
b. It keeps near-perfect time, unlike most of the DMC OE clocks. I never need to adjust mine except when Daylight Savings comes or goes.

It dims slightly when the taillights or headlights are on.

The clock includes the wiring you need for plug and play reusing the OE clock connector. The display and circuits fit inside the OE clock housing. The OE clock lens and black plastic housing are reused as are the two OE time adj. pins. No glue, no soldering. Comes with very good installation photos and instructions in English.

[David T]

I have the ASI radio with the clock built in. I took the fuse out that powers the radio when it is off and stuck a wire with a fuse in it and ran it to the master switch so the radio (and the clock) always has power. You can't see the time when the car is off but it holds the time so when you turn the master on and start the car the time and the radio presets are all still there.

[Nioreh]

This solved that problem for me:

I bought a reproduction clock for the car 2 years ago from a fabricator/seller in Germany. It has a dedicated internal backup battery as you request. Mine has been fantastic. Here's a thread about this clock. (https://dmctalk.org/showthread.php?14994-VFD-replacement-clocks) (VFD = vacuum fluorescent display, the technology the OE clock uses)

It looks and works the same as the factory clock except:

a. It normally on the car's voltage but also has a replaceable (3yr) coin cell battery in it so the clock won't lose the reference time if the car's battery is disconnected. The coil cell doesn't run the clock display - it only keeps the clock's time going in memory when 12VDC is off.
b. It keeps near-perfect time, unlike most of the DMC OE clocks. I never need to adjust mine except when Daylight Savings comes or goes.

It dims slightly when the taillights or headlights are on.

The clock includes the wiring you need for plug and play reusing the OE clock connector. The display and circuits fit inside the OE clock housing. The OE clock lens and black plastic housing are reused as are the two OE time adj. pins. No glue, no soldering. Comes with very good installation photos and instructions in English.

That looks really nice, it might be an option.


I have the ASI radio with the clock built in. I took the fuse out that powers the radio when it is off and stuck a wire with a fuse in it and ran it to the master switch so the radio (and the clock) always has power. You can't see the time when the car is off but it holds the time so when you turn the master on and start the car the time and the radio presets are all still there.

Yeah, I guess doing a wire straight to the battery just for the clock should be an OK solution. I guess it won't pull much current, and can survive for quite some time before draining the battery.

[DMC-Ron]

Yeah, I guess doing a wire straight to the battery just for the clock should be an OK solution. I guess it won't pull much current, and can survive for quite some time before draining the battery.

My car also has the AST radio and I was considering just adding a small AGM battery to keep the radio settings and time. I measured the current draw of the radio when powered off at 15mA. I had a compact battery that would work but it was only 9 amp hour (AH). It would have only lasted about a month. This got me curious as to how long the regular car battery would last. Typical car battery is 50 AH so it would keep the memory alive in the radio for 140 days. But wait, if I want enough left in the battery to start the engine it's down to 97 days.

I would expect the current draw for the console clock module would be less than the radio. I have not been able to measure one but if I were to guess 8mA, the duration would be 260 days, but after 182 days you might not have enough battery left to start the car. Obviously, a lot depends on the capacity and condition of the car battery.

Ron.

[David T]

My car also has the AST radio and I was considering just adding a small AGM battery to keep the radio settings and time. I measured the current draw of the radio when powered off at 15mA. I had a compact battery that would work but it was only 9 amp hour (AH). It would have only lasted about a month. This got me curious as to how long the regular car battery would last. Typical car battery is 50 AH so it would keep the memory alive in the radio for 140 days. But wait, if I want enough left in the battery to start the engine it's down to 97 days.

I would expect the current draw for the console clock module would be less than the radio. I have not been able to measure one but if I were to guess 8mA, the duration would be 260 days, but after 182 days you might not have enough battery left to start the car. Obviously, a lot depends on the capacity and condition of the car battery.

Ron.

If I don't use the car I put a Battery Tender on it for 1 day once a month (I do it the first day of each month so I know when to do it). That is enough to keep the battery charged more than enough to start the car. On other cars I have with a lot of computers, they need to have the Battery Tender every 2 weeks or the battery gets too low! You can tell because during cranking all kinds of weird things happen because the voltage gets too low, the computers don't like low voltage!

[OZ DMC]

This solved that problem for me:

I bought a reproduction clock for the car 2 years ago from a fabricator/seller in Germany. It has a dedicated internal backup battery as you request. Mine has been fantastic. Here's a thread about this clock. (https://dmctalk.org/showthread.php?14994-VFD-replacement-clocks) (VFD = vacuum fluorescent display, the technology the OE clock uses)

It looks and works the same as the factory clock except:

a. It normally on the car's voltage but also has a replaceable (3yr) coin cell battery in it so the clock won't lose the reference time if the car's battery is disconnected. The coil cell doesn't run the clock display - it only keeps the clock's time going in memory when 12VDC is off.
b. It keeps near-perfect time, unlike most of the DMC OE clocks. I never need to adjust mine except when Daylight Savings comes or goes.

It dims slightly when the taillights or headlights are on.

The clock includes the wiring you need for plug and play reusing the OE clock connector. The display and circuits fit inside the OE clock housing. The OE clock lens and black plastic housing are reused as are the two OE time adj. pins. No glue, no soldering. Comes with very good installation photos and instructions in English.

I think I need one of these clocks. Are they still available ?

[Rich]

I think I need one of these clocks. Are they still available ?

I don't know whether they are still available. I think they are.

You can PM the vendor, username Yoda, as shown in the thread that was linked in an earlier post. Here is the link to that thread (https://dmctalk.org/showthread.php?14994-VFD-replacement-clocks/page10) again.

Note my Post #94 in that thread for details about connecting with the vendor.

I sent the vendor your question just now, suggesting he also post an update.

His clock really is a great solution.

[Yoda]

Yes, the clocks are still available.
THANKS Rich for stepping in here.
Just drop me a note via PM and we
can clarify exactly what you need.
:yoda: