Will DIY changing your battery in a BMW 530 XI cause the electric systems to be reset at the dealer? Have seen that this is necessary with BMWs with X Drive

The voltage is ok, maybe the pump's fuel pressure check valve is defective and the fuel pressure bleeds off and that causes a hard start.

I'm not a mechanic but have a few BMWs and have tripped the airbag light(s). As you probably know, the seats have sensors and are integrated into the system, and disconnecting them can trigger the light. Often you can avoid that by disconnecting the battery first, but that's water under the bridge (and doesn't seem to be 100% dependable). Good news is that there may well be nothing wrong with the system assuming the wiring is the same (and the connection is solid). Bad news is that for cars after 2002 or so, resetting the light takes diagnostic software (there are cheap SRS reset tools for the earlier cars). If you don't want to invest the time and cash to learn diagnostic software (i.e. INPA, etc.), I'd take it to an independent garage that works on BMWs and pay them to diagnose and reset it, or to at least reset it (NOT THE DEALER--$$$). If there's a problem, the light will come back on. Obviously, you don't want to fool around with the airbag system, so worth being extra careful and making sure it's OK.

"Diagram?" Really?
PLEASE BE MORE SPECIFIC. WHAT DIAGRAM??????
Also, try doing a Google search to find what you're seeking.

Modern luxury cars have very complex computers that require a certain amount of energy to maintain the memory. At autoparts stores they use a device called a memory minder when changing batteries. it is a 9 volt that keeps the computer from resetting when the battery disconnects. I had a friend with a bmw 7 series and he disconnected the battery without a memory minder and the car wouldnt work right. idling low no idrive navigation system, no acceleration, etc. many car computers will relearn the necessary lost data after being started and turned off a few times 4 to 6. I have done this for many cars and it had worked on newer fords, jaguars, bmws, and others.

Unfortunately, BMW is a pain - in -the - **** and only a BMW dealer or an independent shop with BMW tools can reset this.

Nice car.
Enough power to run the lights and radio is not necessarily enough power to crank the engine over. You did not mention the year, but on a 530, if this is your original battery, you are probably due for a new battery. I suggest that you borrow another car and attach it to the jumper cable connections under the hood (key in Off position on both cars) to keep your 530 computers powered up while you replace the battery. It is not critical to do this on a 530 as it is on the newer generation BMWs, but it is not a bad idea.
Unless there are a LOT of BMWs where you live, the group 94 battery size will be hard to find, and when you find one, it may be quite stale from sitting on the shelf half-charged for months. Most of us choose a smaller, group 48 battery. You have to put a spacer under the battery clamp, but it is a common size so it will be fresh and it will cost less.
If you really want the larger size, a group 49 'should' fit in the hole and is a little more popular than a group 94. It will be tight.

BMWs are very sensitive to overheating, can get very expensive. Bleeding the radiator takes a minute of two, A straight blade screwdriver, just slowly unscrew plastic screw until anti freeze begins to stream out.

it is bad electric water pump, very common problem $465for the pump. 2.8 hour labor

If it's not under the hood, then the only other place BMW places their batteries is in the trunk. Since it's a Sport Wagon, pull up where the rear spare would be and it will be there, usually on the right hand side.

Hope this Helps,

~00 Buck~

"Still living on the Right Side of Dirt..."

your owners manual will have the instructions for that