Battery Conditioner

Because I don't drive this car daily, I am always somewhat concerned about the state of the cars battery. A dead battery is not a minor inconvenience, Some lost settings can only be reset by the Aston Martin dealer.

When I purchased this car (2007 Aston Martin Vantage), all I got was an empty box that said: Battery Conditioner.

The term Battery Conditioner is Aston Martin's way of identifying a battery charger maintainer, sometimes referred to as a battery tender. A battery tender is different from a battery trickle charger.

The trickle charger administers a small, consistent charge to the battery, irrespective of the battery's condition. A battery tender however, determines the battery’s charge, then, if necessary, delivers a small charge to get the battery to full charge. After that it switches to just enough power to maintain the charge.

Reading the car's manual indicates that the factory Battery Conditioner attaches to a special plug in the trunk. Inspection of the trunk revealed no such plug. Instead all I saw was a Power Plug.

There is really no need to use the Aston Martin's Battery Conditioner. Any generic battery tender will do. I purchased an automatic battery charger maintainer from Schumacher designed for car batteries.

I sourced a cigarette lighter plug from my spare parts bin and connected it to the charger. The idea was to use the existing Power Plug port in the trunk to charge and maintain the battery.

Photographed below is the Schumacher charger mounted on the side of my garage shelf. A switched 110V power supply (Red arrow) was installed to power the charger.

I joined the cigarette plug wires to the charger wires by just screwing them together on the side of the shelf using two wood screws.

My problem with these low amp battery tenders is that I was never sure the damm things were working. Sure the lights were on, it emitted a comforting humming sound, but was it putting out any voltage?

More importantly, what was the current condition of the battery when this thing was attached?

I decided the solution was to attach a voltmeter in parallel to the charger. This way I could see the condition of the battery before the charger started and during the charging and maintaining cycle. The idea was that at any time I could see the battery voltage by just walking past the car.

I purchased a small DROK digital voltmeter. Specs DC 0-33 volts accuracy 0.02V. (Photographed below) Note that this unit has three wires. I only need two for this project. The red and green wires are joined together (Red Arrow)

I fabricated a holding surround and a small bracket that would mount close to the charger's connections screwed to the wood shelf as described prior. (Photographs below)

Note polarity of joined charger and cigarette lighter plug wires in photograph above (Red and Black Arrows)

The surround is designed to hold the voltage meter snug. The wires are then connected to the charger maintainer’s wires visible on the side of the shelf in photograph above. (Note, observe polarity here)

The cigarette lighter plug, connected to the charger maintainer, is plugged in the Power Port in the trunk. (Photograph below)

When the cigarette lighter plug was inserted into the trunk's Power Port, initial reading of the voltmeter was 12.87 volts (photograph below)

The charger maintainer is then powered on via the switch (Red Arrow photograph above)

Immediately the voltmeter reads 13.35 volts. After a few seconds it drops to 13.02 volts

As seen in the photograph below, the state of the battery is now readily available whenever I go into the garage. (Red Arrow)

For me this solves two problems. At a glance I not only know the state of the battery, but also whether the battery maintainer is working.



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