Starting a big diesel with lifepo4

[SOLAR SUPPORT]

Originally Posted by Fuss

Thanks again for the very good input.
Ok, then if capacities of around 100AH the LTO are the only chemistry then I have some comments....


This then means that all these drop in Lifepo4 Starter batteries do not work long term ...for example Dakota 60ah 1400cca Lifepo4 will also not have a long life.


The LTO Yinlong 40AH provide a peak discharge of 400AH says the spec, so 12 in 2p6s is 800AH max, which is a long way from 1400 as the Dakota above have for specs. So the LTO equivalent would be 24 in 4p6s costing around 1500€ and taking quite a bit of space.


So maybe I should look at some solutions that make my 12v start batteries similar to my 24v Lifepo4 280ah house batteries.


I could for example make a 12v 280ah start battery from the same cell type as the house bank. The advantage would be that they are not as stressed as 100AH cells (as they are 280AH) but then comes the next uncertainty...these 280AH cells have no peak discharge specs and for long life they are supposed to be charged and discharged at around 0.5c. So would they really be better than the calb solution that you say will not work or would they be better than the Winston 90AH solution that some people say should be ok?

Can a 12 volt starter motor also work with 24 volts? If it works, the power and speed of the starter motor may increase. If this does not create a structural problem and your 24V Lifepo4 house batteries can transfer the initial power required to start your engine, it means you can start your engine with the house battery bank. It is necessary to research very well before trying this.

[CaptainRivet]

Originally Posted by Fuss

Thanks again for the very good input.
Ok, then if capacities of around 100AH the LTO are the only chemistry then I have some comments....


This then means that all these drop in Lifepo4 Starter batteries do not work long term ...for example Dakota 60ah 1400cca Lifepo4 will also not have a long life.


The LTO Yinlong 40AH provide a peak discharge of 400AH says the spec, so 12 in 2p6s is 800AH max, which is a long way from 1400 as the Dakota above have for specs. So the LTO equivalent would be 24 in 4p6s costing around 1500€ and taking quite a bit of space.


So maybe I should look at some solutions that make my 12v start batteries similar to my 24v Lifepo4 280ah house batteries.


I could for example make a 12v 280ah start battery from the same cell type as the house bank. The advantage would be that they are not as stressed as 100AH cells (as they are 280AH) but then comes the next uncertainty...these 280AH cells have no peak discharge specs and for long life they are supposed to be charged and discharged at around 0.5c. So would they really be better than the calb solution that you say will not work or would they be better than the Winston 90AH solution that some people say should be ok?

The LTO‘s in 2p6S will work as they keep their voltage up high with low internal resistance, if it’s a pure starter you can charge it to 16V, your starter will spin like windmill in a hurricane I can promise you that. Have a look at the post of wholybee here, he explained that and the LTO have much higher current delivery then LifePo4.

Very simple how much watt does your starter have? Have a look in your parts catalog, it’s standing there and we finally know how much power you really need.Deriving from the existing lead CCA requirements of lead what you need as starter current for Lithium is simply the wrong way.

You have 280AH cells as house, so they are BAsen or EVE cells?
I have 12x272AH Lishen or 840AH at 14,2V and it’s one bank that starter, house, windlass. All connected to it, the BB hull of my cat has 180AH lead starter and backup house, soon 2p6S LTO 40AH yinglong(problem is how I get them delivered to Canary Islands).
I have a 2000W starter on the D2-50F volvos, so startup surge first 30ms approx 500A, then going to 150A. Well inside the specs of Lishen 1C constant, 2C peak when having 840AH. My Electrodacus BMS carries no current, soo no problem with the BMS here.
As soon as we know the wattage of your starter, I can tell you how big your house of 280AH cells be to act as starter.

Measured that with my old lead…Startup was 800A at 8V for 30ms, then 250A. Voltage sag and peukert effect makes it not possible to deliver instantly high currents on lead. On the LTO that 2000W starter at 16V will have around 350A first 30ms, then 130A constant due to higher voltage of LTO.

Starter LifePo4 is a special topic, my experience is that they don‘t last long if pure LifePo4. Dakota states based on LifePo4 technology, means they are no pure LifePo4 but what’s inside? Maybe additional some supercapacitors inside that helps with the peak or another LifePo4 related chemistry as then they work well. Eg Winston are no LifePo4

[CaptainRivet]

Originally Posted by SOLAR SUPPORT

Can a 12 volt starter motor also work with 24 volts? If it works, the power and speed of the starter motor may increase. If this does not create a structural problem and your 24V Lifepo4 house batteries can transfer the initial power required to start your engine, it means you can start your engine with the house battery bank. It is necessary to research very well before trying this.

No a 12V starter works till approx 16V.
In that case buy a 24V starter, as this also helps with startup current. Starters are not expensive and because most engines are marinised if you know what’s your original engine is, you get starter much cheaper as this is an original part.
Eg the Volvo D2-50 is a Perkins engine and the starters are identical, the Perkins starter cost 200Euro…

@Fuss: how much wattage does your starter have, you find that on the spec sheet of your engine or in the parts catalog.
That’s the info we need, how much CCA your current lead starter has are irrelevant.

[Fuss]

Thanks again


The starter is 3000w


Motor is Perkins Sabre M135, 6 Liter 6cyl



The cells are EVE LF280K 24v

[CaptainRivet]

Originally Posted by Fuss

Thanks again


The starter is 3000w


Motor is Perkins Sabre M135, 6 Liter 6cyl



The cells are EVE LF280K 24v

3000W starter with 12V is 250A constant, start surge 30ms will be approx 1000A on lead, around 750A at LifePo4 and 600A with 16V LTO…so 2p6S LTO 40AH can easily crank your starter.
If with EVE or calb you would need 560AH, better would be 840AH, 12 cells in 3p4S as 12V house. Winston 4x200AH 12V would do it.

Holy smoke that starter is expensive, 800£ so change to 24V if it breaks.

[Fuss]

Thanks for all the replies. I decided to go with the following.
The house bank is EVE LF280Ks 2 x 24v.

So I decided to make one 12v version out of an extra 4 LF280K cells and try it out and see if the engine starts ok.
I will install a 12v 100a BMS and bypass it for starting and running the engine instruments. The BMS's job will be controlling charging.
I will leave the other 12v Lead battery there as support if needed though the original 1 2 both switch (which before was always on both but now will only be on 1 unless I have start problems)
I will then see if over time the Eve cells get damaged.
The advantage if they do not get damaged is that I have standardized all cells to be the same type.
I will then buy another 4 cells and remove the lead battery. Then I would have a spare 12v Lithium for emergencies.
The benefit is that as it is now with 2 x lead in parallel, there is no real backup in case of problems. I like the idea of all cells being the same and also some start redundancy with the batteries.

[mcarthur]

Originally Posted by Fuss

Thanks for all the replies. I decided to go with the following.
The house bank is EVE LF280Ks 2 x 24v.

So I decided to make one 12v version out of an extra 4 LF280K cells and try it out and see if the engine starts ok.
I will install a 12v 100a BMS and bypass it for starting and running the engine instruments. The BMS's job will be controlling charging.
I will leave the other 12v Lead battery there as support if needed though the original 1 2 both switch (which before was always on both but now will only be on 1 unless I have start problems)
I will then see if over time the Eve cells get damaged.
The advantage if they do not get damaged is that I have standardized all cells to be the same type.
I will then buy another 4 cells and remove the lead battery. Then I would have a spare 12v Lithium for emergencies.
The benefit is that as it is now with 2 x lead in parallel, there is no real backup in case of problems. I like the idea of all cells being the same and also some start redundancy with the batteries.

How did you go? I'm in almost the same situation, same engine and similar EVE...

[rwidman]

Originally Posted by Fuss

To start my motor, I need paralleled 2x 12v 750 cca batteries.
Has anyone changed to lifepo4 to start a big diesel?

Most lithium batteries cannot supply enough current to start and engine and the manufacturer's specs will state this.

There are a few that can be used as starting batteries, these will cost more and the manufacturer's specs will state this.

Go by the manufacturer's specifications, not something you may read on a boating forum.

[CaptainRivet]

Originally Posted by mcarthur

How did you go? I'm in almost the same situation, same engine and similar EVE...

You just build a hybrid house bank from all the cells and start from the house. Put LCV at 3.0V and between 2,5V and 3,0V you have more capacity then your full lead starters. Starter and windlass are connected with a breaker directly to house, so i can use it in emergency case even below 2,5V as i prefer to ruin the bank then eg run aground when anchor slips. You most likely don't ruin it even in this case but BMS won't let you charge if below 2,5V. you have to slowly with a power supply recharge then to 2,5V and then BMS charge full normally.

The huge advantage compared to seperate banks is
1) You have all capacity available, starting cost 1-2AH so 278AH is lost, with one bank i can use it.
2) you share the load of starter between all batteries so each gets a very small load compared to one thats at the limits. Additionally the voltage sag is much smaller=starter lifes longer
3) no starter that needs to be seperately monitored and well you only realise something is wrong when you need it. The house is always in use and if something is wrong you right away realize and take maeasures.

want backup keep your lead and 1 or 2 switch you can choose where to start. Want it safer, get 6x30AH LTO yonglong as starter/house backup, you can charge them in parallel to the house bank without any mods...
Your bank you have 2 options then.
Option 1: multiple BMS means you make 1P4S battery and every battery gets a BMS, then you parallel them. By having all BMS parallel they share the current so if you have eg 3x JK BMS 200A thats 600A and will survive start surge. One JK won't but 3 in parallel do.
Advantage:
By having them all parallel you have direct redudancy eg 3 batteries. If one has a problem, isolate it (or BMS will switch that off) and you still have 2 that work. 2nd you can monitor each cell.
Disadvantage:
Its complex and expensive plus if your BMS doesn’t have the option of a master/slave they can fool each other. Rarely happens but because you monitor you will realize and fix it.

Option 2: make one big battery eg 4P4S with one BMS and eg have a BMS as spare. You need a contactor BMS as there is no big enough FET based BMS that survives the surge.
I have this solution with 4P4S 272AH Lishen cells =1088AH with ElectrodacusBMS and i have a 2nd spare thats plug&play exchangable.
Advantage less complex and cheaper, i would advice to max 3p doing that. From then the single bank is to big and i would split it in two 2p4S with each a BMS, thats then between Option 1 and 2.
Disadvantage one bank no direct backup.
The starter spins like a guinipig on epo and engine starts in 1.5sek. Also the windlass does the same as its connected 2.

In both options the BMS is still connected to bank also during start (and you eg see very early when one cell pack is eg pluming under the high load and can take measures) and BMS can control discharge with all loads and has full control.
With LFP there is no need for a dedicated starter, the battery bank is well monitored that you realize the slightest problem right away and option 1 as direct backups.

I have a catamaran so the 2nd engine has the 30AH LTO 1p6S bank with the same BMS as house but actually doesn’t need a BMS but a used ElectrodacusBMS was just 90Euro which is cheaper then a battety monitor and does all. So i have a 3rd BMS in case i need.
My system grew from 544AH 2p8S over 3p8S 816AH to 4S4P 1088AH all from the same batch, we ordered for 3 boats and my 2 buddy boat each ordered 4 cells more then they could fit and i have the space and price fitted. Also got a 2nd Multiplus, which means max current goes up, no problem as system was speced to 500A cont use anyhow. But unexpectedly the 700A main shunt is getting too warm and transfering too much heat into battery busbar when pulling 400A. its a 700A 50mV rideon as main/ load shunt but at 300A is hoter then the 500A 50mV victron charge shùnt with the same 300A). its easier for me to add a 2nd BMS (which i have anyhow) with 2 shunts victron 500A sharing the load = replacing the 700A shunt and then run only 250A per shunt. the 1000A Victron is super massive and won't fit that easily then 2x500A in parallel.

[CaptainRivet]

Originally Posted by rwidman

Most lithium batteries cannot supply enough current to start and engine and the manufacturer's specs will state this.

There are a few that can be used as starting batteries, these will cost more and the manufacturer's specs will state this.

Go by the manufacturer's specifications, not something you may read on a boating forum.

He is asking specifically about his engine with a 3000W starter and EVE 280AH cells.
I answered this already in an earlier post:

Originally Posted by CaptainRivet

3000W starter with 12V is 250A constant, start surge 30ms will be approx 1000A on lead, around 750A at LifePo4 and 600A with 16V LTO…so 2p6S LTO 40AH can easily crank your starter.
If with EVE or calb you would need 560AH, better would be 840AH, 12 cells in 3p4S as 12V house. Winston 4x200AH 12V would do it.

Holy smoke that starter is expensive, 800£ so change to 24V if it breaks.

Issue with 280AH EVE is the 750A surge of the starter...
If you add the planned 1P4S 280AH to your house, which is already a 3p4S 840AH and creating a 4P4S hybrid then you have 1120A const and the 750A is no problem.
Starting uses 2AH so you waste 278AH as pure starter.

[smac999]

The standard drop in group 31 lithium batteries will have a max surge of 200a. The cheaper ones probably only 100a.

So if you need 1500cca. That is between 7-15 group 31 lithuim batteries….

There a few models that claim cca.

[Phil_Fr17]

Originally Posted by CaptainRivet

He is asking specifically about his engine with a 3000W starter and EVE 280AH cells.
I answered this already in an earlier post:


Issue with 280AH EVE is the 750A surge of the starter...
If you add the planned 1P4S 280AH to your house, which is already a 3p4S 840AH and creating a 4P4S hybrid then you have 1120A const and the 750A is no problem.
Starting uses 2AH so you waste 278AH as pure starter.

I've read he is speaking about BMS. In my opinion, BMS will be the major problem.
In my own experience, I use Winston's batteries (in 12 volt) to start my engine or anything I want to do. Take a look to the specs of this kind of batterie, it will survive to 3kW starter in 24 volt. There is NO BMS inside this batteries. You can use 40Ah or 90Ah and mount them in serial or parallel.


Another way is to use LTO cells assembled in 24v. This tech is very safe and accept a huge discharge current.
Sorry for my froggy english... I'm French.

[CaptainRivet]

Originally Posted by smac999

The standard drop in group 31 lithium batteries will have a max surge of 200a. The cheaper ones probably only 100a.

So if you need 1500cca. That is between 7-15 group 31 lithuim batteries….

There a few models that claim cca.

He talks about 280AH EVE cells and no dropin...did you even read the post????

[CaptainRivet]

Originally Posted by Phil_Fr17

I've read he is speaking about BMS. In my opinion, BMS will be the major problem.
In my own experience, I use Winston's batteries (in 12 volt) to start my engine or anything I want to do. Take a look to the specs of this kind of batterie, it will survive to 3kW starter in 24 volt. There is NO BMS inside this batteries. You can use 40Ah or 90Ah and mount them in serial or parallel.


Another way is to use LTO cells assembled in 24v. This tech is very safe and accept a huge discharge current.
Sorry for my froggy english... I'm French.

He writes about budget EVE 280AH cells, most likely grade B that fell through quailty control, because that what you on private market in 99,8% cases get, if lucky they matched the cells.

Yes winston is top notch but also a lifepo4 derivant that shouldn't be kept at 100%SOC or close to it.
So the problem with Winston as pure starter is at what SOC do you keep them? Eg 80%, then you need to setup a DC2DC to charge them and from time to time top balance them. Who do you do that, manual with the DC2DC?

LTO in comparison doesn't care at all at which SOC you keep them, also 100% SOC is ok and simply charging them with Lifepo4 parameters in parallel to house puts them at approx 85%SOC when Lipo4 is at 100% which is perfect and because curve is steeper you can also top balance at that SOC means keeping a 5A active balancer constantly connected solves all balance issues that might appear so you can use cheap grade B, no issue. Cannot do that with winston or other Lifepo4 as a permanent connected balancer will unbalance the pack.
you also need no BMS in 12V config too, in 24V you need as tolerance of 12S in series needs an active balancer and a BMS.

[CaptainRivet]

Originally Posted by Phil_Fr17

I've read he is speaking about BMS. In my opinion, BMS will be the major problem.
In my own experience, I use Winston's batteries (in 12 volt) to start my engine or anything I want to do. Take a look to the specs of this kind of batterie, it will survive to 3kW starter in 24 volt. There is NO BMS inside this batteries. You can use 40Ah or 90Ah and mount them in serial or parallel.


Another way is to use LTO cells assembled in 24v. This tech is very safe and accept a huge discharge current.
Sorry for my froggy english... I'm French.

He writes about budget EVE 280AH cells, most likely grade B that fell through quailty control, because that what you on private market in 99,8% cases get, if lucky they matched the cells.

Yes winston is top notch but also a lifepo4 derivant that shouldn't be kept at 100%SOC or close to it.
So the problem with Winston as pure starter is at what SOC do you keep them? Eg 80%, then you need to setup a DC2DC to charge them and from time to time top balance them. Who do you do that, manual with the DC2DC?

LTO in comparison doesn't care at all at which SOC you keep them, also 100% SOC is ok and simply charging them with Lifepo4 parameters in parallel to house puts them at approx 85%SOC when Lipo4 is at 100% which is perfect and because curve is steeper you can also top balance at that SOC means keeping a 5A active balancer constantly connected solves all balance issues. So you need no BMS too.