Installing a 12V Battery Trickle Charger in the BMW E60 / E61 5 Series - Trunk Mount at Battery

Last weekend I did a winter maintenance hat trick on my 2010 BMW 535xi Touring. I installed an oil pan heating pad, a battery warming blanket, and an 1.1 Amp trickle charger.

I made a quick trip to Canadian Tire and decided on the NOCO Genius G1100. Noco also makes another model with better environmental protection designed to be installed semi-permanently in the vehicle. However I decided I'd try this one - reasonably priced about $60.

Noco Genius G1100 1.1 Amp Trickle Charger

IP 65 rating should mean that this charger is splash proof and dust proof. 
Installation of the harness directly to the car was simple. There is a grounding post direcly on the rear fender, where I installed the negative (black) ring terminal under the OEM hold down bolt.

Black negative cable installs to ground lug on right rear fender - with other car electrical grounds. 
The positive connection was also simple, underneath a bolt in the rear fuse box where the positive battery cable connects to an aluminum bus plate. 

Positive connection on the bus plate in the rear fuse panel, where the batttery cable attaches. There is a black plastic cover for this bolt - which I reinstalled after testing the connection. 
The trickle charger will normally bring the battery back to 100% charger overnight. It's a nice charger - auto voltage sensing, senses the battery is an AGM glass mat battery, and switches off when it reaches full charge. 

I made all the electrical connections and installed the charger in the plastic tray above the battery - and grounded the 110V electrical extension cable ground wire to the body of the car (green wire). This way - if line or neutral ever shorts to sheet metal, it will trip the breaker in the house before presenting a shock hazard to someone touching the car. 

Note green ground wire - grounding the 110V extension cord to the car body ground for safety.

Noco Genius G1100 chager installed in the tray above the battery. The other connections are for the battery blanket warmer, and the oil pan heater. 

I ran the electrical feed through a small hole in the battery box, underneath the car out underneath the rear fairing. This way - it is quick and easy to connect power without having to open the hood or the trunk - quick and easy. When not in use, the cord tucks in above the fairing and is protected from road salt and splashing. 
Works great - quick starts in the morning on very cold days, and no battery issues.


Installing a Temro Battery Warming Blanket in a 2010 E60 / E61 5 Series

In most BMWs, you'll find the battery in the trunk of the car. In the 2010 535xi Touring, it's on the right hand side of the trunk, just behind the right rear wheel well.

Installation of the Temro battery blanket is very simple, and takes about 10 or 15 minutes.

Temro Battery Warmer

There is a gap of approximately 1/2 to 2 inches all around the battery. Installation doesn't require removing any battery cables. I found that removing the upper tray support bar and the rear battery bracket simplified installation.

I used a 36 inch long, 80W model, and it fit about 90% of the circumference of the stock battery.

I oriented the AC power cable to come out between the positive and negative terminals, along the outside of the car. 

Blanket installs between the battery and the hold down bolt, which holds it perfectly in place. 
Check out this post to see how I powered the blanket in parallel with my engine oil pan heater, and trickle charger.

Installing a Polar Pad Engine Oil Pan Heater on a 2010 E61 BMW 5 Series

I was pretty surprised when I learned there is no block heater option on the E60 / E61 BMW 5 Series - these engines use a wide temperature range synthetic oil to keep the viscosity of the motor oil low even in very low temperatures. Nonetheless, after a cold overnight soak at -20 C / -5 F means that the engine will crank for 3 or 4 seconds before the oil pressure builds and the engine fires.

Ultimately it was the known issue with these cars of difficulty producing heat in cold temperatures that pushed me to do something about engine block heating. When I leave the car outside overnight in very cold temperatures, I want it to fire quickly, use the least amount of energy possible from the battery to help prevent the electrical system from going into a preservation mode and shedding non-essential loads - in this case - the ventilation fan motor. See my other post here regarding the ventilation system not producing heat.

Canadian Tire sells an engine heater that sticks onto the oil pan and sends its heat directly into the motor oil, call the Polar Pad. I originally purchased the 250 Watt model, with approximate dimensions of 5.2 inches by 3.5 inches, shown below:

Polar Pad Model CP512 250W Engine Heater Kit - The self adhesive heat pad, sandpaper, silicone aluminum sealant, and a few zip ties.  
The next step in the process was to find a place to install the heating pad. The E60 / E61 5 Series BMW has underbody aerodynamic covers just about everywhere under the car, except in proximity of the exhaust, fuel tank and rear suspension. In order to get access to the oil pan, the car has to be jacked, placed on jack stands, and then the front and front center underbody pads removed. This isn't too difficult to do, but you do need to get the car in the air. Of course - if you attempt to put the car up on jack stands - make sure you know what your doing, and that you double check the stability of the car on the jack stands. Whenever I work under the car - I'll normally put a second pair of jack stands close to where I'm working for a bit of extra safety.

There is a jacking point directly underneath the engine on the main crossmember - which protrudes through a hole in the underbody cover - it's very easy to find, and solid enough for jacking. 

Jacking the E60 / E61 directly under the motor on the engine crossmember jacking point.

Once the car is in the air, on jack stands, this is the view of the underside of the engine from the front. Note there is an aluminum skidplate / stiffening plate underneath the engine oil pan behind the main crossmember / sway bar that will need to be removed in order to give good access to the oil pan. It is held on with 6 8mm bolts - an air impact makes this an easy removal. 

Underbody cover from directly underneath engine. Note oil crud and salt. This cleaned up fairly nicely with some comet and a floor broom. 

Aluminum skidplate / stiffener plate from underneath engine / oil pan. 

Selected mounting location for the polar pad engine heater. In the photo, just behind the sway bar is the steering mechanism. Just behind the steering mechanism is the oil pan - note the drain plug. The oil pan is pretty complicated with the front differential on the X drive model on the righ, and the driveshaft for the right front wheel runs through the oil pan. The only suitable flat surface is vertical between the steering rack and the oil drain plug. 

Comet and some water cleans up the skid plate / stiffening plate quite nicely. 

Setting out the underbody covers to drip dry following cleaning.

Underbody covers - cleaned.
When I went to fit the 250W polar pad, I found it was too large for the only available flat space. Back to the auto parts store for the 125W model, which is about half the size of the 250W model.

Packaging for the 125W and 250W models of the Polar Pad.

125W and 250W Polar Pad sizes compared. 
Now, with the correct size Polar Pad - installation is fairly straightforward. Sand down the mounting location to smooth metal, remove any paint or oxidation.

Mounting location sanded down, ready for application of the Polar Pad
With the mounting location ready, I used a heat gun to heat up the metal surface of the oil pan, and followed the instructions to heat the polar pad for 15 seconds by plugging it in, then removing the protective backing and applying it to the oil pan.

Polar Pad stuck into place with its adhesive backing.
 The next step is to seal around the edges of the polar pad with the supplied silicone aluminum high temperature sealant.

Edges sealed with high temperature sealant.
Polar Pad intstalled.
With the polar pad installed, the sealant is left to harden while the electrical cable is routed. I decided to run an extension cord to the back of the car, into the trunk next to the battery, so that my connections for my trickle charger, battery warming blanket and engine heater are all in one place.
Zip tying the electrical cables to the underframe. Careful not to route the cables where it will interfere with the skid plate once replaced. 

I ran the extension cord to the back of the car alongside the positive battery cable. This way I was sure that I was far enough away from the exhaust not to worry about melting the cable.  
The junction between the cord of the Polar Pad and the extension cord. I coated the connection in silicone electrical insulating compound before taping the connection with electrical tape, to ensure no water would be able to enter the plugged joint. 
Taping the extionsion cord connection between the extension cord and the Polar Pad.This connection is then zip tied to the bottom of the frame.
Once I got to the gas tank along the factory battery cable routing, the battery cable runs up underneath the gas tank, and then underneath the rear suspension. I found it impractical to try to run the extension between the gas tank and the body floor, so instead there was a good route along the top of the suspension brace that runs underneath the gas tank. From the rear side of the gas tank, there is a good route to meet up with the battery cable again and run between the rear suspension and the body. Before getting too close to the exhaust, I ran the extension back into the trunk where the battery cable runs. Note this a wagon, I can't tell you if the sedan is similar or not. 

Cable runs into the trunk, next to where the battery cable runs into the trunk. Cable runs through a grommet to protect the cable from vibration and wear. 
Note the extension cable in yellow, running into the trunk next to the battery cable. 
Once at the back of the car - the cable meets up above the battery for simple connection with the battery warming blanket and the trickle charger. 
Electrical cables in the storage compartment above the battery, ready for connection.


So - how does the Polar Pad engine heater work? In a word - brilliant. -20 C / -5 F starts are just like they are in normal warm weather, the engine cranks much quicker, and fires in a second or two. Much less work for the starter. The ventilation fan in Auto mode starts blowing air in about 2 or 3 minutes after pulling away - which seems to be a big improvement. This work took the better part of a Saturday, but now I'm happy it's done and hope this will pay off in reduced engine wear and longer life for the car. If you have any questions - just leave a comment below and I'll try to get back to you quickly.

Sources and Links

I hope you found this post useful. Feel free to ask questions in the comments section below. I answer all questions.

Cold Weather Heat / Ventilation Problems in a 2010 BMW 5 Series - Battery Charging, Engine and Battery Heating

For the past two winters, on extremely cold days -20C / -5F or below, on my morning commute I'll have problems getting heat out of the ventilation system. In some cases, the ventilation fan will slow down to minimum speed, and for 20 minutes I'll freeze on the drive into work. Eventually the heat will start working in about 20 minutes, and by then my feet will have frozen to the pedals. Some research into the issue on the forums, and a few phone calls to my service adviser at the dealership, lead me to a possible cause for this issue. The BMW battery charging system has a load shedding function to help protect the battery charge level. So, after you've cranked your car after an overnight cold soak at -25C, with the depleted capacity of the battery at that temperature, and you're now driving the car with the heated seats, heated steering wheel, and the ventilation fan on high - the charging system may decide to protect itself by shedding (shutting off or slowing down) non-essential loads. One of these loads is the ventilation fan, when the ventilation system is not in the defrost mode. In defrost mode, the ventilation fan is considered an essential load and will be driven to high speed.

To make a long story somewhat shorter, I decided to take action and make a three pronged solution to this issue, to see if I could reduce the discomfort on cold days. Follow the links below to review the detailed posts on various installations. 

1. Install an oil pan engine pad heater (to shorten cranking times in cold weather, and help reduce engine wear on cold days - I plan to keep this car for a while - at least until BMW North America starts importing the 5 series wagon to Canada again;

2. Install a battery warming blanket to help keep the battery warm on cold nights, and to facilitate overnight trickle charging and short cranking times in the morning; and 

3. Install a trickle charger to bring the battery charge to 100% overnight. 

I also wanted to connect all three electrical loads on the car to a single extension cord plug, tucked up underneath one of the bottom fairings at the back corner of the car next to the trailer hitch, so I only have one plug to manage in the morning for connection / disconnection, and without having to open or close the hood or the trunk.