Our waterproof chargers are designed to charge 12-volt batteries within a 12/24/36 volt system. If you have a Dry Mounted battery charger (ProTech, Flyback, Promatic) then you would need a 24-volt charger for a 24-volt system or a 36-volt charger for a 36-volt system. A 12-volt non-waterproof charger cannot charge a 24-volt or 36-volt system.......the charger has separate positive terminals but only one common negative terminal (so the battery banks are not isolated from each other).

Can I connect the charger to only one battery? What do I do with the unused terminals?

On a Dry Mount charger, you will need to jumper the unused positive terminals to one of the positive terminals that you are using so that the charger will "read" a battery on each lead.

Where can I mount the charger?

Make sure you have adequate ventilation for cooling of the charger, but these chargers are not made to get wet and it will Void the warranty.

My charger is tripping my GFCI circuit breaker on my outside outlet?

All chargers that use this technology to charge batteries bleed a little voltage, which should be below the GFCI trip point. Test the charger on a non-GFCI outlet (inside the house) and see if the charger works. If it works, then most likely something is wrong with the GFCI outlet. If it does not work on an inside outlet, then there is something wrong with the charger.

Can my charger be left on for an extended period of time?

The newer 3-step chargers have a float mode (3rd step) which maintains the batteries at 13.3 volts (for lead-acid batteries) and 13.8 volts (for gel-cell batteries). As long as the batteries are in good condition and you maintain your water levels inside the batteries periodically (for lead-acid batteries), then you can leave the charger on between fishing, boating trips, etc.

What charger setting do I have to use for AGM batteries?

AGM batteries can charge at the lead-acid setting on our battery chargers. Our chargers are factory set for lead-acid so you do not have to make any changes to the charger.

Can I charge a lead-acid battery and a gel-cell battery together?

Our chargers charge and float lead-acid batteries at a different voltage than gel-cell batteries. You should not mix battery types because you are going to compromise a battery if you charge it at the wrong setting.

What is the difference between the older Ferro-Resonant chargers and the newer 3-step chargers?

The older Ferro-resonant chargers were constant volt chargers that put out 13.8 volts. They did not charge at a high voltage and then step down the voltage for a maintenance mode. They are much bigger and heavier and most often louder.

How long will it take to charge my batteries?

The following equation will give you a good idea of how long it will take to charge batteries.

Total Amp Hour capacity of the batteries
------------------------------------------------
Total amperage output of charger
= Total Hours To Charge Batteries

Example: 100 amp hour battery / 10 amp charger = 10 hours

If you drain your battery half-way (50%) then you would need to put 50 amps back into it. Based on the above equation it would take you 5 hours to charge the battery.

If you have more than one battery, you will have to add up the amp hour capacity of all the batteries and then divide by the total amp output of charger to get charge time.