Internal battery not working

[redbeardmark]

I have a EFIS D10 with internal battery for backup power. It worked fine after the initial installation, but no longer. When I switch off the breaker-switch that is dedicated to the D10, the unit turns off rather than going to the internal battery. It is as if there is no longer an internal battery. Any thoughts?
Mark Andrews
p.s. I live in North Dakota and keep the airplane in an unheated hangar... is it possible that it got too cold and ruined the battery?

 

[dynonsupport]

Mark,
Cold shouldn't permanently damage the battery. It can reduce the capacity of the battery while it is cold, but not long term. Unless it got to -20 degrees C you should be fine.

First, can you turn the unit on when it doesn't have power? You should be able to power it on with the left button. If it does that, the battery is working. Also, just to check, you are aware that you have to press a button after the power is removed to keep it "awake." It counts down 30 seconds waiting for a button press and then turns off automatically.

You can do a quick check to see if the unit sees the internal battery at all. Go into the voltage meter (any key, more, info, left, vmeter) and see if any voltage is is listed next to the "I." This is the internal battery voltage. Fully charged is about 16.8V and empty is about 14V. If it's below about 14.5V, you need to leave the unit on for about 4-8 hours to charge the battery. You can turn the unit off with the button, but it needs to have master or keep alive power.

If the battery isn't showing up there, you can check the battery youself to figure out if it is the battery or your EFIS unit. You can take the battery out by removing the three screws at the bootm back of the unit that hold the door on. Right inside the door will be a connector that you must squeeze to allow it to pull apart. Once the connector is apart, you can use the cable to pull the battery out. With a voltmeter, check the battery voltage. If it is reading a voltage, we'll probably need to get the unit back, but if there is no voltage, it sounds like just the battery is broken and we'll just need the battery back.

Obviously only do this if you feel comfortable taking the back of the unit off and also measuring the battery. If not, do some of the diagnostic steps above and call us at 425-402-0433 and we'll set you up to get the correct parts repaired.

 

[redbeardmark]

Minus 20C? Let's see, that's about minus 4F. Yep, it definitely gets colder than that here in North Dakota. Seems we had a week or two of minus 20-25F(we were dreaming of warmer temps like... minus 4F).

I'll check the internal voltmeter readout on the display tomorrow.

If the battery is ruined from too much cold, there's not much point in fixing it as it will get frozen again next winter.
Mark Andrews
RV8A

 

[dynonsupport]

Mark,
We highly doubt that the cold hurt your battery. We had a bad batch of batteries a while ago, and from looking at our records, it looks like you have one of those battery packs. We've never heard of a bettery being damaged by the cold, and we've sold plenty of units to cold places like ND (and Sweden!).

If you could, please use the voltmeter that is built into the EFIS to check the pack. It is most likely reading zero. If it is, please remove the battery and give us a call at 425-402-0433 to arrange a replacement at no cost.

 

[redbeardmark]

Went to the airport today for a flight and checked the internal voltmeters:  main(M) is 14.6 V and internal(I) is also 14.6 V.  So, is it time to remove the battery and send it in? And, if the battery is removed, will the EFIS and blind encoder still work?
Mark Andrews

 

[dynonsupport]

Mark,
The EFIS and all of its functions will work fine without the internal battery.

However, that voltage you gave indicates a very low charge, but still working battery. Before you take anything out, I think that you need to try and let that pack charge up. A full charge takes about 8 hours, but you don't need to go that long to tell if it is working. Just leave the unit on for a while (in flight is fine) and keep the voltmeter up. Look and see if the internal battery is charging by checking to see if the voltage is going up. 16.8V is fully charged.

The reason we ask you to do this is that the problem may not be the battery pack, it might be the unit not charging the pack. We want to make sure we don't ask you to send back a good battery if the issue is in the EFIS.

Also, about what temperature do you estimate the battery is during this testing? There's a possibility the protection circuit on the battery won't allow it to charge at very cold temperatures but I'll have to double check that before we're sure of that.

 

[redbeardmark]

Well, after a couple hours of flight in warm weather (60-70F), the internal battery is registering 14.7V and the main is 14.4V. So, it must be charging.

I don't have "keep alive power" on the unit and perhaps during the really cold months when not flying much, the internal battery runs down. The reason for not wiring in "keep alive power" direct from the battery was the concern of running the battery down during winter. Is this an unreasonable concern? Perhaps I should wire in keep alive power?

So, it looks like no problem with the unit after all. This forum is a great idea and resource.

Thanks again for the assistance.

Mark Andrews RV8A

 

[dynonsupport]

Hi Mark,

Glad to hear that it's charging back up. As long as you have the latest software, hooking up Keep Alive to your EFIS shouldn't be a problem. It draws enough current to get the battery to a fully charged state. From then on, it only draws miniscule amounts to keep the battery topped off. The latest software optimizes this process and won't drain your plane's battery even over many months.

Let us know if you have any other questions or concerns.