charging ammeter

[tckearney]

Hi all,  I have just been looking at the charging circuit on my B42 2000.  The ammeter does not work as the shunt is not connected.  I have put a 1.5v  size D battery across the shunt and it reads 10A fine on the meter so I know the basic circuit is working.  However the shunt  has been disconnected at some point and I am wondering where the wires to and from it would have connected.  The metering wires Blu/Wht are still connected to the shunt, it’s the main charging wires that are not.  Any ideas where these would be connected to.  I think I have attached a picture

[Lyra]

A shunt should be connected in between the battery and the charger/load - disconnect the cable going to the + of the battery and connect it to the shunt and then connect another cable from the other side of the shunt to the + of the battery.

[tckearney]

thanks which battery the engine start of the service batteries

[Lyra]

The one you wish to monitor.

Frankly, I see little use to to if you do not have some kind of a charge/discharge logging system (a dedicated microcontroller that monitors the shunt voltage constantly).
The engine battery typically needs no monitoring because it is very little discharged and immediately charged by the engine (and also has a warning light on the VOLVO engine panel).
The house battery charge/discharge should be logged and "accumulated" in order to know at what state it is - the momentary discharge rate does not give any useful indication (except maybe if you see a large discharge while nothing is operating or no charge when the charger is on, cases which indicate a problem).

[tckearney]

Thanks, I just wanted to check that my alternator was charging correctly.   I have since found "Anschlublan  Panel 418  E08-012 418" with the details on it.   It shows the shunt wired in series from the original mains charger (no longer fitted)  and the start battery.  so as you say, of little use.  I may put it in the alternator output between the alternator and the blocking diode.  Any reason why I should not do this.  I was unaware the engine start panel had indication for charging.  I will check this out on my next vist..  Many thanks

[Lyra]

The engine panel does not have an indication for charging - it has a warning light for discharge (or maybe it is an indication for low voltage - the light with the battery icon) - never checked, but I think that if for some reason the alternator does not charge it will turn on.
A shunt can be placed almost anywhere you want since the voltage drop on it is very low (typically 50-100mV at the designated full scale).

[tckearney]

Next to the ammeter on the 418 panel there is a green LED lamp  and a small  green LED pushbutton.  Any idea what they what these are for?  They have no effect, I assume this is because the shunt is disconnected