[trumble]

I am locked down and only driven about 10 miles in 10 weeks.can I just put a charger on the connections under the bonnet.battery is ok at the moment.
thanks
trumble

[Abrek]

That’s what I do, every couple of weeks.

[un1eash]

Mine sat for 8 weeks, took it shop and it flashed up battery discharge so put it on the trickle for 10 hours. That was 2 weeks ago and it's ok still.

[nc30v4]

Just check the battery in case it's an AGM. I think there is a certain setting for AGM on modern chargers

[HighlandPete]

Originally Posted by nc30v4

Just check the battery in case it's an AGM. I think there is a certain setting for AGM on modern chargers

Good point to raise.

AGM mustn't be charged at over 14.8 Volts. (Some rapid chargers have higher voltage outputs). But AGM does benefit from the setting that gives close to that voltage. Something like a CTEK is 14.7 Volts, in AGM setting.

[trumble]

I have this old Halfords charger will it be ok? also I looked for a new one and some say not suitable for cars with Stop / Start why is this?

Thanks
trumblehttps://f30.bimmerpost.com/forums/attachment.php?https://f30.bimmerpost.com/forums/at...1&d=1590791174

[nc30v4]

The small print on your charger states it's ok for Absorbed Glass Mat batteries, is AGM. Suggest you physically look at your battery and determine if it's AGM and use the most appropriate setting on your charger. PS if you're a smoker, don't smoke near your battery during or just after charging 😃

[pete18]

Lots of chargers out there. Look for a “Smart Charger” if your in the market for one. AGM are becoming a standard battery fit for stop/start cars and you should not charge these types of battery with a standard charger. B&Q used to sell there own branded smart charger (Torq )and still might do. It is really well made with all the safety and charging features required.

[trumble]

Does this mean it is ok for my battery 318i 2017. not flat yet but just in case only done 150mls since April. stop / Start has stopped working so guess it could be low.

thanks

[Kendo67]

I purchased a new BMW trickle charger for around £50 from the dealers, just clip it onto the terminals under the bonnet and let it do its thing.

K

[trumble]

Will this charger be ok please

thanks

[t5pilot]

Whilst in most circumstances the battery will charge by using the terminals under the bonnet, it's certainly not optimal.
The correct way is by direct connection to the battery. You're then not putting higher current, the wrong way through the BMS.

[trumble]

Could somebody tell me if I can use this charger to charge my 318i battery. I have start / stop


thanks

[t5pilot]

Originally Posted by trumble

Could somebody tell me if I can use this charger to charge my 318i battery. I have start / stop


thanks

The one you posted pictures of?
Yes it should be absolutely fine. It will do all except lithium, which you won't have.
Don't mess about connecting it under the bonnet.
Connect it directly in the boot.

[HighlandPete]

Originally Posted by t5pilot

Whilst in most circumstances the battery will charge by using the terminals under the bonnet, it's certainly not optimal.
The correct way is by direct connection to the battery. You're then not putting higher current, the wrong way through the BMS.

BMW recommend using the charge points under the bonnet (hood). This ensures the IBS is in circuit to interpret the SoC.

[HighlandPete]

BMW data.

Charging and trickle charging of the battery

The battery may only be charged using the chargers approved by BMW at a constant charging voltage of 14.8 V. If possible, the battery temperature during charging should be between 15 °C and 25 °C. Under these conditions, the battery is adequate charged if the charge current has fallen below 2.5 A. If the charging process is carried out at low temperatures, it is only to be terminated after the charge current falls short of 1.5 A. If the battery is charged when fitted, the charging process must take place via the jump start terminal point. This is the only way to ensure that the charging process is detected correctly by the vehicle electronics on vehicles with an intelligent battery sensor (IBS). If the battery is charged directly at the battery terminals, misinterpretations of the battery condition and, under certain circumstances, unwanted Check Control messages or fault code memory.

[t5pilot]

Originally Posted by HighlandPete

BMW data.

I happily stand corrected

But I prefer to charge my battery to its full capacity so will continue with a direct connection.

[dizzy619]

My battery on the 340i died the other day on the school run.. Bmw sos came out.. Tech said yep its knackered but we had to let the laptop assess the battery.. Took 45 mins.. It then said it was fine... Which we knew it wasn't.. He then did and old school battery check which confirmed it was toast... New battery for me... :

[trumble]

Thanks for your help

trumble

[NanasBack]

The official BMW guide, as listed in earlier posts, is to "connect a battery charger to the jump start points under the bonnet.
This allows the IBS to monitor the charge state of the battery".

People should follow BMW guidelines.

However, I believe it is better to directly connect the charger to the battery terminals as long as it is suitable for AGM batteries.
(Assuming there is an AGM battery fitted).

The following explains why. Skip it if your not interested


BMW Efficient Dynamics.

The car braking system is used to slow a vehicle down and looses energy in the form of heat, dissipated by the brake discs & pads.
Some of this energy could be used to charge the battery, in the form of regenerative power.

The Intelligent Battery Monitor system is used to protect the battery from over charging.
The battery capacity must be registered with the IBS system, in order for it to monitor how much energy can be dumped into the battery, without over charging it.

The IBS system uses a 70% charge target for the battery. (70% charge of the battery capacity rating).
Regen braking can use the 30% available capacity to dump energy, reducing brake disc & pad wear.

The IBS also has a derating curve for the battery age and reduces its capacity rating accordingly, again to prevent overcharging.

The problem I see here is, there is a likely safety factor, used to keep the values on the low side to ensure no overcharging occurs.

So the battery capacity will be under-rated.
The aging capacity reduction will be over estimated
(There's probably a temperature derating function and maybe others).

All leading to the battery capacity being well under estimated.

The biggest killer of lead acid batteries is under charging.
This leads to sulphation.

So the principle of keeping the battery at a nominal charge of 70% is not doing it any favours.
In reality, it's problably kept at a level of charge significantly less than its actual capacity.

Using the under bonnet terminals for charging allows the IBS to monitor the energy the charger puts into the battery.
It'll adjust what the car alternator puts into it on subsequent journeys and likely well under-charge it again.


So, get on those battery terminals. Charge away!
I do.

[dizzy619]

Originally Posted by t5pilot

The one you posted pictures of?
Yes it should be absolutely fine. It will do all except lithium, which you won't have.
Don't mess about connecting it under the bonnet.
Connect it directly in the boot.

If you have an f31 it is way more messing about doing it straight to the battery believe me...

[ar68]

Originally Posted by dizzy619

If you have an f31 it is way more messing about doing it straight to the battery believe me...

After having to get to the battery today in my F31 I agree with this.