Many people are in need of new batteries for their electric trolling motor but are not sure which type of battery is best for them. AGM and lithium batteries are two types that you may be interested in.
If you plan on fishing for many years to come a lithium battery will outperform an AGM battery. There are other characteristics that may affect that choice listed in the article below and other battery types that also might be suitable.
What are the Different Types of Batteries for Electric Trolling Motors?
There are four different types of batteries that can be used for electric trolling motors. They are: Flooded Lead-Acid, Gel, AGM, and Lithium. Each battery is constructed differently, has different charge cycles and durability.
Flooded Lead Acid batteries are the least expensive to purchase. However, they have the tendency of allowing the acid to spill from the battery if it is not maintained properly or if the water level drops below a certain point. This can cause serious damage to your boat and other gear that may be stored in it.
Gel battery is another type of battery that can be used for electric trolling motors. Gel batteries are also known as sealed lead-acid batteries. Gel batteries have a number of features that make them different from AGM and lithium batteries. The main difference is that gel cells have to be charged within the manufacturer’s recommended voltage range. If they are not, then they will lose their ability to maintain charge capacity and may even break down, if overcharged.
AGM or Absorbed Glass Mat batteries are more resistant to vibration and shocks because they contain a fiberglass mat. The mat is soaked with electrolyte so there is a very low chance of leaks.
Lithium-ion batteries are made of lithium, which is a light metal. Lithium-ion batteries are often used in mobile devices, like cell phones, because they charge quickly and hold their charge for a long time without dying. Lithium-ion batteries can be expensive and require a special charger.
AGM vs Lithium Battery for Trolling Motor
We are going to compare the two types of batteries for trolling motors, AGM and lithium. Here are some key advantages and disadvantages when comparing these batteries head to head.
advantages of AGM batteries:
- Durable, resistant to vibration, impacts, and shocks
- They can be mounted in any position
- Wide operating temperature range
disadvantages of AGM batteries:
- Very heavy
- Maximum 50% depth of discharge
- Mid-range price
- Special charge require
- Medium cycle life of 300 to 500 charge cycles
advantages of Lithium batteries:
- Can be discharged up to 90% depth of discharge without harming battery life
- High cycle life of 3000 to 5000 charge cycles
disadvantages of Lithium batteries:
- Require a special charger
- Limited temperature range
Both battery types are very versatile but each type of battery has its pluses and minuses. AGM batteries are strong and durable making them perfect for use on a boat for an electric trolling motor. The main downside is that they are very heavy. AGM batteries also have a limited charge cycle life and only 50% of useable energy. Lithium batteries also have their strengths and weaknesses too. Lithium batteries are lightweight and have the ability to discharge up to 90% depth of discharge without risking battery life, which is something that AGM batteries cannot do. However, Lithium batteries are expensive and require a special charger.
Which battery is best for my Electric trolling motor?
As mentioned earlier in this article, AGM batteries are sturdy and durable. They can withstand the harshness of the marine environment and last for a long period of time. AGM batteries can be charged hundreds of times with little wear and tear on them. This means that they are perfect for use in a boat that will be used in rough conditions or at high speeds.
However, lithium batteries are great because they can discharge up to 90% depth of discharge and 3000 charge cycles without risking battery life. That is one thing that AGM batteries cannot do. If upfront cost is not an issue the lithium battery will win out over time.
Use a charger that matches the battery type for your electric trolling motor. Different types of batteries have different charge profiles and you should ensure that you use a charger that supports it. While most chargers work, if they don’t match your battery’s profile, your battery will not live up to its potential, have a shorter life, and may even be damaged
Will a Flooded Lead-Acid Battery Work for an Electric Trolling Motor?
a flooded lead-acid battery will work just fine in your boat, but there are some pluses and minuses that come with this type of battery. They are cheap and easy to maintain, which is great for the average user.
For clam water flooded lead-acid batteries are perfectly fine. However, one downside is that these batteries use liquid acid, which can spill in rough water or during travel to the lake. Another downside is that flooded lead-acid batteries only have a service life of 2 years before they need replacement.
If you go with flooded lead-acid batteries here are a few tips to maintain your battery.
- Don’t allow the fluid level in the battery to run low, check it before and after charging. Then add distilled water as needed, but never overfill.
- Make sure your battery is fully charged before storage and always store it in an area that is well ventilated. Keeping a trickle charger or battery maintainer will preserve your battery’s life.
- Check the battery with a hydrometer every month or two of use. There are kits with Hydrometers and acid to keep your battery at maximum performance.
Will a Gel Battery Work for an Electric Trolling Motor?
Gel batteries work well in boats that are used rarely because they store well. They also do extremely well in hot and cold weather. A gel battery can be charged over 500 times before needing replacement.
The downside to a gel battery is the cost, which is higher than flooded lead-acid batteries. Gel batteries also have a sensitive charge profile, so you must have a charger that is compatible.
Conclusion: AGM vs Lithium Battery for Trolling Motor
In conclusion, both AGM and lithium batteries are great battery choices. The main differences between the two are their weight, charge cycle life, depth of discharge, and price. Lithium batteries are the best long-term value, a great option if you live in a mild climate, and fish in average water conditions.
AGM batteries perform better in a wider range of temperatures and are very durable. however, serious drawbacks to AGM’s are battery weight, low number of charge cycles, and depth of discharge.
If you plan to fish many years to come a lithium battery will cost you less over the long term.