Some people confuse maintainers with battery chargers. They are different in that a charger does not provide a consistent voltage whereas a maintainer can maintain, say, 13 volts. Chargers merely charge batteries.
- There are automatic options on some battery chargers that enable them to stop charging when they reach a pre-set point. Manual modes mean you got to keep an eye on things and manually stop charging.
- The typical charger will have 10 amp and 2 amp modes (i.e., charge rates). It will come with manual and automatic switches. Most people prefer automatic so do not worry if your charger has no manual option. It is purely situational (depends on the application).
- In case your car battery is badly discharged, an auto setting will not detect voltage presence and trigger the process. Manual modes come in handy during such rare times (when the battery is probably under 8 volts). After an hour’s charging, you can shift to automatic mode.
- Automatic modes can be tricked into charging an extremely discharged vehicle battery. Use jumper cables in parallel by hooking your dead battery to one that has a charge. The dual battery scenario will encourage a charger’s automatic mode to come on and get charging; because it sensed a voltage in the non-dead battery. Remember, jumper wires in parallel.
- Similar low-voltage charger-un-recognition can happen with motorcycles, not just cars. You can salvage batteries despite them being in this condition so do not rush to replace the battery just because it is almost fully or entirely discharged.
Let us discuss another type of charger, namely one that has 2, 10, and 55 amp modes
- Most people have no real use for the 55-amp option, so do not consider this an upgrade from the battery charger we discussed earlier.
- This one too has automatic and manual modes, sometimes solely the former.
- You can use the parallel wire battery trick to get such a charger going if it does not immediately start work on a discharged car or motorcycle battery.
- You can even use the 55-amp mode to do this, because the charger will force all that charging rate and sense a tiny volt spark in your dead battery. Same trick, different idea.
- Shift to ‘engine start’ mode, plug the charger in and fix the terminals in the right places, turn on the charger, wait about 10 seconds, and see what happens. Use a voltmeter to keep track of voltage variations. When you see the charger has reached 13 volts charge limit in the car battery, unplug the charger, change the mode to 2 amps and continue.
You now have a good idea about battery chargers and how they work. Specific scenarios determine what kind of measures you need to take to charge your car battery. It is advisable to charge your battery at the lowest amp setting available. When in doubt, call a professional.