Modifying SO45 electrical system to accept Lithium batteries

[jasont]

Hi,

I apologise if this is an old topic, I had a look around the forum and couldn’t really find what I was looking for.


I have recently bought a 3 cabin 2005 SO45 which was pretty much standard as from the factory. I would like to upgrade my domestic batteries to Lithium however I want to ensure I do it properly.


The yacht has a Bow Thruster, Windlass, Electric halyard winch, a 60amp Victron battery charger and I have just fitted 150amp solar panel with Victron smart MPPT regulator.


Would anybody have a wiring schematic or a description for a similar installation using Lithium batteries they could send me or point me in the direction of it would be most appreciated?

I plan to keep the lead acid batteries for the bow thruster and the engine start and replace the domestic batteries with Lithium Ion which should improve my capacity. I will probably also continue to use Victron equipment as I like their WiFi BMS.


I am unsure how the factory split charging arrangement works with the current assumed 3 separate circuits Engine, Bow thruster, domestic which I assume is via some sort of split diode device? The Victron mains charger also appears to feed 3 separate charging circuits via monitoring shunts, it looks quite old and doesn’t appear to be configurable for lithium.

Suggestions please for:-
• How best to add a batter to battery (B2B) charger for the lithium to the existing system?

• Should I retain the existing split charger and connect the B2B charger to it or direct to the start battery / alternator?

• Should I also replace the factory split charger and use a B2B charger for the bow thruster batteries?

• Are lithium battery suitable for the Halyard winch & anchor windlass or should these be fed from Lead-acid batteries due to the type of load?

• Is the windlass fed from the engine start battery or domestic?


On my previous boat I connected the B2B chargers to the start battery and set them to kick in once the start battery had been charged I then connected the windlass and thruster to the lead acid bow battery bank. This appeared to work well as the B2B chargers fooled the standard alternator into producing more charge for longer than it would have done without it. I also connected the shore battery charger to the Start battery only and this then charged all the various batteries at the correct voltages etc via their B2B chargers.


Many Thanks
 Jason

[moonshadow]

This is a bit out of my knowledge base but I’ve also been researching it. Even though the LiFePo batteries are really in pretty common use now it seems many insurance companies still require these installations to be done by professionals.
But, that said, I upgraded my alternator, belts, regulator etc to be able to safely provide the fast charging profiles needed.

[svejk]

Having gone through this the first step would be determining if your charger/alternator are capable of supporting lithium profiles.  Lithium have very little internal resistance and can quickly burn up a standard regulator.  Using lead acid charge voltages on a lithium can really spoil your day.  I love the Victron line -  I have the Multiplus 3k for a charger intervter and an Orion-TR for my DC-DC charger.

I would not/not put lithium on your bow thrusters and winches.  These can draw a considerable amount of current all at once and the spike will likely shut down the lithium battery management system (BMS).  My windlass is fed from my engine battery and only used when the engine is running.

As Moonshadow has stated, insurance companies are more accepting of LifePO4 batteries onboard now but if you're going to install them yourself you may want to check first.

Lastly, I would stick with a name brand LifePO4 with a warranty (e.g. RELiON, Dakota Lithium).  Amazon may seem an affordable alternative right up until the fire department arrives.  There's too great a chance you'll be getting a counterfeit knockoff.

[captbillh]

I installed 3 RB100 Lithium batteries to replace the 4 AGM Lifeline grp 31s. I kept the bow thrust and engine batteries alone. I used 2 Orion 30 A mp B2Bs connected to the starter battery. I used an aluminum plate behind them and starboard 1/2" shims to space them out since the fins reach 140 d F. I also have a Victron BMS and Smart Battery Sensors on the alternator and the bow thruster motor for temperature and voltage monitoring. I installed a switch on the engine blower to manually energize it since it can pull from the compartment (behind the battery switches along with the original charger and the battery isolator) where the Orions are installed. There are 2 grooves which I enlarged under the mattress shelve above the battery switches.
I fused everything as by ABYC guidelines.

[slo0079]

Jun 5, 2023 12:31:26 GMT jasont said:

I am unsure how the factory split charging arrangement works with the current assumed 3 separate circuits Engine, Bow thruster, domestic which I assume is via some sort of split diode device? The Victron mains charger also appears to feed 3 separate charging circuits via monitoring shunts, it looks quite old and doesn’t appear to be configurable for lithium.

Suggestions please for:-
• How best to add a batter to battery (B2B) charger for the lithium to the existing system?

• Should I retain the existing split charger and connect the B2B charger to it or direct to the start battery / alternator?

• Should I also replace the factory split charger and use a B2B charger for the bow thruster batteries?

• Are lithium battery suitable for the Halyard winch & anchor windlass or should these be fed from Lead-acid batteries due to the type of load?

• Is the windlass fed from the engine start battery or domestic?

I have a 2008 SO45DS and installed LiFePO4 in my boat (with the assistance of an electrician, for insurance purposes).

I used 4x these batteries to provide 400 Ah of LiFePo4. I did this for two reasons: use same cables, they provide equivalent energy to previous 4x130Ah Gel batteries (in reality the new set provides far more since one can use 100% capacity). In retrospect, I should have used 1x or 2x their 410 Ah batteries; but I didn't want to blow the piggy bank.

To charge the batteries, I use the Solar MPPT set to lithium. This works very well.

Alternatively, the existing Hitachi 80 A alternator does a decent job. Mine is fitted with an alternator controller ("Sterling alternator to battery 80A" model) which keeps it from burning out by supplying excessive current. In reality, I found the alternator only provides 30-40 A so is never overwhelmed. My controller has a temperature sensor but it's clear if it's doing anything. I'm considering replacing the alternator with a smart 100A model in 2024.

The antique Cristec 60A shore power (3x output) is set to lead acid with boost turned OFF. This provides similar voltages to what the lithium set wants so works ok. Replacing with a new unit wouldn't necessarily help since the other batteries are agm.

Finally, the main issue I had after the upgrade is lifting the anchor. The factory installed Cristec split battery isolator always sends power to the lithium bank, unless the latter is full and declines all input (the built-in BMS does this). This made our windlass very slow and unhappy and it tripped a few times due to low voltage (since it's powered by the motor start battery). The solution is either replace the unit with a charger from the motor start battery and turn it OFF when using the windlass (most people do this); or, as I'm planning, simply install a switch in the output from the battery isolator to the main bank. This is far cheaper and maintains the full charging capacity of the alternator to the main bank.

I also installed a shunt with the new lifepop4 batteries so I can keep track of everything. It turns out our fridge and freezer are using far too much power and are the next target for some sort of upgrade.

Note the typical lifepo4 batteries are limited in output to c. 100a so are not good to use for the windlass or bow trusters. The 300A model (brand I linked above) can supply up to 150A but be carefull on the wiring specs, distance, etc.

[jasont]

Sept 9, 2023 13:51:09 GMT slo0079 said:

Jun 5, 2023 12:31:26 GMT jasont said:

Many thanks for your response, not surprisingly your setup sounds similar to what I want to achieve.


I am interested that you have retained the CRISTEC charge splitter, I have what I think is a Sterling diode charge splitter which I suspect isn’t as smart as your unit. Are you charging the AGM batteries with the same voltages and charge characteristics as the Lithium?


Since I first posted in June I have been doing more research and was thinking of removing the diode splitter and connecting the alternator direct to the engine battery, then adding a 30amp VICTRON battey to battery (B2B) charger from the engine battery to the Lithium (300-500amps) and another 18amp B2B unit to the bow thruster AGM batteries. I was also planning on initially retaining the standard 80amp alternator and limiting the B2B’s so they don’t overstress the alternator (30+18/80amps =60%) and I don’t have to upgrade the cable sizes, I may upgrade the alternator in the future. I was also planning on disconnecting 2 of the 3 old mains charger outputs and only feed the start battery so the charge still goes through the B2B’s.


I was also thinking that connecting the alternator direct to the start battery and configuring the B2B’s to disconnect when the voltage drops so that when using the windlass the full power goes to the start battery, and then when the load is off and the voltage rises sufficiently the B2B’s cut back in.

[slo0079]

I've been tempted to replace the alternator with a bigger model (Balmar XT-170), but that requires upgrading the belts to serpentine and adding a new controller (wakespeed or similar); thus, binning the Sterling AtoB 80Amp device. The Cristec isolator is too small so would need a new solution (likely a Blue Sea smart charging relay or Victron Cyrix). This setup would fix the supply issues we have with the windlass not getting enough power (as the isolator sends the powert to the LFP service bank instead) and quickly charge up the service LFP bank. It would probably save the AGMs we have onboard which are not getting the right charging voltage and, I suspect, suffering damage.

The issue with solution above is cost: c. $2500. Programming the wakespeed and finding a competent electrician would be challenging.


Alternative option would be to replace the 2x 245w solar panels on the arch with bigger and more efficient panels (60-70 Amp supply instead of 30 Amp); wire the windlass from the bow battery, add a smart charging relay from the service bank to the motor start and a DC DC charger to keep the bow battery full. Now the Hitachi 80A (really only 30-35A ouput) alternator only needs to supply the motor start battery and a smart charging relay sends excess supply to the LFP. I would keep the Sterling AtoB due to its temperature sensor to prevent the alternator from burning up. New solar panels would need a larger mppt and a new SS316 base to hold them.

This option would cost c. $1000-1500. The arch work could be challenging since it involves working 5m up high in the air and I suspect the crew is going to want to take apart the existing setup to make their life easier which adds on cost!


Final option under consideration is to install a switch between the Cristec isolator and the LFP. Whenever I use the windlass, turning switch off would ensure all alternator output goes to motor start battery. However, we find the supply is too small for the needs of the 12v 1000w windlass if the motor start battery is not full. For reasons unknown, our motor start battery keeps losing voltage (it's brand new!). To resolve this, I would rewire the windlass from the BT battery and add a Cyrix device from the LFP to the motor start battery. The ensures the windlass is using nearby power supply and the motor start battery is replenished from the LFP (no more voltage drop issues).

This option would cost very little, say $100. However, it doesn't solve my power supply shortage. I would probably have to buy a Honda portable generator to run my water maker ($1500).

[petros42]

A mix of Lead and Lithium is also possible.  Check out these youtube videos:   and their latest:  

Somewhere, I don't know where, I saw a vendor that has a device that will equalize the Lead with the Lithium to avoid large currents when they are initially connected.

I haven't done any of this yet ... but I'm intrigued.