alternator charge and battery health?

1976-1985: 230T, 230E, 230TE, 230CE, 280E, 280TE, 280CE, 240D, 300D, 300CD, 300TD,
Post Reply
Posts: 325
Joined: Wed 19 Oct, 2016 11:34 pm
Model you own: w123
Location: eaglemont + cranbourne sth

alternator charge and battery health?

Post by 230ew123 » Wed 12 Apr, 2017 11:49 am

I think it is a really good thing to have a voltmeter as a dash gauge. Yonks ago in my bj40 I picked a volvo voltmeter and installed in the dash. No more having to open the bonnet and get the multimeter out. but diesel electricals are quite different to petrol..

so now we have ebay and cig lighter plug in voltmeter with phone chargers, excellent.

I think it is a good way to monitor battery health.

I recently replaced the regulator in the merc alternator, just as well as the bushes were pretty worn. New tight belt goes without saying.. Good cheap preventative med.

so on my voltmeter I would get a pretty constant 13.9v when cruising, so I consider this pretty good juice for the battery. As long as it is over 12.6 v(ish) I am happy and satisfied I am not draining the battery. Long periods below 12v with lots of things running on electrical, like on rainy nights with headlights, wipers and fans running whilst idling at railway crossings in drive would drain the battery. Putting her in Neutral helps a bit with a bit more revs, but still..I don't think my charge is satisfactory for rainy night time city driving. I don't want to up my revs as the engine is happy in idle, sounds good, just enough air/ fuel.

What sort of charge are folks getting with all their aux's running?

However, smart chargers go up to 14.4v (ish) for a period to peak out the charge. I imagine too much at this rate would cook the battery tho. I think the smartypants gives 14.4v for about an hour then slowly decreases..

Is anyone out there monitoring their voltage whilst starting and driving? what are you getting from your alternator?

S Class
Posts: 98
Joined: Tue 31 Jan, 2017 8:38 am
Model you own: w123

Re: alternator charge and battery health?

Post by hazzac181 » Wed 12 Apr, 2017 6:15 pm

My battery has been on the verge of dying for many months. I just drive it... Although a voltmeter would be very, very convenient. I'm 90% sure I have some minor belt slip somewhere.

Sent from my ASUS_Z008D using Tapatalk
W123 300D - The White Maiden

Located: Sale, Victoria.

User avatar
Posts: 1
Joined: Thu 20 Jul, 2017 5:33 pm
Model you own: w123

Re: alternator charge and battery health?

Post by Phydoux » Wed 30 Aug, 2017 6:22 pm

For what it is worth.
I charge Calcium batteries up to and then to help to desulphate them. Ordinary lead acid batteries 14.2 v. AGM batteries 14.6 v.
Being a pensioner I have learned to recycle. I buy scrap batteries that show 12 v. without load and charge them for up to 3 weeks and have had fairly good results. In the last 10 years have done many thousands of ks. around Aust. in a motorhome with a electric fridge and solar and have not been let down.
I have just registered our 300D W123 1979 as a classic. The battery in that is 3 years old to me, purchased for $35.00 as scrap.
With the Sprinter Motor Home I disconnect the motor battery now and then to boost charge it as I do not know if the Puter would like the extra volts.
All the best with your project.

Post Reply

Return to “W123”