Mercedes Vario Second Alternator

Anton2k3

Adventurer
Hey guys,

I've been thinking about installing a second alternator onto our 814d. We had a sterling battery to battery charger (24-12v), but it stopped working some time ago. Since then we have relied on the solar panels and the generator. However i'd like to be able to charge while driving (particularly in winter). The problem with the battery to battery charger was that is only charged at 30A max. The alternator i'm looking at (http://sterling-power.com/collectio...wer-performance-alternators?variant=892057503 OR this one is it comes into stock: http://sterling-power.com/collectio...wer-performance-alternators?variant=892057491), and depending on which one I get can charge at up to 140A or 200A. So my question it, has anyone done this before? I know i'll have to fab up a bracket, but (i'm not in the country so can't check for myself) are there any spare pulleys on the crank? If not, I guess a longer belt and positioning the alternator to suit with possibly an additional tensioner will do the trick. From what I can remember the varios are serpentine belts. Does anyone know how many ribs it is?

Sorry for all the questions, but I'm seldom in the UK to check the answers for myself!

Thanks

Anthony
 
When I had my Unicat camper built I was told installing a 2nd alternator on the 906LA motor would be difficult to impossible. If you have an OM904 it would be the same. If it is a OM366 then it might be feasible.
And why don't you replace/upgrade your defunct battery-battery charger?

Charlie
 
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mmmartin

New member
Hi Anthony

The rule of thumb on charging battery's is 10% in or 10% out per hour, more than this can reduce the life of battery's significantly due to the heat generated. I would suggest you reconsider such a large second alternator and size it more to suit your battery pack assuming of course you have not fitted a huge battery pack. With this in mind a direct replacement of the battery to battery charger could be the most suitable way forward. I fitted 600 amp/hour battery pack and found the same charge most suitable considering that you should also not discharge to a level more than 25-30% full. I hope this helps
 

docka

Adventurer
Have a look back at IanC's build thread, I'm pretty sure he has accomplished this...
 

ianc

Adventurer Wannabe
I did accomplish this.
I extended the existing belt and added an extra jockey pulley. My engine has a number of additional mount points for Aircon etc on the lower right side as you look at it from the front. The picture below shows approximately where I mounted it. Ignore the lower stuff in German - That's not on my vehicle and needs a second belt race on the crank pulley.


mount alt.jpg

I think there are actual picture in the blog also. I used a 200a alternator from a Sprinter (I think) where the mounting bolts ran perpendicular to the spindle.
Regarding the point raised by Martin above - I have the option to allow the alternator use it's build in regulator (giving only modest output when charging (unless the batteries are very low) or using an external Sterling controller. I often run a 220v AirCon when driving feeding it from the 2nd alternator via a 2.5KVA inverter.
BTW the AirCon is only marginal at cooling the cab so I would not recommend following this route.

If you are going to go this route I would have some suggestions on how to make the bracket a little easier to fit.
 
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Anton2k3

Adventurer
Thanks for the information guys. So my battery capacity is around 420ah. Based on the information given above perhaps just renewing the battery to battery charger would be the simplest and most effective thing to do. The Sterling 2015 range is coming out soon, i'll wait for that.
 

part time nomad

Adventurer
I have looked into this and dont want extend the original belt because it only needs to be slightly out of line with the pulleys and it will give trouble in time. Ian did you say you got an extra crankshaft pulley? as I have been looking for one without success! also there does not seem to be enough space to fit one.
 

julius0377

Adventurer
Look at the 24v/12v battery to battery chargers from Votronic in Germany. I have good experience with it in my Atego 4x4. (440ah,12v for living, 220ah/24v for truck.)

Here is a link:
http://www.votronic.de/index.php/en/products2/series-vcc

Also look at the battery computer, it gives a precise status of charge/drain/voltage as well as capacity/remaining AH for 12v batteries, as well as voltage for the 24v batteries.

http://www.votronic.de/index.php/en/products/measuring-display-systems/battery-computer
 
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Mutumbo

Observer
1b4999cs-960.jpg

b74999cs-960.jpg
 

Anton2k3

Adventurer
Where did you get the idler pulley from? And the alternator pulley? What size belt did you end up using?
 

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