Battery Charging

Post Reply
Posts: 5
Joined: Wed Feb 20, 2013 12:36 pm
Anti Spam measure: No
AntiSpam Text: Easterly

Battery Charging

Post by Dougal » Wed Dec 10, 2014 3:47 pm

I have 2 domestic 100amp and 1 starter 70amp batteries. I am on a swinging mooring so most of my battery charging is done from the Volvo 2020 engine.
I suspect the original mains charger was designed for one or 2 batteries at the most and probably lower capacity. Is it worthwhile considering a new charger, such as
C-Tek M300, as the batteries which are new do not seem to last long, even when mains charged.
I have noted something called "back current drain" from a battery to a charger. My charger is permanently wired to the battery so should I have a switch between the battery and the charger to stop leakage back.
I am thinking of changing cabin lights to LED which should help.
Any advice appreciated

Jolly Roger
Posts: 1005
Joined: Mon Sep 02, 2013 1:08 pm
Anti Spam measure: No
AntiSpam Text: Westerly
Location: Kent, UK

Re: Battery Charging

Post by Jolly Roger » Wed Dec 10, 2014 4:07 pm

My advice would be to fit a solar panel. The one on my Fulmar seems to work well and keeps two 105 amp batteries charged.
Concerto Fulmar FR38
Photos at ... 2/library/

User avatar
Posts: 484
Joined: Tue Jan 13, 2009 10:42 am
Anti Spam measure: No
AntiSpam Text: westerly
Location: Windermere/Tayvallich

Re: Battery Charging

Post by aquaplane » Wed Dec 10, 2014 4:12 pm

On my Centaur, but the boat doesn't matter, I have the same size domestic bank and engine battery.
We are also on a swinging mooring and rely on the engine to charge up the batteries.
I do have a 40W solar panel which keeps the batteries in good nick when we aren't there but isn't big enough to do serious charging when we are there.
I went for the Ctek M200 charger, Santa brought it last Xmas, and have only used it once this last season but the batteries were vertually full so it wasn't a demanding test.
We only have cabin lights and basic instruments/GPS/VHF so we don't make excessive demands on the batteries.
The M200 is rated for 200Ahr batteries, the M300 may be a bit of overkill, or maybe not if you don't have a bit of solar to help out.
Centaur now sold. Boating from Tarbert.

Posts: 41
Joined: Sun Sep 14, 2014 2:42 pm
Anti Spam measure: No
AntiSpam Text: Westerly
Location: West coast Ireland.

Re: Battery Charging

Post by Eeyore » Wed Dec 10, 2014 6:36 pm

Most battery charger will have a diode to stop current going the other way, if you have a loss you need to identify it accurately.If you are sure the charger is causing a problem you could indeed fit a switch. Do you isolate the batteries every time you leave the boat? Is there something on the circuit that bypasses the isolator such as an automatic bilge pump.? Even on a mooring and using only the engine ,it seems odd that good batteries don't last. I would definitely suspect a current draw somewhere that you need to identify, start with an accurate ampmeter in series on the battery positive and then the negative to see if there is a draw.
Tempest Isabella TT6

Posts: 22
Joined: Tue Oct 07, 2014 6:15 pm
Anti Spam measure: No
AntiSpam Text: westerly
Location: Sunny! Barmouth.

Re: Battery Charging

Post by Miranda » Wed Dec 10, 2014 6:40 pm

I have the same battery set up as you, also on a swing mooring ( so no mains ) I have a rutland 913 wind genny which more than keeps on top of things, I know some people don't like them but I've had them on my last 2 boats and never had any issues wired through a smart controller that will also take solar panels. Got a mains charger but never use it as battery's are always topped up, even using the fridge (carefully)
Changed all my lights to LED even the spots over the berths but only changed bulbs not the fittings, these are very cheap if bought in multiples from ebay etc.
Tim, Tempest TT23 Miranda

Posts: 137
Joined: Tue Jan 20, 2009 5:42 pm

Re: Battery Charging

Post by mikebuggy » Tue Dec 16, 2014 8:08 pm

My experience is much the same as the foregoing. I do have 5 X 110 AH batteries though!
I use a very old Aerogen wind generator and 2 old 20W solar panels. Between them they keep things topped up when Im away. Have to run the engine at odd tmes when on board if weather is hot and fridge, chartplotter, and autohelm is on.
Do regular checks with an ammeter on losses and stray currents.
I changed all my lights apart from deck nav lights to LED. Amazing difference in consumption. They are also much better and cheaper than they used to be.
Out of interst, as an experiment Ive just bought a pack of 2 12V LED bulbs from ASDA (!). They are new in. Grey and pink bubble pack called TCP. First time Ive bought boat electronics from ASDA! The bulbs have a little 2 pin base, called a G4. As it happens, most of the cheaper good deal internal LED lights now come as G4, so its worth buying a set of G4 adaptors for your boat (they are still a bit pricey though). These can be bought with different base plugs (screw, bayonet etc) to suit any 12V fitting, but the socket bit on top just has 2 little holes for G4 pins. Alternatively, you can also just modify your lamps and replace the bayonet fittings with little crimp on electrical connectors to take the bulb pins directly.

Post Reply