Battery Vent Line Routing

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Kurt h
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Battery Vent Line Routing

Post by Kurt h »

Replacing the battery in our DA40, I disconnected the battery leads and the vent line. I decided to remove then vent line hose out of the way, then realized I did see where it was routed. Apparently it just routes loosely through the engine compartment somewhere (no attachment on the other end). If I just drop it straight through, it hangs about a foot below the plane.

Anyone know the routing of this hose?
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Steve
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Re: Battery Vent Line Routing

Post by Steve »

Kurt:

My recollection is that it goes to the "drain manifold", that aluminum tube that extends down into the slipstream below the belly. It shares the common drain with the crankcase breather and the engine driven fuel pump drain line.

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Kurt h
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Re: Battery Vent Line Routing

Post by Kurt h »

Thx Steve. I'll take a look when the new battery comes later this week. On first look today, it wasn't obvious how to route it over to the drain tube, but that makes the most sense.
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Charles
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Re: Battery Vent Line Routing

Post by Charles »

Replacing my battery earlier this week, I noticed that the battery vent hose is missing. It is referenced in the AMM but I can't find it in the IPC. Does anyone know the P/N or the inside and outside diameters of this hose?
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Charles
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Re: Battery Vent Line Routing

Post by Charles »

Nevermind, I found it in section 71 of the IPC (71 Powerplant/71-70 Engine Drains). It simply says 6.3mm hose without a PN. I assume that's a generic 1/4 in. OD hose?

Can someone describe the proper routing of this hose?
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Charles
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Re: Battery Vent Line Routing

Post by Charles »

Well, I found the vent hose is installed after all, it's on the bottom of the battery compartment. But the most likely way for a acid to leak out of the battery is through expansion of the liquid and leaking from the hole on the battery cover to which no hose is attached (at least on my plane right now). Are we expecting that any acid overflow from the top of the battery would make its way along the side of the battery to the drain at the bottom?

I'm thinking of running a hose from the fitting on the battery cover to the bottom of the compartment. Or even connect it with a T fitting to the hose at the bottom. Thoughts?

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Re: Battery Vent Line Routing

Post by Steve »

On my airplane, the battery tray drain is simply a short steel tube with no hose connected to it. The battery vent you circled in the photo is attached via a white silicone nipple (MS25171) to the quarter inch clear plastic vent line that runs to the common drain mast on the left lower firewall.
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Charles
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Re: Battery Vent Line Routing

Post by Charles »

Interesting, thanks Steve. I have a hose from the bottom drain tube and a nipple but no hose on the battery. What you describe makes more sense, the bottom drain is probably for water so needs no hose while the battery drain is for acid so needs a hose. I’ll see if I can just re-route the hose from the bottom to the battery drain.

Is there a diagram somewhere that could confirm this?
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Steve
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Re: Battery Vent Line Routing

Post by Steve »

Charles wrote: Sun Aug 21, 2022 5:04 pm...Is there a diagram somewhere that could confirm this?
I'm not aware of one. On mine, the clear line just runs along the firewall, only affixed at each end.
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Re: Battery Vent Line Routing

Post by Rich »

The G-243 looks to be a flooded (aka vented) battery, with removable caps. This type of battery is what was delivered initially in my plane, though I don't recall the original part number. Normally these types of batteries vent electrolyzed water (i.e. H2 + O2) out the caps when charging current is applied. This is the ordinary state during operation and is why one periodically needs to add water (not electrolyte) to these batteries. Of course you want to vent that Hydrogen for obvious reasons so providing a route to dump it overboard is highly desirable. Whether or not the BatteryMinder would be harmful to this battery is an open question.

Neither the flooded nor RGM types should emit acid, save some sort of breach of the case.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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