Backup battery isn't working

eswallie

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Jul 21, 2019
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Both my screens shut down in just a few minutes when my alternator is not putting out enough voltage (below 2700 rpm on Rotax). Isn't the backup battery supposed to kick in and carry the load?
 

preid

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A few reasons. I power up my plane on bu battery every time and have for three years, I also run the battery test every year. If it passes I continue using it, otherwise time fo replace.
opton 1 battery not connected- check battery status under setup
option 2 battery is dead if used for a while
option 3 not enough time to recharge the battery
let us know if one of these options applied.
 

eswalllie

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I have a similar problem.
Battery test ok and ran for 45 minutes on both screens.
Under battery status, the backup battery is connected and fully charged.
However, the aircraft battery voltage is just over 9 volts.
While taxiing, the alternator is not putting out enough voltage to charge the aircraft battery or Dynon backup battery (under 12.25V). After 10 minutes, one, or sometimes both of the Dynon screens shut off. Nowhere near the 45 minutes that the test showed. Shouldn't the backup battery last longer than 10 minutes in this case?
I get around this by taxiing at a high idle in order to get the alternator to put out more than the 12.25 V needed.
I know that the aircraft battery being so low is a problem and a new battery is on order, but it appears that the backup system is not working properly.
How do I know when the system is running on backup battery power?
Is there a recommended aircraft battery size or maybe a minimum ampere-hour size?
Ernie
 

preid

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If you go to setup screen there is the battery status under “local display setup/ battery backup status” that should show you the battery current change and you should see the battery volts diminishes, how quickly will tell you if the battery is reaching end of life.
as you covered;
you should also see a “caution” bottom right that tells you battery is powering the display.
SkyView system voltage is above 12.25V: SkyView runs on master power and charges the SV-BAT-320.
• If SkyView system voltage is above 10V, but below 12.25V: SkyView runs on master power but does not charge the SV-BAT-320.
• If SkyView system voltage is below 10V: SkyView runs on the SV-BAT-320. This discharges the SV-BAT-320.

it appears to me that the battery isn’t getting recharged enough between flights. But honestly this whole fast taxiing to get alternator working sounds odd overall.
 

eswalllie

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If you go to setup screen there is the battery status under “local display setup/ battery backup status” that should show you the battery current change and you should see the battery volts diminishes, how quickly will tell you if the battery is reaching end of life.
as you covered;
you should also see a “caution” bottom right that tells you battery is powering the display.
SkyView system voltage is above 12.25V: SkyView runs on master power and charges the SV-BAT-320.
• If SkyView system voltage is above 10V, but below 12.25V: SkyView runs on master power but does not charge the SV-BAT-320.
• If SkyView system voltage is below 10V: SkyView runs on the SV-BAT-320. This discharges the SV-BAT-320.

it appears to me that the battery isn’t getting recharged enough between flights. But honestly this whole fast taxiing to get alternator working sounds odd overall.
Thanks for the info.
Are you saying that "battery status" should show battery voltage going down while the system is running on battery? I guess it should run for 45 minutes as it did on the battery test.
At what voltage should the unit die?
Ernie
 

cbennet12

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Mar 21, 2011
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Thanks for the info.
Are you saying that "battery status" should show battery voltage going down while the system is running on battery? I guess it should run for 45 minutes as it did on the battery test.
At what voltage should the unit die?
Ernie
According to page 2-8 of the installation manual, the SV requires 10v minimum.
 

eswalllie

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I understand that it requires 10 V minimum.
If the voltage drops below 10 volts (which it is) the backup battery should kick in. In my case, I do not think the SV backup battery is going into backup mode because it shuts off after just a few minutes even tho the battery test ran for 45 minutes and passed.
How can I tell if the SV is going into backup battery mode? I get no indication that it is in backup mode.
Ernie
 

cbennet12

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I have never simulated an under volt bus condition but if I turn off the master, the SV prompts me to either confirm I want it to remain on (using b/u battery) or it will power down.

Sounds like a call to Dynon support is in order if your b/u battery passed it’s test.
 

preid

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cbennet is right.
You should see a 30 second (battery) countdown after shutting down plane with master off, if youre not, the battery isnt connected or working.
Try this (install manual 9-5 for more details)
Enter the Display Hardware Information Page (SETUP MENU > LOCAL DISPLAY SETUP > BATTERY BACKUP (SV-BAT-320) STATUS to check the status of the battery.
• BATTERY CONNECTED (BATTERY DETECTED): YES / NO
o WEAK BATTERY: SkyView detected a low battery voltage condition when SkyView was last shut down. The battery may be discharged or may need replacement. SkyView will annunciate a warning if this happens repeatedly.
page 9-6
This is what I was referring to previously for current status
BATTERY STATUS: (voltage)
• CHARGE STATUS: CHARGING/DISCHARGED/CHARGED/STANDBY/NO BATTERY


it may have passed the 45 minute test once, but since than maybe you've worn down the battery slowly. It takes almost 4 hours at above 12.25v to recharge a battery.
 

maartenversteeg

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I have never simulated an under volt bus condition but if I turn off the master, the SV prompts me to either confirm I want it to remain on (using b/u battery) or it will power down.

Sounds like a call to Dynon support is in order if your b/u battery passed it’s test.
In case you get that message you have 30 seconds to make the decision to either leave the unit powered from the backup battery, shut down immediately or if you don't do anything the unit will after the 30 seconds turn off automatically, so if you don't pay attention the unit might have powered itself down already
 

Raymo

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If I recall, the BU battery will keep power to the screens on low voltage only if it detects airspeed. Others had issues with it not turning off because airspeed was detected, though sitting in a hangar.
 

eswalllie

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What I am getting out of this is that the backup battery is not activated automatically if the Dynon detects a low voltage situation like aircraft voltage below 10 Volts, it also needs airspeed. If on the ground, it just shuts off. But if you are in flight, it will stay on and go to the backup system if it detects airspeed and low voltage.
If on the ground (no airspeed detected) the backup battery is activated only if the master switch is turned off (removing all power). You then are given the option to leave it on (the 30 seconds warning).
Do I have this right?
 

preid

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you should see the 30 second warning if the battery is running the display Air or ground. It should also give a CAUTION that it is doing so. Turn on your display using #1button on bottom, than power up the plane with master. Than power off the master and you should see the battery 30 second warning, if you do go to setup and see what the voltage of the bu battery is at, if no 30 seconds, you may have a separate issue all together that your battery isn’t kicking in when aircraft power is lost.

Get the install manual off the Dynon website and review 9-4 on about the details of the battery.
 
Last edited:

dbuds2

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Jan 18, 2009
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I rebuilt my Dynon BU battery with these batteries, https://www.amazon.com/5200mAh-Lithi...72710400&psc=1. My skyview still shows status standby with these and the original factory batteries. If i unplug the bu battery, the text on the setup page lights with yes/no, plugged in the text is unlit. Skyview isnt detecting or charging the bu batteries. With engine running, the system voltage is 13.2, the bu pack is around 11.5
 

dbuds2

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Both the original Dynon factory battery and the new ones show about 11.5 volts, but Skyview won't charge.
 

Rhino

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If your system shows STANDBY, then it is detecting the battery. It displays NO BATTERY if no battery is detected. What are your internal voltages showing? If none of them display FAIL, it is probably time to contact support.

 

dbuds2

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If your system shows STANDBY, then it is detecting the battery. It displays NO BATTERY if no battery is detected. What are your internal voltages showing? If none of them display FAIL, it is probably time to contact support.

Internal voltages? How do i see that? I have not seen a fail message.

Skyview shows 13.2 volts in the whole aircraft system, it shows ~11.2 in the BU batteries.
 

maartenversteeg

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dbuds2, take a look at the answer from Preid:
cbennet is right.
You should see a 30 second (battery) countdown after shutting down plane with master off, if youre not, the battery isnt connected or working.
Try this (install manual 9-5 for more details)
Enter the Display Hardware Information Page (SETUP MENU > LOCAL DISPLAY SETUP > BATTERY BACKUP (SV-BAT-320) STATUS to check the status of the battery.
• BATTERY CONNECTED (BATTERY DETECTED): YES / NO
o WEAK BATTERY: SkyView detected a low battery voltage condition when SkyView was last shut down. The battery may be discharged or may need replacement. SkyView will annunciate a warning if this happens repeatedly.
page 9-6
This is what I was referring to previously for current status
BATTERY STATUS: (voltage)
• CHARGE STATUS: CHARGING/DISCHARGED/CHARGED/STANDBY/NO BATTERY


it may have passed the 45 minute test once, but since than maybe you've worn down the battery slowly. It takes almost 4 hours at above 12.25v to recharge a battery.
 

Rhino

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Internal voltages? How do i see that? I have not seen a fail message.

Skyview shows 13.2 volts in the whole aircraft system, it shows ~11.2 in the BU batteries.
SETUP MENU > LOCAL DISPLAY SETUP > DISPLAY HARDWARE INFORMATION (right below battery management)

Skyview will not charge the battery if the system voltage is less than 12.5 volts. In that case it shows STANDBY. But depending on how your system is configured, system voltage may not be the same as aircraft voltage.
 

dbuds2

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Jan 18, 2009
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Took me a day to get back to the plane.

I powered up the Skyview with a long press of button 1 without powering up the plane with the master. Skyview started fine, so the BU battery is working.
1. This all unlite or dim : Battery Connected (Battery Detected) yes. Battery Status: 10.44V.
2. Powered the plane with master on: Battery Status: 11.18V. Saw a status of standby and charging cycle 2-3 times then steady with Standby.
3. Voltage reported by Skyview on the main engine page and measured with separate voltmeter; 13.1v.

Last time I flew and skyview was reporting 13.2v, the charging status never came up.

Thanks for your reply and input, what next?
 
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