What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Battery selection

T

T.O.Craig

Well Known Member
Howdy again,
My 10 year old RV10 plans call for a concord battery es-25 RG-VC. I have been having a hard time locating this battery in the usual places.. Is that still the battery of choice?
Second question.. Battery tenders/minders. What is the group using and are we connecting to somewhere on the outside of the plane. I suppose it could attach to the baggage compartment bulkhead and leave the baggage door open. Curious what others are doing.:))
 
A lot of us use Odyssey 925s. I have a 3-prong mil style ground power point on the bottom of the tailcone left of the battery tray but I fly often enough I don't worry about hooking up a battery tender.
 
I copied Mark Cooper and installed a Powerlet Plug http://www.powerlet.com/product/standard-powerlet-socket/280 in the rear wall of the baggage area. I also purchased a powerlet cable that adapts to typical battery chargers http://www.powerlet.com/product/powerlet-straight-plug-to-sae-battery-charging-cable/644 as well as a few of their powerlet straight plugs to modify for any additional uses. The plug is wired though a 15A fuse in an always hot battery buss fuse block right next to the battery.

I am also using an Odyssey PC-925 battery which I widened the tray to accept. The stock battery hold down bolts are too long if you go this route. I ordered AN4-55A bolts to replace the stock ones. You can use a PC-925L instead which sits on its side and doesn't require modifying the tray as much. You only need a small block to fill the width difference instead of widening the entire tray.

powerlet_1.jpg


powerlet_2.jpg
 
Last edited:
I too use an Odyssey 925. But I put mine on its side, because Odyssey said I could, and it's a good fit to the existing tray that way (just a small additional angle to keep it from moving fore-aft).
However, I am not happy with its lifetime. Two batteries in a row seem to lose about 20% of their capacity very quickly (under even a small load, the voltage drops quickly to 12.2 volts. After that it shows a normal rate of loss). I wonder if mounting on its side is really not so good, despite what Odyssey says. It still starts fine, just not much reserve.
 
I did find the concorde battery but it is $265. Just not sure if it is worth the extra money. Odyssey 925 for about $148. I'll see how much modifying I will need to do with the Odyssey to make it work...
 
You can buy an Odyssey 925-L that will sit on its side and have the terminals in the same location as the Concord just about. That battery cranks with much more oomph (to use the technical term) than the Concord.
 
I put in a pair of 680s along with the powerlet jacks for charging. I use one for an ebus , but I can also put them in parallel for cold starts if needed.

I did have to modify the tray, but it's not that difficult.
 
I did it per plans with the Concorde specified. Still going great after 5+ years. Never used a tender. Keeping it simple...

-Rob
 
Charging voltage

BobTurner said:
I too use an Odyssey 925. But I put mine on its side, because Odyssey said I could, and it's a good fit to the existing tray that way (just a small additional angle to keep it from moving fore-aft).
However, I am not happy with its lifetime. Two batteries in a row seem to lose about 20% of their capacity very quickly (under even a small load, the voltage drops quickly to 12.2 volts. After that it shows a normal rate of loss). I wonder if mounting on its side is really not so good, despite what Odyssey says. It still starts fine, just not much reserve.
Click to expand...

What do you have your alternator output voltage set at? The Odyssey's like a good 14.5 volts and if you have the typical 13.8 v output then the life of the battery will diminish as well as the reserve capacity.

Vic
 
vic syracuse said:
What do you have your alternator output voltage set at? The Odyssey's like a good 14.5 volts and if you have the typical 13.8 v output then the life of the battery will diminish as well as the reserve capacity.

Vic
Click to expand...

Thanks for the suggestion Vic. Buss voltage in flight is 14.4 volts. Think that is just a bit too low?
 
Bob,
My buss voltage is 14.4-14.5 and I am using a 925L for 3 years without issues. I have noticed that the resting voltage has declined slightly from the 12.8V, but never as bit of an issue.
Have you ever performed the de-sulfation process on the battery that is detailed on their website http://www.odysseybattery.com/documents/ODYSSEY_Battery_Reconditioning_Charge_Procedure.pdf

I have brought back several friends 680s on the field by doing this.
 
BobTurner said:
Thanks for the suggestion Vic. Buss voltage in flight is 14.4 volts. Think that is just a bit too low?
Click to expand...

14.4 should be ok, but it depends on where you ar measuring it. Put a voltmeter right on the battery and run the engine and see what you get. The rv-10 battery is quite a distance and you can get a voltage drop across that length that you may not be aware of. While you're at it, disconnect the + lead and put an ammeter in series between it and the battery and make certain you don't have a parasitic leak from something that is wired hot to the battery.

Vic
 
Thanks for the suggestions.
1. I did have a parasitic load (clock keep alive) but that has been removed, thought I fixed the problem but second battery suffered the same loss-of-capacity fate.
2. Performed the deep discharge-recover technique, that seemed to work. Battery is sitting on my shelf marked 'probably okay'.
3. I have not measured voltage at the battery, engine on. Guess that is the next step.
 
Vic,
You may be on to something. My D6 showed 14.4 volts on the main buss, but the GRT showed just 14.1 on the avionics buss. I ran a wire from the battery up to the cockpit and put a voltmeter on it, engine running; showed 14.1 volts.
So I guess I'll put a diode in the sense line, to pick up the alternator output, unless there's an easier way(?)
 
Spare wire?

Any chance you ran a spare wire to the back? If so, you can sense it right at the battery.
 
You must log in or register to reply here.
Back
Top