Sneaky Amps

IPNRight after we installed the satellite TV antenna, we spent several days metering what it meant to us in battery consumption. The antenna and receiver are both 12 volt DC. The number we got was a bit steeper than we hoped for, but not outrageous.

And it was wrong.

Day before yesterday, I noticed all the status lights on the navigation laptop were off, and I knew we hadn’t shut it down. This is a ten year old IBM x40 Pro*. Given the way it has been treated, 10 years seemed a bit soon for it to drop dead, but it’s tech, so there is always the random element. The light on its 12 volt DC transformer/charger was on.

Then I noticed the router, which is on the same bus as the laptop, was frozen in stand-by mode. I touched the laptop transformer…and immediately unplugged it. It wasn’t, “melt things hot,” but it was too warm. My first thought was the after market battery in the laptop had failed.

I fired up the laptop using the 110 v AC charger and the battery was at 2.5%! Yep, failed!

Nope, it immediately began accepting and holding a charge. (Well, at least as well as it had been. Not all after market batteries are created equal, and this one is five years old.)

Apparently, the DC charger failed the day we fired up the satellite TV for the first time. Prior to the satellite TV installation we would have an early morning dockside deficit of about -50 to -60 amp hours (aH) (starting from zero about an hour before sunset). With the new TV antenna-receiver in use this had increased to -80 to -90. Like I said, not great, but not impossible. I attributed it to boat movements driving antenna realignment.

What I know now is the the laptop DC transformer shorted internally. With the laptop now charging off AC, our morning aH deficit is back where we expected it to be, about -5aH more than it used to be.

Clearly at anchor it will be greater than that because more antenna realignment is required.

So once again a battery charger failed us, and I am reminded that once again I need to check current draw on an item by item basis more often than I have been.

We ordered a new charger and will evaluate it here at some point. The ordering process was certainly easy.

*Reading this old x40 review with the current state of the art for digital devices in mind leaves me wondering just how much will things change in the next ten years?

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