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RV-10 Battery

Pat Stewart

Well Known Member
I am looking for ideas on batery' and locations other than what the kit has defined. Anyone using the odysee battery and if so how are you mounting.

Pat
 
Most common variations are an Odyssey 925 on its side or a pair of PC-680s (have to widen the battery tray a bit).

Location is right because of CG issues.

Bob
N442PM Flying
 
Battery Location

My question was not because I am opposed to the kit location, I have in the past viewed pictures of multiple battery's and modified locations. Just looking at all ideas, as for why, Vans also has an option to put a battery on the firewall of the RV8 but unless you have an 0320 and fixed pitch prop that's not a good idea either. Just interested in other idea's.

Pat Stewart
RV8
RV8A
J3Cub
RV10 Building
 
RV-10 battery

I am glad that you asked this question. Vans had no choice but to put it there to off set the heavy Hartzell prop. I am considering mounting the odyssey on the firewall and use the new Whirlwind RV-10 prop which is 20lbs lighter than the Hartzell. This should save weight all the way around since I do not have to run the battery cables so far + lighter battery than G-25 + lighter prop. Should be close to 30lbs overall lighter than the factory bird with a better empty cg location.
 
I used to wonder about that, but Van wants it back there and the pieces required are already in the kit. It's pretty straight forward and the only pain in the rear for me was drilling holes to get the big wire forward.
I just bought a brand new Odyssey 925L from our local Summit Racing store for $150 and it fits Van's battery tray just fine in the up position. It's actually quite easy to work back there - until you close up the top (g). I'm sure that others will point out that both sides of the firewall are going to get pretty cluttered as you finish up.
John
 
I started with two 680s in the standard location; they are wired in parallel with two master contactor toggle breakers on the panel. I later added a single 680 on the firewall as backup/startup for the EFiSs. It is also there to ensure forward CG when loading the baggage area.





My question was not because I am opposed to the kit location, I have in the past viewed pictures of multiple battery's and modified locations. Just looking at all ideas, as for why, Vans also has an option to put a battery on the firewall of the RV8 but unless you have an 0320 and fixed pitch prop that's not a good idea either. Just interested in other idea's.

Pat Stewart
RV8
RV8A
J3Cub
RV10 Building
 
My question was not because I am opposed to the kit location, I have in the past viewed pictures of multiple battery's and modified locations. Just looking at all ideas, as for why, Vans also has an option to put a battery on the firewall of the RV8 but unless you have an 0320 and fixed pitch prop that's not a good idea either. Just interested in other idea's.

Pat Stewart
RV8
RV8A
J3Cub
RV10 Building

The RV-8 is a totally different airplane design compared to an RV-10. It uses a wide variety of engine / prop combinations which does through in many more C.G. variables. This is not the case with an RV-10...builders don't use light O-540's and fixed pitch props...so as long as builders use a typical engine installation, the rear battery location is the best choice.
One thing that should be consider when thinking about using alternate battery's is the difference in amp hour rating. It is true that a P680 has nearly the same cold cranking amps as an RG25 but it only has 2/3's of the amp hour rating. If you had an alt. failure while using an RG25, and your minimum load endurance until battery went dead was 1 hour, you would only have about 40 minutes with the P680 (assuming both batteries were in top condition) in the same conditions. Something else to think about....
 
Replacing my generic SLA battery with an Odyssey for better snort. Standard battery tray in the tail cone, positive cable forward and negative aft. I'm not 100% confident the cables will reach the terminals in all configurations of the 925 mounting, but likely so.

What's the "preferred" mounting position - terminals on top, or sides? If on sides, then high or low? I have to choose a 925L or 925 vanilla. The safe way to go seems to be 925L with the battery on its side, terminals low, cables folded over and down to reach them. But I'll take any recommendations before I do the one-click on Amazon.
 
EarthX batteries

This question keeps resurfacing from time to time, but I don’t really understand the solution seemingly in search of a problem.

I installed two EarthX ETX900 batteries, which was a slight mod from plans, but in the same location and total weight of about 10 pounds, 11 with three contactors.

This location gives me options. If for some reason I find I need to shift weight aft, I can just swap out one of the light batteries for a nice heavy lead acid one. But I just don’t see that happening based on my math. And I’ve bought a WhirWind 330-3B-78” prop that should weigh about 55 pounds with spinner.
 

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When I had a 925 I installed it with the terminals pointing to the side with the battery turned so they were “high” vs “low”.
 

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This is how we mounted our PC950. Gives a more compact and similar capacity to the Concorde, but in our opinion a more modern and better battery. Naturally, opinions vary ;)
 

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I guess I should have added when my Odyssey 925 was ready for replacement I went with an EarthX ETX1200 giving me significantly more battery capacity at a 1/3 of the weight of the 925 it replaced. It does cost more but that’s offset by the longer lifespan.
 
Thanks, everybody. I'll go with the 925 on its side with terminals high. Maybe an earthX one day, when I'm confident I understand and can mitigate its BMS failure modes. Not ready for that yet. As it is I have to fly with 30# of ballast in the baggage area solo.
 
Easy to have two PC-625 batteries mounted in the standard location and create two independent power feeds to the plane. With some thought, you can have a very redundant electrical power system that will keep power to the panel for most all practical failure scenarios.

Here you see:
- Two master solenoids. Normal operations have both closed, the batteries in parallel and on the alternator. POH immediate action on any electrical fault is to open both master solenoids. This isolated the big wires as well as placing the system in its most reliable state, each battery feeding half the panel.
- Four “avionics” relays (30 amp contacts and 100ma coil). Normal is to have one shut on each battery. Backup modes have a combination of the second “alternate” relay feeding the opposite side of the panel.

Note - the PC-625 is a good form factor for our use, has a little more CCA and AMP-HR capacity and is a little lighter than a PC-680. I change one out every three years so neither exceeds six years old. The pulled batteries go on for a second life in tractors and such.

Carl
9081-AC88-9152-463-C-8-DAC-D06-CE5-D806-CA.jpg
 
I considered your architecture, Carl. Really well done. At the end of the day I went with a single cranking battery and dual alternator design (part of the reason I need that ballast) with a TRW backup battery for avionics brown-out protection during cranking and a separate backup battery from Ross for the CPi-2 ignitions.

Not back-pedaling now ;)

I was surprised to see the 925 vs 950 specs, but my 925 is on order now so I guess that ship has sailed until time to replace the 925 in a few years.
 
An Odyssey 925L on its side lets you keep the standard Van’s wiring. I started with an Earth X. After the BMS failed and left me stuck for 5 days, I had to buy an Odyssey to get home. The Earth X does save weight and cranks the prop better. But if the BMS goes off line, you loose your thermal run away protection, so your grounded if you want to be safe. Also, you can risk damaging the battery if you need a jump by an FBO truck. RV 10 is nose heavy so the cg station for the battery is in a good location. If you go Earth X (standard battery location) you may need some ballast in the baggage area when single pilot and light.
 
...I started with an Earth X. After the BMS failed and left me stuck for 5 days, I had to buy an Odyssey to get home. The Earth X does save weight and cranks the prop better. But if the BMS goes off line, you loose your thermal run away protection, so your grounded if you want to be safe. Also, you can risk damaging the battery if you need a jump by an FBO truck. ...
I have an EarthX in a KTM motorcycle. After three years, it's been pretty much set-it-and-forget-it.

How did you know the BMS failed? How did it manifest itself?
 
An Odyssey 925L on its side lets you keep the standard Van’s wiring. I started with an Earth X. After the BMS failed and left me stuck for 5 days, I had to buy an Odyssey to get home. The Earth X does save weight and cranks the prop better. But if the BMS goes off line, you loose your thermal run away protection, so your grounded if you want to be safe. Also, you can risk damaging the battery if you need a jump by an FBO truck. RV 10 is nose heavy so the cg station for the battery is in a good location. If you go Earth X (standard battery location) you may need some ballast in the baggage area when single pilot and light.

I have a pair of EarthX in my 10 for about three years. I’ve only had one BMS issue, which was self inflicted. I left the master on and the BMS did it’s job. I always carry my charger with me when I fly. It will allow me to reset The BMS and charge the battery if ever needed.
 
When I had a 925 I installed it with the terminals pointing to the side with the battery turned so they were “high” vs “low”.

This my setup also. But I bought a battery try adopter form Steve melton to fit the battery on the existingTray. Works great.
 
How did you know the BMS failed? How did it manifest itself?

The EarthX is wired to the G3X touch in case of a BMS fault. My situation was it was a cold start in 28 degree weather. Two seconds after starting to crank the engine I lost all electrical power, but then it recycled. Second attempt the same occurred. A third attempt engine cranked and everything seemed normal. Long warm up and system check and all seemed good. About the time I was being given my IFR release, battery fault showed on the screen. Based on EarthX documents (and my experience) this was a no go. Called EarthX. I was told they had changed their procedure from “land at nearest” to “continue to to destination”. But you do not have the BMS protection. Maybe if I was airborne it’s an option but not prior to launch. Battery was a few months out of warranty so no coverage. I am not saying their battery is a bad product. Everything has its pros and cons. I just lost confidence in that battery. I did not like being left out in the cold………..literally. I believe the BMS is a good thing even though some say their batteries cannot go into a thermal run away. But if that was the case the BMS would not be required. Since the battery sits above the elevator push rod, it would not be a good place for a melt down to occur. When I spoke to the EarthX people at Osh, they recommended to go to a 1200 series, same footprint and the 900. They could not explain what occurred. Maybe just bad luck. But for 725 vs 200 dollars for the 925 Odyssey, I will stay old school for a while.
 
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How did you know the BMS failed? How did it manifest itself?

The EarthX is wired to the G3X touch in case of a BMS fault. My situation was it was a cold start in 28 degree weather. Two seconds after starting to crank the engine I lost all electrical power, but then it recycled. Second attempt the same occurred. A third attempt engine cranked and everything seemed normal. Long warm up and system check and all seemed good. About the time I was being given my IFR release, battery fault showed on the screen. Based on EarthX documents (and my experience) this was a no go. Called EarthX. I was told they had changed their procedure from “land at nearest” to “continue to to destination”. But you do not have the BMS protection. Maybe if I was airborne it’s an option but not prior to launch. Battery was a few months out of warranty so no coverage. I am not saying their battery is a bad product. Everything has its pros and cons. I just lost confidence in that battery. I did not like being left out in the cold………..literally. I believe the BMS is a good thing even though some say their batteries cannot go into a thermal run away. But if that was the case the BMS would not be required. Since the battery sits above the elevator push rod, it would not be a good place for a melt down to occur. When I spoke to the EarthX people at Osh, they recommended to go to a 1200 series, same footprint and the 900. They could not explain what occurred. Maybe just bad luck. But for 725 vs 200 dollars for the 925 Odyssey, I will stay old school for a while.

Interesting. Thanks for the comprehensive explanation.
 
How did you know the BMS failed? How did it manifest itself?

I just lost confidence in that battery. I did not like being left out in the cold………..literally. They could not explain what occurred. Maybe just bad luck. But for 725 vs 200 dollars for the 925 Odyssey, I will stay old school for a while.

Yes it's a little hard to justify 3X the cost of an Odyssey and bad luck. Heck you could play the lottery with those odds!

-Marc
 
That PC 950 recommend looks good. A minor modification to the tray would be required, but definitely more cranking amps and a few pounds lighter then the PC 925. Thanks for mentioning it Mike. One question. Did you mount the PC 950 battery laterally vs longitude because of the battery’s length?
 
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Battery tray already fitted and I copied another install. You make do and mend ;)

If a fresh install, you could fabricate a custom tray, but to be honest, a couple of angles sorted the mount out to use existing clamp down bar with shortened bolt downs.
 
I used an EarthX ETX900 for my RV10. I have a 40 pound Whirlwind prop up front so I was able to put the battery on the firewall, lower right. I am still in the CG envelope until I get down to a 100 pound pilot and no fuel where it creeps out the front, unless I have my standard equipment in the baggage compartment, Towbar, toolkit, Optimate Battery Charger and a few parts. Then it is still in.
 
Interesting. Thanks for the comprehensive explanation.

Hello Dad's RV-10,

We just received a call from one of the Van's forum readers asking if we could add more to this situation and explain what happened with the BMS.

We can only speculate as to what happened as we offered to get the battery back to evaluate it, and repair it if able, but did not have it returned. The temperature that was mentioned on the phone call for the engine start was -32 degrees. Regardless, the colder it is, the less cranking a battery will have, and the lower the voltage will drop at engine start. This also happens for an aging battery. When it drops below 8V, it will trigger the LED light to come on solid as it thinks it has been shorted due to such a quick and low voltage drop. Typically, this light would go off 60-90 seconds later.

Based on the multiple start attempts in succession, we can only speculate that the BMS board did suffer a damaged component as the light remained on.

This is not a BMS failure, it did as it is designed to do, alert you to an issue.

Hope this helps shed some "light" on the LED illumination. We are always available to answer your questions or concerns so please email us at [email protected] and we will get back to you as quickly as possible.
 
2 of these is what I have been using

https://www.amazon.com/Mighty-Max-B...locphy=9031996&hvtargid=pla-568908882946&th=1

They also sell a version of these at the local ACE hardware store under the name of "Universal" and sometimes Panasonic and other brand names.
The specs are all the same from what I can tell and they all perform very well.

Cheap, proven and solving the second battery back up problem if that is what you want/need.
I have used these for 20 years, first in my RV-8 and later in my RV-10.
I generally replace them at 5 years, they are still good but for $79 a pair its like buying new socks.
They crank my IO-540 with gusto and are mounted in Vans intended location.
 
My plane (which I bought around 6 weeks ago) has 2 EarthX ETX900 batteries mounted on the front of the firewall. The previous owner (who had bought it from the builder) had replaced the original prop with a Whirlwind composite prop and given the light weight of the EarthX batteries and the a desire to keep the batteries close to the Lightspeed electronic ignition setup, he moved the batteries to this location and was able to keep the CG in bounds. That having been said, I have found that when I am flying alone or with one passenger, adding about 50-70 pounds of ballast helps a lot with having enough elevator authority in the flare and it makes for much more consistent and smooth landings.

The rest of the EarthX story is that once I bought the plane, during the transition training (where we did a fair amount of pattern work and some slow flight), I started to see the 2 second BMS message from the main battery which sits lower down on the front of the firewall (the previous owner had never seen the messages). It continued on parts of the flight from New Mexico back to the Bay Area and then showed up whenever I was flying in hot conditions.

I called the EarthX folks (who are extremely responsive!). They suggested I use an Optimate charger to rebalance the cells but the messages continued after I did that. They said it was likely due to the BMS seeing high temperatures and they shipped me a new battery free of charge since this battery had been replaced only 6 months previously - they thought that perhaps the sensor had gone south.

I replaced the battery a couple of weeks ago but the messages showed up again. I came to the conclusion that it was probably not a battery issue and there was something in how or where I was flying it (higher humidity, more pattern work, etc.) that was resulting in higher temperatures seen by the battery.

I had an email exchange with RV-10 owner Mike Cingari about it and he suggested diverting some of outside air from the scat tube to the heat exchanger using an aluminum T "doodad". To test out whether it would work, we cut the scat tube (since there is no need for the heater currently) and strapped it in a fashion that it would send outside air onto the top of the main battery (which was giving the message). This was done last Friday and the great news is that even though I have been flying in hot conditions which previously resulted in the message, I haven't seen the message since we made the temporary fix. The (hopefully) final solution will be to put in this aluminum doodad.

If the messages come back once we put in the doodad, the next step will be to switch from the current lightweight battery box to a steel thermal box that EarthX also sells and then add a shielded lid to it. The thermal box also has the ability to accommodate a duct to provide additional cooling inside the case. It will add a bit of weight (about .29 kgs for the steel box plus the lid) but it looks like the same bolt holes can be used.

The previous owner has been very happy with the EarthX batteries and once I am comfortable that the heat issue has been resolved, I will be happy too. Putting a battery, especially one with a Lithium formulation in the engine compartment does raise concerns but given that the LiFePO4 formulation is very stable, with the right level of cooling air, I am hoping that it works out well for my plane.

Vas
 
Our Earth X battery is on the inside of the FW, no heat issues. Had to put a 26 lb lead weight under the tail transition cover in the tail for CG to be good in the envelope.
 

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Did I read that right?

26 pounds of lead in the tail? That's like buying an EarthX and an Odyssey and installing both, to negate the weight savings of one and the cost savings of the other.

I suspect there will be some interesting comments here to follow. Popcorn stocks will see a brief surge despite recent overall market decline.

Can you share pictures of how this weight was secured to the structure?
 
26 pounds of lead in the tail? That's like buying an EarthX and an Odyssey and installing both, to negate the weight savings of one and the cost savings of the other.

I suspect there will be some interesting comments here to follow. Popcorn stocks will see a brief surge despite recent overall market decline.

Can you share pictures of how this weight was secured to the structure?

No pics, but ran 2 bolts through the block of lead, on the ledge right in front of the Tail under the plastic transition piece. Just finished CI, nothing moved.
 
I too need aft ballast for CG when solo - but opted to use a 5 gallon collapsible water jug, which with the tool kit I now carry is even more weight than necessary. Easily disposed of if passengers or baggage are added en route, or left behind on trips with baggage or rear pax.

26 pounds that far aft seems like a lot more than most 10's would need. Making it unremovable limits options to essentially zero. I'm glad you've gotten away with it, but remember this is now an ongoing experiment in polar moment/rotational inertia. I would do whatever I could to make sure this airplane is never in a spin.
 
The removable ballast (particularly the water jug) is very nice as Bill said - when I have passengers in the back seat, I can offload it and as he also said, it can be adjusted enroute if you are adding or dropping passengers or baggage enroute.
 
If you need 26# of lead in the extreme aft tail cone, that probably equates to about 75# of ballast in the baggage compartment, maybe more. That's a lot of water.

I can imagine myself concocting some kind of externally fillable/drainable water ballast tank in the rear of the tail cone if my initial CG numbers crunched that badly.
 
How is that possible?

Our Earth X battery is on the inside of the FW, no heat issues. Had to put a 26 lb lead weight under the tail transition cover in the tail for CG to be good in the envelope.
I know this is about batteries but something is not right if you need 26# of weight in the RV-10 tail??
Sounds like the CG may be out of limits when empty (that's ok) but with a pilot on board it is just hard to believe.
Back to batteries.
 
During the rewire / panel upgrade we moved the battery to the firewall and switched to an EarthX.

Solo (I am 155#) with full fuel I am just aft of the fwd most CG limit. I usually fly with my tool kit and 25# of lead shot in the baggage area if I am just flying around doing takeoffs and landings. Just makes the flare / landing easier.

In my mind this is a near ideal setup for the -10, as it allows me to fill the rear seats and baggage area without much concern for aft CG loading. I’ve carried some pretty heavy stuff out to the cabin in CO, and was still well ahead of aft CG.
 
In my mind this is a near ideal setup for the -10, as it allows me to fill the rear seats and baggage area without much concern for aft CG loading. I’ve carried some pretty heavy stuff out to the cabin in CO, and was still well ahead of aft CG.

I’d say a more ideal situation is to replace the lead with 3 gal of water in a plastic jug. If the day comes when you’re up against the aft cg, just pour out the water!

PS always remember to check cg in landing configuration (low fuel).
 
I know this is about batteries but something is not right if you need 26# of weight in the RV-10 tail??
Sounds like the CG may be out of limits when empty (that's ok) but with a pilot on board it is just hard to believe.
Back to batteries.

One last comment, then yes back to batteries. Just about any combination of 973 LBs of useful load is within the CG envelope (within reason). Our empty weight includes the O2 bottle, tools and paraphernalia in the baggage compartment that is always there.
 
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