Not exactly sure about the AGM vs LA vs CAD controversy......??? The chemistry is the same . The plate materials are: Pb (lead) and PbO2 (lead dioxide) with sulfuric acid as the electrolyte (in either liquid or gel form. The major difference is the construction....absorbent glass mat with semi solid electrolyte or standard plates and liquid electrolyte.
In my opinion, the reason for buying a generator in the first place is to keep the home safe and secure during a utility power outage. The generator, transfer switch and their installation (if included in the package cost) can amount to $ 5000+, why are we quibbling about the cost of the starting battery ($ 100 - $ 200)?
The AGM battery will provide the lowest internal resistance which will yield the highest cold cranking amps (CCA), with the highest terminal voltage for the longest time. Just buy the best battery available not the cheapest cost battery. BTW...the AGM batteries when being correctly charged, out gas the least, minimizing the possibly of terminal and surrounding corrosion.
The battery in my vehicles, get ONE (1) chance NOT to start the car....then it's replaced....no fooling around with coaxing by jumping it or charging it.
Just my opinion of course...
I'll second that. Unless the battery ran down for a known reason (lights left on, etc.), the first time it won't start the engine, or cranks very slowly - it should be replaced.
In a car, slow cranking will be noticed. In a generator, most folks won't notice, unless they are near it at exercise time. So to be safe it should be replaced every 2 -3 years or so. If that's done, it may not have to be top of the line. But it's still only a small percentage of the cost of the generator.