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Lead Acid Sealed vs Odyssey 680 Question

Tcheairs

Well Known Member
According to numerous posts, quite a few Vans aviators are replacing the Odyssey 680 with sealed lead acid batteries due to the "fickle" nature of charging/re conditioning procedure required to maintain the life of the Odyssey AGM battery. Frequent flying with the alternator charging seems to be important for the maintenance of the Odyssey AGM battery. A desulfation procedure seems to be required for non frequent flyers also.

My question: Is the sealed lead acid battery less susceptible to improper charging procedures, ie. not so frequent flying, and use of trickle or batter maintainer chargers? Also, what is the down side of a sealed lead acid battery?
Comments on experience with the SLA battery?
 
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Using a lead acid battery in an aeroplane this far into the 21st century makes about as much sense as using feathers for ballast in a boat. Why wouldn't you get a lithium iron phosphate (eg. EarthX) instead? Last way longer, they don't mind sitting unused for months, and save you a bunch of weight that you don't have to lug up to 8,000' every time you go flying. Although they are more expensive upfront, they save a bunch in the long run.

Tom.
RV-7
 
So, you are saying that the Lion EarthX will tolerate infrequent flying and charging/maintaining better than the Odyssey? Can you be specific about which model (dimensions wise) would be used to replace an Odyssey 680?
 
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Tom, an Odyssey is a sealed lead acid battery. "AGM" simply means Absorbed Glass Mat. Think of the glass mat like a wet rag, a mat soaked with acid sandwiched between metallic plates.

Yes, lithium iron batteries (a different technology) reportedly maintain high charge levels much longer in storage than any sort of lead acid battery. However, that's probably the least valuable attribute. The big plusses are very high cranking amps with very light weight. Downside is an ugly failure mode which has involved smoke and melting battery cases, so you must be sure your airframe electrical system incorporates overvoltage protection before installing one. If inside the cabin or tailcone, some owners install them in vented cases.

The "fickle" nature of a PC680 in an RV is due to it being a minimal size for the Lycoming application. They work, and give good service, but there is not much margin.
 
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I would love to utilize a Lithium X battery in my aircraft. Picking up a Li Fe battery at the airshows almost seems like you're being pranked; the weight is so light. That said, the current forms do not come without their own sets of problems. Most everyone is familiar with the thermal runaway potential of Li Ion batteries. Very low probability but very high consequence.

Li Fe batteries have their own issues. A battery management system is another level of complexity and failure point. There was reportedly a rash of the subject OEM issues due to the BMS. My biggest concern = BMS actions under certain sensed conditions. The BMS can isolate the battery from the buss to protect the battery. These consequences can be huge depending on an aircraft's "essential" systems, electrical architecture, etc.

There's other pluses/minuses to the different tech which I believe have been hashed out here before.

Quick summary. There's no right or wrong answer to either. The OP gets to look at lots of opinions and gage his risk. Be cautious of anyone posting that their approach is "the best" without a decent level of substantiation. Just sayin'. Best of luck, Sir.
 
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The reason for my battery consternation is that when I key my comm radios the voltage drop is sufficient to interrupt power to some of my other components such as autopilot and EMS. I need to check my output from the alternator first and it's possible that my Odyssey 680 (installed in Feb this year) is faulty. So, lots of troubleshooting before i change batteries. I'm a little skittish about having LION sitting up there so may just stay with lead acid for safety's sake. FYI My batteries are located forward of the firewall. But that doesn't negate the fire emergency.

Thanks for the responses
 
Dan speaks wise words, as he says, the Odyssey is a splendid battery, requires a correct charger/maintainer, and should last ages.

Our RV7 has had 2 PC680's in 10 years. The old battery is still in the shop as a local 12v power source.

Our RV10 will have a PC-950 and will be many times better than a Concorde boat anchor battery....;)
 
The reason for my battery consternation is that when I key my comm radios the voltage drop is sufficient to interrupt power to some of my other components such as autopilot and EMS. I need to check my output from the alternator first and it's possible that my Odyssey 680 (installed in Feb this year) is faulty. So, lots of troubleshooting before i change batteries. I'm a little skittish about having LION sitting up there so may just stay with lead acid for safety's sake. FYI My batteries are located forward of the firewall. But that doesn't negate the fire emergency.

Thanks for the responses

First, most SLA batteries are AGM. They need the matt to be sealed, unless using gel, which is very different than AGM. Second, the voltage drop on transmit is very unlikely to be related to the battery.

Larry
 
Some thoughts:
- Never use a trickle/battery maintainer on an Odyssey battery. Not required and many can kill a good battery. A standard Odyssey battery will maintain a good charge for months.
- Do not “desulfate” an Odyssey battery.
- If you abused your battery (left a master on or such) replace it. It is no longer airworthy, even if you can breath some life back in it.
- Your problem with voltage drop could indicate a bad battery - but I suspect the root issue is a bad charging design that resulted in a bad battery. Here a diagram of your power distribution system would be very helpful.

Side not, I personally would not consider the EarthX type battery for my airplanes.

Carl
 
I have learned from personal experience that Dan is ALWAYS wise. A visit to his hangar is well worth the time and money.

Question: If i see 14.5v on the main bus (with my current battery) when the alternator is charging, does that not tell me that the alternator setup is doing it's thing?

I'll try to find and post the electrical layout among the 50# of build documentation that the builder gave me when the airplane was delivered.
 
easiest first

I have learned from personal experience that Dan is ALWAYS wise. A visit to his hangar is well worth the time and money.

Question: If i see 14.5v on the main bus (with my current battery) when the alternator is charging, does that not tell me that the alternator setup is doing it's thing?

I'll try to find and post the electrical layout among the 50# of build documentation that the builder gave me when the airplane was delivered.

The easiest thing to do is just check all your connections first.
Then put a voltage meter on your battery and key the mic. If the voltage drops a lot, it is your battery, if it doesnt, it is your system.
 
Check your belt tension before going crazy . . .

I have learned from personal experience that Dan is ALWAYS wise. A visit to his hangar is well worth the time and money.

Question: If i see 14.5v on the main bus (with my current battery) when the alternator is charging, does that not tell me that the alternator setup is doing it's thing?

I'll try to find and post the electrical layout among the 50# of build documentation that the builder gave me when the airplane was delivered.

Wait . . . DanH is charging for tours now? :D

You must get more information via some diagnostics or time and money is being wasted.

Yes, to your question . . if the alternator has 14.5 volt output then it is operating properly.

When keying the mic and having other stuff reboot, is this with the engine running? and buss voltage at 14.5? Does it drop? Amperage? While you may have a weak battery, the system would not have this issue when running as everything is running off the alternator not the battery.

If the voltage drops, you should see a corresponding increase in amps. If not, you could have a loose alternator belt. A load could cause it to slip, drop voltage and then when the load is removed, the alternator spins back up and restores voltage. The belt tension is most easily measured by holding the prop and measuring the slip torque with a torque wrench.
 
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So, you are saying that the Lion EarthX will tolerate infrequent flying and charging/maintaining better than the Odyssey? Can you be specific about which model (dimensions wise) would be used to replace an Odyssey 680?

The reason for my battery consternation is that when I key my comm radios the voltage drop is sufficient to interrupt power to some of my other components such as autopilot and EMS. I need to check my output from the alternator first and it's possible that my Odyssey 680 (installed in Feb this year) is faulty. So, lots of troubleshooting before i change batteries. I'm a little skittish about having LION sitting up there so may just stay with lead acid for safety's sake. FYI My batteries are located forward of the firewall. But that doesn't negate the fire emergency.

Thanks for the responses
I am not DanH so I guess you will have to decide if my post is worth reading. I could repeat what Dan and others have said but, let me just say, +1 for agreeing with their posts.

One thing that I will comment on is your repeat of saying you are “skittish about having a LION” battery. Please revaluate your knowledge about what others are saying about the EarthX LiFePO battery. It is NOT a LION battery! It is a Lithium (Li) Iron (Fe) Phosphate (PO) battery. Very different chemical makeup from the LION battery to which you have referred. That different chemistry has very different characteristics from a LION battery.
 
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The reason for my battery consternation is that when I key my comm radios the voltage drop is sufficient to interrupt power to some of my other components such as autopilot and EMS. I need to check my output from the alternator first and it's possible that my Odyssey 680 (installed in Feb this year) is faulty.... SNIP.....

If keying the transmitter drops the voltage that much, I would suspect a bad connection somewhere in the power feed to your radio, or the power circuit ground. Seems to me that otherwise it would take both a bad alternator AND a bad battery to produce the symptom you are reporting.
 
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We are not quite there yet.

If keying the transmitter drops the voltage that much, I would suspect a bad connection somewhere in the power feed to your radio, or the power circuit ground. Seems to me that otherwise it would take both a bad alternator AND a bad battery to produce the symptom you are reporting.

Pete we still don't have all the picture from panel information available. Low belt tension would cause this to happen and a weak battery at the same time.

He needs to do some more detailed examination to get a definitive diagnosis.

If this thread can stay on topic. ;)
 
Thanks to all for the responses. There’s plenty posted here to keep me busy with the troubleshooting. Either I (or an avionics shop) will get to the bottom of this. Could be RF interference and not a voltage issue. Thanks for the clarification about the EarthX battery as well.
 
Charging an Odyssey

I confess that I leave my 680 plugged into a Batteryminder for AGM that Odyssey has approved:

https://www.odysseybattery.com/wp-content/uploads/2020/05/ODYSSEY_approved_12V_chargers.pdf

May well be unnecessary, but it saves me if I leave the master on. Totally agree that the battery is toast if you abuse it. They can usually be brought back to life but they just won’t be reliable after that.

In general I’ve been very happy with the 680. One nice feature is that they are fairly easy to find if you kill one on the road. Ask me how I know. :)

Some thoughts:
- Never use a trickle/battery maintainer on an Odyssey battery. Not required and many can kill a good battery. A standard Odyssey battery will maintain a good charge for months.
- Do not “desulfate” an Odyssey battery.
- If you abused your battery (left a master on or such) replace it. It is no longer airworthy, even if you can breath some life back in it.
- Your problem with voltage drop could indicate a bad battery - but I suspect the root issue is a bad charging design that resulted in a bad battery. Here a diagram of your power distribution system would be very helpful.

Side not, I personally would not consider the EarthX type battery for my airplanes.

Carl
 
If you leave your master on with an AC powered charger, it has enough noise on it to trash many sensitive items IF powered with the master. Plus, the master is 2 amps drain and may cause the charger to call a bad battery and not save a discharge.
 
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Leaving the master on

For whatever reason, the Batteryminder seems to bail me out with no issues. I think my only drain with the master on is my electronic ignition.

If you leave your master on with an AC powered charger, it has enough noise on it to trash many sensitive items IF powered with the master. Plus, the master is 2 amps drain and may cause the charger to call a bad battery and not save a discharge.
 
For whatever reason, the Batteryminder seems to bail me out with no issues. I think my only drain with the master on is my electronic ignition.

If the master controls the power to your electronic ignition, it is not wired properly.

Check your installation manual for correct wiring method before your next flight.
 
I fitted a rotary switch battery isolator accessible thru the oil dip stick door on my 8, also acts as a anti theft device as it can’t be seen only felt.
I fitted a Fullriver HC20 AGM battery, a 680 clone half the price:)
 
If the master controls the power to your electronic ignition, it is not wired properly.

Check your installation manual for correct wiring method before your next flight.

From E-mag manual:

Note 1: Whenever the aircraft bus is powered up, the ignition is “awake”. It draws a small amount of current even when not firing the plugs. Use the main bus switch (or breakers if necessary) to power down the ignitions when not in use.

Note 2: DO NOT power the ignition ON if/when you have a battery charger connected to the bus. Some chargers are designed to pulse the battery with high voltage that can damage electronics.
 
From E-mag manual:

Note 1: Whenever the aircraft bus is powered up, the ignition is “awake”. It draws a small amount of current even when not firing the plugs.


Yes, the P-mag is an odd exception. I think they specify connection to the main bus for operating simplicity when paired with a magneto, which makes sense. Both ignitions are ON-OFF using a p-lead switch, and the mag keeps the engine running even when the master is off and RPM goes low.

Given a lot of owners install a test switch in the power line anyway, it can be wired battery direct like the rest of the EI's, with four toggles for a dual install. I'd argue a dual P-mag setup should be wired battery direct. I recall at least one owner who killed the master in flight, then lost engine power on short final when the P-mag internal alternators couldn't fire the ignitions at low RPM.
 
From E-mag manual:

Note 1: Whenever the aircraft bus is powered up, the ignition is “awake”. It draws a small amount of current even when not firing the plugs. Use the main bus switch (or breakers if necessary) to power down the ignitions when not in use.

Note 2: DO NOT power the ignition ON if/when you have a battery charger connected to the bus. Some chargers are designed to pulse the battery with high voltage that can damage electronics.

I have two PC680s in parallel and have had no reason to re-think that approach. I can’t imagine that any other battery technology would improve things for me or solve a particular problem. I’m not very familiar with LiFeION batteries, but really haven’t had the need to investigate.

For years, the previous owner of my airplane kept these two batteries on a plain old hardware store float charger. Worked fine but that finally went belly up after I bought the plane so I replaced it with an OBC-6A Odyssey charger, which is a float charger and has all the conditioner doo-dads. I just leave the plane plugged in when not flying, per Odyssey’s recommendations. That plan is working fine so far, although unlike the previous little maintainer, I note that turning on the avionics with the OBC-6A connected results in a pulsing static noise. through the headphones from the radios. No harm done, but I don’t do that anymore.
 
My apologies for the drift. Do the 680s fare well forward of the firewall? Blast tubes required? What do you know/what are your experiences?

Thanks
 
My apologies for the drift. Do the 680s fare well forward of the firewall? Blast tubes required? What do you know/what are your experiences?

Thanks

My 680's (and cheap clones) have been happy on the engine side of the firewall of my RV-6 for many years. I think that is the default location for the RV-7.
 
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