With lithium do we actually need a dedicated starter battery?

[CaptainRivet]

Originally Posted by JBP

One of the first rules of seamanship is to always have a backup plan. Having two separate battery systems may have been a good idea since starting batteries and deep cycle batteries were different construction. A single LFP system can now do both, but now what is your backup plan? It might be to keep two battery systems, but for some people it might be fine to rely on a different backup plan. It might be call Tow Boat US, they are pretty pervasive in popular boating areas. It might be to carry an emergency starter pack if it can do the job. For some, the backup plan might be to anchor while the solar does it's Job.

Did you read my post?
Obviously not as i suggest to have a buffer battery as backup plan that creates actually a 2nd battery system used to isolate the spike from starter, windlass, power whinches... from the senstive nav electronics but that can also start the engine in emergency.
Not needed for costal boats due to reliability of LFP but definitely needed on bluewater cruisers...and having lead or lfp isolate your sensitive electronics is a good idea anyhow...i have it doubled by an galvanically isolated DC2DC converter 12/12/30A which keeps the buffer battery charged.

That jumper packs are mostly the Li-ion devil chemistry that should be avoided. Well we all have them already with power tools onboard as all of them are Li-ion

[rslifkin]

Originally Posted by CaptainRivet

Did you read my post?
Obviously not as i suggest to have a buffer battery as backup plan that creates actually a 2nd battery system used to isolate the spike from starter, windlass, power whinches... from the senstive nav electronics but that can also start the engine in emergency.
Not needed for costal boats due to reliability of LFP but definitely needed on bluewater cruisers...and having lead or lfp isolate your sensitive electronics is a good idea anyhow...i have it doubled by an galvanically isolated DC2DC converter 12/12/30A which keeps the buffer battery charged.

That jumper packs are mostly the Li-ion devil chemistry that should be avoided. Well we all have them already with power tools onboard as all of them are Li-ion

I did. However, on a coastal boat, knowing that the engine will always start and run with no electrical concerns when you turn the key is probably more important than on a bluewater boat. Bluewater puts you further from help, but coastal settings are where you're more likely to need the engine on short notice, or be in a situation where an electrical issue causing an engine stall would be dangerous.

[CaptainRivet]

Originally Posted by catsketcher

A couple pf points from someone who doesn't have a start battery (I have outboards that take very little starter current)

I think Nigel Calder and others sometimes recommend having lead acid as a starter because of the way Lithium BMS monitors will turn off the whole system if they get over voltage. So you can be going along charging your batteries and then, next thing you know everything powered by batteries is dead as the BMS turns off the Lithium battery to protect it from too high a voltage. This is supposed to fry the alternator because of the switch (same as when you switch to off with engine running IIRC). So you either need a smart alternator or a lead acid protecting the lithiums.

Cycling is also not a thing that is 300 cycles or so. The number of cycles from a lead acid is dependent on the number of cycles and the depth. Because starter batteries get so lightly discharged they have many more cycles than normal. Battery manufacturers can give you this data too.

Ask this question over at Nigel Calder's channel - he will be better able to answer it than me.

Wow so much wrong info. An alternator that delivers to high voltage in worst case the chargebus gets cuts off by bms and the lithium is still there and connected and deliver power. 2nd the BMS gets not destroyed by that.
The alternator has a surge protector connected if the LFP install is done right. But before that its regulator should have been turned off as battery is full. In worst case the diodes of alternator gets destroyed and its not working anymore....all nothing to do with having a dedicated starter or not bying it lead but nothing else then a poor install.
Yes a hybrid LFP bank needs
A) argofet aplitting diode with AGM or LTO buffer!! battery as surge protector. Where the starter is connected doesn't matter, its connected to hybrid and only in emergency via switch to buffer. The 2nd battery is used as buffer and not as dead sitting around starter waiting to be used.
B) regulated alternator, that can be the newer 115A mitzi/125AH Valeo with internal temp protection that are regulated with a VSR200 Nordkyn or classic external regulation via Balmar, walkespeed or alike regulators.

Instead a lead acid to prorect the alternator in the argofet/ starter setup you can also use an LTO.

[CaptainRivet]

Originally Posted by rslifkin

I did. However, on a coastal boat, knowing that the engine will always start and run with no electrical concerns when you turn the key is probably more important than on a bluewater boat. Bluewater puts you further from help, but coastal settings are where you're more likely to need the engine on short notice, or be in a situation where an electrical issue causing an engine stall would be dangerous.

Bluewater cruisers stay 90% at anchor...for sure not in the middle of the ocean.
But on a remote island with no supply or even inhabitants. Plus they have a lot of navigational equipement, often triple backup. Makes sense to protect that better as this will cost more then your engine...well and in emergency you can use this buffer to start the engine.

On mostly small coastal cruisers space is premium and they normally are in areas they know well and know well which tow service to call. Plus they stay mostly in marina or on a mooring ball.
Its just the tradeoff to have more complexity in your system and need more space for install..for me not equal to the gains you get here.
These coastal boats mostly have very limited power needs anyhow, often not even a plotter. A hybrid that runs all is very simple to install.

[Rohan]

Originally Posted by rslifkin

Batteries also last a long time when their only job is to start an engine and then get topped off again. My AGM start batteries are now 6 years old and doing just fine. They never get meaningfully drained and live a generally very easy life.

My AGMs lasted 13 years before I had to replace them. And then only one went out, but I decided to replace both anyway. They were installed by the previous owner and possibly lightly used, I don't know - but I still got heavy use out of them for four years after I purchased the boat.


Since most (if not all??) alternators are designed to work solely with LA batteries you need a work around to use them safely with lithium.

I prefer to keep things simple. I just keep a dedicated LA battery as my start, and that one is topped off with the alternator. I have a separate robust bank of lithium batteries for my house bank which is topped off with solar, and I can also use that for starting the engine if I absolutely have to.

[CaptainRivet]

Originally Posted by wholybee

You can go in circles forever with arguments like that. They just don't follow logic. Following your argument, if the SOC meter fails, and the solar controller fails, the alternator would still charge the LFP and keep the boat running.
Lead Acid batteries are far far more likely to have a problem than an LFP. By an order of magnitude, at least. They are more likely to fail than the SOC meter, or the solar controllers. So, the more reliable system is to remove the less reliable component. To really make the system reliable, you would also look at all single points of failure, and add redundancy there. A separate solar controller for each panel for example. A second alternator, or carry a spare, or have a generator on board as a backup. But no matter how you do it, throwing a Lead Acid starting battery in the mix will bring overall reliability down, not up. And a Lead Acid battery certainly isn't going to help in any way if a solar controller fails.

Fully agree on that.
My aim is yes for bluewater cruisers and whoever wants that redundancy i need a 2nd battery backup system for redundancy that is also able to emergency start the engine but how can i make the most use of this.
A starter battery being it lead or Lithium sitting dead around and waiting to be used is not a great value and i only figure out if it works at the moment of truth when i start the engine and need it! Bad timing if its not working then...
So how to make this better with mantra "my engine must always start"

So i came to the conclusion and idea its best to start from house and that this 2nd battery is best used as buffer battery to a) optimize voltage drop and b) be able to run only nav eletronics if rest of electric is dead c) isolate the senstive nav electronics from all the spikes and distortions. This is getting even more important as manufacturers like raymarine and B&G lately massivly saving on the input filtering on their devices so spike will kill your radar or chartplotter more easliy...told to me by several repair shops for these equipment and you can easliy see yourself if you take an old c70 plotter and a new axiom and just look at its power supply... or even worth the Quantum radars.
D) used as buffer the battery is automatically always full but in use and under load (eg in my case deliver the peaks of my 600W stereo amplifier requests to sound good or loud on a boat party;-)) means i know it works when i need it in the moment of truth starting my engine because hybrid failed due to whatever reason.

And lithium gives you the opportunity to use a small 20(LTO)-40AH battery (eg Winston) as buffer that can also start your engine in emergency. I personally would use only Winston or LTO here, best is just good enough and small capacity means they are at approx afforable 250Euro...but you can use any LFP starter battery from eg cars you trust too. Lead is excluded because that buffer sits inside at navstation or close to it as possible.
If you have 70ft with 150hp yes you will need to scale that concept up and use a bigger buffer. But majority here have 35 till 60ft and that should fit.

[CaptainRivet]

Originally Posted by Rohan

My AGMs lasted 13 years before I had to replace them. And then only one went out, but I decided to replace both anyway. They were installed by the previous owner and possibly lightly used, I don't know - but I still got heavy use out of them for four years after I purchased the boat.


Since most (if not all??) alternators are designed to work solely with LA batteries you need a work around to use them safely with lithium.

I prefer to keep things simple. I just keep a dedicated LA battery as my start, and that one is topped off with the alternator. I have a separate robust bank of lithium batteries for my house bank which is topped off with solar, and I can also use that for starting the engine if I absolutely have to.

Nope all newer yanmars, volvos, betas and many more with serpentine belt have an alternator ( mostly the 115A mitzi or 125A Valeo )that has a working internal temp protection can directly charge lithium. And thats getting more and more due to refits...

But yes there is a huge number of boats out there with total dumb car alternators up to 80A (which can deliver max 30-40A and V-belt drive that need a solution.
For the small coastal cruiser with very small energy need and little till no nav electronics and this setup its an economical solution to use DC2DC with a dedicated lead starter.
For the rest you can still use the buffer concept and start from the house and use the lead as buffer instead start battery. Yes it must be in engine room and you loose the advantage of voltage drop reduction but still have all the other.

Or get rid of your useless alternator and use the serpentine conversion kit plus mount the 115A or 125A (as remanfactured they are 250Euro), thats a 500-600Euro invest to get reliable constant 80A charge directly to lithium which everyone can buy, works out of box also with Volvo D+ and everyone can fit themselves who does maintenance on his engine.

[Rohan]

Originally Posted by CaptainRivet

For the small coastal cruiser with very small energy need and little till no nav electronics and this setup its an economical solution to use DC2DC with a dedicated lead starter.

Even that gets a little complicated for me. I don't have a DC-DC connector, I simply flip the battery selector to the start battery when I use the engine, flip it to house when I anchor.

Or get rid of your useless alternator and use the serpentine conversion kit plus mount the 115A or 125A (as remanfactured they are 250Euro), thats a 500-600Euro invest to get reliable constant 80A charge directly to lithium which everyone can buy, works out of box also with Volvo D+ and everyone can fit themselves who does maintenance on his engine.

That is a very tempting modification - but only if it's smaller or same size as my factory installed alternator, because there is no more room in the engine compartment for an alternator any larger than the current one. So I'm limited by that.

[CaptainRivet]

Originally Posted by Rohan

Even that gets a little complicated for me. I don't have a DC-DC connector, I simply flip the battery selector to the start battery when I use the engine, flip it to house when I anchor.





That is a very tempting modification - but only if it's smaller or same size as my factory installed alternator, because there is no more room in the engine compartment for an alternator any larger than the current one. So I'm limited by that.

What engine do you have with which alternator? Will 99% fit as its a standard case sized alternator and in the same position then older versions on eg volvos replacing the 60 or 80A Hitachi car alternator find on a lot other engines too. Volvos and yanmar even supply original serpentine conversation kits if not you find aftermarekt ones.
Can be done on every volvo, yanmar and many others.

[Pete7]

Originally Posted by CaptainRivet

Or get rid of your useless alternator and use the serpentine conversion kit plus mount the 115A or 125A (as remanfactured they are 250Euro), thats a 500-600Euro invest to get reliable constant 80A charge directly to lithium

Not quite. The serpentine belt option for my Volvo 2003 is $500 plus import duty from the US.

Then add the alternator at E250.

Then add the VSR200 Nordkyn $400 from NZ.

So that's $1500 or E1500 imported into Europe or the UK. Quite a bit of expense particularly if solar is the main charging resource as ours is. I chose to fit an OEM 100A alternator instead which generates 50A due to the pulley ratios but doesn't over heat even with prolonged use.

Pete

[CaptainRivet]

Originally Posted by Pete7

Not quite. The serpentine belt option for my Volvo 2003 is $500 plus import duty from the US.

Then add the alternator at E250.

Then add the VSR200 Nordkyn $400 from NZ.

So that's $1500 or E1500 imported into Europe or the UK. Quite a bit of expense particularly if solar is the main charging resource as ours is. I chose to fit an OEM 100A alternator instead which generates 50A due to the pulley ratios but doesn't over heat even with prolonged use.

Pete

You don't need the nordkyn to directly charge lifepo4. An 80Euro argofet 100A is enough with the lead as surge protector. But you need to change cables and connect the starter directly to LFP house or starter, the alternator goes via argofet onto LFP and lead. Standard volvo connects starter to alternator to starter battery and you need to change that. If the lead is near dead doesn't matter, it still works as surge protector.
Ok there should be cheaper options, for the old D2-55 i found a 300Euro kit dor my buddy boat. Plus 250alternator...
you right that conversion kits also.went up in price...the was 300 2years ago for the kit is now 420...sucks

[Donahue]

If you're going to remove your lead starter bank, make sure the BMS that you're relying on will allow you to crank the engine for much longer than a normal start--for example, if it's really cold or you need to bleed the engine--without going into shutdown/protect mode.

Due to some poor advice from a guy selling LFP batteries (and perhaps some bad math on my end) I removed my starter battery when installing an LFP bank that was spec'd with sufficient cranking amperage for my Perkins. It worked fine for a normal 2-3 second crank when I tested it the first couple of times. About two hours into a gulf stream crossing from Marathon to Bimini, however, the engine died due to a clogged filter and when I went to give her a bit longer crank to bleed the engine, the BMS shut things down and the boat went dark. Couldn't crank sufficiently to get the engine started without the BMS kicking in. Luckily the breeze was picking up and we had a great sail for the rest of the trip into Bimini and onto the dock. I eventually got the engine bled and running through a series of 2-3 second cranks followed by BMS shutdown and reset. I think this led to the premature death of one of the LFPs (replaced under warranty by the LFP seller who gave bad advice).

Eventually bought a $50 dollar starter battery for $250 dollars in Georgetown and installed a DC-DC charger. This has worked flawlessly for years.

[CaptainRivet]

Originally Posted by Donahue

If you're going to remove your lead starter bank, make sure the BMS that you're relying on will allow you to crank the engine for much longer than a normal start--for example, if it's really cold or you need to bleed the engine--without going into shutdown/protect mode.

Due to some poor advice from a guy selling LFP batteries (and perhaps some bad math on my end) I removed my starter battery when installing an LFP bank that was spec'd with sufficient cranking amperage for my Perkins. It worked fine for a normal 2-3 second crank when I tested it the first couple of times. About two hours into a gulf stream crossing from Marathon to Bimini, however, the engine died due to a clogged filter and when I went to give her a bit longer crank to bleed the engine, the BMS shut things down and the boat went dark. Couldn't crank sufficiently to get the engine started without the BMS kicking in. Luckily the breeze was picking up and we had a great sail for the rest of the trip into Bimini and onto the dock. I eventually got the engine bled and running through a series of 2-3 second cranks followed by BMS shutdown and reset. I think this led to the premature death of one of the LFPs (replaced under warranty by the LFP seller who gave bad advice).

Eventually bought a $50 dollar starter battery for $250 dollars in Georgetown and installed a DC-DC charger. This has worked flawlessly for years.

Thats a very good point for all boats and ALL installs. Doesn't matter if you start from house or you rely on your house as backup BUT if the house is not able to start your engine for because BMS is not able to handle the load then you made a mistake in the design of the system and must fix it! Not only by adding a starter as this one day will die and exactly then when you need the house to start.and as lead are unreliable murphy is waiting for that to happen.
My general advice on BMS;
For hybrid banks i would always use contactor and non current carrying BMS but NO mosfet BMS, my favorites here are eletrodacus BMS, REC BMS and TAO BMS.
If you use Mosfet BMS then the constant current capabilities must be equal to the surge current the starter can produce. For the typical JK,JBD.....use the following rule of thumb (back up by 10 years R&D of my buddy producing powerwalls and commercial RV): as example my favorite here JK 200A 2A active blanacer rated: use to spec your system constant current with 150A, 2 in parallel 300A, 3 in parallel 400A, 4 in parallel 500A. Means 4 BMS in parallel will handle 500A constant means crancking your engine for 30min because you got the diesel bug is possible.
Your starter will have 2-2.5time surge of constant use, so a 2000W starter uses 160-180A constant has 350-480A surge, so to start this savely for 30min you need min 3xJK BMS in parallel AND not 1 because its rated 200A constant and 400A peak!!!

My personal choice(!!!) in hybrid is i connect the starter and windlass with a breaker directly to the battery after the main battery fuse partly bypassing BMS (its after shunt so BMS knows and accounts for the load also in energy monitoring). I always know where SoC of my batteries are and cutoff is at 3.0V, so if BMS sends boat inyo dark (and the buffer battery still on and run the whole navigational equipemnt incl. Autopilot) i still have over 80 starts or cranking the engine for 45min till bank is at 2.5V. But i want to be able to make the choice and deep discharge the bank before boat is on the rocks. If i have time i switch to backup but if no i prefer to damage the bank before boat is on the rock. Nothing can happen here from security as your BMs won't allow charge then but discharging it below 2.5V will cause no fire and no other damage then bank might be dead. In case of starter or windlass malfunction or a cable short the breaker will trip, in case of a bank short the bank fuse will trip and won't allow me to use the starter or windlass so perfectly save to do this...accepted by surveyor and insurance as my install is approved like this.

[more]

what lithium/AGM/lead have with a dedicated starter battery for engine,nothing.house bank is only reserve if starter battery die.
and lithium starter batery is good backup for lead starter battery

[Pete7]

Originally Posted by CaptainRivet

You don't need the nordkyn to directly charge lifepo4. An 80Euro argofet 100A is enough with the lead as surge protector.

I would loose the BT monitoring of the Victron Orion and the ability to select a LFP profile and limit the charge voltage. Since its not the primary charging source the Orion is fine, it just works.