Marine Electrical Diagnostics

Why does it seem like my AGM battery is bad, weak or goes bad quickly?

We typically find this is an issue on Ranger boats factory equipped with Dual Pro - Pro Charging Systems battery chargers.

Although they are programmed to charge AGM profiles, many times when a customer comes in and they have problems with their AGM marine batteries, it's actually due to these chargers not fully charging AGM's.

Over time they become weaker and weaker from not getting a full charge. In this case we determine if the battery is good or bad, and in most cases replace the on board charger.

Why do my fish finders cut out when I start my engine?

This is most likely caused by voltage drop- the distance between your battery and fish finder - and improper wire gauge size.

When you start your boat motor, it drops the voltage feeding your graphs.

More information on correct wire size can be found here.

How can I tell if my on board charger is working correctly?

Use a multimeter to measure the voltage at the leads coming out of the on board charger.

We recommend trying to charge the battery in question with an automotive style charger, depleting the battery some, then trying your on board charger and testing the voltage at the leads. This will give a more accurate indication on whether or not you have a bad charging bank.

Why isn't my lithium battery taking a charge?

All lithium batteries are equipped with a BMS - or battery management system. These sometimes go into a lockout mode where they no longer allow the battery to take a charge. Also make sure the charger you are using is compatible with the lithium marine battery you are using.

Lithium batteries come in many different voltages such as 12V, 14V, or 16V and using the correct charger is critical.