Fresh air to ... the battery ?
 

Looking under the hood of my Volvo V50, I noticed there's a small air duct in the hood's sound-proofing that force-feeds fresh air from behind the grill to the largely enclosed battery.

For me, it's the first time I've seen anything like this on any car. :confused:

Why would Volvo do that ?

If I block the grill, that'll also bock the air to the battery.
What effects are to be expected ?

It is there to keep the battery cooled. If it is mostly enclosed than most of the heat from charging or discharging is contained (not good) and can cause the battery to over heat. I would still let some air flow into that area (it will also help keep other under the hood electronics cool).

If I remove the enclosure along with the airduct, the battery will be in the hot engine compartment - like most other car batteries.


It goes only to the battery as far as I can see.
Where it goes after that, I still have to find out, but by the looks of it, it's not going to other electronics. Probably just spills out at the rear / bottom of the battery.

yes it likely just spills out into the engine compartment, but it is good to have some cooling in there. Under hood temps are a key factor in how long electric components last.

As for the battery enclosure, the designers must have decided that it needed shielding from the under hood temps, that's why they put it in an enclosure. Heat kills batteries (speeds up the chemical break down process) this is not a big deal with lead acid
batteries but it still is a factor.

Can you post some pictures of the current set up and of you planed mods (tape some cardboard up)?

Move the battery to the back seat like I did. More room to work on engine. More weight out of the front allowing 155/80/r13 wheels. Also cooler battery.

That's not really an option ...
But the spare wheel well is empty now.
Mmmmmmm :rolleyes:

It's not for heat/cooling. Batteries emit gasses thus need to be vented.

Cool battery makes better FE and longer battery life.

When battery get hot the voltage of the battery goes down and battery gets overcharged. (I might say that overcharging is just boiling water) Cool battery has higher voltage and alternator won't overcharge it.

I haven't been any kind of Volvo fan but past year have been different. Volvo has done many basic and reasonable things for better FE and reliability and this is one more thing to list.

...yep, HYDROGEN (ala' "Hindenberg") gas...which might be an idea to the HHO generation advocates.

The battery has been in there for almost 5 years.
I've only used the preheating maybe 1 or 2 times.
In winter it starts easily without using preheat, even though the car is not kept in a garage.

I could monitor the voltage using the Scangauge and see if there's any difference.


Fortunately - or unfortunately depending on your PoV ;) - a car battery won't produce nearly enough hydrogen to have an effect on FE.

But in an open engine compartment, battery ventilation surely would be better than in an enclosure ?

Tollo - Many vehicles use temperature compensated charging to avoid that problem. My Jeep has a temp sensor in the battery tray to monitor battery temp. In hot summer weather, the voltmeter sits around 13.8 or so normally, a little less if the engine bay is really heat-soaked. In cold winter weather, it's around 14 - 14.1 due to the colder battery.

I think some vehicles use temperature compensated charging and many does not. :) ... (I might be also wrong) How common is it ?

High temperature damage battery even when temperature compensated charging is used. (cool or "room temperature" is better)

euromodder - Cold temperature lowers the capacity of the battery. You won't probably not see any difference in battery voltage if you don't have temperature compensated charger.

Cold battery has less energy loss. That is the reason for better total FE.

I've left a gap in my grill block, right where the intake to the battery is located.

Photo

It's so common I've never heard/read/seen it before :confused:

Another issue with grille blocks on a V50 is the ECM, which sits right behind the grille in front of the engine block.

chrylser loves the temp compensated charging concept..... i've seen it on no other vehicles though. the earlier models have a temp sensor inside the ECM itself, later seems to have moved it closer to the battery.

but, yes, high temps will reduce battery life. cold temps are temporary reductions in capacity/output/input. you'll see this in some vehicles that moved the battery into the passenger cabin that in otherwise similar vehicles, the underhood battery might last 5 years, while one hidden underneath the rear seat lasts 10. YMMV though.

I do not know much about cars, I have only seen that on HMMWVs, and it is under the front... "passenger."

The Hindenberg blew up cause it was coated in rocket fuel, not filled with hydrogen. :eek:

The question remains: "...which occurred first? (a) the spark igniting the paint or (b) the spark igniting the free hydrogen gas?"

However, because hydrogen gas is far more easy to "ignite" than the metallized paint, your question seems mute [check ignition energy requirements].

Replace your battery with a Supercapacitor bank!

You dont know which either, but your siding with the hydrogen thing anyways? :eek:

Yeah, supercaps FTMFW!!!!

I've checked the Minimum Ignition Energy (MIE) requirements of free hydrogen...have you?

• NASA: http://www.hq.nasa.gov/office/codeq/...led/871916.pdf

Well, Im glad you agree with me. The flash was the hydrogen and the burning seen in the news reel is the coating of the ship burning. :thumbup:

My old ford had one, I removed it, the battery lasted only 2 years instead of the much more average 4 years or greater. Its designed to thermally insulate the battery from the rest of the engine bay and give it a slight cool air source.

Simple stuff really, when charging a battery it produces heat, when discharging a battery it produces heat. When you run an engine it produces LOTS of heat, combine the 3 and you get a recipe for boiling electrolyte away which isn't good for longevity of a battery.

The fact that batteries produce oxygen and hydrogen and acid doesn't even factor into the reason why the battery box is there, the vents are still exposed at the top with or without the battery box that they put into most car engine bays (some cars have them fully enclosed), so the battery is going to be venting those gases into the engine bay anyway, and engine bays generally do not produce naked sparks, usually the sparks are enclosed inside of the engine.

The second reason why the battery box is there is for a slight amount of mechanical vibration insulation to the bottom of the battery, lead acid batteries are made up of semi-fragile lead plates and leads connecting each plate to each other, to form a pack of cells which gives you 12volts nominal per battery.

Without the battery box the battery would be sitting directly onto the metal chassis of the car, absorbing every pothole and all the vibration the engine can put out.

It is there to keep battery power cooled. If it is mostly enclosed than most of the heat from charging or discharging is contained (not good) and can cause battery power to over heat.