Batteries - Lithium and AGM

"Which batteries are available for my boat?" - You can easily find the right engine type and model for your boat in the categories. Here you will find almost all manufacturers and models available on the market for maritime application.

You are not sure which battery fits best to your electric boat motor? Give us a call or drop us a quick email! We have a selection of over 450 different e-drives and 100 batteries from over 20 manufacturers in our shop.

Which battery you need depends heavily on your usage and budget. Motor and sailing boats are usually powered by modern lithium batteries. Alternatively, AGM or lead batteries are also possible. However, these are more likely to be used on smaller boats or increasingly by anglers.

Outboard engines in the lower power range from 0.5 kW to 2 kW even have integrated lithium batteries. The batteries can be attached to the shaft by a click mechanism and supply the electric motor with power via a cable. This makes it very easy to transport the battery and motor separately and allows flexible use of exchangeable batteries. A similar model of ePropulsion is now also available for pod motors on sailing boats.

Batteries are available in all variants and capacities. You will find the most diverse forms from 0.1 kWh to 112 kWh in our shop. Upwards there are hardly any limits to the capacity. Depending on your requirements, you need about 0.5 kWh per tonne per hour in displacement mode, and exponentially more in gliding mode or above hull speed. The most important value for you is the usable capacity (kWh). This is calculated from voltage (V) times current (Ah). Example: 4.8 kWh = 48 V * 100 Ah. With a 95% dischargeable lithium battery and a 4.3 kW boat engine, you can run at full throttle for about one hour. With half-load already 2 hours and with 25% partial load over 4 hours.

Normally you should reach 70% of the hull speed with partial load and sail at a decent speed. Depending on the controls you have a display with information about speed, remaining range, current battery capacity, and values such as current or voltage. Often you get an additional display or have a display directly on the electric motor or the battery.

There are differences in the use of batteries on the boat for leisure and commercial use. For leisure use, the Torqeedo, ePropulsion and Aquamot models have the best conditions with an unbeatable price/performance ratio.

If you use your boat as a rental company or for other commercial purposes, we recommend using motors and batteries specially designed for this purpose. The same applies to frequent drivers who travel more than 50 times a year in terms of travel time and frequency. Batteries from Victron Energy or Aentron are ideally suited for this purpose.

Most boat owners are familiar with Torqeedo with the bright orange logo. Torqeedo has also developed battery systems especially for its motors and even works together with BMW.

The absolute top seller in the field of battery and charging technology is the company Victron Energy. The blue-orange boxes are known worldwide. Victron supplies both lithium and AGM batteries.

Most manufacturers also offer their batteries for the motors. These include the up-and-coming ePropulsion brand with a virtually unbeatable price/performance ratio for LiFePO4 batteries. RiPower and edyn offer Lithium batteries and Aquamot AGM batteries. Other manufacturers such as E-Tech, FMT, or Kräutler do not have their batteries and cooperate with specialized partners.

A big advantage of lithium batteries is the depth of discharge and the capacity per kWh / kg usable. Lithium batteries can usually be discharged to 95%. Depending on the technology, AGM batteries are already damaged from 50% discharge and should not be deeply or completely discharged.

Furthermore, a lithium battery weighs only a third of an AGM battery. Also, lithium batteries with up to 3000 cycles have a longer life compared to AGM batteries with mostly 750 cycles. LiFePO4 batteries can also be charged and discharged quickly without degrading performance. The only disadvantage is the higher price, which is significantly higher. The bottom line is that the advantages are clear for the lithium battery, especially when lifetime is taken into account.

Also important: AGM is not equal to AGM. Besides the conventional models, which can be used up to 50% discharge depth, there are several innovations on the market. Victron Energy is a pioneer in this field. Just like Aquamot, Victron Deep Cycle AGMs can be discharged up to 80% without being damaged. In this area, AGM batteries will become much more interesting. In the meantime, Victron Energy has even developed Super Cycle AGM batteries that can be discharged up to 100% and then recharged only after 2 hours and still work perfectly. Of course, the charging cycles are less than when discharging up to 50%, but this is good security for the individual case.

Depending on how fit you are in handling batteries, we recommend ready-made solutions or at least individual components. Ready-made systems are usually easy to connect via Plug & Play. However, you can save a few euros if you do the cabling yourself or do not use a protective plug but connect the poles directly to the cable.

If you have any questions about the installation, let us know at any time. We will be happy to help you in every detail or help you via telephone, e-mail, and video chat wherever possible. Otherwise, you will find all the necessary information in the descriptions of the manufacturers.

In the high-voltage range for motors from 15 kW upwards, the installation must necessarily be carried out by a master electrician. If possible, we rather recommend motors in the low voltage range. This also simplifies the connection of the on-board electrical system and increases safety.