Blue Mana Battery {4}
Artifact
{2}, {T}: Put a charge counter on this artifact.
{T}, Remove any number of charge counters from this artifact: Add {U}, then add an additional {U} for each charge counter removed this way.
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Cards that do something similar expected a card that isn't here?
Reports become test cases the matcher is graded against before an update ships. Delvefall isn't a chatbot guessing, it compares the printed rules text of every card with plain math, and examples like yours decide which differences should count.
Black Mana Battery 100%
$0.67#25529
"{2}, {T}: Put a charge counter on this artifact."
+1 more matching line
Green Mana Battery 100%
$0.37#27424
"{2}, {T}: Put a charge counter on this artifact."
+1 more matching line
Red Mana Battery 100%
$0.52#26688
"{2}, {T}: Put a charge counter on this artifact."
+1 more matching line
Magistrate's Scepter 99%
$3.42#5640
"{4}, {T}: Put a charge counter on this artifact."
+1 more matching line
Jeweled Amulet 97%
#3622
"{1}, {T}: Put a charge counter on this artifact. Note the type of mana spent to pay this activation cost. Activate only if there are no charge counters on this artifact."
+1 more matching line
Conversion Chamber 96%
$0.10#23220
"{2}, {T}, Remove a charge counter from this artifact: Create a 3/3 colorless Phyrexian Golem artifact creature token."
Trigon of Infestation 89%
$0.21#22876
"{2}, {T}, Remove a charge counter from this artifact: Create a 1/1 green Phyrexian Insect creature token with infect."
Surge Node 89%
$0.36#17588
"{1}, {T}, Remove a charge counter from this artifact: Put a charge counter on target artifact."
Trigon of Thought 85%
$0.09#29056
"{2}, {T}, Remove a charge counter from this artifact: Draw a card."
+1 more matching line
Empowered Autogenerator 84%
$0.30#4112
"{T}: Put a charge counter on this artifact. Add X mana of any one color, where X is the number of charge counters on this artifact."