Over-Voltage

[gderamel]

Just yesterday, I started getting an over-voltage (OV) indication on the "#2" side (right side) of the voltage display. It was sporadic, dancing between 14.9v to 15.0v. Wondering what's causing this and how to fix it?

A friend/AP/IA suggested an over-voltage condition can happen when a battery is starting to fail. Oddly, I just installed a NEW Odyssey PC680 battery (primary batt). I fastidiously keep the battery charged with the NOCO Genious G3500 12v safe charger after every flight.

Also, would someone explain why the two voltages? Is the left side (#1) the Primary battery, and the right side the Emergency Backup Battery? When I do the preflight Ignition check, with the key on Right "mag" (electronic Ignition) and the Emerg. Backup Battery switch "ON" the #1 or #2 voltage drops to 12.0v (ish) and the other voltage stays at 14.4 (ish). I'm assuming the 14v is showing the charging Primary BATT and the 12v is the current state of the Backup BATT?

Note: the attached picture does not show the over-voltage condition. I took the picture for another issue regarding the high/low CHT spread between the front and rear cylinders. Clearly, on colder days, the front cylinders needs better baffling.

Equipemnt:
- Garmin G3X Touch running version 4.10 software
- Odyssey PC680 Battery
- NOCO Genious G3500 12v safe charger

[ceslaw]

Could the back up battery be the issue? Loose connections? Due for replacement?

[gderamel]

Could the back up battery be the issue? Loose connections? Due for replacement?

Problem seems to be fixed! I replaced the Primary battery (Odyssey) with an EarthEx Lithium battery and the voltage is back to normal... so the Odyssey must have been failing. Weird, as I just bought it in August and its only seen 2 months use -- first cold-ish flight and adios, not good.


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[Daveembry]

Problem seems to be fixed! I replaced the Primary battery (Odyssey) with an EarthEx Lithium battery and the voltage is back to normal... so the Odyssey must have been failing. Weird, as I just bought it in August and its only seen 2 months use -- first cold-ish flight and adios, not good.


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Which Earth X battery did you get and where did you get it? (Cost?)

[gderamel]

Odyssey batteries seem to not do well if a battery maintainer is used. Keep them off the charger, fly often and they will last you many years. EarthEX is an excellent choice though.

Thanks for the info on the Odyssey. I wonder what the reason(s) for the battery deteriorating with the use of a maintainer??

Which Earth X battery did you get and where did you get it? (Cost?)

I purchased the EarthX ETX680C ($380?) directly from EarthX. I'd discourage buying elsewhere... I had an issue with the first battery and they immediately sent me their latest version which has an additional (redundant) fault protection feature to protect it from not waking up from 'safety mode.'

Having used both the Odyssey and the EarthX... I can provide the following PROS/CONS. I'm only providing my thoughts on limited knowledge of each, and by no means this is not meant to be an extensive comparison. Feel free to add/subtract your own pros/cons.

EARTHX ETX680C
PROS:
- Extremely compact and light weight (3.9 lbs!)
- No maintenance and advertised 8 yr life
- Excellent Cranking power (turns prop without any hesitation)
- Lithium Iron Phosphate (LFP) (LiFePO4) - per wikipedia LFP technology does NOT explode following a short-circuit, however tradeoff with LFP technology is that it has "25% less capacity than other lithium batteries due to its material structure."

CONS:
- Carefully Read about the battery's Fault Protection feature... this can be a deal-breaker for folks running dual electronic ignitions a) if battery voltage falls below 11v, the battery 'turns off' - completely! b) can't jump the battery like a Lead Acid - re-awakening battery requires a semi-complicated procedure which requires their special Battery Charger and another healthy 12v battery.
- Expensive ($$$)


ODYSSEY EXTREME PC680
PROS:
- No Maintenance
- Inexpensive ($97 on Amazon)
- Keeps 'kicking' -- no Fault Protection
- Easy to Jump (hand-prop even with Electronic Ignition??)

CONS:
- Heavy (15.4 lbs)
- Cranking power not as good as the EarthX
- NEW Apparently doesn't like to be "tended" (battery maintainer) as evidenced by the Over-Voltage condition described/experienced

[Daveembry]

Thanks for the info on the Odyssey. I wonder what the reason(s) for the battery deteriorating with the use of a maintainer??



I purchased the EarthX ETX680C ($380?) directly from EarthX. I'd discourage buying elsewhere... I had an issue with the first battery and they immediately sent me their latest version which has an additional (redundant) fault protection feature to protect it from not waking up from 'safety mode.'

Having used both the Odyssey and the EarthX... I can provide the following PROS/CONS. I'm only providing my thoughts on limited knowledge of each, and by no means this is not meant to be an extensive comparison. Feel free to add/subtract your own pros/cons.

EARTHX ETX680C
PROS:
- Extremely compact and light weight (3.9 lbs!)
- No maintenance and advertised 8 yr life
- Excellent Cranking power (turns prop without any hesitation)
- Lithium Iron Phosphate (LFP) (LiFePO4) - per wikipedia LFP technology does NOT explode following a short-circuit, however tradeoff with LFP technology is that it has "25% less capacity than other lithium batteries due to its material structure."

CONS:
- Carefully Read about the battery's Fault Protection feature... this can be a deal-breaker for folks running dual electronic ignitions a) if battery voltage falls below 11v, the battery 'turns off' - completely! b) can't jump the battery like a Lead Acid - re-awakening battery requires a semi-complicated procedure which requires their special Battery Charger and another healthy 12v battery.
- Expensive ($$$)


ODYSSEY EXTREME PC680
PROS:
- No Maintenance
- Inexpensive ($97 on Amazon)
- Keeps 'kicking' -- no Fault Protection
- Easy to Jump (hand-prop even with Electronic Ignition??)

CONS:
- Heavy (15.4 lbs)
- Cranking power not as good as the EarthX
- NEW Apparently doesn't like to be "tended" (battery maintainer) as evidenced by the Over-Voltage condition described/experienced

Great info. Thanks much. Apparently you though the pro's outweighed the cons. Not being able to jump start and the fact it shuts down at 11v doesn't seem too good. I wonder if you couldn't just disconnect it and jump start? Probably wouldn't work because you need battery power to run the engine right?

[TroyBranch]

Odyssey batteries seem to not do well if a battery maintainer is used. Keep them off the charger, fly often and they will last you many years. EarthEX is an excellent choice though.

[EVRoosevelt]

I keep 3 Odyssey batteries on trickle chargers and they last around 2-3 years.
EV

[TroyBranch]

I keep 3 Odyssey batteries on trickle chargers and they last around 2-3 years.
EV

Never trickle charged mine unless I played with the Efis for to long. Got 6 years out of my last one and was still turning the engine over very well when I changed it.


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[dayoung107]

Also, would someone explain why the two voltages? Is the left side (#1) the Primary battery, and the right side the Emergency Backup Battery? When I do the preflight Ignition check, with the key on Right "mag" (electronic Ignition) and the Emerg. Backup Battery switch "ON" the #1 or #2 voltage drops to 12.0v (ish) and the other voltage stays at 14.4 (ish). I'm assuming the 14v is showing the charging Primary BATT and the 12v is the current state of the Backup BATT?

This is a great question, hopefully the following will answer it.

When the backup battery is engaged it isolates the backup system such that only the backup battery is connected to the right-hand (R) ignition and only the R ignition is connected to the backup battery. This is done for two reasons.

The first reason is so that the pilot can check the operation of the complete ignition backup battery system at the pre-takeoff check. During normal operation the R ignition is running from the main battery that is tied in with the rest of the electronics. The backup battery is getting charged through a diode so that a main system low voltage condition cannot discharge the backup battery. This diode is the reason why there is a slight voltage difference between the main battery and the backup battery during normal operation. When the backup switch is turned on, the two electrical systems are separated, and the backup battery is no longer getting 14.4v from the alternator and it drops it's internal voltage. If the systems weren't separated, the pilot could not be sure that the backup battery is in good state because the alternator or main battery would still be providing the power that could mask any shortcomings in the backup battery. The same reasoning that this check must be done with the key in R, so that the L ignition system doesn't mask any problems by running the engine during the check of the R ignition system and the associated backup battery.

The second reason is that isolation, once that backup switch is engaged, none of the rest of the electrical system can interfere with that backup battery powering that R ignition.

That said, you are seeing normal operation when the main battery is still charging via the alternator and is at 14.4v (ish) and the backup battery drops to 12.0v (ish) because it is disconnected from the rest of the electrical system including the alternator.

I hope this answers your question and helps others in understanding the ignition backup battery system.

I also agree that is great info on comparing the batteries, thanks for sharing.