Hi,
I have a twin engine boat with two batteries, one for starting and one for house. One alternator is charging the starter battery, the other is charging the house battery.
I would like to have full redundancy with the 2 alternators, each alternator beeing able to charge the 2 batteries.
What is the best way to achieve that ? Argofet Battery isolator?
What kind of batteries did you have? And all have the same voltage?
Starter battery is a Varta N9 12V 225 Ah, House battery is a bank of 2 Varta LED 12V 190 Ah in parallel.
These are both standard lead batteries.
I would take another look at the alternators and regulators and check whether the charging voltages are exactly the same.
If you don’t want to change anything else, then TWO of the Argofet Battery isolator are the simplest option.
Ok thanks. In this configuration (2 Argofet), where to take the reference voltage for each alternator regulator On each battery ?
A relatively simple method is to use a Bluesea DualCricuitPlus isolator
https://www.bluesea.com/products/6011/m-Series_Mini_Dual_Circuit_Plus_Battery_Switch_-_Red
I assume that you have two identical main engines with two identical alternators.
The Argofets are only available with one input. You need two, so this means that you need one Argofet per alternator with two outputs. The outputs go to the two battery banks respectively.
The alternator regulates the voltage itself.
There is no voltage measurement at the battery terminals.
The voltage drop of the Argofet is very low and insignificant.
Ok thanks. I have a wire coming from the alternator regulator which is supposed to be connected to the battery + for voltage reference in case of voltage drop in the circuit. I don’t know if I can let this wire unconnected, or connected to the battery anyway.
OK, I’m starting to understand.
Your alternator has a voltage sensor to compensate for voltage loss on the cable and the diode distributor, and you want to know where to connect it.
As shown in your picture, directly to the positive terminal of a battery.
I would have the alternator (1) to monitor battery (1) and the alternator (2) to monitor the other battery (2), as before
Since the voltage loss is compensated, it would even be possible to use the cheaper
ARGODIODE Battery Isolator as an alternative
However, your wiring diagram shows a 24V system with one alternator and one diode distributor for charging the two battery banks. Is that just an example or your system?
The diagramme was just an example from Volvo documentation. My system is in 12v.
Thank you for your help. It is now clear for me.
