Actually, it really does matter, otherwise it won't work. It simply has reverse polarity protection so that if it is connected incorrectly, in reverse, it won't damage the battery or the charger

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Michael
Yes, I said that wrong. You need positive to positive and negative to negative but you do not need to put the positive on first. If you have a battery tender junior or plus.
SPECIAL FEATURES: The Battery Tender ® Junior and Plus
Chargers have the following special features:
SPARKPROOF: The battery charger DC output leads,
either ring
terminals or alligator clips must be connected to a battery before an output
voltage is developed by the battery charger.
SHORT CIRCUIT PROTECTION: The battery charger can sustain a
short circuit connection directly across its DC output terminals indefinitely
without any risk of either electric shock or excessive heat.
REVERSE POLARITY PROTECTION: The battery charger is
protected internally against any damage due to the DC output leads being
connected to the opposite polarity battery post. No damage will result to either the battery or the battery charger.