I know NOTHING about batteries. But, I do know something about bad lower backs, herniated discs, old age (well, kind of …) and other woes that have a connection to the size and weight of boat batteries. Wet batteries have a dangerous habit of leaking acid all over the poor sap who is breaking their back, carrying the thing to his car (so it will leak, maybe, in the trunk). A good friend who does have expertise in the battery area strongly advised me to NEVER heft my single Deka House/Starter battery out of the boat (which is on the hard, way up in the air, accessible by ladder … that maybe isn’t even tied on)) over the winter, in order to bring it home, keep it in a nice, warm spot (totally unnecessary) and charge it occasionally (remembering that I know NOTHING about batteries and haven’t the foggiest notion of how to maintain it over the winter.) My battery is a ten-year old wet battery. I remove the caps after haulout and before launch. I put in a tad of distilled water or none at all - the levels are usually good.
Over the winter (5 - 6 wretched months of it), my battery is hooked up to a $60.00 Canadian Tire FIVE watt (with no voltage control - not needed on so small a charger) SOLAR PANEL. It provides a trickle charge, that’s all. It works perfectly and the battery has always read over 13.5 volts at launch - more than enough to turn the engine over, etc.
Most boats have more than one battery and a much more complex setup (more batteries, more sophisticated batteries, etc.). I may be mistaken (and, please, someone, enlighten me if I am wrong) but can all of us just hook on to the smallest capacity solar charger that will do the job, for our particular needs ?? All it takes is a trickle charge, no ??
NOBODY should ever carry a big and heavy battery - it is very unhealthy.
I agree with you, Ernie. Keep it simple!! To have the solar panel charge all the batteries, simply put all your batteries in parallel with the battery switch/switches.
Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA
Hi Ernie et al;
I just replaced the engine battery, only to find that a downstream connector (which I had checked) was loose. Regardless, new battery and new info. Crosstown Battery in Toronto, a real hole in the wall but reliable place, said that wet batteries freeze if not kept charged over the winter. The reason is that as it discharges, the acid turns to water, so I am told. That 5W panel will do the trick.
Regarding backs, we have two 58kg batteries in the SB lazarette and they ain’t coming out! Kept charged, they survive the winters.
Alan & Tracy, Corvus NS30C, Toronto
Here’s two cents worth from a battery engineer of >25 yrs- (wow, time flies). - yes, as lead acid batteries discharge, the acid is consumed and water is produced, so discharged batteries freeze easily. On charging, the acid is regenerated and water is consumed, making them quite freeze resistant. (From the internet: At a 40% state of charge, electrolyte will freeze if the temperature drops to approximately -16 degrees F. When a battery is fully charged the electrolyte will not freeze until the temperature drops to approximately -92 degrees F.) This is also the basis for estimating battery state of charge with a hydrometer, which measures electrolyte density (which goes up as the battery is charged)
The flooded/wet batteries had at some point in my Nonsuch’s (Lily Pad) history been overcharged or tilted and spilled, eating up the wood the batteries were mounted on, leaving a charred mess easily pulled to pieces by hand..So I am very happy to spend on the AGMs at Batteries Plus Bulbs - No spill risk. https://www.batteriesplus.com/productdetails/sli24magmdc
Thanks for the clarification, Phil. For us Canucks, 40% charge freezes at -27C which covers half the winters. Say 50% to be safe (linear interpolation is -35C). We went for flooded cell for the engine simply because the house are that type, can’t mix and match. Besides, a third the price of AGM. The boat came overbuilt with a Xantrex system with 500AH of house batteries and 3KW inverter - we can now microwave while making toast and drying hair at the same time. I have yet to do that.
Nn my compact N22, I have just one machine that does, in fact make toast, microwave and dry hair, all at the same time. It broke, tho, and for a short time it was microwaving hair … Now. it’s fixed !
One reason I like golf cart batteries is the weight. At 65 lbs each they are more manageable than those 12 v beasts. Start batteries are not very heavy. If you can visit you boat periodically a solar panel makes sense. But any unattended live electrical connection on a boat can be a fire risk. Many marinas and YC do not allow AC based charging over the winter months.