Second battery, Auxiliary battery DIY install on X5 F15

[fm16nfd]

As we know all BMW F85 AND F86 have auxiliary battery (second battery), a very good a very good option, especially when it comes to additional installed accessories. For example, I have an X5 F15 on which I did not have an auxiliary battery from the factory and which put me in difficulty when I wanted to install a dashboard camera with remote access with notifications and all kinds of alerts to monitor my car and in parking mode. Well, because I wanted to install a second battery (auxiliary battery), I had problems finding parts. Initially, all the cars in this range are somehow prepared for pre-installation, but I couldn't find the support on which the auxiliary battery sits either at the factory or at the disassembly, so I resorted to my DIY engineer way. I bought a battery holder, I bought a DC to DC charger, a 700A AGM battery, relays, cables and all kinds of connectors and I succeeded. I'm still working on it, but I'll leave you a picture. Now I have the dashboard camera, gps, 4G always active in the car, I have a consumption of 350 milliamps, which can keep my equipment 7 days without starting the car.

[Qsilver7]

The aux battery in the F15 is a smaller H4 battery class size and there’s the PCU (power control unit) that sits between the main battery and aux battery.

Installing a larger H8 or H9 battery next to the main battery would present a challenge you seemed to have conquered…you had to be creative to make it fit.

Hopefully you added the additional VENT TUBE (and the little black elbow that connects the vent tube to the battery) so that you can vent any off gasses from the additional battery to the exterior of the car (#9 & #10 in illustration below). . And if you haven’t thrown the cover from the battery posts on the new battery…make sure you pop off the additional vent plug so that you can insert it into the other vent hole on the new battery to prevent off gasses from venting from the other side of the battery that is NOT connected to the vent tube.

You can see the holder (#5) and the clamp (#3) in the illustration below that holds the aux battery and PCU.




This is the PCU & additional holder that sits between the main and aux battery:

[Qsilver7]

If I confused you about the battery vent tube and vent plug…see the pics below. The vehicles vent tube on the main battery and aux battery is gray…and is connected to the battery by a little black elbow…then the other side of the battery should also be plugged up since the batteries are enclosed. Most aftermarket batteries will come with an extra plug either in a little baggy stuck to the side, or sometimes it’s built into one of the protective battery post covers.

Example below shows the snap-out battery vent plug built into the battery post cover on a battery sold at Walmart…which is required when installing a battery in an enclosed space:



The images below shows the additional plug & little black elbow that facilitates plugging the vent hole & connecting the car’s vent tube to the battery that came in a little baggy stuck to the side of the replacement BMW battery on my f06:

[fm16nfd]

Well....i proud about my results, it's almost like the factory fitted. All the best way fitted for my peaceful mind about security and safety. This is the final picture in action and working perfect.after of hundreds tests. x

[fm16nfd]

Everything is documented from ISTA and hundreds of hours unfortunately, could more easily if it was already on it , more pictures with the process

[Qsilver7]