Battery management

[edwalker]

Several of the owners have been having an email exchange about battery management that is worth preserving in this archive. In my aircraft, SN05, I have an auxiliary battery mounted behind a bulkhead immediately to the rear of the passenger seat with a battery switch and extra outlet immediately above on the shelf. I did some testing this weekend to tease out some of the connections.

The battery switch has 4 positions: 1, 2, 1+2 and Off. I didn't know about the off position until this weekend. It takes both batteries off the bus completely. The panel-mounted DC outlet is switched by the master, however the shelf-mounted outlet is always on even if the master is off AND the battery switch is off. It appears to be wired to one or both batteries, not sure. This means that one or both of the batteries can be trickle charged without the master being on. It's hard to trace the wiring, but someone with better equipment might be able to sort this out.

Several of us with Dynon glass panels observed that the 18 Ah aux battery gets used up fairly quickly if the Skyview is left running. There are at least two reasons why one might want to leave it running. First, according to Dynon the XPDR and ADS-B cannot be run separately, so they are disabled with Skyview power down. I've been impressed over and over about the ADS-B, so I'm reluctant to shut it down anymore. Second, flight timers no longer run. The second is really just a nuisance, but one needs to remember to keep an alternate timer going, and your SV log is going to reflect lower than actual operating times. This can be adjusted in the SETUP menu, however.

Some of the owners are considering adding an Aux2 secondary 18Ah battery in parallel to the Aux1 existing installation. Another possible workaround is to prepare a battery with an extension cord that can be plugged into the DC outlet and strapped into the passenger seat. Both DC outlets have 5A fuses, so this seems to be a good solution to keep the Skyview running.

Another point is that about half the SV power drain is screen brightness, and there is a manual control for dimming the screen. That frees up about 2A per hour.

I've become quite religious about reserving the main battery for engine starts only and keeping the soaring on the Aux battery. The option of having more power is attractive.

[kd6veb]

Hi Gang

We all have different perceptions on what we want from our batteries and panel equipment. Some of it depends on our flying desires. I rarely do more than a 4 hour soaring flight and I set up my system to be optimum for that. At all times my battery switch is set to both on. This includes charging with a single maintenance charger. My equipment consists of a Garmin 496, a PNA flight computer using free LX 8000 software, transponder, radio and the factory installed glass panel with autopilot. I do not switch on or of any of the instruments when power flying or soaring. I like things simple. My system works well and I would recommend it to you all.

Dave