With lithium do we actually need a dedicated starter battery?

[CaptainRivet]

Originally Posted by rslifkin

Needing a battery rated for 1400CCA isn't necessarily because the engine actually will draw 1400 amps when cranking. CCA is a measure of how much current you can draw for 30 seconds at 0* F before the battery drops below 7.2V during the test.

Because of that, CCA is generally not a concern if starting from a lithium battery, the concern is just whether you can handle the brief large inrush current when cranking starts and then the sustained starter current. Unless it's a very small battery voltage sag during cranking and the length of time it could support cranking for are unlikely to be limiting.

Exactly and if they used cheapest FLA for that test then you get crazy CCA numbers. And it also matters if the engine was at 0F for a week or an hour before the test….
That’s why simply calculate like above the current and add glow plug, specs for both you find in your engine manual or the parts catalog. That’s why it’s so much easier to start from LFP and spec the right LFP for it.

[Wandering1]

Originally Posted by CaptainRivet

Exactly and if they used cheapest FLA for that test then you get crazy CCA numbers. And it also matters if the engine was at 0F for a week or an hour before the test….
That’s why simply calculate like above the current and add glow plug, specs for both you find in your engine manual or the parts catalog. That’s why it’s so much easier to start from LFP and spec the right LFP for it.

That might be fine if you are starting from scratch with a new boat but for most people on this forum, converting the engine start to lithium is a lot of money for little gain. Unlike conversion of the house bank, where you gain massively.
A cheap FLA battery does the trick for me and I can't ever see myself changing anytime soon. I don't need to upgrade my alternator at £2000 a go either

[Pete7]

Originally Posted by CaptainRivet

With 18$ for basically new 20AH LTO Toshiba SCiB cell that can do 25C you can build a starter in 1p6S that has 20000 cycles and lasts >20 years for 108$…for the cost of a cheap FLA…there is not even the simple purchase price factor anymore to stay with lead.

So these are 2.4v per cell and 6 would give 14.4v when fully charged. However, much less if at 50% SOC.

Do you know anyone using these for starter batteries on a yacht?

Seems like most of the LTOs for sale are second hand which doesn't inspire confidence.

[rslifkin]

Originally Posted by CaptainRivet

Exactly and if they used cheapest FLA for that test then you get crazy CCA numbers. And it also matters if the engine was at 0F for a week or an hour before the test….
That’s why simply calculate like above the current and add glow plug, specs for both you find in your engine manual or the parts catalog. That’s why it’s so much easier to start from LFP and spec the right LFP for it.

The test isn't for the engine, it's for the battery. So it's battery at 0* F and a test of what it'll deliver. The engine manufacturer gives a CCA spec not based on any actual power draw, but based on the idea that a better with at least their recommended CCA will adequately crank the engine in all expected operating conditions.

[lifeofreilly57]

In my case I have a lithium house bank and a lead acid starter battery. The starter battery is charged by a DC to DC charger, it keeps it at optimum charge, which is what lead acid likes.
I also have a relay that allows me to use the house bank to start it if needed, so I'm covered both ways, the whole lot is kept charged by 1000 watts of panels.
If damaged the lead acid is cheap compared to my large lithium house bank.
On my previous boat the lead acid starter battery lasted 8 years in a similar set up, then only died because I had disconnected it while doing some winterizing on the boat, then forgot to reconnect it, it went flat over the winter.
Simple, cheap, effective.

[s/v Jedi]

Originally Posted by Fore and Aft

Jedi that is an interesting system and shows how our lifestyle has completely missed the modern bus. We still cook with gas at home and have no air-conditioning in the house. I can honestly say the only time I have eaten cold beans was in a cafe in Hong Kong and the language barrier made it to hard to get them heated.
I can see how your system is all part of the wave of new sailors that want and have everything onboard and consider any boat under 40 feet camping.
I still like the separate start battery as any luddite can go to the local store pick up a battery and install it. Knowing that as long as the alternator is working then this system is foolproof. That's why I think there is always going to be the die-hard AGM crowd who just want simplicity.
To be honest my eyes start glazing over reading what you and CaptainRivet have written.
Cheers

You are Dutch, like me, right? You better switch to electric because soon there’s no more gas in Holland

I had a Wibo 930 for 17 years… yes, it was camping. But many homes use induction cooking, I think in Holland most of them. Also, I consider myself the “old school” as I’m still a baby boomer

[Fuss]

Originally Posted by Pete7

So these are 2.4v per cell and 6 would give 14.4v when fully charged. However, much less if at 50% SOC.

Do you know anyone using these for starter batteries on a yacht?

Seems like most of the LTOs for sale are second hand which doesn't inspire confidence.

More than likely he doesn’t know someone using these LTO scib cells because there is something that makes them not as good as lifepo4, this is possibly that they do not work as well nominal voltage and capacity wise, making them not as compatible with existing chargers etc as lifepo4 is… otherwise they would be used in boats more often right.
Sure you can probably find someone making it work, but this is not rivet and the solution they have means that there is some sort of downside that means they are not ever going to be as popular as lifepo4 is at the moment.

[CaptainRivet]

Originally Posted by Wandering1

That might be fine if you are starting from scratch with a new boat but for most people on this forum, converting the engine start to lithium is a lot of money for little gain. Unlike conversion of the house bank, where you gain massively.
A cheap FLA battery does the trick for me and I can't ever see myself changing anytime soon. I don't need to upgrade my alternator at £2000 a go either

thats why you start from the LFP house and use eg an AGM as buffer if you need a lead as surge and resistance protection because you have a dumb alternator with lead regulator.
starter will work much smoother and lives longer starting from LFP house. Also the AGM will live much longer as buffer as its automatically always floated (what they like most) and also the load on it is very small.

[Wandering1]

Originally Posted by CaptainRivet

thats why you start from the LFP house and use eg an AGM as buffer if you need a lead as surge and resistance protection because you have a dumb alternator with lead regulator.
starter will work much smoother and lives longer starting from LFP house. Also the AGM will live much longer as buffer as its automatically always floated (what they like most) and also the load on it is very small.

So you are suggesting mixing lead and LFP?

[CaptainRivet]

Originally Posted by Fuss

More than likely he doesn’t know someone using these LTO scib cells because there is something that makes them not as good as lifepo4, this is possibly that they do not work as well nominal voltage and capacity wise, making them not as compatible with existing chargers etc as lifepo4 is… otherwise they would be used in boats more often right.
Sure you can probably find someone making it work, but this is not rivet and the solution they have means that there is some sort of downside that means they are not ever going to be as popular as lifepo4 is at the moment.

Again you have no glue what Toshiba LTO Scrib cells are, just as headline the are the holy grale of lithium and the state of the art cells beside Winston.


let me educate you:
they where originally developed by Toshiba to work as boast cells for Lifepo4 in EVs as in EV during acceleration you need high C-rates which Lifepo4 cannot deliver. you cannot use supercapcitors as the duration of accerlation is much longer them they can contain in AH. That was necessary as due to fire risks they needed to move away from Li-ion which have capacity and high c-rates but are unstable and can get runaway.
So the capacity and steady driving are covered by Lifepo4 while when you accelerate the current comes from the Toshiba with up to 25C !!! for the motor to spin up. finished accelerating the lifepo4 take over and also recharge the LTO. compared to Li-ion and Lifepo4 the LTO cannot get termal runaway, can be kept at any SOC as long as you want to (also floated) and can be balanced at any SOC. They are ultrastable, you can use 100% of capacity, deviation between cells is minimal and don't need a BMS and just a balancer to keep the pack running.
Voltage range is 1.6V till 2,8V but 85% of capacity is between 2,0 and 2,4V means 6x2.0V is 12V and 14,4V, so you can simply charge them in parallel with your Lifepo4 with the same settings (or with any lead settings) but compared to lifepo4 you can completly discharge them and also float at 2,8V...only way to destroy them is charging with >3,5V for longer duration but even then they don't catch fire or get a runaway...they just bloat and then stop working. they produce 3 types but only 2 are really avaliable...the combined type in 20AH which have 25C pulse for 10 sec straight (thats what you want) or 20 and 23AH high energy density type that only have 10C.

Why they are not widely used or exclusvly in EVs is very simple, they are very expensive (average 1,08$ per AH while lifepo4 at 0.2-0.4$ per AH) and heavy as energy density is close to lead. Additional limited production capacity, only Thosiba produce the LTO SCIB and has longtermed contracts with manufacturers. so they are not sold via reseller normally and only spec fitting cells are sold like winston. Due to EV crisis some manufacturer sold the overstock to resellers and you can get them for a huge bargain (far below production cost!)

they are the prefect starter battery as every start needs less then 1AH, so you don't need huge capacity but can deliver the surge a starter need easily.
you can keep/balance/float them at any SOC/voltage. 20AH 1p6S can handle a 2000W starter found on most leisure boats engine up to 75hp.
original they are white with toshiba logo and sold in ready assembled packs, the overstock sold to reseller take this pack appart, heatshrink and weld studs on, thats why is blue without branding.


batteryhookup bought a huge lot and selling them for 18$ per piece, trustworthy reseller.

[CaptainRivet]

Originally Posted by Wandering1

So you are suggesting mixing lead and LFP?

no not mixing as buffer you connect/charge them via isolated DC2DC converter or charger from the LFP but you can directly connect the alternator to the buffer and charge the buffer. but you don't connect the starter to the AGM.

or if you have a 115A Mitsubshi or 125A Valeo alternator that have an AGM regulator but internal temp protection you simply connect the alternator to an Argofet on one output LFP hybrid starter/house and on other the AGM buffer.
like this your sensitive electronics are galvanically isolated from the LFP so the starter on house doesn't matter and cannot do any harm.


and by the way you can bring your dumb 80A alternator with V-Belt just to the next alternator shop and let it modify for external regulation, normally in the 100Euro range. then you get a Balmar 614 or ars 5 mastervolt which is 350Euro and you get 50A save and regulated charge. So for 500Euro thats done.

A 30A DC2DC is 300 and not really protecting the alternator...just limiting the current but is that enough if motorsailing with low rpm on an exceptionally hot day??? plus you still need a lead...so costs are equal.

[ranger58sb]

Originally Posted by CaptainRivet

Yes 1p4S 180AH Winston or 200Ah to have some headroom will do that very long. Use a BMV712 as „BMS“ with relay outputs to do LVC and HVC plus a Neey 4A active balancer which also does the cell monitoring.

Thanks, I'll check that out.

I should have included in my first note that our banks are @24VDC and the two engine start banks are also house banks... so decent bank capacity, perhaps ideally ~300Ah or so) would also be a goal. The third bank is a combo inverter/thruster bank the "current/minutes" requirement, and ~400Ah capacity (for the inverter) would be nifty.

-Chris

[CaptainRivet]

Originally Posted by ranger58sb

Thanks, I'll check that out.

I should have included in my first note that our banks are @24VDC and the two engine start banks are also house banks... so decent bank capacity, perhaps ideally ~300Ah or so) would also be a goal. The third bank is a combo inverter/thruster bank the "current/minutes" requirement, and ~400Ah capacity (for the inverter) would be nifty.

-Chris

To clarify:
What boat do you have?
Motorboat or sailboat, both engine close or far like cat in different hulls?
You have two engines each need 560A surge capability to start in 24V, so both banks are in the rear, so on them is the whole house loads too, except inverter.
Inverter/bowtruster is in front I assume?
Your bowtruster can run on Lithium? Have a look in the manual or ask manufacturer as they are models that need the high resistance and voltage drop of a lead otherwise the motor burns out/shorts as current goes too high.

You have space for cells?
Because you have 2 ways:
1) simple, small space but expensive: winston cells can do 3C constant and 6C peak and come in all sizes till 1000Ah. Means you just make 2 engine banks with each 8x300AH cells and a bowtruster/inverter wit 8x400AH. Top notch rolce royce cells but each AH costs 1$, means 8x300AH=2400$ so 4800$ for starters and 3200 for bowtruster. Advantage 1p8S banks, small space and only need 3 contacter BMS, I suggest REC BMS

2) you get the AH for buck cells 304AH EVE which are 90Euro/cell can only do 1C means to fit yor starting requirements you would need to use 2x 1p8S banks per engine and also bowtruster/inverter. Gives you 600AH capacity per engine/house bank and also bowtruster/ inverter but only cost 16×90=1440Euro per bank, so 3x1440Euro and 3x600Ah@24V. But thats more space needed, more work as you need to build battery cases and you need 6 BMS.

As you are at 24V you cannot just use winston cells and battery monitor as 8 cells in series are not that stable anymore and you need a BMS. As all banks have motors with high surge loads you cannot use mosfet BMS as you will kill them over time with the surge...so you need contacter based BMS means which switches the loads and charge with relays and not with mosfets...would highly recommend REC BMS. Calculate with 1000Euro for first REC BMS and 500Euro per BMS additional ones

[Wandering1]

Originally Posted by CaptainRivet

To clarify:
What boat do you have?
Motorboat or sailboat, both engine close or far like cat in different hulls?
You have two engines each need 560A surge capability to start in 24V, so both banks are in the rear, so on them is the whole house loads too, except inverter.
Inverter/bowtruster is in front I assume?
Your bowtruster can run on Lithium? Have a look in the manual or ask manufacturer as they are models that need the high resistance and voltage drop of a lead otherwise the motor burns out/shorts as current goes too high.

You have space for cells?
Because you have 2 ways:
1) simple, small space but expensive: winston cells can do 3C constant and 6C peak and come in all sizes till 1000Ah. Means you just make 2 engine banks with each 8x300AH cells and a bowtruster/inverter wit 8x400AH. Top notch rolce royce cells but each AH costs 1$, means 8x300AH=2400$ so 4800$ for starters and 3200 for bowtruster. Advantage 1p8S banks, small space and only need 3 contacter BMS, I suggest REC BMS

2) you get the AH for buck cells 304AH EVE which are 90Euro/cell can only do 1C means to fit yor starting requirements you would need to use 2x 1p8S banks per engine and also bowtruster/inverter. Gives you 600AH capacity per engine/house bank and also bowtruster/ inverter but only cost 16×90=1440Euro per bank, so 3x1440Euro and 3x600Ah@24V. But thats more space needed, more work as you need to build battery cases and you need 6 BMS.

As you are at 24V you cannot just use winston cells and battery monitor as 8 cells in series are not that stable anymore and you need a BMS. As all banks have motors with high surge loads you cannot use mosfet BMS as you will kill them over time with the surge...so you need contacter based BMS means which switches the loads and charge with relays and not with mosfets...would highly recommend REC BMS. Calculate with 1000Euro for first REC BMS and 500Euro per BMS additional ones

Or stick with the 2x100Ah lead starter batteries that cost me €105 each and should last 5 years in the tropics and 7 or 8 in more temperate climate.
Your system looks bpvery expensive for little gain.
Our starter motor is 4kw so 16kw surge is possible.

[Thomas1985]

Depends how important starting the engine is in the event you drain the house batteries