harati

Hi friends!
I have some issue with my Webasto aux heater.
When i bought the car (2008 ML W164 320 CDI) i noticed that i have this feature installed on, but never used a single time until a couple a of weeks ago. I have the car more than a year. Well - i started it manually from inside button. After several smoky attempts the webasto started....
And now to issue part : the heater starts but remain operational for a 30-40sec. after that stops and on the dashboard emerged in white "Inoperational! Weak battery" The battery have 11.9-12.3V constant. Even after recharging with Bosch C7 the Webasto heater shos me this message..
What can be the problem except the battery wich is OK?

Maj. Dundee

The battery is not OK, and it isn't SPAM.

harati

Hi Maj Dundee
I do the recharge 5 days ago. After the charger shows me that the battery is 100% full, the vehicle shows me 12.2-3V. I did not measure with voltmeter, that's a fact.
So you thing that the aux heater is OK but the battery is faulty indeed?

Maj. Dundee

According to the chart, your battery is only 60-70% charged. With that rate, the signal to turn on the heater might not be sent because the stored battery voltage is not enough.

If the signal was sent, when you came out to start the car, it wouldn't be able to start the truck.

harati

That's correct i agree.
So when the charger told me that the battery is full, is actually not the case. I have to check somehow how many power is stored actually inside the battery.
Well the car starts up without any problems or misbehave even at subzero C temp. I will check it up again. It is Varta AGM battery after all.

Maj. Dundee

In the morning, open the hood and go to the charging port and with the volt meter you can find out what your batt. voltage is.

harati

This morning i checked the battery with volt meter. The reading was steady 12.4V - 75% full battery. So i think the Websato unit can start at 75% full battery?
The reading of the car tough was 11.9V. It's a bit strange mismatch between what the vehicle shows and the actual volt meter reading....

Maj. Dundee

I believe that the eng. is not running when Websato is actuated. Therefore if you start the process with a 75% charged battery, when you decide to start the veh. you might not have sufficient voltage to start the veh.

harati

Can it be any other software settings to be done or check with STAR?
For hardware - the rumbling starts and goes off in 40 sec. The smoke of diesel fuel is clean when in this 30-40 sec the booster is active. I thing the glow plug is OK but will check the fuel pipe and the glow again.

Maj. Dundee

We are discussing battery voltage and you are responding with hardware and software.

harati

Well the nowadays mercs are 70% software trough STAR and only 30% hardware that's why i ask about some software changes that can be made with STAR for the Webasto heater.
The battery remains steady 12.4 in the morning. I guess i have to charge it again to achieve full battery and after that to try with the heater?
Since i have AGM battery how often i can recharge it?

Maj. Dundee

You have to research your own information on the charging if the battery you bought.

https://www.batterystuff.com/kb/arti...ry-basics.html

As for the heater, yes you can make changes with Star.

harati

Yes i already have done my research for battery recharging. Thank you for the codes, Maj. Dundee!