Thx Ward. I will read that next.
Big picture I am shopping on the West Marine site. I just finished looking at the third brand of 2 bank chargers they stock. It is from no.co. It is completely water proof and salt water tested. It plugs in too. Freaking crazy.
First, shop somewhere else for a charger unless you particularly like paying higher prices. Defender.com, PKYS.com, the SBO store are all good alternatives.
The charger size should match the battery type and size. Using a charger that is too large is a waste of money and using a charger that is too small will undercharge the batteries. For standard Flooded Lead Acid batteries the charger should be rated at a little more than 10% of the bank's size. For 2 Group 24 or 27 batteries this would be a 20 amp charger.
A charger with multiple outputs divides the maximum output between the outputs, thus a 20 amp 2 battery charger will provide 20 amps to one battery or 20 amps to both batteries with the amperage divided between the batteries. It will not put out 40 amps.
Chargers should be hardwired into the circuit. This is a more secure way of connecting the power source and it will be easier than adding an outlet and box. Plugs can come loose and they offer another place for corrosion to rear its ugly head. A hardwired charger with proper heat sealed terminal connections will be safer, more trouble free, cheaper, and less prone to corrosion.
The ProMariner ProNautica (also branded as a Sterling) charger is a great charger, it is "smart" and provides the proper charging profiles for your batteries. Charging batteries properly will extend their life.
With the money you save by not shopping at West Marine, consider adding a battery monitor like the Balmar SG 200. A good monitor will help you avoid over discharging your batteries thus extending their life.
Maine Sail's site has more information about them. While visiting, consider a small donation to help Rodd out. There is a message on his site from his brother. Rodd has generously given of his time and knowledge to the DIY Boating community, now is the time to pay him back.
For DIY boaters in an attempt to try and keep the sport as affordable & safe as possible. How To articles for sailboats and powerboats.
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