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EarthX blast tube

sahrens

Well Known Member
I have an EarthX 680 installed on the firewall of my RV-7. It has a dedicated blast tube for cooling (5/8"). I live near the coast so the OATs are pretty mild compared to the midwest. On my flight to and from Oshkosh the battery got pretty warm especially after engine shutdown (144F.) I am increasing the size of the blast tube and thought I would check with the collective.

If you have an EarthX battery on your firewall what diameter blast tube are you using? Are you measuring temperatures? And if so, what temps are you recording on 90+ OAT days?

Thanks for your time.
 
I'd expect that with the peak temperatures occurring after shutdown, that a blast tube might be ineffective.

Dave
 
Heat soak

Yes it is ineffective after shutdown. After refuel and restart it represents a starting point (heat soaked battery) that needs to be addressed by airborne airflow. Which is why the question, what size blast tube has been found to be effective.
 
I have an EarthX 680 installed on the firewall of my RV-7. It has a dedicated blast tube for cooling (5/8"). I live near the coast so the OATs are pretty mild compared to the midwest. On my flight to and from Oshkosh the battery got pretty warm especially after engine shutdown (144F.) I am increasing the size of the blast tube and thought I would check with the collective.

If you have an EarthX battery on your firewall what diameter blast tube are you using? Are you measuring temperatures? And if so, what temps are you recording on 90+ OAT days?

Thanks for your time.

I think I posted this before, but here (this was on my RV-10).

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.

289dbo0.jpg


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.

2dqvarp.jpg


The shield in place.

2qio0h4.jpg



The box in place.


25stlxy.jpg


The flange installed where I took air from the plenum.
 
A big contributor to the heat is after shutdown, when all the convective heating of the air from the exhaust, which goes straight up to the battery case. Mine actuallt softened and deformed. After the above fix, I've had zero problems.
 
Recording temps

Are you recording temps surrounding the battery? It would be interesting to know if a very focused 1" blast tube is sufficient or if the battery box cover adds significantly to the cooling efficiency.

The heat shield idea is worth exploring although its a little tighter around the battery box. The battery and starter solenoids are directly below the box on the -7.

Thanks for showing your solution.
 
EarthX Battery Insulation Blanket

I did something similar to Larry. Not on a RV but on a Glasair Sportsman 2+2. I had a lot of "Thermal Warnings" before I added the blast tube. After I added the blast tube, no more warnings during flight. However, after shut down, I would get the warnings if it was a hot day.

I used some double-sided Thermo-Guard (https://www.aircraftspruce.com/catalog/eppages/thermoguard.php) and some 2" wide aluminum tape to seal the edges (https://www.aircraftspruce.com/catalog/appages/alum_foil.php) to make a "blanket" that wraps around the EarthX battery. Only the side next to the firewall didn't have a blanket on it (no hot air can get to that side of the battery anyway). I used a 5/8" diameter SCAT tube to provide cooling air to it. I used Velcro to attach blanket to the battery box. Since the aluminum tape is conductive, I used some "Gorilla Tape" to provide electrical insulation and abrasion resistance where the battery cables passed thru the blanket.

It works great. No temperature warnings since I added the blast tube and the blanket. Even in hot and toasty Houston. When I need to access the battery, just peel off the thermal blanket. Very easy.

I hope this helps.

Jeff
 
Temps from RV9A

EarthX box and EarthX900. No blast tube but I like the idea of shielding the exhaust.

iYwzieafmsiGqMBvYMFojotf9CNZGfxrC-dfSwXMlDQpnWwRrY_soPDdpegWvw6eBSelBSCqrTNLuJWaL8CfxxRV4JfDHJncE7RmRAGOs3x4iYETHQ5c13AG1Y_EvGbA35mSs3J7iNzIh1VvLm1E7HWS56spAVIzJkOKTBSOwLnLkHbdH72GeE_i9so_9z8_XSEvUGT2eNFXhJrdpZRXIPapIqnCHl1_EpISK4kaRQV9_QSU7G9f4JlJPPbGaOJfYJbWEMBl_7EynozVf8KrG9zR327r-lSchDC6KzzYvQnQRGEgQanb2WIGq0PIj3Hg8XAxZZGLQ2_56_dHxP9cK1ejzdSa13MR51_MOYbt3g5xFDW1v9s4yaIfFcBnwt4kFoX3PNmuu8Id1SAw8FPhckHYmjQjOerwgSX4ICIgfFMTfCt0aogpTKbD5RKkOfRCTBmgGesFnPHAUG5Jm6eY09jVAvlLkjiGUlGb63eGtR8mP0jRK7Z1tOx-LE-oUW6xfhlsxETi3ELUSMfHmpAYLhnaUX_DF7auDrKl8iVTvaLRCr3PRgNEJI_6opyPXpnoLGDas9RrqLuDhTuR98AJNzCwZ34xUSS_tzXrNLe9zpqC8pR-e5ELQCnan7bF_NIl80Dxsvnpc9IvDEAqHFoee0ekvZqGHxk=w800
 
Patient: "Doctor, it hurts when I do this."

Doctor: "Ok, don't do it."
______________________________________

If an EarthX isn't happy in the engine compartment, why put it there?
 
blast tube

what about extending the downwards tube vent about 2 ft to clear the aircraft and a stainless steel check valve for the upper vent so that if the battery catches fire the blast would provide additional upwards thrust. I couldn't resist....
 
The original oops

Excess heat and pressure has a bad track record with Lithium...

https://youtu.be/b5tmkna-k-U?t=79

Remember the Castle Bravo chemistry experiment.

I like the idea of a sealed 30 cal ammo box in a cooler location and perhaps with external sealed vent ducts.
 
I didn?t know my EarthX was unhappy FWF until 90+ *F quick turns, it was always the ground ops/heat soak that set off the high temp alarms. Shut down heat soak was fine, several 10 second cranking sessions to start (boiling fuel in the carb) followed by the rapid charging would set my high temp alarm off.

My Odyssey batteries ran in the same environment, never had an overtemp sensor. Pretty sure they didn?t like the summer temps either, I replaced yearly when they had trouble cranking after the temps got colder.

Best solution is prob aft of the firewall, but following plans and W&B put it FWF. I did make my oil door into an inward folding cowl flap for low airspeed and ground cooling, I just need more hot quick turns to see if it helped.
 
Are you recording temps surrounding the battery? It would be interesting to know if a very focused 1" blast tube is sufficient or if the battery box cover adds significantly to the cooling efficiency.

The heat shield idea is worth exploring although its a little tighter around the battery box. The battery and starter solenoids are directly below the box on the -7.

Thanks for showing your solution.

I've not recorded temps, but there has not been one warning of high temp from the battery, since I shrouded/shielded the thing.
 
Patient: "Doctor, it hurts when I do this."

Doctor: "Ok, don't do it."
______________________________________

If an EarthX isn't happy in the engine compartment, why put it there?

For me, I went with the Hartzell 2 bladed composite prop on my RV-10. That prop is 12 to 14 pounds lighter than the blended airfoil AL blades. This allowed me to move the battery to the FW, shortening the run to the starter, got the battery out of the empennage, which eliminated the long 2O cable to the front with it's voltage drop during cranking. Also, the battery is in front of the stainless firewall if things go south, instead of right behind the aft baggage bulkhead. In short, many pluses, and few negatives. I would do it again in a second one, if I build another.
 
I've never had a "high temp" alarm on my EarthX, but did have an alarm within the first year. No visible damage, but EarthX replaced it with a new design with an improved BMS (not sure what was improved.) . The battery is mounted fairly high up on the firewall, using EarthX's mounting box which I suppose could act as a heat shield. I also open the oil door just after shutdown to help with evacuating hot air.
 
For me, I went with the Hartzell 2 bladed composite prop on my RV-10. That prop is 12 to 14 pounds lighter than the blended airfoil AL blades. This allowed me to move the battery to the FW, shortening the run to the starter, got the battery out of the empennage, which eliminated the long 2O cable to the front with it's voltage drop during cranking. Also, the battery is in front of the stainless firewall if things go south, instead of right behind the aft baggage bulkhead. In short, many pluses, and few negatives. I would do it again in a second one, if I build another.

I hear you. All design is the art of compromise.

Is there nowhere to locate the EarthX (in a sealed and vented box) on the cool side of the firewall?
 
The PC680 has a 114*F limit when installed in a Vans battery frame ( Odyssey website, not in a box), yet I would think the area on the firewall would exceed that after shutdown. Vans selected that area and most everyone have no issues for years of service. Also, no BMS.
EarthX has a 140*F limit and a BMS that will send a fault alert.
I would like to install a EarthX, but this thread has raise some questions.

Would installing a 1/4” thick concrete fiberboard side, front, bottom help or would it trap any heat buildup preventing cooling?

Does the BMS FAULT interrupt power until the temperature drops below limit?

What has started me down this road is the PC680 I installed must have been dropped or was defective and oozed something creating Corrosion on the Vans battery frame.
Perhaps giving Odyssey another chance should be considered.

R
RV-14
 
Last edited:
I hear you. All design is the art of compromise.

Is there nowhere to locate the EarthX (in a sealed and vented box) on the cool side of the firewall?

I don?t see where that would be possible. It would interfere with the pedals down low and I don?t see room for it up high either...at least in the 10.
 
Temps

See the picture in post #8.

The temperature strips are mounted directly on the battery and they show a highest recorded temp of 150F.

The EarthX battery was installed on 2/27/16. I live in Phoenix part of the year and the ambient temperature in the hanger can easily exceed 110F.

I have never seen the overheating pulse, "2 sec on/ 2 sec off", but I have seen the charging pulse, "5 on/5 off", once in the last 2 years.

The battery is mounted per plans on the passenger side of the firewall. The engine is an IO-320 and I do not open the oil door for cooling.

Your mileage may vary.
 
Yeh, thanks.....looks like the 160*F level is partly shaded. 155*F maybe.
Your battery frame covers more, smaller openings.

R
 
I hear you. All design is the art of compromise.

Is there nowhere to locate the EarthX (in a sealed and vented box) on the cool side of the firewall?

Ditto what RandyAB said. Also, if I mounted it on the cold side of the firewall, I would want a sealed box with overboard venting, which would be much heavier.
 
Heat in engine compartment

On 10-27-2018 I posted a thread on the Vans RV-10 forum about burning up a EarthX battery because of the heat in the engine compartment. Vans does not recommend it and although EarthX makes a battery box that is supposed to shield it from the heat, the problem, as many have noted, is after the engine is shut down. After I ruined the first battery I contacted both Vans and EarthX and NEITHER actually knew what the temps reached, Vans just said it was too hot, especially for the six cylinder IO-540 engine. I did extensive testing on the temps in the engine compartment under flight and ground operations and posted them on the RV-10 forum. I ended up buying a new battery and moving it to the rear of the aircraft where the main Concord battery is located. It only weighs 3 lbs but since the RV-10 is nose heavy anyway, this transfer of weigh also helped in the flight characteristics, especially when the power is retarded for landing. I am not sure if putting this link in here will take you to the previous thread but if not you just search the RV-10 forum for "heat in engine compartment".
http://www.vansairforce.com/community/showthread.php?t=165447&highlight=engine+compartment+temps
 
Good info.
So why is Vans favoring putting the battery frame on the upper right firewall (RV-14) and installing a PC680?
Is the PC680 Odyssey that much more resistance to heat than the EarthX?

R
 
Heat in the engine compartment

After I contacted Vans and EarthX about the heat in the engine compartment, as I said, Vans said do not put the battery in the engine compartment, it's too hot. In reality, Synergy Air, a Vans builder assistance center in Oregon was the one that suggested that I move the EarthX to the firewall while they were doing a panel upgrade for me. I thought that they knew what they were doing and said OK. A few flights after that, the battery failed. After a bunch of back and forth with EarthX, Vans and Synergy, I found that while Synergy had been mounting the EarthX on the firewall for their four cylinder aircraft, they had NEVER done it on a RV-10. As I said in an earlier post, the difference between the four cylinder engines heat and the six cylinder is significant. Actually the vice president of Vans called me (I do not remember his name) and said that there is too much heat in the engine compartment for the battery to be mounted on the firewall and that is why they do not recommend EarthX batteries. I do not know about the PC680 Odyssey battery but the EarthX is a very thin skinned battery that can not take much abuse (heat). Put it in the back (where Vans advises) and you will have blue sky's....................................
 
You don?t want to hear this, but batteries really should not be mounted firewall forward. Have you considered installing a much more powerful EarthX EXT900-VNT on the other side? It is the only LifePo battery designed for the passenger cabin, and now certified for that role!- Otis
 
LifePro Battery

After reading the thread above, I went to their website to read about the batteries. I read all of the reviews and all of the FAQ but I did not see anything about using these batteries in a aviation application. Everything on their site says that these are great batteries for RV, Boat or Off-grid power systems.
 
YOU MISSED THE POINT COMPLETELY!!!!!!!!

The last two threads include links to the EarthX site. I KNOW that it is for aviation and is certified, I was responding to HARTSTOC who said that LifePro was the only one certified for inside the aircraft. My response to him was that the LifePro website shows that they are for use in RV's, marine and solar systems....................no mention of aviation anywhere on their site.
 
Back to the OP?s original question

Yes it is ineffective after shutdown. After refuel and restart it represents a starting point (heat soaked battery) that needs to be addressed by airborne airflow. Which is why the question, what size blast tube has been found to be effective.

Scott,
I?m sorry I took so long to get back to this thread, but I finally got the cowling off KELLI GIRL and measured my blast tube. I?m using a 1? ID scat tube blasting air from over the #3 cylinder to the battery. I?m using their thermal battery box with the bracket that anchors the blast tube over the battery:
https://earthxbatteries.com/shop/thermal-battery-box-etx680-900-900-vnt-120

She has flown over a year now with no thermal warnings, even in this summer?s 100+ degree days. I do admit, though, that I haven?t measured the battery heat-soak temps after shutdown. I am pretty religious about opening the oil door after shutdown to let the hot air flow out.
 
Thanks Scroll,

I have insulated the battery box with a heat barrier and that caused about 10-15F decrease measured at the battery. The insulation on the EarthX box looks thicker but I don?t know it?s thermal efficiency. My thermocouple is between the battery and the firewall just inside the top edge of the box. The way the battery is formed there is a small space large enough for the thermocouple. During yesterday?s flight the temp was down to 99F at cruise (80F OAT) normally 109-115. On my way to Oshkosh and back I was seeing temps in the 130s. But it was a lot hotter outside.

I will change out the 5/8? blast tube for 1?. Hopefully that will bring the temps down a little more. It would be great if someone else was monitoring battery temps for comparison. Just another note my CHTs run 340-350 in cruise, I don?t think my engine compartment is running hotter than most RV-7s. O-360 with CS.
 
I think I posted this before, but here (this was on my RV-10).

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.

289dbo0.jpg


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.

2dqvarp.jpg


The shield in place.

2qio0h4.jpg



The box in place.


25stlxy.jpg


The flange installed where I took air from the plenum.

Here are the relevant pictures again:
 

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