Volvo 2040 alternator and Starter

[jac]

At present my Alternator, starter and battery all form one circuit. The only cable from the B+ goes to the starter then a separate cable to battery. There is no second cable from alternator to battery.

I am fitting a sterling alternator to battery charger and need to take the output from alternator to the sterling. I suspect that I will need to disconnect the alternator from the starter and then run a cable from alternator to sterling, then to the batteries.

I have a query outstanding with sterling re the impact on the alternator to battery charger of not disconnecting. I suspect that as this will leave a direct connection from the alt to the engine start battery it will negate one of the benefits of the charger!

So the question is does anyone know why the alt and starter are connected and will it cause any problems if I disconnect. I suspect it's a simplicity thing but be good to get expert opinions!!

 

[seadog30]

Hi

I installed a 2040 a few months ago and asked the same question as you about Alt to Starter Motor.

The reply I had from the Agents Engineer was that this connection is just the default connection for a simple single battery installation where the battery + terminal is connected to the same starter motor terminal.

I took the B+ to an on/ off switch and then onto a semi conductor (low volt drop) splitter where the power is routed to battery one and battery two (as determined by the semi conductor splitter).

The starter motor is connected by a very heavy duty cable to battery one (via an on off switch).

Battery two is charged from the semi conductor splitter.

Good luck

 

[Hoolie]

I'd follow what the Sterling instructions say. Connecting the alt to starter is a wiring convenience, but not always without problems. If yours works fine, OK.

 

[jac]

Sterling assume a more sensible approach of 1 cable alt to battery and 1 cable battery to starter.

I was assuming that their must be good reason for alt to starter to battery but couldn't think of it. Alt can't start the engine and starter only needs power for a few secs so had assumed was wiring convenience but wanted to ensure nothing more important.

 

[VicS]

At present my Alternator, starter and battery all form one circuit. The only cable from the B+ goes to the starter then a separate cable to battery. There is no second cable from alternator to battery.

I am fitting a sterling alternator to battery charger and need to take the output from alternator to the sterling. I suspect that I will need to disconnect the alternator from the starter and then run a cable from alternator to sterling, then to the batteries.

I have a query outstanding with sterling re the impact on the alternator to battery charger of not disconnecting. I suspect that as this will leave a direct connection from the alt to the engine start battery it will negate one of the benefits of the charger!

So the question is does anyone know why the alt and starter are connected and will it cause any problems if I disconnect. I suspect it's a simplicity thing but be good to get expert opinions!!

Yes you are right. Remove the existing direct connection to the starter and connect the alternator output to the input of the A_B charger. Connect the outputs to the starter and house batteries as indicated in the wiring diagram. You will then get enhanced charging of the of the house battery and bog standard charging of the starter battery.

However you don,t say how your charging is split between the battery banks at present. Manually, diode splitter or VSR. Diodes or VSR will be redundant as far as alternator charging is concerned and you may want to revise the battery isolation if it is manual.

Leaving the exiting connection to the starter motor will bypass the A-B charger. I suspect if you ask Mr Sterling about this you will get a very curt reply to follow the instructions provided

 

[jac]

Yes you are right. Remove the existing direct connection to the starter and connect the alternator output to the input of the A_B charger connect the outputs to the starter and house batteries as indicated in the wiring diagram. You will then get enhanced charging of the of the house battery and bog standard charging of the starter battery.

However you don,t say how your charging is split between the battery banks at present. Manually, diode splitter or VSR. Diodes or VSR will be redundant as far as alternator charging is concerned and you may want to revise the battery isolation if it is manual.

Leaving the exiting connection to the starter motor will bypass the A-B charger. I suspect if you ask Mr Sterling about this you will get a very curt reply to follow the instructions provided

Thanks for that, it's manual at the moment, basically an isolation switch for each battery, the two isolation switches are wired so that which ever battery bank is on powers everything. I will remove the link between the two switches so that starter powers start and domestic bank powers domestic. (Call me conventional) see other thread re emergency paralleling.

 

[VicS]

Thanks for that, it's manual at the moment, basically an isolation switch for each battery, the two isolation switches are wired so that which ever battery bank is on powers everything. I will remove the link between the two switches so that starter powers start and domestic bank powers domestic. (Call me conventional) see other thread re emergency paralleling.

When you fit your paralleling switch consider the relative merits of connecting to the circuit side of the isolators vs the battery side. The former will allow you to isolate one battery if it fails totally and run everything on the good battery as well as using both for starting if necessary.

 

[jac]

When you fit your paralleling switch consider the relative merits of connecting to the circuit side of the isolators vs the battery side. The former will allow you to isolate one battery if it fails totally and run everything on the good battery as well as using both for starting if necessary.

Yes - that's the plan. It also mirrors what is there so far so fitting the parallel simply needs a switch and another short length of suitable cable