Originally Posted By: Smoky14
Taking a voltage reading on an unloaded charger won't prove too much. It must be in a balanced circut.
+1. Often the chargers have a delay before they start to put out any voltage/current, so that they can determine if the connected load is the right voltage, determine what they need to put out, etc. 1.8V may just be some leakage.
Id do this:
-Obtain a multimeter, use it for voltage readings.
-Read the battery voltage without the charger attached, report.
-Attach the charger, read the battery voltage, report.
-Start up the charger with the right voltage and current settings utilized. Measure voltage after a few minutes, report.
If your battery is bad, like it has a shorted cell, the voltage of the charger may drop, or it may get cut via a current limit because the battery is accepting too much too fast. There are all kinds of schemes that are used...
A slow rate (low current) charger will not take the voltage too high for a while. It may even just float at a single voltage and just limit the current it provides. So some may just be a 13.5 or so voltage source.