SonexBuilders.net

I've made cardboard models of several batteries and because it appears firewall space will be extremely limited for the Aerovee Turbo on my Onex tri-gear, I sent the following query to EarthX:

"Is there a reason why your ETX680 is listed in places as an aviation battery but the ETX36C is not shown as such? I have extreme firewall space constraints in a SONEX, LLC (ONEX ) tri-gear aircraft that I'm building with a turbo Aerovee engine. The smaller size of the ETX36C looks like it might just fit on the firewall. Don't think either the ETX 680 or the Odessy PC680 are going to work given their dimensions. Other than dimensions what are the differences between your 680 and 36C as it might impact an aviation application?"

Received the following reply which I thought might be of interest to others:

"Their battery management system is different in the aircraft batteries than the power sport batteries. We will be introducing the ETX680C that will be the exact size of the ETX36C in less than a month that will have all the redundant aircraft safety features that you should have. Thank you for the question and we will have exactly what you desire very soon! Keep a look out."

Tom Jones
Onex Trigear #0133
Aerovee turbo

Thanks for posting that. I'm glad to hear that they made changes in the management system to make the "aircraft" batteries safer for aircraft use. It would be interesting to know what those changes were. Hopefully it will do everything it can to keep providing power, even if it has to shut down the charging operation.

I ordered the EXT680 version specifically to have it be the same size as the Odyssey, only because it gives a fallback plan if the EarthX ends up not being reliable. I plan to move the battery somewhere behind the firewall either way, just to keep it out of the heat and out of the way of the turbo installation.

Cheers,
Rusty

13brv3 wrote:I ordered the EXT680 version specifically to have it be the same size as the Odyssey, only because it gives a fallback plan if the EarthX ends up not being reliable. I plan to move the battery somewhere behind the firewall either way, just to keep it out of the heat and out of the way of the turbo installation.

Just something to consider: given the history of lithium batteries, do you want the battery on the "wrong" side of the firewall? And in close proximity to a fuel tank?

mike.smith wrote:
Just something to consider: given the history of lithium batteries, do you want the battery on the "wrong" side of the firewall? And in close proximity to a fuel tank?

It's not ideal, but it's the fuel tank I'd rather move ;)

Seriously, these are a relatively safe variety of lithium, and they're electronically controlled, so the risk is probably minimal.

Cheers,
Rusty

13brv3 wrote:

mike.smith wrote:
Just something to consider: given the history of lithium batteries, do you want the battery on the "wrong" side of the firewall? And in close proximity to a fuel tank?

It's not ideal, but it's the fuel tank I'd rather move ;)

Seriously, these are a relatively safe variety of lithium, and they're electronically controlled, so the risk is probably minimal.

Cheers,
Rusty

That's probably what Boeing said about the 787 :-(

mike.smith wrote:

13brv3 wrote:I ordered the EXT680 version specifically to have it be the same size as the Odyssey, only because it gives a fallback plan if the EarthX ends up not being reliable. I plan to move the battery somewhere behind the firewall either way, just to keep it out of the heat and out of the way of the turbo installation.

Just something to consider: given the history of lithium batteries, do you want the battery on the "wrong" side of the firewall? And in close proximity to a fuel tank?

Remember these are lithium iron (phosphate) batteries.
Although they are not as light as the classic lithium ion batteries found in your phone (or the 787), they are much more stable.

Thinking one of these might be nice in my Waiex when I get the new CAmit3300 installed. Will definitely help with some weight offset.
I'm curious as to why, on their site, they indicate this battery will not work in a four sided battery box. The dimensions of an Odessey PC625(my current battery at 13.1lbs.) and the XL680 are very similar.
6.7x3.9x6.95 for the Odessey. 6.5x3.1x6.6 for the XL680. What am I missing here.
Honestly don't know much about them. Expensive little buggers. Would be nice to offset the weight penalty on the newer engine. Would help in several ways. Pure weight savings and heavier engine would help with aft CG migration with fuel burn off.
With max seat load I've always run out of down trim after about 7 gallons remaining on fuel load. Could be a win, win.

LarryEWaiex121 wrote:I'm curious as to why, on their site, they indicate this battery will not work in a four sided battery box. The dimensions of an Odessey
PC625(my current battery at 13.1lbs.) and the XL680 are very similar.

Where are you reading this? All I see on the Sonex site is: "The ETX680 fits in the same battery box as the Odyssey PC680 battery used in many Sonex Aircraft"

Ryan,

I was on the Earth X site and it makes reference to the EXT680 fitting into battery boxes that previously held PC680 battery. I reread the reference to 4 sided battery boxes and now believe it will work if I'm reading the information correctly.
I'm still uncertain as to the operating temperatures listed in the specs. Seems the operating range is too low to be under cowl? More investigation necessary.

Larry

Hi Larry,

I purchased an EarthX 36E several months ago to lighten the forward CG for my CAMit. I am still installing, so I haven't needed it yet. I too was concerned about the max operating temp of 140 degrees. I was about to install a blast tube to the battery box to keep the temp down when Sonex came out as distributors. I can't remember what triggered me to check the operating temps for the my Odyssey 625 battery. The upper operating temp for the Odyssey 625 and 680 batteries is 113 degrees F, as per their website. Looks like I won't have to install a blast tube after all.

Ken W
Sonex 959