On a BMW with electric power steering (no fluid) the steering seems to go heavy up an incline and be not too great in general elsewhere. Sometimes it will feel as if the steering is pulsing back against you when you're going up a hill with only a slight turn.

Car's about 5 years old now, so I'm guessing if the battery was a bit weak it wouldn't help?

It's got stop/start and an AGM battery, so not entirely sure if charging it will help, but I lent them a charger and it's on top up charge now.

What do we think, a dead battery causing this odd steering effect?

Hmm, oh well guess it's not just me that doesn't know then.

I test drove a 1 series a few years ago and the steering was super heavy to the point where I told the salesman that I thought the car was knackered. He fobbed me off and we walked away.

No help to you other than maybe it a beeme thing?

I have seen it on other cars, but not on BMW. The BMW system only charges the battery under braking unless charge is critically low. If the battery is getting tired, it is possible that it shows good voltage, but may not be able to supply enough current to comfortably run the power steering.

Hope you get it sorted soon.

Chris

I've given it a charge until the charger showed green and it felt a little better, so I left it on overnight to maintain.

It felt much better after that, so I guess we'll see if it just felt better for some other reason or not.

Will have to keep an eye on it over the week, but the steering systems don't have take a drain on the batteries these days.

IIRC up to 60A

Ok, with a BMW's fancy "fuel saving" (I'm not convinced that this saves significant fuel; I suspect maybe 1% with engine, radio and dipped headlights on) charging system, this may not entirely apply, but I'd check the aux drivebelt tension, and if it's not that, fault codes relating to the steering angle sensor, and then battery capacity and charge retention.

Sounds more like an alternator fault with it not supplying enough power to maintain the battery or the ancillary systems, especially if it worked better after externally charging the battery.

Some BMW AGM batteries can suffer from acid lamination. This can affect measured voltage and can prevent proper charging of the battery.

To remove the acid lamination, remove the affected battery, turn it over once and install again.

The service life of these batteries are usually quoted by BMW as available capacity vs mileage in km. IIRC, the available capacity is shown as 75% at 75000km.

Faulty voltage regulators kill these batteries in no time flat and they are quickly damaged if charged at more than 14.7v.

Ok, with a BMW's fancy "fuel saving" (I'm not convinced that this saves significant fuel; I suspect maybe 1% with engine, radio and dipped headlights on) charging system, this may not entirely apply, but I'd check the aux drivebelt tension, and if it's not that, fault codes relating to the steering angle sensor, and then battery capacity and charge retention.

Bing, yes it's got the daft regenerative braking system.

Alternator stops at a certain percentage and the brakes top it off (unless you're on the m/way, then they fail to top it off)

Alternator belt seems plenty tight to me.

Sounds more like an alternator fault with it not supplying enough power to maintain the battery or the ancillary systems, especially if it worked better after externally charging the battery.

Alternator seems to be putting out correctly, but I'll double check it.

Some BMW AGM batteries can suffer from acid lamination. This can affect measured voltage and can prevent proper charging of the battery.

To remove the acid lamination, remove the affected battery, turn it over once and install again.

The service life of these batteries are usually quoted by BMW as available capacity vs mileage in km. IIRC, the available capacity is shown as 75% at 75000km.

Faulty voltage regulators kill these batteries in no time flat and they are quickly damaged if charged at more than 14.7v.

Hmm, the car's most of the way to 70k miles.

Current is rated at 70Ah, so 75% of that could be a bit close to a car with leccy steering.

The battery is an OEM varta jobby, but I could be tempted to take it pout, invert it and then put it back.

I wonder....

Edited 28 June, 201213 yr by cheezemonkhai