Simplest and cheapest pure lithium system

[Happ]

Originally Posted by Josephcrawl

Do they not make some kind of dummy battery that can take the place of the lead acid with the DC to DC charger?

And yes I want all three

My Father taught me there are 3 pieces to any business deal, price, service and quality. Pick 2. Three doesn’t exist.

[cottonsail]

Originally Posted by BlueH2Obound

https://dakotalithium.com/product/da...ttery-1000cca/

But you're still going to have to modify the charging system (alternator in your case) so that it will play well with LiFePO4 batteries.

Oh, and by the way, you mentioned easy, cheap, and Lithium. Which ONE do you want?

Good, fast, cheap. You can only pick 2.

[Josephcrawl]

Originally Posted by wholybee

There is a diy external regulator project based on an Arduino or esp32. If you are experienced with that platform, it might be a cheap way to go. If you are not experienced with it, it's probably just as expensive as buying one.

You won't get (super) cheap, (super) easy, and Lithium all together. But all and all, Lithium is not that expensive or difficult.

I found a few references to Arduino external regulator projects but they are either defunct(pcb no longer available/turned commercial) or haven't left the drawing board but it sounds intriguing.


I probably should have substituted the words most affordable for cheapest. In my mind they are synonyms. At least it gives everyone a chance to pull out their favorite adage.

I would love to see a concise diagram for what I want to do. It doesn't seem radical and certainly has been done already.

Also my alternator is a stock one not some amp pumping monster and it does have an external regulator on the back.

I should also add that my starting bank is my house bank two t105 format batteries and despite their low CCA I have no issues starting the engine.

[MHTinkler]

70 amp Balmar alternator thru Balmar charge controller direct to fully fused 360 amp hr LifePo battery pack. (8 CALB 180 amp/hr cells arranged in a 2p/ 4s configuration)
On a boat with 490 watts of solar (thru Victron 100/30 MPPT charge controller), 500 watts wind generator and Honda 2200 generator for backup.
3 years and counting - flawless so far.
Located mostly in mid to southern Florida - so lots of sun.
No starter battery. LifePo does it all. No starting issues.(27 HP Westerbeke diesel)

[Nicholson58]

Originally Posted by Josephcrawl

What's the easiest and cheapest pure lithium system design for starting and charging from a diesel?

Is there anything that will allow charging from a stock alternator that isn't a lead acid battery and a dc to DC charger?

Is it possible to get enough CCA with standard 12 volt lithium pre made batteries?

We upgraded to Blue Heron LiFePo this season for both house and starting. 24 volt system. We have two in series 12X110 AH dual purpose with a built in BMS. In series-parallel, six house batteries totaling 630 AH. Together, these start our humongous 6- cylinder Westerbeke. The Blue Heron rep was instrumental in locating software upgrades, etc for my charging devices.

As noted by others, you will need to modify your charging devices. You will need to modify the alternator to externally regulated either yourself or at a shop. There are several makers on these regulators. Ours are Balmar. Balmar also recommends a suppressor they sell to keep sudden shut down by the BMS from damaging the alternator. Wind, solar and shore power chargers also need to be programmed for the lithium batteries.

[boat driver]

Originally Posted by Josephcrawl

I have SOKs for my land based house batteries and so far I'm pretty happy with them but it's only been a few months.

I wonder if something as simple as a high wattage resistor would help reduce the current flow from the alternator.

I'm fairly confident that two soks in parallel with a max amperage of 230 would be able to handle the starter surge on my 3 cylinder diesel.

I believe you might start your conversation with googling all the negatives of lithium batteries, the cautions, and the maintence.

Lithium is an asset in many applications, but not a general use application that is inexpensive nor well tolerant to charging abuse and non-specified adaptability. You sound like someone who has been sold the highlights and never inquired about the negatives.

[Pete7]

Originally Posted by T1 Terry

A properly built LiFeP04 (LFP) lithium battery will deliver 200 amps from a 100Ah battery for 30 mins, are you game to try that test on your drop in battery?

We don't have anything on board that could draw 200A from a 100Ah LFP which is pretty severe, nor do I think anyone setting out would design such a system in real life. The maximum we have tried is 1C or 119A from 120Ah LFP drop in with a hybrid lead acid set up . The limit wasn't the batteries but the PSW inverter which complained btw.

Originally Posted by T1 Terry

It doesn't take a lot of thinking to realise the drop in approach is not going to give you the results a properly designed and built system will .....

I disagree with this. The drop in can give good results with a properly designed system and many of us are now doing. We have seen some huge installations on CF but on the smaller yachts I think a more balanced approach needs to be taken. Since any battery is just a store of power, there is a need to balance the daily needs with charging resources first and foremost. LFP have dropped in price over the last 3 or 4 years but they are still expensive and not forgetting new cables, switches and fuses etc. Therefore you really need to choose a bank size that meets the requirements for the majority of the time. On a smaller yacht that could be 100 - 200Ah of LFP based on the appliances you intend to run. Add a suitable sized inverter if needed and sort out the generating systems should give a balanced system. We chose to go down the LFP route for electric cooking, others may have different needs. However, choosing appliances carefully that are frugal means we don't need a huge LFP bank and can charge with a modest solar system. With an increase in solar this past winter we will know more at the end of this season, but its been pretty successful for the past two years on a smaller solar system.

It also means its affordable. Bigger solar arrays on arches, huge inverters and LFP banks, heavy cables and good quality switches soon mount up. Finally space for solar and batteries is always a delemma on a smaller say 31ft yacht.

Originally Posted by T1 Terry

How you treat the system will determine how long it survives, but you bought a lithium battery system to be fit and forget and to do what the lead acid system would not .... didn't you? T1 Terry

I would agree with that, our average draw is 0.5C or 75A for the kettle and induction hob. Yes its fit and forget and does what our lead acid bank couldn't.

Pete

[Pete7]

Originally Posted by Josephcrawl

I wonder if something as simple as a high wattage resistor would help reduce the current flow from the alternator.

I'm fairly confident that two soks in parallel with a max amperage of 230 would be able to handle the starter surge on my 3 cylinder diesel.

You don't need a resistor, the same effect can be achieved either by the long wire approach or a DC>DC charger. The long wire is the cheaper option.

Pete

[T1 Terry]

Each to their own I guess, what induction hub do you have that only draws 75 amps @ 12v to power then inverter that powers the induction hob?

The units in Australia start at 2400w, 10 amps @ 240vac, the standard Australian power point capacity, we can get 1500w kettles and even down as far as 750w kettles, but the heat loss compared to the heating energy generally results in the same amount of battery capacity being used in the 2400w kettle as in the smaller power ones, because they take a lot more than twice as long to boil the water.

T1 Terry

[Pete7]

The induction hob is a single Sterling Power unit rated at a maximum of 1500w. However, that is too much and burns anything very quickly, so we run it at 800w or 1000w just to sear steaks. Or once boiled we simmer rice and pasta at 200w with a lid on the pan to cut down condensation and save on power needed.

https://sterling-power.com/products/induction-hobs-1

The kettle is a Russel Hobs 0.8L and 1000w. Half full its enough for two mugs of tea and because its small encourages you to boil just enough water and less than you might at home. It is surprisingly stable and just lives on the galley counter even when sailing to windward. Takes 4m 5s to boil which is quite acceptable.

The 75A draw is a maximum normally only seen when boiling the kettle at night. During the day solar is used first so we see a draw of say 60A from the LFP for the kettle.

https://www.argos.co.uk/product/4821...ettle:13:136:1

Originally Posted by T1 Terry

Each to their own I guess, what induction hub do you have that only draws 75 amps @ 12v to power then inverter that powers the induction hob?

The units in Australia start at 2400w, 10 amps @ 240vac, the standard Australian power point capacity, we can get 1500w kettles and even down as far as 750w kettles, but the heat loss compared to the heating energy generally results in the same amount of battery capacity being used in the 2400w kettle as in the smaller power ones, because they take a lot more than twice as long to boil the water.

T1 Terry

[T1 Terry]

I like the single induction hob, it appears to have inverter control to limit the power rather than the ones we have used that are temp control and switch on/off at full power. I wonder if I can find any this side of the planet, I like the look of the twin hotplate models, I'm guessing they use the same inverter technology to control the power for each induction coil.

The wife put one of those screw together expresso coffee pots on the single one we use and it took off like top, the full power cycle instantly boiled the water and made the pressure relief valve to vent, steam powered spinning top :lol:

T1 Terry

EDIT: Just read the thumbnail photo and it is the pulse version like we have, although the pulse timing might be PWM rather than temp driven ....

[Statistical]

Originally Posted by Josephcrawl

I would like to replace the lead acid bank I currently have with a lithium bank. I don't have space for an additional lead start battery. I know the lithiums will set me back about 2gs. My solar side will work with them no problems so that leaves the alternator. If it is possible I would prefer not to replace it. That's the long and short of it. Sounds likely I won't do anything and give the technology a few more years to catch up to reality.

There is no technology to catch up. Your alternator can't handle high current sustained loads because it was designed around lead acid and that is a non-issue. Likewise your alternator can't handle being load disconnected something that can't happen again with lead acid batteries.

So there is no future tech. Your solutions are
1) don't use an alternator
2) replace/upgrade the alternator with one that can handle lithium batteries
3) use a lead acid battery and DC to DC charger

All three essentially do the same thing they keep your existing alternator never designed to regulate charging of lithium ion batteries from being destroyed by LFP bats.

The issue isn't the lithium batteries. If someone was building a brand new boat with brand new components there is no issue. The issue is your alternator was not designed around the high charging current of LFP nor the potential for them to be disconnected by the BMS.