LA-Lithium Battery Transition - An Alternative Solution

[CaptainRivet]

Originally Posted by s/v Jedi

Downstream? I compare electric with water streams now and then, but what you describe here defies laws of nature (electricity is not subject to gravity)

The Smart Orion dc-dc converters/chargers are actually smart and can detect a spinning alternator. You want the dc-dc converter to start charging the lfp from alternator power immediately in order to reduce charging time, reduce engine run time and increase engine load. The alternator regulator, with it’s alternator-mounted temperature sensor regulates alternator output to prevent overheating.

LFP does not work well for start batteries; the idea you describe with a lfp battery in parallel with a super capacitor will lead to a short lifespan of the lfp. The reason is that lfp does not like to be fully charged. The reason I use AGM is that it loves to be fully charged

AGM ran dry when overcharged and get a runaway. tossed 3 out of my cars and on my last ketch too...unsafeset chemistry for me after Lion....AGM is not tolerant to charging faults at all and well death of a battery is in 95% a charging fault. I hate AGM, only bad experience with them...
small area between fully charged and overcharged.
use 6 LTO 40AH yinlong cells in 1p6S, no BMS NEEDED as starter if you wanna have the best available.
they are better and last longer then super capacitors. you cannot overcharge them as their overcharge limit is above 20V, even if your regulator breaks no problem. using them since 15 years in multiple cars incl. 7lV8 engines and the 5lV10 diesel...
you can multiple times cranck without waiting 3-5 sec like with the supercapacitor...sometimes you simply don't have the time eg when the anchor drags and the diesel won't start...
if not use FLA hybrid starter/house batteries as starter, I have very good experience with the Fiamm power cube EHD which are commercial grade starter batteries for cooling trucks. You can refill them when overcharged and gased out, they can deliver high cracking amps for longer them normal starter batteries and can be also discharged to 50%, so they work well as emergency backup for LifePo4 too. and they are cheaper then equivalent AGM.

there exists nothing like a maintenance free battery. you have to always manually control your batteries doesn't matter if LFP, FLA, AGM, LTO,GEL or whatever chemistry you have. even the best BMS on a LFP cannot cover all use cases and having a automatic cut off will always cut off several times where there is no insidence.
there is no replacement for knowing your system well, regularly check them yourself and adjust the pre-warings over time along the way. automatic switch over or cut off are worse then you don't know the condition before and how it arise...better a prewarning a bit earlier and do the switch over yourself if you cannot eliminate the issue manually yourself.
And a manual top balance of Your LFP bank once a year when on Shorepower won't hurt the bank....
and if you have a seasonal boat or because of any other reason leave the boat for longer, charge LFP to aarox 40% and completely disconnect it. then run your boats electric of a good quality FLA Hybrid. the Shorepower keeps it charged and well if there is an incident where Shorepower gets cut for a long time and solar cannot keep it alive its a cheap FLA that's dead and if the Shorepower comes up again and tries to charge a dead FLA nothing happens, a AGM gets a runaway...

[CaptainRivet]

well exactly that happened during covid on my pier in Mallorca where due to nobody was on Bord and due to building works they cut the Shorepower for 3 weeks without giving notice...result 6 motor yachts with LFP banks, 4 newly installed short before where dead, damage 140kEuro. one of them catches fire due to a AGM runaway of the starter bank used as emergency bank.

[goboatingnow]

Originally Posted by CaptainRivet

well exactly that happened during covid on my pier in Mallorca where due to nobody was on Bord and due to building works they cut the Shorepower for 3 weeks without giving notice...result 6 motor yachts with LFP banks, 4 newly installed short before where dead, damage 140kEuro. one of them catches fire due to a AGM runaway of the starter bank used as emergency bank.

Did the AGM engage automatically , if so , bad idea.

Don’t see how LFP was discharged to damage levels the BMS should disconnect

As I said many times on disconnection no charge sources should be automatically reconnected

Again I don’t see how the Mallorca experience occurred unless there was very poor installations

[s/v Jedi]

Depending on shore power is mind blowing.

There are many stories about dead LFP batteries after charge sources fail and BMS self-consumption kills the battery it is supposed to protect. Not very smart BMS’s imo.

[goboatingnow]

Originally Posted by s/v Jedi

Depending on shore power is mind blowing.



There are many stories about dead LFP batteries after charge sources fail and BMS self-consumption kills the battery it is supposed to protect. Not very smart BMS’s imo.

Agreed but the more boats I see the more bizarre the systems get often led by owners with very poor understanding of what they have installed.

[s/v Jedi]

Originally Posted by goboatingnow

Agreed but the more boats I see the more bizarre the systems get often led by owners with very poor understanding of what they have installed.

Exactly. I find that Victron doesn’t have good fitting diagrams for blue water cruisers (vans, grid connected systems etc. are the huge market for them I guess) so by creating a couple for the best option for some of the most common scenarios, I try to guide it in the right direction.

Many people use it for that purpose, but then there’s many who immediately want to change it to their ideas even when they do not have the knowhow to be able to do this properly. I also find there is no way to convince them of anything differing from their dream setup

[goboatingnow]

Originally Posted by s/v Jedi

Exactly. I find that Victron doesn’t have good fitting diagrams for blue water cruisers (vans, grid connected systems etc. are the huge market for them I guess) so by creating a couple for the best option for some of the most common scenarios, I try to guide it in the right direction.



Many people use it for that purpose, but then there’s many who immediately want to change it to their ideas even when they do not have the knowhow to be able to do this properly. I also find there is no way to convince them of anything differing from their dream setup

I agree with you Nick the solution is you and I should be given worldwide absolute authority !!! [emoji5]

[Melbourne Park]

Originally Posted by s/v Jedi

Depending on shore power is mind blowing.

There are many stories about dead LFP batteries after charge sources fail and BMS self-consumption kills the battery it is supposed to protect. Not very smart BMS’s imo.

Yes. As far as lead acid batteries go, if their charge sources fail, they also loose much of their capability. And even if they will not be declared "dead", it's not fun when that happens.