I will be leaving my boat unattended for 9 months I have a full Victron system What steps do I need to take to stop my batteries discharging The bms and colour controller appears to put a small drain when everything else is turned off Thanks Stuart
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What steps do I need to take to stop my batteries discharging
My measurement of a SmartSolar MPPT 150/35 said less than 10mA at 12V standby draw (about 1.5AH/week, 6AH/mo). The 70AH battery in my shed means I could just leave it with the panel disconnected for two or three months and not expect problems. I haven't measured my bigger system because I always have solar panels feeding into it and they keep it charged.
More concern is normally the other loads on the system and what they actually use over weeks or months.
The usual first step is to identify the loads by turning everything off then one thing on at a time, noting power consumption for each item. It seems you may have done that or at least started already. If you are intending to simply switch everything off, charge lead acid batteries fully and lithium ones to 50% (https://batteryuniversity.com/index.php/learn/article/how_to_store_batteries) then turn off the battery isolator. With most batteries at most temperatures that gives you at least a year of safe storage.
I'm not sure what you mean by "full Victron system", presumably everything is Victron? But it would help to confirm that you do have solar or some other power source active while you're away. Otherwise things get quite tricky unless you disconnect the battery.
My strong preference is to have enough solar input that even in long periods of poor weather I can comfortably support the loads I'm leaving on. That way I only have to worry about system failures. In my case I normally only leave the power system plus remote access, alarm and tracker active and the average load there is under 100mA at 48V (less than 5W) so my system is ridiculously overpowered (2kW of PV, ~4kWh battery). I usually unplug or isolate loads when I'm not using them, but doubly so if I'm leaving it unattended for a long time. Last thing I want is a leak to dump rainwater into live electrics and start a fire (or just drain the battery). So if I don't need it running while I'm away, I disconnect it.
What kind of batteries? solar? does your boat have a bilge pump? do you want the bilge pump to have power? etc.
lot's of variations, but generally (when no power needed on board):
-lead-acid: fully charge and disconnect from system
-lithium: charge 50% and disconnect from system
Thanks for the help
The boat is out of the water
I don’t have solar with batteries (li-ion)
The bms and colour controller are still connected when battery isolated.
I think I will disconnect leads to the battery to be sure
