EarthX wants your opinion for a new RV-10 battery

[chris1seto]

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Do you have a specific location in mind and have you seen one installed there on a -10? The challenge is that the firewall and space behind the engine is absolutely packed with stuff. Fuel lines, oil lines, oil cooler, hose for the heating system, etc. For me, it was a chore getting everything in there AND leaving room to change the oil filter, access the mags, etc.

Admittedly, no not yet...

I've seen a number of builds do it, and my build is simple FWF (no AC or EFI) so I wasn't too worried about space. My engine still isn't here yet so all I've had to go off of is other build logs.

I was thinking it would go about the same height, opposite side as the oil cooler.

At least the good news is that if it doesn't fit FWF, I have a shot at putting it just aft above the pedals. I've seen that location work too.

 

[rocketman1988]

Admittedly, no not yet...

I've seen a number of builds do it, and my build is simple FWF (no AC or EFI) so I wasn't too worried about space. My engine still isn't here yet so all I've had to go off of is other build logs.

I was thinking it would go about the same height, opposite side as the oil cooler.

At least the good news is that if it doesn't fit FWF, I have a shot at putting it just aft above the pedals. I've seen that location work too.

Honestly, the only "unpopulated" area was where you're considering; passenger side about the height of the oil cooler. That is where I located my Airwolf remote oil filter.

 

[Hangar 1271]

A picture is worth a thousand words, thank you! This looks very similar to an Aviat Pitts installation, and we do have a hold down bracket for our battery that works it. We do not offer it as a standalone product, (but maybe we should). It goes in the STC installation kit for the Aviat. We have the terminals down the center so that we did not need to have "left" or "right" polarity batteries, which doubles the sku's, and if you turn the batteries 180's degrees, one battery works for any polarity installation.

Do you have any pictures of this in use? I went to your website and didn't see any.

Also, I 3D printed a spacer for the EarthX ETX900 for someone on VAF and have a link for the stl file on EarthX battery "topper" thread, if anyone is interested. The hold down EarthX sells isn't a plug and play option especially if the battery box is on the firewall, like mine on an 8.

 

[MElstien]

I am finishing up my RV-10 Build The engine is electrically dependent. I built a custom battery box to fit Qty 2 ETX1200. Being an experienced manufacturing engineer, I do not think a new battery size is the thing I need or want. I dont think EarthX needs to be carrying the cost of another set of materials on the inventory books.

I am able to isolate each battery via separate solonoids and each battery has a direct feed with 20 Amp locking toggle switches to the engine buss. Those 2 wires are protected by separate fuses at the battery . Each engine buss feed is diode protected to prevent back feeding. I also monitor the engine buss voltage on my G3X as that can tell me a lot. It can tell me if the Alt 1 or Alt 2 is active as both are set at different voltages and it can also tell me if I am feeding only via Battery.

What I wouuld like, and what would potentialy be under consideration for any EarthX customer, is a specialized meter I can mount on my panel, or bluetoothed to my phone with following Capababilities, specifically tined to EarthX batteries:
- needs to monitor at least 2 ETX batteries and the ability to label them and understand size of battery 900/1200/1600. This would be my situation or possibly a twin.
- Monitor voltage
- Monitor charge and discharge and rate of charge / discharge
- Supply AMPHr remaining and time to empty at current discharge rate.
- Bluetooth built into the battery or a sperate device that communicates to the battery that can be mounted near both batteries and the connected via bluetooth or hard wired to a panel mount display
Bluetooth audio warnings since many of our headsets are also capable of Bluetooth.


If I was to design this, I would add the monitoring smarts into the BMS and allow for a serial bus to come out of the battery and connect to the "collection unit via the serial buss . Then bluetooth to it to my phone or bluetooth to a panel mount display. This may be the easiest route to introducing a new product that is relatively easy to install new, or retrofit, and could be considered by all your customers, not just the RV-10.

Mike

 

[dmattmul]

Admittedly, no not yet...

I've seen a number of builds do it, and my build is simple FWF (no AC or EFI) so I wasn't too worried about space. My engine still isn't here yet so all I've had to go off of is other build logs.

I was thinking it would go about the same height, opposite side as the oil cooler.

At least the good news is that if it doesn't fit FWF, I have a shot at putting it just aft above the pedals. I've seen that location work too.

Maybe I am missing something but 10's need weight aft especially if not using a composite prop and no A/C or built in O2 if not carrying passengers in the back seat. I know several builders who have A/C (And a Earth X battery aft) and albeit metal props that still required to add ballast in the baggage area to get their CG within limits. A friend built a 10 and permanently added 20 lbs. of ballast in the tail as his airframe did not have A/C and a metal prop. My 10 has a very light weight composite WW prop and 2 Earth X batteries (ETX 1200 and 900) aft of the baggage area and built in O2 along with pad mounted B&C alternator (weight 5.75 lbs.) with a full interior including baggage area and it BARELY falls in the recommended CG limits. When the CG falls this far forward the plane just feels clunky especially landing where I almost run out of elevator trim, so I carry a bag of salt in the baggage area when 2 people or less on board. This to safe ~ 4- 5 lbs. of #2?

The other issue as I found out with my 14 (2 Earth X batteries FWF) is although safe, higher temps do degrade battery life. Earth X will state the same. My battery located FWF low runs around 120 to 130 F and after 4 years fell out of the 80% ampacity rating while the one that is located higher FWF runs 100 to 120 F and after 6 years still passes the 80% ampacity test. BTW I have 2 - 5/8 blast tubes going to each battery FWF to help moderate battery temps. We go through great lengths sealing tiny cracks in our plenum but then add 4 - 5/8 holes for blast tubes! I was not going to do this for the 10. BTW I've seen more than one 10 where builders added cowl flaps or louvers to get better cooling. 10's seem to need every bit of cylinder cooling possible and then some. Adding blast tubes does not help and certainly cowl flaps reduce performance.

 

[chris1seto]

Maybe I am missing something but 10's need weight aft especially if not using a composite prop and no A/C or built in O2 if not carrying passengers in the back seat. I know several builders who have A/C (And a Earth X battery aft) and albeit metal props that still required to add ballast in the baggage area to get their CG within limits. A friend built a 10 and permanently added 20 lbs. of ballast in the tail as his airframe did not have A/C and a metal prop. My 10 has a very light weight composite WW prop and 2 Earth X batteries (ETX 1200 and 900) aft of the baggage area and built in O2 along with pad mounted B&C alternator (weight 5.75 lbs.) with a full interior including baggage area and it BARELY falls in the recommended CG limits. When the CG falls this far forward the plane just feels clunky especially landing where I almost run out of elevator trim, so I carry a bag of salt in the baggage area when 2 people or less on board. This to safe ~ 4- 5 lbs. of #2?

The other issue as I found out with my 14 (2 Earth X batteries FWF) is although safe, higher temps do degrade battery life. Earth X will state the same. My battery located FWF low runs around 120 to 130 F and after 4 years fell out of the 80% ampacity rating while the one that is located higher FWF runs 100 to 120 F and after 6 years still passes the 80% ampacity test. BTW I have 2 - 5/8 blast tubes going to each battery FWF to help moderate battery temps. We go through great lengths sealing tiny cracks in our plenum but then add 4 - 5/8 holes for blast tubes! I was not going to do this for the 10. BTW I've seen more than one 10 where builders added cowl flaps or louvers to get better cooling. 10's seem to need every bit of cylinder cooling possible and then some. Adding blast tubes does not help and certainly cowl flaps reduce performance.

For the CG issue, I was expecting to need ballast no matter what while solo. It seems like that's pretty normal for the fleet?

Thanks for the beta on temperatures. There are a few useful data points in there. I suppose I could also try to locate it over the pedals, as I've seen at least one other build do.

 

[rocketman1988]

I have the heavier mtv9 prop and dual earthx 900s in the back. Also CAI, engine preheat system a some other extra stuff fwf. Flying solo or with 1 passenger, I carry ballast o bring the cg into the middle of the range. Basically, everything you load into the -10 moves the cg aft so you need to start with a forward cg. You can also play around with a W&B calculator and see that starting with a more forward cg will allow you to reach gross weight before going out of the aft cg limit. If you start with a more aft cg empty, it is easier to go out of the aft cg limit before you reach gross weight.

 

[Kyle Boatright]

I have the heavier mtv9 prop and dual earthx 900s in the back. Also CAI, engine preheat system a some other extra stuff fwf. Flying solo or with 1 passenger, I carry ballast o bring the cg into the middle of the range. Basically, everything you load into the -10 moves the cg aft so you need to start with a forward cg. You can also play around with a W&B calculator and see that starting with a more forward cg will allow you to reach gross weight before going out of the aft cg limit. If you start with a more aft cg empty, it is easier to go out of the aft cg limit before you reach gross weight.

Yep. A forward CG give you more payload flexibility. The only downside is the need to load ballast in the cargo area for flying solo or with one passenger. With a forward CG, you run out of elevator authority in the flare. Using less than full flaps helps.

 

[Tassie]

What I would like, and what would potentialy be under consideration for any EarthX customer, is a specialized meter I can mount on my panel, or bluetoothed to my phone with following Capababilities, specifically tined to EarthX batteries:
- needs to monitor at least 2 ETX batteries and the ability to label them and understand size of battery 900/1200/1600. This would be my situation or possibly a twin.
- Monitor voltage
- Monitor charge and discharge and rate of charge / discharge
- Supply AMPHr remaining and time to empty at current discharge rate.
- Bluetooth built into the battery or a sperate device that communicates to the battery that can be mounted near both batteries and the connected via bluetooth or hard wired to a panel mount display
Bluetooth audio warnings since many of our headsets are also capable of Bluetooth.

I have the same arrangement - two ETX1200's and an electrically dependent engine - in a phase2 flying RV-10. It's easy to modify the existing mount for the two ETX1200's in the same space, I don't think it's useful to do a new battery profile.

I actually did a test flight, flying for 45 minutes with both alternators off + full avionics, starting with fully charged batteries, to prove the endurance of the arrangement under a primary alternator out condition. I did this based on the battery curves, and knew it would work, but had low confidence in how much longer I could have pushed it and did not want to risk taking it anywhere near primary battery cutoff while in the air.

I agree with Michael, the most useful thing you could do - across your entire battery range - is to supply more information for monitoring. If the bluetooth suggestion is a bridge too far, then simply add to the function of the existing open collector fault wire. Without compromising the existing "led flashing" function of this wire, you could superimpose a brief 9600 baud data burst once per second, that dumped a simple string representing the battery condition. This would make no visible difference to an external LED, but someone like me - or many others on this forum or in the experimental industry - could level shift and extract this data and display/alarm it on a panel instrument.

Whether it is this minimal change, a separate RS232 wire, or bluetooth, one way or another you should aim to end the current silly situation where all sorts of knowledge about the battery condition exists within the BMS, but it's all locked up inside the battery case and can't be viewed/monitored by the pilot.

 

[rocketman1988]

Yep. A forward CG give you more payload flexibility. The only downside is the need to load ballast in the cargo area for flying solo or with one passenger. With a forward CG, you run out of elevator authority in the flare. Using less than full flaps helps.

With the performance of the -10, especially solo, performance is never an issue and the ballast goes unnoticed.

As far as flaps go, I almost always land with half flaps. Half flaps and mid cg feels the best, imo. The difference in approach speed is a few knots but again, the -10s performance is such that it doesn't really make a difference to me on a 2800' paved runway with displaced thresholds at both ends. Never use more than 1500' with light braking...

 

[Kyle Boatright]

With the performance of the -10, especially solo, performance is never an issue and the ballast goes unnoticed.

As far as flaps go, I almost always land with half flaps. Half flaps and mid cg feels the best, imo. The difference in approach speed is a few knots but again, the -10s performance is such that it doesn't really make a difference to me on a 2800' paved runway with displaced thresholds at both ends. Never use more than 1500' with light braking...

We are in complete agreement...

 

[MarkStringfellow]

We have been exploring the idea of designing a new battery specifically for the RV-10 market and we want your input. The plans for this kit currently mentions the Concorde RG-25 battery and the tray is designed for that sized battery.

RG-25 Spec's

Weight 22.75 pounds

CCA 225

Capacity: 22Ah

Dimensions 190.5mm x 126.2mm x 172.9mm ( L x W X H)

Cost: $368 today on ACS



We are contemplating a new model with these spec’s:

Weight 6 pounds

CCA: 600

Capacity: 20Ah

Dimensions 166mm x 129mm x 168mm (L x W X H)

Cost: $679

(and of course the same BMS features of the other batteries)

Currently, many of you use the ETX900 or the ETX1200 to replace this battery.

ETX900 Spec's

Weight 4.9 pounds

CCA: 400

Capacity: 15.6Ah

Dimensions 166mm x 76mm x 168mm (L x W X H)

Cost: $449

ETX1200 Spec's

Weight 5.4 pounds

CCA: 600

Capacity: 20Ah

Dimensions 166mm x 76mm x 168mm (L x W X H)

Cost: $649

And another common choice you have is this battery:

Odyssey PC925 (ODS-AGM28L)

Weight 23.8 pounds

CCA 330

Capacity: 20Ah (1 Hr rate to compare apples to apples)

Dimensions 168mm x 175mm x 127mm ( L x W X H)

Cost: $279 today on Amazon

I'm very happy with the ETX900 and carry a spare but never need it.

 

[MElstien]

I have the same arrangement - two ETX1200's and an electrically dependent engine - in a phase2 flying RV-10. It's easy to modify the existing mount for the two ETX1200's in the same space, I don't think it's useful to do a new battery profile.

I actually did a test flight, flying for 45 minutes with both alternators off + full avionics, starting with fully charged batteries, to prove the endurance of the arrangement under a primary alternator out condition. I did this based on the battery curves, and knew it would work, but had low confidence in how much longer I could have pushed it and did not want to risk taking it anywhere near primary battery cutoff while in the air.

I agree with Michael, the most useful thing you could do - across your entire battery range - is to supply more information for monitoring. If the bluetooth suggestion is a bridge too far, then simply add to the function of the existing open collector fault wire. Without compromising the existing "led flashing" function of this wire, you could superimpose a brief 9600 baud data burst once per second, that dumped a simple string representing the battery condition. This would make no visible difference to an external LED, but someone like me - or many others on this forum or in the experimental industry - could level shift and extract this data and display/alarm it on a panel instrument.

Whether it is this minimal change, a separate RS232 wire, or bluetooth, one way or another you should aim to end the current silly situation where all sorts of knowledge about the battery condition exists within the BMS, but it's all locked up inside the battery case and can't be viewed/monitored by the pilot.

Yes Yes Yes!!!