Gents,
It seems to me many of you feel that purchasing batteries these days is a bit of Russian Roulette, but if you just understand the basics, you should get years of service out of even the "bargain" batteries. I read up on the subject after getting frustrated from constantly replacing moto batteries, and learned it wasn't crap batteries, just operator headspace and timing issues..
Wet or flooded batteries are the traditional style most are familiar with. These batteries have lead plates mounted in a liquid electrolyte that can vent/off-gas (spill)freely. The lead type was mentioned earlier, and that is a major factor in wet batteries. Thinner plates/high plate count make a wet battery perform better as a starting battery, and cheaper to produce, but they are more fragile. In order for the plates to be physically stronger, antimony-lead alloy is used. This produces stronger plates, but it also drastically increases the internal discharge rate. When a wet battery is allowed to sit unused, it will deeply discharge. Once it drops low enough, sulfation occurs. If you stay in the "deep discharge, then charge up for use" cycle, you will kill it, like lint building up in a dryer. When you do charge it, use a modern charger that detects/corrects for sulfation with an internal microprocessor. I imagine most guys on here are like my Pops and own one of those old metal cased Sears DieHard chargers that hum loudly, smell like ozone, and are generally terrifying to be in the same room with. I have had great results with the Schumacher chargers that can be had fairly cheap at Wally World. If you run a Battery Tender on your wet battery, just know that they can keep the battery topped off, but they lack the power to really overcharge it to stir up the electrolyte chemistry properly. They can hold off internal discharge and sulfation, but wet batteries needs a good hot maintenance overcharge now and again to stay healthy. And of course, keep an eye on their water level and don't let them run dry
Sealed Lead Acid or spill proof, maintenance free, dry cell, etc. These have lead plates along with an electrolyte that is either absorbed into a glass mat(AGM) or in a gel medium(GEL) and are fully sealed. They use thin plates/high plate count as well, but since the plates are supported by the mat or gel, they do not need the high antimony content. Instead a weaker lead-calcium alloy is used. This greatly reduces the rate of internal discharge, and supresses off-gassing since the battery is sealed. SLA batteries will hold a charge longer than wet batteries, but if allowed to discharge, will sulfate as well. It is very important that you use a modern charger with SLA batteries as they are much more sensitive to overcharging, especially the GEL. When overcharged, bubbles can form in the gel and pretty much trash it. The AGM isn't as sensitive, but remember those older chargers are designed to charge wet batteries, and they benefit from overcharging, so you are risking damaging that $200 investment. And if possible, avoid using the high forced "quick charge" setting that are often seen on cart chargers or wreckers as these heat the batteries up and can damage them. Modern chargers with a desulfation mode pulse power through the battery like a hammer drill to break up the sulfation, but do not over heat the battery.
Major take away- regardless of type, wet, sealed, cheap, expensive, old, new, American or Chinese, to get your money's worth, keep your battery fully charged with daily use or battery tender, and along with routine maintenance desulfate with a modern "smart" charger. Calling unmaintained batteries "crap" is like calling a carb crap when its bowls are filled with old soured gas.
The Lithium Iron Phosphate(LFP) batteries are a rabbit hole I'm sure y'all don't want to go down on this forum. My opinion is that they will be the newest thing for automotive batteries. They are safe compared to Lithium Ion(LIB) when talking overheating and exploding. They are expensive, but those costs are steadily coming down as production increases. They do not require the close charge monitoring the LIB's do, and only require a routine balancing 1-2 times a year. This balancing will ultimately make it's way into the internal construction of the battery and won't be a requirement in the future. They are incredibly, almost comically light, and can sit for 10+ months before seeing any notable discharge. You will be seeing more of these little guys in the future.
I'm in no way an expert, so if I'm wrong on any point, please feel free to jump in and correct me, and I hope this helps prevent some frustration and keeps gas money in your pocket
