There is a lot of misinformation in that article. I'll start with just the above quote from the article.
Flooded batteries are cheap but come with their own list of disadvantages: They’re really heavy,
Yes, flooded are cheaper in the short and long run vs AGM. They are cheaper than Li in the short run. Li
should have lower cost over time if the user doesn't smoke them with overtemp conditions, undertemp charging, etc.
Yes, FLA are heavy, like AGM is heavy. They are both made of lead.
produce explosive hydrogen gas,
Yes, like AGM if overcharged. Both need to be vented.
The difference is flooded is not damaged by overvoltage; AGM sustains permanent damage. And folks running consumer grade AGM at the voltages in the article will outgas/kill the AGM quickly. Example: here are the Vabs for T-105 flooded and AGM:
FLA - 2.45v/cell (14.7v)
AGM - 2.40v/cell (14.4v)
need to be replaced more often than most other batteries,
Flat out wrong. AGM have fewer duty cycles at a given DoD, have less capacity for a given size, and they cost 2X what FLA cost.
and require ongoing maintenance that can be a real hassle.
I know. Watering the batteries 1x/month for <5mins is real beatdown. To me, the real hassle is ponying up 2x the price for an excellent product hamstrung by being used outside it's designed purpose. If you are offroading you need a jeep, not a corvette.
The only ways AGM are a practical compromise:
- price, which is silly
- throughput, assuming the charger can provide the minimum C/5 rate, and preferably C/3.