I'm thinking my original 90amp alternator in my 2.1 Dj is probably overworked when running the engine, split charging and running the fridge.
Could I fit something more modern? This one is about 25 years old. Are newer alternators lower drag for the same output?
Alternator upgrade
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Re: Alternator upgrade
I upgraded from a 45A to 90A, because I felt that 45A wasn't enough for a camper. I wrote about it here.
However, I'm of the opinion that 90A is enough. Ghost did a worst case sum in this post in that thread.
However, I'm of the opinion that 90A is enough. Ghost did a worst case sum in this post in that thread.
"I'm a man of means, by no means....King of the Road!"
1983 Viking Xplorer, 2.1DJ
1983 Viking Xplorer, 2.1DJ
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California Dreamin
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Re: Alternator upgrade
There is no doubt that alternators used in T25's with full camper conversions are working harder, however, you already have the highest rated standard unit with the one you have and others rarely complain about under charging with one of these fitted.
The majority of T25's came with a 65ah and some base vans just a 45ah. The 90ah was fitted by VW with extra consumers in mind.
Obviously the input needs to exceed output with a safe margin, although working out how much of your alternators power is going into the batteries is more difficult.
Fitting anything bigger than a 90ah is going to be difficult but not impossible. Some 'specialized' German vans even had 2 alternators, which kinda makes sense as one could be dedicated to the leisure side.
German ebay might be an option however, parts for mounting etc aren't going to be easy to find.
Is this a 'perception' thing? or do you really have a problem? some of these old setups can 'degrade' over time leading to under charging. This is mainly down to voltage drop caused by the long cable run on petrol engined vehicles where the batteries are under the front seats. Corrosion in these heavy wires can have a significant effect on the actual charge voltage reaching the batteries.
You should be seeing a minimum 13.9 volts or higher across the batteries with the engine running and ideally a little higher than that ( 14.2 - 14.5 volts). This charge voltage can sometimes be 'improved' by fitting a new voltage regulator brush pack as many of these are now set to charge at 14.5 volts as apposed to the 14 volts of the original.
A definitive 'check' is to compare the voltage coming from the main 8mm B+ post on the back of the alternator compared to the reading across the battery. If you are seeing anything more than a 0.3 volt difference you could have a cable erosion issue.
It is also worth checking your main 'earths' ..at the battery and on the gearbox nose cone, as these are vital to complete the charge circuit. There is also some evidence that the alternater itself can benefit from a seperate braided earth lead as it would normally rely on the mounting points and adjusting bracket to complete its earth return..ideed some Bosch alternator are fitted with a braided earth as standard for this reason.
Martin
The majority of T25's came with a 65ah and some base vans just a 45ah. The 90ah was fitted by VW with extra consumers in mind.
Obviously the input needs to exceed output with a safe margin, although working out how much of your alternators power is going into the batteries is more difficult.
Fitting anything bigger than a 90ah is going to be difficult but not impossible. Some 'specialized' German vans even had 2 alternators, which kinda makes sense as one could be dedicated to the leisure side.
German ebay might be an option however, parts for mounting etc aren't going to be easy to find.
Is this a 'perception' thing? or do you really have a problem? some of these old setups can 'degrade' over time leading to under charging. This is mainly down to voltage drop caused by the long cable run on petrol engined vehicles where the batteries are under the front seats. Corrosion in these heavy wires can have a significant effect on the actual charge voltage reaching the batteries.
You should be seeing a minimum 13.9 volts or higher across the batteries with the engine running and ideally a little higher than that ( 14.2 - 14.5 volts). This charge voltage can sometimes be 'improved' by fitting a new voltage regulator brush pack as many of these are now set to charge at 14.5 volts as apposed to the 14 volts of the original.
A definitive 'check' is to compare the voltage coming from the main 8mm B+ post on the back of the alternator compared to the reading across the battery. If you are seeing anything more than a 0.3 volt difference you could have a cable erosion issue.
It is also worth checking your main 'earths' ..at the battery and on the gearbox nose cone, as these are vital to complete the charge circuit. There is also some evidence that the alternater itself can benefit from a seperate braided earth lead as it would normally rely on the mounting points and adjusting bracket to complete its earth return..ideed some Bosch alternator are fitted with a braided earth as standard for this reason.
Martin
1989 California 2.1MV