Backup battery low - charge?

[swatson999]

I think my backup battery has gotten low since I installed it maybe 9 months ago or so, as the SV shuts down before the 30 second timer expires when I shut off the master (this is all in the garage). I have not done the first engine start yet, but that's coming up in a few weeks, and I don't want the SV to drop off-line as I need it to see oil pressure, etc., on starting. I think all of my ground/assembly testing combined with just sitting (I know batteries will lose some charge even if they're not being used) has caused the backup battery to fall below the needed voltage.

Is there a way to charge it on the ground? I'd hate to have to shell out for a second backup battery, but what I read says that it will require some amount of time with the engine/alternator putting current on the buss and powering the SV.

Help?

 

[dynonsupport]

You need your system voltage to be above 12.25V. A battery charger will generally do this.

You can see the battery status (voltage and charging status) in the setup menu under local screen setup-> screen hardware information

 

[flyingboy]

Steve

For what it is worth I have had the same issue just due to time in the build. I have also had concerns with the start so I have installed an oil pressure light just adds some comfort while the screens are booting up. A very easy and inexpensive insurance option.
Cheers
Hugh

 

[larrynew]

Just a note to those with low Skyview backup battery issues. I'm charging my main battery (PC680) with a Schumacher 1.5A trickle charger and my backup battery continues to charge from Skyview even when it drops below 12.25V. At least the battery status number continues to go up. It took about an hour to go from 9.95 to 10.54V as the system (battery) voltage dropped very slowly. Also, the installation manual states:

"To conserve your aircraft battery, the SV-BAT-320 is only charged with [sic] SkyView detects your alternator/generator to be online."

I was concerned that I couldn't charge it while I'm still working on avionics in the garage but the trickle charger must make it think the alternator is online because it charges fine. Oh, and I'll be upgrading to the latest software version soon as I'm still doing installation.

 

[dynonsupport]

The SkyView does technically trickle charge any time it's on. The thing is, with a lithium-ion battery, voltage change from 9.95 to 10.54 volts is about 1% of the battery capacity. So it would take about another 99 hours (probably more) to fully charge that battery, instead of 2 when the SkyView above 12.25V. So we don't exactly consider it to be "charging". In fact, with a 30 second countdown timer, you would need to run SkyView about 1 hour after every power down just to recover the power used in the 30 second countdown.

 

[DonFromTX]

This seems to be a problem, not envisioned during engineering the system of course, of we who have a Skyview installed, with backup battery, and yet it will be quite some time before we actually are flying with a completed electrical system to recharge the backup battery.  Can you think of an easy quick way to keep our backup battery charged (or recharge it) while still building the plane?
I could envision a small wall charger used for many LiOn battery tools etc, that we could plug into the backup battery receptacle when needed. Would that work?.

 

[larrynew]

Any problem with running a battery charger (as opposed to a trickle charger) on the aircraft battery to get Skyview above 12.25v so it can charge the Skyview backup battery properly and faster?

 

[jakej]

No problem at all

Jake J

 

[larrynew]

No problem at all

Thanks, Jake. Tried it just now and the backup battery charges great. Just need to understand how not to damage my PC680 with the old style battery charger.

 

[DonFromTX]

I did that out of desperation, put the charger on the main battery, got the voltage up to 13-14 volts, and watched the standby battery start charging. Definite abuse of the main battery, but no other options have been presented.

 

[dynonsupport]

It is not an abuse of a lead acid battery, including AGM, to charge it at 14.7V or float it at 13.6V forever. You can actually keep an AGM battery at 13.6V with a power supply all day with no harm.

Your alternator is not a sophisticated charger and your battery will be subjected to that every flight...

Read the Odyssey manual here (page 12):
http://www.odysseybatteries.com/files/techbook.pdf