EarthX STC approved!

[bfmetcalf]

I don't buy this explanation. People aren't (only) worried about killing their batteries; they're wanting to be sure they have enough Amp-hours to get out of the soup when the alternator quits. Concorde measures their capacities to an end-point voltage of 10V, a level at which the battery may be damaged but your avionics might still work. At this EPV the Concorde has 2x the amp-hours of the EarthX at an EPV of 11V (at which point I assume it shuts down).

P.S. I don't necessarily think that the 15.6Ah capacity of the EarthX is insufficient, but it certainly seems like it will provide less staying power in the event of an alternator failure and you'd need to run the numbers to decide if that's enough for you.

It's still not apples to apples. In bass boats, everybody is switching to the lithium batteries because of the additional power you get to your electronics. A 50aH lithium will run the electronics in a boat (fish finders, trolling motor, motor starter etc) for the same amount of time as a 100aH lead acid and has been proven again and again over on that side. You're still comparing apples to oranges when comparing simply aH ratings on lithium and lead acid.

 

[Eric Pauley]

It's still not apples to apples. In bass boats, everybody is switching to the lithium batteries because of the additional power you get to your electronics. A 50aH lithium will run the electronics in a boat (fish finders, trolling motor, motor starter etc) for the same amount of time as a 100aH lead acid and has been proven again and again over on that side. You're still comparing apples to oranges when comparing simply aH ratings on lithium and lead acid.

Maybe Ah in boat batteries are measured differently (e.g., at slower than C1 rate), or boat electronics don't tolerate any voltage dip. I don't see this necessarily directly translating to aviation, where batteries are tested to comparable cutoff voltages at C1 and electronics generally tolerate voltage dips.

 

[bfmetcalf]

Maybe Ah in boat batteries are measured differently, or boat electronics don't tolerate any voltage dip. I don't see this necessarily directly translating to aviation, where batteries are tested to comparable cutoff voltages and electronics generally tolerate voltage dips.

Amp hours are amp hours. Boat electronics don't tolerate voltage dips well (most shut off at 11 or so volts) so that is a good point. What voltage will a Garmin GPS stay on until or an electric gyro stay running at the proper speed for accuracy?

 

[Eric Pauley]

Amp hours are amp hours

I ammended my above comment after you quoted it, but this is not the case. Batteries can be measured at different discharge rates. Lead acid batteries are well-known to have lower Ah capacities at higher discharge rates. In the less-regulated marine space, it seems very likely that manufacturers would test their batteries at lower current to maximize stated life. Indeed, my (extremely cursory) analysis of marine batteries would indicate that these are usually tested at C20.

 

[bfmetcalf]

I ammended my above comment after you quoted it, but this is not the case. Batteries can be measured at different discharge rates. Lead acid batteries are well-known to have lower Ah capacities at higher discharge rates. In the less-regulated marine space, it seems very likely that manufacturers would test their batteries at lower current to maximize stated life. Indeed, my (extremely cursory) analysis of marine batteries would indicate that these are usually tested at C20.

I stand corrected on the amp hour comment.

But real world, guys are getting the same useage out of lithium batteries with 1/2 the ah capacity than the lead acid counterparts. With the stricter standards in aviation I would think it would be a very similar curve. My dad running his camper starting with lead acid and going to lithium has has pretty much the same experience as well. Twice the run time out of the same amp hour rating.

I'm personally not for or against either, but if I wanted the weight savings, I wouldn't hesitate to do the lithium earthx personally.