Our Lithium battery Installation ( 2024 Australia):
Contents:
A Do we need lithium?
B Charging?
C What type of battery?
D Capacity?
E Manufacturer
F Safety and Regulations
G Installation
I Conclusion and notes inc our wiring diagram
J Our typical electrical operating regime
K Major items we used
Before:
After :
Things we considered when replacing our batteries. Joline - 17 m Lagoon 570 catamaran 2024
A. Do we need lithium?
This is doubtful if you are marina based and the vessel spends most of its time plugged into the shore supply and used for weekends and short holidays. If you are a liveaboard then its a game changer due to:
Weight and Size Lithium are approximately 30% of the weight of a lead acid battery and half the size.
Faster charging Lithium charging time is typically half that of Lead acid. This is due to an almost constant internal resistance compared to a lead acid battery. A lithium battery will continue to absorb a constant high charging current right up to almost 100% capacity, where as a lead acid battery will increase its electrical resistance and hence the charging current will drop considerably before the battery is anywhere near full capacity.
Usable capacity A typical deep cycle lead acid battery, will have a practical usable capaicty of 40% of its total capacity where as a lithium battery will be 60 - 70% You can totally discharge a lithium battery but this will reduce its life. A good range to work a lithium battery would be 90% to 30% of its capacity.
Life Span If the manufactures are to be believed a lithium battery will last in the region of 2000 - 6000 complete cycles. Compared to lead acid batteries life of around 1000 cycles Time will tell.
B. Charging
Lithium batteries require charging at a constant voltage for the batteries we selected that is 14.4 V +/- 0.2 . Our existing charging devices were convertible by programing parameters from our deep cycle gel batteries to the constand voltage required by the lithium. Joline was fitted with one 1760ah house battery bank that was also used for engine starting. This was not ideal due to the very long starter cable lengths between the main house battery bank (Port Hull), and the starboard engine. We installed a dedicated engine start battery in both Port and Stdb engine room with short battery leads and an emergency interconnect between Port and Stbd should one battery fail. The next decision is how to charge the lithium house battery bank from the main engines. There is a lot of discussion about this. There are 2 main options.
i). Fit a DC to DC converter that once the voltage of the starter battery, which is charged from the engine alternator, goes above about 13.8 v, then it will take that 13.8v and step it up to 14.4 v and charge the lithium bank. ( See our electrical layout)
ii) The second option is to have an externally regulated engine alternator which is capable of charging at a constant voltage for lithium.
There are three considerations with this option:
How do you charge the engine start battery?
Will the external voltage regulator protect the alternator in the event of the BMS shutting down the batteries? If the battery BMS shuts down it will disconnect the battery much quicker than most voltage regulators can turn the alternor off and the alternator output could go over 100 v and destroy the alternator output diodes.
How do protect the alternator from overload? The lithium batteries will try and over load the alternator so the alternator voltage regulator must be able to keep the alternator within its designed loading and operating temperatures.
We decided to keep life simple and fit DC to DC converters and stay with our standard alternators especially as we try not to use our main engines and rely on our solar and diesel generator for charging.
C. What type of lithium battery?
All lithium batteries for marine market are now Lithium iron phosphate LiFePo4 , these are much safer and reliable than the first generation Lithium iron batteries.
All lithium batteries should have a Battery Management System ( BMS), this will ensure that the battery remains within its designed parameters. The BMS should protect from, High Voltage, Over Current, Low Voltage, High Temperature and Short Circuit. Some BMS s will also give a prewarning alarm before shut down. The BMS will shut down the battery if out side its parameters and hence black the boat out.
There are 2 types of batteries , Batteries with an internal BMS, (These are sometimes referred to as “drop in batteries”), and batteries with no internal BMS, so these need an external BMS often connected via a network.
We decided to purchase batteries with internal BMSs, ( Having 3 BMSs must be better than 1), with separate battery monitoring and voltage monitoring relays. We decided this for reliability having a BMS in each battery and then the external battery monitoring is not critical to operation. (See Joline electrical layout drawing.)
D. Capacity
What size of battery bank?
We are a 17m catamaran with Starlink, 2 fridges, 1 freezer plus a few lights this is roughly a base load 15 A at 13V approx 200 w . Assuming 16 hrs battery use is required then we will use approx 240 ah over a 16 hr period. Round this up to 300 ah. This is for the base load , but we can double this using other electrical appliances so we need around 600 ah. Hence if we use 50% of battery capacity then we need a 1200ah battery bank. If in doubt go large.
Arrangement:
Our logic was to use as few batteries as possible to reduce cabling and to keep things simple,so we selected 3 x 400 ah batteries with internal BMSs giving 1200ah total capacity. ( We were replacing 1730 ah of gel batteries)
E. Manufacturer:
Use a well know brand such as Victron, Mastervolt, Litime, Renogy, itech,VoltX just to name a few. As of 2024
F. Safety and regulations.
All batteries are a fire risk if over charged i.e. the charge voltage is too high. Both Lead acid and Lithium batteries could catch fire if subjected to over voltage , the difference with Lithium is that it is much harder to put out a lithium battery fire. Often a battery fire regardless of the battery type would be terminal to a small yacht. This applies to all rechargeable batteries, phone, laptop, e scooter / bike, hand tools, etc
Look up the local regulations
In my view regulations and best practices can generally be summed up as:
The Batteries must be installed and used as per the manufactures recommendations.
Lithium batteries should be protected so they stay within the manufactures specifications.
That is protected from Over Voltage, Over Current, Over discharge, Over temperature, Short circuit.
The most important of these parameters and the one that the regulators hone in on is over voltage. To ensure the batteries are protected and operated within the correct parameters the following is good practice.
All charging devices are correctly programed / adjusted to the correct charging voltages as per the battery manufactures specifications. (not to the standard settings of the manufactures of the charging device )
In the event of High voltage an audible and visual alarm activates before any shut down to warn We achieved this via Voltage sensing relay, (see last page)
At very high Voltage charging devices are deactivated or disconnected before the voltage reaches the manufactures maximum value We achieved this via a voltage sensing relay (see last page)
At any dangerously high voltage or any other dangerous parameter the battery must shut down.
G. Installation
Can I install myself?
Its not rocket science . For us, yes I am a marine engineer and have owned a marine engineering and several industrial manufacturing companies. I would say for a good proportion of mechanically minded yachtsmen and wowen its very possible. You will need a few special tools such as. Battery lug swaging machine, hot air gun for heat shrink, cable cutters, electrical crimpers, a muitimeter and possibly a cable chaser.
Get a professional to install.
If you dont feel confident and wish to employ a professional I hope this information will help you ask the appropriate questions and keep an eye on their work.
H. Reliability :
In our experience if it is electrical, is installed on a boat, has an IP address, sits on a network then it will at some some fail. Some question to either ask yourself or your installer:
What if a battery shuts down ? We have 2 others
How would we know if one battery fails? We have a remote monitor for each battery visible at the chart table.
What if a battery monitors fails? We have both a master monitor and a monitor for each battery
What happens if all our lithium batteries fail? We can start the diesel generator and the battery chargers will supply Joline with 14v or start one of the main engines and the DC to DC converter will supply Joline with 14v
What happens if our diesel generator fails? We have other charging sources, 2 main engines and 1200w of solar
What happens if a charging source fails and charges at too high a voltage? The audible and visual alarm activates we investigate and stop the charger, if we miss this then the charging source is shut down by the voltage monitoring relay, if this fails the batteries shut down and Joline goes dark..
I. Conclusions and Notes
The lithium batteries have been a bit of a game changer.
Our voltage is now far more stable and sits between 13.3 and 13.0 v when not charging regardless of capacity.
Having the lithium has dramatically reduced our diesel generator hours.
Joline is now 470 kg lighter and the batteries look a bit lost in battery compartment
Notes:
The standard lithium setting within all our Victron and Mastervolt units were not correct for our new batteries so we had to reprogram accordingly. These manufactures don't make it that easy from the information in their standard literature. It took a lot of internet research to find these. Victron were much easier.
Our static/ships battery charges ( 2 x 100A Units) are 6 meters away from the batteries which is not ideal due to the voltage drop in the cables. So we have to accept that these chargers will only charge at about 80A each due to the voltage drop. Maybe one day we will switch to battery sensed units.
You tube and the internet was a good source of information, but there is also a lot of misinformation out there.
J. Our typical daily electrical regime
At Anchour: When at anchor with plenty of sun and just us onboard we are just about self-sufficient using the solar panels only.
We only run the generator to make and heat hot water and run the washing machine which we do all at the same time.
Sailing: Ocean cruising 24 hours a day sailing with all electronics on, we tend to run the generator 30 minutes over breakfast , and one hour in the evening to top up everything for the night, and run the water-maker.
With guest coastal cruising: When we have guests onboard we often run the generator for 30 mins at breakfast while, coffee machine, toaster and kettle are on. We then run the generator for about an hour or so in the evening to make and heat water, run the ice machine , bread machine, microwave and top up batteries.
Our monitoring panels:
