Thanks, Jeff. You put things in perspective and in order.
Is it true that, because of their internal construction, AGM batteries have lower internal resistance, and that enables them to deliver the higher amperage for cranking power than other types of lead-acid batteries? It's been a long while since I read up on them.
Dan Branstrom On 7/2/2022 8:01 PM, Jeff Scott via KRnet wrote:
I'm seeing a lot of misinformation about batteries being bandied about. There are three types of batteries. All have their good and bad points and any of the three types can be used with any type of engine. The most common is the old lead acid batteries. Of course they require a vented battery box and sometimes will spill acid, even if they are the sealed recombinant batteries. They also must be mounted with the terminals up to avoid spillage. The most popular now for a similar price is the AGM (Absorbed Glass Mat) type batteries. The most popular of these is the Odyssey battery, specifically the PC-680. They deliver good cranking power similar to the lead acid batteries and have as good or better life for a similar weight and price. Additionally, they can be mounted in any position with now danger of acid spillage. My experience has been that I typically get 7+ years of service from these batteries. The less popular, mainly due to price is the EarthX Lithium Iron batteries. Note that these are Lithium Iron, not Lithium Ion. They are not the highly flammable mess the Lithium Ion batteries are, but I see that incorrectly stated over and over as a criticism. It just ain't so. The EsrthX Aviation batteries have a redundant battery cell management systems on board now with a warning light to let you know the primary system has failed and that the battery is now operating on the backup system. They also have a wire that can be hooked ot a warning light on your panel or your electronic display to notify you to check the battery. However, in the case of a charging system runaway, the battery management system will disconnect the cells, so using this type of battery alone in a plane with an ignition system that requires a battery may not be the best idea. These batteries are also very expensive with starting costs close to $400 per battery. The big selling point is that this bat
te
ry weighs 4# as compared to 14# or more for your typical lead acid or AGM battery, and provides almost twice the cranking power as the Odyssey battery. Additionally, this battery can also be mounted in any position. I have used all of these types of batteries in my planes. The EarthX was a necessity for the raw amperage available when I had a plane with Emags to provide sufficient power for the Emags to fire while cranking on the high torque starter. But my choice for most applications seems to be the Odyssey battery as I currently have all three of my planes equipped with Odyssey PC-680 batteries. -Jeff Scott Arkansas Ozarks
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