Lithium battery conversion

[kevsbox]

Hey all

Returning to the possibility of converting my 2 leisure batteries to a single Lithium this winter
So I see this battery on sale on eBay for £470 - Pardon our interruption...

My first question is has anyone tried this one on their yachts?

My current system is 2 110Ah batteries for leisure and a separate battery as the starter.
I have a 50w Solar panel which links to a Rutland HRDi Charge Regulator and I am also thinking of replacing this solar panel with a pair of matching 50w panels

The Charge Regulator then charges the batteries
Then engine (Beta 20) also charges the existing batteries when running of course.

So my next question is could this be a straight swop and a simple case of lifting out the 2 batteries and dropping in the new, shiny lithium number?
Do I need to add anything else?

Thoughts please..

 

[Sea Change]

Not a straight swap. It rarely is!
I'm not aware that the Marlec HRDi has a lithium setting, so that will need swapped out for an MPPT.
Your alternator will also need protection, most easily done via a DC-DC charger.
So you're probably looking at £200-£250 on top of the battery cost.

 

[rogerthebodger]

Is there any way to use an alternator to charge a lithium battery bank by using a regulator on the alternator?

I have 2 alternator one for my engine LA battery and the other to my domestic battery currently also LA.

I would like to change my domestic LA for lithium. I also have solar charging my domestic bank at the moment.

My engine battery also has a separate solar panel for charging

 

[Sea Change]

There are a few different ways of doing engine charging for lithium.
DC-DC charger is popular because it's easy, requiring few other changes.
A hybrid system where lithium and lead acid batteries are permanently in parallel is another way, but I'm not sure if anybody on this forum has tried it.
Perhaps the best, but most expensive/complicated, is to fit a high output alternator with the correct regulator. This will maximise charging and effectively turn your engine in to a generator. It may involve new pulleys and vee belt.

There is another way... ignore your engine, charge from solar alone, and sail somewhere sunny. It worked for me

 

[rogerthebodger]

My engine LA is separate from my domestic except for a emergency parallel switch.

My domestic charge alternator is off a BMW, and I understand its 110 Amp, but I have never seen that level of current ass my domestic batteries we kept charged by my solar.

I do live and sail in a sunny place so I could just replace the LA domestic with Lithium and disconnect the 2nd alternator.

I will just need to check if my solar regulators can be set to lithium which I doubt

 

[PaulRainbow]

There are a few different ways of doing engine charging for lithium.
DC-DC charger is popular because it's easy, requiring few other changes.
A hybrid system where lithium and lead acid batteries are permanently in parallel is another way, but I'm not sure if anybody on this forum has tried it.
Perhaps the best, but most expensive/complicated, is to fit a high output alternator with the correct regulator. This will maximise charging and effectively turn your engine in to a generator. It may involve new pulleys and vee belt.

There is another way... ignore your engine, charge from solar alone, and sail somewhere sunny. It worked for me

My recent Lithium installation is hybrid. I have 2 x 60a @24v alternators (twin engine mobo) and don't feel inclined to spend close to £200 for a Victron DC-DC charger with just a 17a output. Also not inclined to spend the excessive cost of high output alternators.

So far, it's looking good, not seen the alternators putting out more than 30a each. Just connected the Victron system to the N2K network, so i'll be able to monitor everything from the flybridge next time we're out.

 

[geem]

My recent Lithium installation is hybrid. I have 2 x 60a @24v alternators (twin engine mobo) and don't feel inclined to spend close to £200 for a Victron DC-DC charger with just a 17a output. Also not inclined to spend the excessive cost of high output alternators.

So far, it's looking good, not seen the alternators putting out more than 30a each. Just connected the Victron system to the N2K network, so i'll be able to monitor everything from the flybridge next time we're out.

Daygreen do some 24v24v DC/DC chargers. Just ordered one to see what they are like. 30A at 24v. I already have a couple of the woeful Victron 17A DC/DC chargers that produce very little output once they get warm. Even adding computer fans to each unit with temperature control, made little difference. In addition, they mess up my rev counter with electronic interference. Not impressed

 

[geem]

My engine LA is separate from my domestic except for a emergency parallel switch.

My domestic charge alternator is off a BMW, and I understand its 110 Amp, but I have never seen that level of current ass my domestic batteries we kept charged by my solar.

I do live and sail in a sunny place so I could just replace the LA domestic with Lithium and disconnect the 2nd alternator.

I will just need to check if my solar regulators can be set to lithium which I doubt

Build your own. I just finished this one. 280Ah at 24v. 45kg weight. A useful capacity, equivalent to about 1000Ah of lead at 12v. 450x 350mm foot print

 

[rogerthebodger]

Build your own. I just finished this one. 280Ah at 24v. 45kg weight. A useful capacity, equivalent to about 1000Ah of lead at 12v. 450x 350mm foot print
View attachment 184417

Thanks, geem

I am not averse to making my own, but could you send me info as to from where you got yours and all the bits you used

Do bear in mind I live at the southern end of Africa so shipping may be costly

There are local suppliers of LiFi4PO of various sizes.

I will look at what is available and at what costs to me.

My setup is 12 Vdc and will also need to drive a bow thruster from my domestic bank otherwise I will have to rewire extensively

 

[PaulRainbow]

Thanks, geem

I am not averse to making my own, but could you send me info as to from where you got yours and all the bits you used

Do bear in mind I live at the southern end of Africa so shipping may be costly

There are local suppliers of LiFi4PO of various sizes.

I will look at what is available and at what costs to me.

My setup is 12 Vdc and will also need to drive a bow thruster from my domestic bank otherwise I will have to rewire extensively

I wouldn't try to run a bow thruster from a Lithium bank.

 

[rogerthebodger]

I wouldn't try to run a bow thruster from a Lithium bank.

Why

If the bank is big enough what is the issue

 

[PaulRainbow]

Why

If the bank is big enough what is the issue

How many amps does your bow thruster use ?
Is it 12v ?

 

[rogerthebodger]

How many amps does your bow thruster use ?
Is it 12v ?

Maximum 600 Amp and my windlass is also driven from the same connection.

The wiring is by 38mm x 22mm aluminum bus bars with 800 amp fuse

 

[PaulRainbow]

Maximum 600 Amp and my windlass is also driven from the same connection.

The wiring is by 38mm x 22mm aluminum bus bars with 800 amp fuse

LifeP04 is rated at 1c, so you'll need a minimum of 600ah, as well as a BMS that can handle that much current. If you exceed the BMS limit it will shut the load down, so no thruster or anything else on the domestic system. So a current inrush on startup will shut the system down, unless the BMS is rated for the whole load.

You could probably fit multiple Lithiun batteries, each with their own BMS, with sufficient total Ah's and BMS current capacity. Each battery should have it's own fuse and isolator switch.

Worth considering leaving in a couple of LA batteries for the thruster and connecting in parallel with the Lithiums.

or

Run the thruster from the engine bank.

 

[rogerthebodger]

LifeP04 is rated at 1c, so you'll need a minimum of 600ah, as well as a BMS that can handle that much current. If you exceed the BMS limit it will shut the load down, so no thruster or anything else on the domestic system. So a current inrush on startup will shut the system down, unless the BMS is rated for the whole load.

You could probably fit multiple Lithiun batteries, each with their own BMS, with sufficient total Ah's and BMS current capacity. Each battery should have it's own fuse and isolator switch.

Worth considering leaving in a couple of LA batteries for the thruster and connecting in parallel with the Lithiums.

or

Run the thruster from the engine bank.

600Ah does not concern me as I currently have 1200 Ah so 600Ah LiFi4po would give me similar capacity to my old LA.

To power my BT from my engine start would be a major rewire and adding extra LA would put more weight at the bow also major rewire and the m=need to have DCtoDC charging

 

[geem]

600Ah does not concern me as I currently have 1200 Ah so 600Ah LiFi4po would give me similar capacity to my old LA.

To power my BT from my engine start would be a major rewire and adding extra LA would put more weight at the bow also major rewire and the m=need to have DCtoDC charging

With some boats, coverting to lithium is very easy. Others, it's a lot of work and expense. Yours appears to be the latter. You need to decide if it is worth it for you. lithium is great but there are some things it does very well and some things it is better off not doing. Running bow thrusters is one of them. You could go down the route of using the type of BMS that doesn't run the load through it but instead uses a contactor. These are far more expensive than the mosfet type bms.
The ideal lithium set up is two batteries, each with their own bms, fuse and isolator. This gives you redundancy and therefore resiliance should something go wrong with a battery.

 

[PaulRainbow]

600Ah does not concern me as I currently have 1200 Ah so 600Ah LiFi4po would give me similar capacity to my old LA.

To power my BT from my engine start would be a major rewire and adding extra LA would put more weight at the bow also major rewire and the m=need to have DCtoDC charging

1200ah of LA is what, 250kg ? Usable ah at 50% discharge = 600ah

560ah of Lithium weighs about 40kg, About 450 usable ah

Swapping the LA to Lithium give a weight reduction of circa 210kg, leaving 2 x LA batteries @ about 50kg still gives a wight saving of 160kg. Fitting in the current battery space shouldn't mean a major rewire. You can configure in a few ways, dedicated to the thruster and charged by current systems, with a DC/DC charger for the Lithiums, or fitted in parallel with the Lithiums and no DC-DC charger (needs some monitoring to make sure it all works satisfactorily).

No easy drop in solution for your setup, sorry.

 

[Trident]

600Ah does not concern me as I currently have 1200 Ah so 600Ah LiFi4po would give me similar capacity to my old LA.

To power my BT from my engine start would be a major rewire and adding extra LA would put more weight at the bow also major rewire and the m=need to have DCtoDC charging

There is a new JK BMS just out with a 300 amp limit which makes it easier

There has been a lot of talk about using LiFePo4 for thrusters and windlass and engine start etc with most coming out against it but this has always been because the BMS on many batteries would cut out at the big draws (and initial rush) but provided you have sufficient capacity and a good margin on the BMS to allow for greater draw than advertised if things stick etc there is no reason not to use Lithium - the question is really for something so rarely used that has no benefit to being lithium , why bother.

Even on my weight sensitive cat I have a separate 110ah lead acid battery for the windlass (1500w) - It's been in 5 years, still shows full charge, has never let me down and costs £100 and weighs £20kg. I could put in a LifePo4 pack for 11kg, with a 300 amp BMS for £300 if I build it , and save 9 kg and double the capacity but why bother? The weight saving is minimal, the lead acid has never let me down.

In your case as you say you are running it off the house bank it may be a no brainer to change your whole bank but looking at the heavy weight of cables to run the length of a boat to the bow thruster , its worth considering having a lead acid up front with a short cable to the thruster and a suitable charging method . There is no reason the LiFePo4 wouldn't work though with the right BMS and al the usual safety stuff and correct calculations for maximum draw - it just may not be worth it for what you gain

 

[Trident]

Hey all

Returning to the possibility of converting my 2 leisure batteries to a single Lithium this winter
So I see this battery on sale on eBay for £470 - Pardon our interruption...
View attachment 184398
My first question is has anyone tried this one on their yachts?

My current system is 2 110Ah batteries for leisure and a separate battery as the starter.
I have a 50w Solar panel which links to a Rutland HRDi Charge Regulator and I am also thinking of replacing this solar panel with a pair of matching 50w panels
View attachment 184399
The Charge Regulator then charges the batteries
Then engine (Beta 20) also charges the existing batteries when running of course.

So my next question is could this be a straight swop and a simple case of lifting out the 2 batteries and dropping in the new, shiny lithium number?
Do I need to add anything else?

Thoughts please..

Be very careful about some of the "unknown" brands of LifePo4 - the BMS etc are often not great and the cells not the best.

I can build you a 280ah pack for around the same cost, using the best grade A EVE cells and a top line JKS BMS but that's based on trade cost on the parts etc (I buy so many EVE cells each year that I pay less than lead acid prices) - but even on scale to give the manufacturer , the distributor and then the dealer a margin , what goes in to these "drop in" brands is less than the best... (BTW I'm only at Chichester so if you want a pack I'll be happy to help)

You will generally need to change fuses , put in bus bars if you don't already have them and a high amp battery cut of switch if you don't have it. You can then charge the LifePo via the start battery with a DCDC or even a VSR if you want to save money but a good quality DCDC can be under £100 now. You will need as others have said a suitable MPPT for solar to charge the LifePo in the optimal way but for your small panels a Victron MPPT is under £60 so not a big deal .

 

[Seven Spades]

The batteries last a very long time I don't think it is worth making your own. Victron have brilliant inteligent batteries and they talk to the Victron eco system and whats more the system will be fully supported by a world wide dealer network. A further consideration is your insurer, they are more likely to be happy with an all Victron system than something you have constructed yourself. A short term saving might work out more expensive in the end.

We have done thing and it is a game changer. The huge benefit is the efficiency of charging rather than the additional capacity. The batteries charge in engine, shore power, solar and generator. We hardly need to run the generator now.