The other chargers I have need to have power going in them thru the leads to excite them before they will put out any charging power thru the same leads. In other words, if I plug them in and turn them on, I can touch the leads together with no sparks or hook a voltmeter to them and it shows zero current or voltage. To cook a rusty tank with them, a battery must be hooked up to get the chargers to charge. An old six volt charger I have and the three bank marine charger are the opposite, when they are turned on, the leads are hot, just like an arc welder. It’s probably a safety thing.
The CTEK smart charger pictured here is a bit different as it has a supply mode which puts out a constant voltage and could possibly be used to clean a tank.
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