gman6262

Guys - I'm posting this for whoever may be interested in this - for cold weather driving. I live in Montreal, Canada, and we usually get about 2 or 3 weeks in the winter where the temperature goes below -20C (-5F). When it does - I'll have the known issue where the ventilation fan sometimes will slow down to conserve battery power - and consequently - my feet will freeze on the drive into work.

So - I ended up installing a Polar Pad engine heater that sticks onto the oil pan, a battery warming blanket, and a battery charger - installed at the rear, above the battery. All three items are wired together in the trunk to a short length of extension cord I tuck up in the rear underbody fairing under the rear bumper. If you're interested, you can read about the installation here:

The Fix-it Blog - Sorting Things Out: Installing a Polar Pad Engine Oil Pan Heater on a 2010 E61 BMW 5 Series

The Fix-it Blog - Sorting Things Out: Installing a 12V Battery Trickle Charger in the BMW E60 / E61 5 Series - Trunk Mount at Battery

With this done - no issues at all with the car heating up on really cold days - it makes a huge difference.

I don't mind answering any questions about the install.

Lotus99

Wow, nicely done. I can see how you'd plug in the heaters overnight, but Why the battery charger?

gman6262

The engine management system doesn't keep the battery fully charged. It keeps the battery partially charged (80%??) to keep some charging capacity available for the Brake Energy Regeneration system to use (part of the EfficientDynamics features). Even after a long highway run - when I hooked up the trickle charger - it will charge at 1.1 Amps and required about 12 hours to top up the battery. I've been checking this over the past week - and that seems to be about average.

Lotus99

You sure about that? That's the first I hear our cars have this Brake Energy Regeneration system?

Either way, if you're driving the car daily, it's overkill / should be unnecessary to put a trickle charger on it. If you're having problems starting the car without the charger, I'd think you've got a battery issue that needs to be addressed.

gman6262

Here's the discussion on brake energy regeneration:

https://5series.net/forums/e60-discu...ration-107119/

I totally agree that the battery charger is overkill - but I didn't want to have one more instance of the heater fan slowing down due to low battery levels following cold starts. I don't necessarily want to keep my car in the garage on cold nights - I prefer to keep it outside and keep the garage clean - so I decided to go all-in and do the trifecta with the oil pan heating and the battery heating.

I love the car, I plan to keep it for a long time (I can't replace it with a new 5 series touring since they're not being imported - and I'm not an X5 kind of driver) and I'm not ready to go for an E-class wagon. So - might as well treat the engine / battery well in the winter since it's my daily driver, and maybe I'll get a few extra years out of the battery.

FormerE30Owner

Well I am also from Montreal and have owned 8 BMW since 1971 and not one has needed any of the devices that you installed. Cars were always parked outdoors (heated garages are the worst thing for body and component corrosion and for condensate in gasoline) and the only thing I made sure of is to have a healthy battery. Also, I have used synthetic oil since 1973, which really helps with starts. Theother thing to do is not have the engine idle too long before moving - better to just drive off after about 30 seconds to establish oil flow - the engine heats up more quickly under load.

If you really insist on keeping a trickle charge on the battery, then you needn't keep the battery warm, since the trickle charge will do that and you don't want to overheat the battery! Overheating the battery will contribute to shortening the battery life.

Presently I am using a solar panel to charge my battery during the day.

Salut, Bob P.