Alternatorless & preparing for winter

[Daox]

I'd have to imagine that polystyrene is a superior insulator, its also way cheaper.

[Christ]

I think the reason for the neoprene being such a good insulator has more to do with it being semi-impermeable when wet.

When you dive, your skin gets wet, but the film of water doesn't move, and your body heat warms the water, which then acts as an insulator. This is why in cold climates and waters, you want to move more slowly to stay warm under the water. The faster you move, the more of the warm water you force out and induce influx of cold water against your skin. If you move more slowly, this happens less.

This comes from one of my uncles who was a Navy boat captain and has a few hundred dives on his record.

[Christ]

I'd just hit up a construction site for some pieces of foam board and use them, if you can.

You might also have luck (if you don't mind getting dirty) finding a party or something where they're using foam cups (wedding, etc) and seeing if you can get them to keep the cups separate for recycling, or if you can even take the throwaways. If you crush them up, you can insert them in vacuum bags and make decent insulation panels that way, too.

Lastly, Sand (I know... ) might work well. If you can put your battery in a battery box, put a layer of sand about 1/2" or 1" thick under it, and around all sides of it, then some spray foam to hold the sand down, and foam in the lid of the box, as well.

The issues with sand are obvious... it's friggin heavy.

[RobertSmalls]

Originally Posted by Daox

Well, thats kind of the thing. Do I leave it uninsulated to absorb engine bay heat and just let it cool down faster? Or, do I insulate it as best I can to keep in the heat it does have? I'm not sure.

The engine bay is hot maybe one hour a day, and cold the rest of the time. I'd insulate it.

[Daox]

I have some sheets of polystyrene laying around that I can use.

Good point point about the engine only being hot for a short period of time.

[Phantom]

Why I mentioned neoprene was for its flexibility, durability, resistance to crushing/crumbling, more resistant to fire, can easily be adapted for vent holes, helps with vibrations, and can wrap the whole battery.

I under stand the semi-permeability of neoprene and that can be easily fixed by adding something like fiberglass resin, super glue, contact cement, ect. I have never worn a suit on polystyrene but put a wetsuit on even on a 70 degree breezy day and you will be burning up in no time.

If you are adding a heater any way what will warm the battery more the heater sealed away from the engine heat in polystyrene? Or the heater and allowing the engine heat soak in? I guess it could be tested in an oven with the materials and two thermometers.

[BamZipPow]

Keep in mind that excessive heat will kill a battery's life in short time.

[BamZipPow]

From this thread...

11.1. Protecting your car battery from high underhood temperatures with a heat shield or case, keeping it full charged at all times, and maintaining it are the easiest ways to extend it's life. In hot climates and during summer, the electrolyte levels need to be checked more frequently. In a study conducted by the Society of Automotive Engineers (SAE), the underhood temperature has increased more than 30% since 1985. For every increase of 18° F (10° C) above 77° F (25° C), positive grid corrosion or self-discharge rate is doubled.

Chrysler studies have shown that relocating the battery outside the engine compartment has increased the average OEM battery life by eight months. Relocating the starting battery to the trunk or passenger compartment, as Mazda did in their Miata a number of years ago, is becoming more popular by the car manufacturers to protect the starting battery from the high underhood temperatures. However, use sealed AGM (Ca/Ca) or Gel Cell (Ca/Ca) VRLA type batteries because they normally do not produce gas when recharged or use wet batteries vented to the outside. If you use a Gel Cell (Ca/Ca) VRLA as a starting battery, you might have to lower the charging system voltages because they are very critical and to keep from overcharging the battery.

For motive and stationary deep cycle batteries, temperature is equally as important for extending the service life of the battery or battery bank. Common sense and chemical intuition suggest that the higher the temperature, the faster a given chemical reaction will proceed. Quantitatively this relationship between the rate a chemical reaction proceeds and its temperature is determined by the Arrhenius equation. Battery life, due to positive grid corrosion, is reduced by 50% for every 18° F (10° C) rise in ambient temperature over 77° F (25° C).

[BuckarooBanzai]

If it's still of interest, I've actually seen a neoprene battery jacket in a jetta before. Not sure though if its for keeping it warm, cool, or just plain swagger lol

first result from ebay:
VW BEETLE BATTERY COVER : eBay Motors (item 180559684363 end time Sep-18-10 07:55:44 PDT)