Batteries that have liquid electrolyte sloshing around in them are sometimes referred to as 'wet', 'flooded' or 'wet lead acid' batteries. To start the engine, boats have a starting or 'cranking' battery, like those used in cars, which delivers very high loads for a few seconds. Only a small portion of the battery's capacity is used. An 'in-between' option is the 'dual' or leisure battery. A compromise between starting and deep-cycle batteries, these are popular on boats that carry only a single battery, or prefer to. Nobody wants battery acid leaking into the bilge, but there's a price to pay if you want more durable batteries. Sealed lead acid batteries are sometimes referred to as VRLA (valve regulated lead acid) and there are two main types –. Lithium-ion is a broad chemistry of batteries, the most common being LiFePO4 (Lithium Iron Phosphate). They can withstand four or five times the number of cycles compared to most deep-cycle lead acid batteries. Lead carbon batteries are not widely known. Our electrician had never fitted them, and indeed I hadn't considered these until I spoke to.
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Because lead acid batteries can supply such high currents, it's important to assure that you use the right wire thickness / diameter. If the wire is too thin, it causes too much resistance and thus may overheat, causing the insulation to catch fire. Lead acid batteries can be very dangerous, so you have to be very carefull with them.
Personally, I always make sure that anything connected to a lead acid battery is properly fused. The common rule of thumb is that a lead acid battery should not be discharged below 50% of capacity, or ideally not beyond 70% of capacity. This is because lead acid batteries age / wear out faster if you deep discharge them.
For a lead acid battery, lifetimes of 500 to 1,200 cycles are typical (double for lithium-ion batteries), but the ageing process results in a gradual reduction in capacity over time.
Are lead acid batteries bad for solar power?
So the first issue with lead acid batteries is that they don't take well being in a discharged state for more than a day or so. It will make them deteriorate faster. I think the second issue with lead acid batteries as a solar power bank is their slow charging speed.
Are flooded lead-acid batteries better than gel batteries?
Flooded lead-acid batteries have a lower cost than AGM, gel, and lithium-ion batteries. The performance of a starting battery is measured in cold-cranking amps (CCA). Higher CCA ratings indicate more power. Check with your engine manufacturer for the recommended minimum CCA for your boat's engines. Flooded lead-acid batteries are cheaper than other types.
Why are lead acid batteries not able to charge?
Lead acid batteries often can't use all available solar power to charge because they just can't charge any faster, no matter their capacity. This means that even though there would have been enough energy available to fully charge the batteries, it was not available long enough to fully charge the batteries.