Battery charger advice

[LadyInBed]

Fine if he's day sailing, but if he's spending time aboard when plugged into shore power 3-5a may not be enough to keep up with demand, let alone charge the batteries at the same time. Although i'm not suggesting any particular size of charger, let alone 40a. Without knowing his pattern of usage, it's not possible to say how powerful the charger needs to be.

True, my suggestion was for use whilst the boat was unmanned.
If spending time aboard on shore power 5A might be a minimum, but it depends on the boat setup. If it is wired for mains lighting, etc. the battery draw should be quite small, assuming nav kit switched off. The biggest draw would probably be a fridge if it isn't dual powered.

 

[gordon029]

Once again thanks all for the replies. I use the boat a few times a week and mainly use the engine to get out of the marina and if there is little wind.I don't have many electric items on board except a small fridge. I really just want to replicate the simple system which I have had on my old boat which kept the batteries charged up and a trip switch which covered the twin sockets that I used to run a dehumidifier and an electric kettle when on shore power.Thats it , I don't need anything more elaborate than that as I prefer to keep electrical systems simple as possible .

 

[Richard10002]

Apropos of nothing:

When I am onboard I seem to use between about 70Ah and 100Ah in a 24hr period. TV, fridge, laptop, phones, mifi, car radio, led lighting.

Off grid, so use a genny to charge, via an 80A Sterling inverter charger, 3 to 4 hours a day to get to “full”.

Fitted 490W of solar in September which has just started to show signs of contributing and, as the year moves on, I’m expecting them to provide for most of my useage.

4 x Trojan T105 batteries, nominal capacity 450Ah, but severely sulphated, so now have a capacity of about 200Ah.

 

[VicS]

Once again thanks all for the replies. I use the boat a few times a week and mainly use the engine to get out of the marina and if there is little wind.I don't have many electric items on board except a small fridge. I really just want to replicate the simple system which I have had on my old boat which kept the batteries charged up and a trip switch which covered the twin sockets that I used to run a dehumidifier and an electric kettle when on shore power.Thats it , I don't need anything more elaborate than that as I prefer to keep electrical systems simple as possible .

Do not skimp on the basic safety devices though. An RCD plus circuit breakers for the individual circuits is the minimum

Some alternative ideas that might be of interest ( others will shoot the suggestions down in flames no doubt)

A caravan mains hook up kit:
https://www.towsure.com/caravan-mains-electric-diy-installation-kit

A camp site hook up unit:
https://www.towsure.com/camping-site-mains-supply-unit-3-outlet
https://www.towsure.com/powerpro-multi-use-15m-mains-extension

Other mains connection equipment which may be of interest:
https://www.towsure.com/caravanning...al/mains-to-caravan-connector-campsite-hookup

 

[JumbleDuck]

Once again thanks all for the replies. I use the boat a few times a week and mainly use the engine to get out of the marina and if there is little wind.I don't have many electric items on board except a small fridge. I really just want to replicate the simple system which I have had on my old boat which kept the batteries charged up and a trip switch which covered the twin sockets that I used to run a dehumidifier and an electric kettle when on shore power.Thats it , I don't need anything more elaborate than that as I prefer to keep electrical systems simple as possible .

I chose a 6A charger for my marina winter because I am happily self-sufficient in summer with two solar panels giving 4A on a good sunny day. I don't use significantly more power in the winter, because I have no fridge and heating is by extension lead in a marina and charcoal heater elsewhere. Like you, I like to keep my electrical systems simple.

 

[JumbleDuck]

Do not skimp on the basic safety devices though. An RCD plus circuit breakers for the individual circuits is the minimum

I'm not convinced that individual circuit breakers are any more necessary on an extension used on a boat than on an extension used anywhere else. The marina outlet will be protected and anything plugged into it will be protected. They are not bad things to have, but perhaps a bit over elaborate.