v-belt alternator amps limit

[mattnj]

i am about to upgrade my 50amp alternator to the largest one i can get on my 2003turbo, the limit will be the v-belt i guess, what is the sensible limit of amps on a v-belt setup, any other obvious solutions, serpantine belt kit for a 25year old 2003t

 

[Fr J Hackett]

Once you go above 90 / 100 amps you need to upgrade to two belts with twin pulleys below that a single belt will be sufficient, suggest you look at getting a segmented / notched belt of the right section as well.

 

[pvb]

i am about to upgrade my 50amp alternator to the largest one i can get on my 2003turbo, the limit will be the v-belt i guess, what is the sensible limit of amps on a v-belt setup, any other obvious solutions, serpantine belt kit for a 25year old 2003t

Space limitations mean you can only fit a small-case alternator. About 90A is the max you could effectively get with the single belt, especially as the standard alternator only has about a 135 degree belt wrap. You can't easily upgrade the standard alternator to twin belts as you'd need to modify the water pump too.

An alternative, which I've done on my 2003T, is to fit the Volvo second alternator bracket and mount a 90A alternator on that. The original 50A alternator just charges the start battery; the 90A alternator just charges the domestic bank with Adverc control. There are advantages in not needing any split-charge system, plus redundancy in case one alternator fails.

 

[mattnj]

Space limitations mean you can only fit a small-case alternator. About 90A is the max you could effectively get with the single belt, especially as the standard alternator only has about a 135 degree belt wrap. You can't easily upgrade the standard alternator to twin belts as you'd need to modify the water pump too.

An alternative, which I've done on my 2003T, is to fit the Volvo second alternator bracket and mount a 90A alternator on that. The original 50A alternator just charges the start battery; the 90A alternator just charges the domestic bank with Adverc control. There are advantages in not needing any split-charge system, plus redundancy in case one alternator fails.

got a picture, space is very tight, where does the second one go?

 

[savageseadog]

The rule of thumb and from experience of various machines seems to be that the the power limit for a small belt is about 1HP which equates to about 60A at 12V. Not hard and fast and depends on belt type, wrap, form and size. I've seen 90A on some installations so it must be possible but probably not ideal.

 

[pvb]

got a picture, space is very tight, where does the second one go?

Here's the picture from the VP website. You'll see that belt wrap is nearly 180 degreees on the second alternator.

 

[Chris_Robb]

i am about to upgrade my 50amp alternator to the largest one i can get on my 2003turbo, the limit will be the v-belt i guess, what is the sensible limit of amps on a v-belt setup, any other obvious solutions, serpantine belt kit for a 25year old 2003t

I have done just this on a 2003T on an Oceanlord.

Go to Adverc, Buy the 110amp Prestolite open frame alternator

http://www.adverc.co.uk/product/579

Note the proper ventilation. It fits perfectly and comes with the field wire already installed to fit to an alternator charge controller such as Adverc or Sterling - both good - I have a sterling. If you do not a controller the output of this automotive alternator is 14Volts - not enough for serious battery charging. so think about getting one - easy to fit as the worst part of the job, fixing the field circuit on the new alternator has already been done.

Note that the volvo normally has 10mm width belts. This alternator comes with a pulley designed for a 13mm width belt, and is a slightly smaller diameter - so you will need to adjust your rev counter to reflect the correct revs (Your rev counter is driven by pulses from the alternator W terminal)

I originally used a 10mm belt. This was a big mistake! when the batteries were low the boat filled up with black smoke from the belt!

I rang Adverc - who said - what did we fit the bigger pulley for then??!!!! Go and get a 13mm belt.
Belts from Bearing boys
http://www.bearingboys.co.uk/AX33_Cogged_V_Belt-11135-p
This is the belt I am using, so should be right for you.

The larger belt will run proud on the other pulleys, but that does not matter at all but does not slip AT ALL. I live aboard in Greece for the summer - so run each day......so plenty of stress testing done.

Other considerations:
You will almost certainly need to double the wiring size on your pos and neg from the engine to carry the increased amps. I just added another larger cable to each - or rather an electrician did as I did not have any crimping gear. The increase in amps into the battery was from 75 amps old wiring to 95 on the upgraded wires. Significant increase. Lost amps go as heat in the cable.....

Good luck

 

[mattnj]

Here's the picture from the VP website. You'll see that belt wrap is nearly 180 degreees on the second alternator.

I like it, thanks, i guess i just speak to my Volvo dealer to get the bracket...sounds expensive already!

 

[pvb]

I link it, thanks, i guess i jsut speak to my Volvo dealer to go the bracket...sounds expensive already!

They normally sell the bracket with a 50A alternator as a kit. I got my local dealer (Volspec) to credit the cost of the alternator and just sell me the bracket.

The bracket is expensive, but it's very well engineered and it would cost quite a bit to fabricate a custom bracket which works as well and, importantly, maintains access to service parts.

 

[mattnj]

They normally sell the bracket with a 50A alternator as a kit. I got my local dealer (Volspec) to credit the cost of the alternator and just sell me the bracket.

The bracket is expensive, but it's very well engineered and it would cost quite a bit to fabricate a custom bracket which works as well and, importantly, maintains access to service parts.

can you remember how much it was, roughly?