The number shown on the chests of "Batteryman AA", "Batteryman AAA", "Batteryman C" and "Batteryman D" corresponds their Levels. This also relates to what their respective battery sizes are called in Japan.
"Batterymen" with the recycling symbol on their heads are the ones able to be returned from the graveyard by "Recycling Batteries".
The "Batteryman" has a lot of powerful specific support cards that have massive destruction capabilities. Although most of the "Batteryman" archetype is made up of weak monsters, poweful effects more than make up for it. "Batteryman 9V" is the key card of the archetype. By summoning it, any "Batteryman" card in the deck can be searched. "Batteryman Micro-Cell" can special summon any "Batteryman" from the deck, usually "Batteryman 9V" for additional searching power and a 2000 DEF monster. "Batteryman Charger" is one of the most useful cards in the Archetype, because it can Special Summon a "Batteryman" of any Level from your Deck when you Normal Summon it. Through cards like "The Monarchs Stormforth", it is easy to abuse. It also makes a good beat stick, as swarming them can get its ATK up to a max of 3300 with relative ease. "Batteryman Industrial Strength" is the most powerful "Batteryman" (in terms of its destructive effect and original ATK) because he can destroy two cards the opponent controls with his effect, simply by banishing a Thunder monster from the Graveyard. "Batteryman Fuel Cell" is one of the most important "Batteryman" card since most "Batteryman" OTKs rely on it. "Batteryman AAA" is also often used in "Batteryman" decks for quick XYZ plays. Since "Batteryman AAA" is a LIGHT monster, it allows access to powerful Rank 4s like "Starliege Paladynamo" and "Constellar Omega".
"Thunder Seahorse" aids this Deck very well because of its ability to thin the Deck by searching "Batteryman" monsters, since most have low ATK. It can also be used to fuel the effect of "Batteryman Industrial Strength".
A vital card in a deck revolving around "Batteryman AA" is "Inferno Reckless Summon", which can instantly bring out 3 "Batteryman AA".
"Ally of Justice" and "Koa'ki Meiru"s pose an extreme threat to the "Batterymen" since they have effects that will negate and destroy them with ease because all of the "Batteryman" monsters have LIGHT attributes. "Light-Imprisoning Mirror" can help too.
Also, mass-removal cards like "Torrential Tribute", "Dark Hole", "Mirror Force" and even "Doom Donuts" have the power to shut down "Batterymans", destroying all of their monsters before they can attack and potentially OTK. In addition, cards that remove them from play and cards that hinder special summoning them from the Graveyard or Deck will pose a threat to them. Worse, "Deck Devastation Virus", "King Tiger Wanghu", and "Kotodama" can be more permanent solution for greatly hindering "Batteryman" Decks, especially OTK builds. Also, more peculiar cards like "Prohibition", "Psi-Blocker", "Dark Designator" "D.D. Designator" and "Mind Crush" can prevent "Batteryman" Decks from flourishing at all.