Last week we had a question, which turns up regularly in the interactions we have with friends and followers.

Why would you want lithium batteries, aren’t they more expensive?

Battery talk is one of the favourite topics for avid cruisers and as I usually just listen, I have been able to gauge a few strands of knowledge along the way… not at all an expert though, so this blog will simply answer in a basic way the questions we received.

Nearly a year ago now we replaced 8 Lifeline Absorbent Glass Matt (AGM) batteries with 2 Lithium Iron Phosphate (LiFePO4) batteries on Impi.  At the moment we are doing a bit of an evaluation of the system with the help of Jack Peters, Outback Marine, Southport.

So this blog will explore the basic differences between AGM and LiFePO4 batteries, more in particular the batteries as sold by EV Power on the West Coast of Australia. It is aimed at people with little knowledge of batteries and is not trying to educate electronics engineers!

Let’s take a hypothetical case of a boat where the owners want to have 300 ampere hours (Ah) per day available to use.

In theory a 300 Ah battery pack can deliver 300 amperes (amps or A) for 1 hour or 10 amps for 30 hours.  In practice however if you let an AGM battery discharge to more than 50%, the number of cycles expected in the life cycle of the battery, reduces.  It is even better to stay over 60% meaning that you can utilize 40% of the total capacity before recharging. For full article click here