[richard_tricky]

Hi need some help. I've been noticing my 335d has been slow to turnover first thing in the morning. It seems if the battery was going flat.

So i bought a new battery, checked it was fully charged and fitted it. It seemed a bit better for a day or 2 but now is back to being slow.

Ive measured the battery over the last few days and theres no sign of a parasitic drain anywhere.

I did also try connecting a jumper lead from the engine to an earth point as ive heard the earth strap can go bad, but this made no difference.

Is there something else im missing?

Thanks

[Owen81]

Starter connection or starter issue?
Or maybe a short in the glow plug system taking too much power during pre-heating?

[richard_tricky]

Sorry for the late response.

I've noticed if I start the car. First time it's slow. If i immediately stop it take the key out and restart it again. It turns over really quickly.

I've pulled the codes and the only thing that shows is a glow plug out on cylinder 6. I have a new plug ready but the weathers bad here right now.

Apart from that the cars fine.

[Mik325tds]

Did you buy an AGM battery? I went cheap and bought a normal battery for my X5 35d a year ago and now have the same problem like you. My guess is that the non-AGM batteries just don't have enough cold cranking ability to source the glow plugs, heating accessories and starter motor.

Either way, don't forget to register your new battery in the DDE if you haven't already done so.

[richard_tricky]

i bought this one https://www.tayna.co.uk/car-batteries/yuasa/ybx5019/

Its 100ah slightly longer than the 90ah in size but it it fits in the trunk fine.

I re registered the battery using Protools i used the 90a/h hour setting as it was the closest available the next was 110a/h and that will over charge the battery.

Thanks

[Mik325tds]

Originally Posted by richard_tricky

i bought this one https://www.tayna.co.uk/car-batteries/yuasa/ybx5019/

Its 100ah slightly longer than the 90ah in size but it it fits in the trunk fine.

I re registered the battery using Protools i used the 90a/h hour setting as it was the closest available the next was 110a/h and that will over charge the battery.

Thanks

That is a non-AGM battery. Make sure your original was not an AGM battery, otherwise you have to re-register your current battery as the AGM and normal batteries have different charging strategies.
Another reason for the slow crank could be the engine ground strap near the driver side engine mount. If that is heavily corroded it may limit the current that the starter can draw during the pre-heating phase.

[rtd2]

I had the same issue a few months ago and it was a corroded ground strap. I replaced it with a generic one from an auto parts store. If it is a corroded ground strap, slow start will eventually lead to no start. Before replacing the ground strap, you can use jumper cables to test if it is a ground issue.

[nidaven]

Hi and thank you in advance for helping me. My 2011 335d with 88k miles started fine until a couple days ago. When I got in it it had a warning light on for battery while the car was off. The car started but cranked slowly. I charged the battery for a few hours and the next morning it wouldn't turn over at all and had the same warning about battery drain. I jump started it fine and hooked it up to the battery charger for 5 or 6 hours. The next morning it wouldn't crank due to a dead battery. I have done nothing to the car maintenance wise for a couple months so I don't see how anything has changed and would be responsible for this battery drain. Is there a typical part that wears out on these cars? Obviously could be the battery needing replacement but it seems odd that this issue suddenly arose. Thanks again for anyone pointing me in the right direction.

[335dlci]

Do a draw test.

[335dlci]

[QUOTE=richard_tricky;27159398]

Ive measured the battery over the last few days and theres no sign of a parasitic drain anywhere.
/QUOTE]

How did you monitor this?

[nidaven]

Charged it last night on a "smart" charger (viking brand from Harbor Freight) and after an hour so the charger would show the indicator of a "bad battery". Used my normal charger today and while charging my colt meter read 14 +/- and when I removed the charger my volt meter would drop to 10 +/-. I'm convinced I most likely have a battery with a dead cell or 2. Battery is BMW part with white top and several filler caps on top so I believe it's a standard not agm ... ? Any thoughts on if I'm correctly diagnosing as a bad battery?

[nidaven]

Update: bought a new battery yesterday. Today I'm working on getting my trunk open due to closing my trunk with battery removed 🤦🏼*♂️. Thankfully there's a thread on that too 🤣