[lazytornado]

Hi all,

I plan to bleed out my system with the gas pedal technique and it seems like that it'll take a considerable amount of battery to do so. How can I check if I have enough battery for it?

I don't want to end up having a car with a dead battery. I can obviously drive it up and charge it, but does anyone know how I can check the charge?

It's a 2011 328i.

Thanks for all the help.

[RocketSurgeon]

It takes roughly 10 minutes to do the bleed procedure. I always connect a battery charger or power supply when I run it, since it can use some serious power. I wouldn't rely on the battery alone for that.
You could use jumper cables to another running car, that works well as an improvised power supply.

[lazytornado]

Originally Posted by RocketSurgeon

It takes roughly 10 minutes to do the bleed procedure. I always connect a battery charger or power supply when I run it, since it can use some serious power. I wouldn't rely on the battery alone for that.
You could use jumper cables to another running car, that works well as an improvised power supply.

I don't have another car or jumper cables, so I'm thinking of getting a battery charger or power supply. Could you please explain what exactly this would mean? Can I pick up something from an autoshop or walmart to do this?

Thanks!

[RocketSurgeon]

Originally Posted by lazytornado

I don't have another car or jumper cables, so I'm thinking of getting a battery charger or power supply. Could you please explain what exactly this would mean? Can I pick up something from an autoshop or walmart to do this?

Thanks!

You could certainly use a battery charger from walmart or the auto parts store. Get one with at least 10 amps. Just connect up the battery charger to the jump points under the hood, the manual explains how. Red clamp to the positive jump point under the hood, black clamp to the ground post on the passenger side of the engine bay. Turn on your battery charger to at least 10 amps, and start the coolant bleed procedure. Once the bleed procedure is done, you can turn off the car and let the charger top off the battery.

[Welcome to NBA Jam]

Use a battery charger.

[Needbmwpartzz]

:
What he said!

[dauble2k5]

The whole process took me maybe 10 mins. I didn't use a battery tender or charger, but had a brand new battery.

[tlow98]

Done this twice on two different cars. One with a two year old battery and one with an 8 year old original battery.

Both worked out just fine.

As long as your battery maintains a decent charge level when the car is off you’ll be fine.

[Shane335]

always use a charger like everyone a
else said. I use one any time I need the battery on for any period of time.

[TemjinX2]

get a quality charger...a decent one is $35 on amazon so its not too bad.

[ChuckThomas]

There's no way to check the battery strength without a scan tool or an multimeter. You may be able to hack into the menu to check it but that's probably beyond your scope at the moment and you could possibly kill your battery that way too by it being "on" and not running. Best possible solution is to go to walmart and get a battery charger. If your battery is in limbo, attempting to bleed the system without an external charger will definitely cause it to die completely, and probably FOREVER. A battery charger and scan tool are two must haves. Also, when you do get the charger, hook it up to the front of the cars charging system, not directly to the battery in the trunk; maybe you knew this already, maybe you didn't.

[Efthreeoh]

Just run the procedure. IIRC the N52 water pump is 250 watts. So it's 250 watts at 12 - 14 volts for 12 minutes. That is not enough to drain the battery. It's a 90 amp-hour battery in the E90 (most of them), so that means the battery most likely would last over 4 hours running the water pump at 20 amps. The heat REST function takes far more power running the water pump and blower motor and it doesn't drain the battery even after all the heat is removed from the water after 20 minutes or so.