BlackhawkSP
Well Known Member
For the builders that have, or plan on mounting the Earth-X battery on the firewall, I wanted to show what I did to protect/isolate the battery from the heat under the cowl. Everything was OK with mine till warmer weather set in. I took off for a long cross country at 78 degrees ambient and after 30 minutes of flight, I started getting the battery fault light 2 seconds on/2 seconds off light, which means the battery is above 150, or 170 degrees F (depending on which literature you look at), which is not good for longevity. I want this battery to be happy, and at $449.00 a pop for the ETX-900 (ACS price), I want this thing to last as long as possible.
Anyway, I solved my problem by fabricating a three-sided shroud, enclosing the top to bathe the battery in ambient inlet air taken from the top of the plenum above the engine. Since I did this, I haven?t had one overheating alert. This works. The shroud is about .060 to .075 larger in dimension that the outside of the battery box mounted on the firewall. This makes a curtain of cooler air around the front and sides of the battery box, and keeps the electronics (the BMS) cool inside the top of the battery case. I used 1 inch scat tube and two 1 inch flanges from ACS for the air connections. Since it?s a fairly snug fit on the box, the amount of air I?m taking off the plenum hasn?t raised my CHT?s , that I can tell. Also, I added heat shields on the nearest exhaust pipe and shielded below the battery bottom to protect from the convection heated air that happens after shutdown. This can actually melt/soften the molded battery case (this happened to my battery initially). The following pictures should explain things nicely.
Another ACS part shielding the exhaust pipe.
Here is the insulated shield I put under the battery/box on the firewall. It attached to the Adel clamp hardware for the pipe brace-no new hardware required.
The shield in place.
The box in place.
The flange installed where I took air from the plenum.
Here is everything hooked up.
The finished product: I added dielectric RTV to tighten up the air loss around the terminal penetrations. The top of the box is removable to allow access to the terminals. The exhaust of the cooling air shoots out the bottom of the shroud to exit the cowl bottom.
Anyway, I solved my problem by fabricating a three-sided shroud, enclosing the top to bathe the battery in ambient inlet air taken from the top of the plenum above the engine. Since I did this, I haven?t had one overheating alert. This works. The shroud is about .060 to .075 larger in dimension that the outside of the battery box mounted on the firewall. This makes a curtain of cooler air around the front and sides of the battery box, and keeps the electronics (the BMS) cool inside the top of the battery case. I used 1 inch scat tube and two 1 inch flanges from ACS for the air connections. Since it?s a fairly snug fit on the box, the amount of air I?m taking off the plenum hasn?t raised my CHT?s , that I can tell. Also, I added heat shields on the nearest exhaust pipe and shielded below the battery bottom to protect from the convection heated air that happens after shutdown. This can actually melt/soften the molded battery case (this happened to my battery initially). The following pictures should explain things nicely.
Another ACS part shielding the exhaust pipe.
Here is the insulated shield I put under the battery/box on the firewall. It attached to the Adel clamp hardware for the pipe brace-no new hardware required.
The shield in place.
The box in place.
The flange installed where I took air from the plenum.
Here is everything hooked up.
The finished product: I added dielectric RTV to tighten up the air loss around the terminal penetrations. The top of the box is removable to allow access to the terminals. The exhaust of the cooling air shoots out the bottom of the shroud to exit the cowl bottom.
