Lithium and cca

[mcarthur]

I can buy a relatively small starter lithium battery that can put out enough CCA to start a 6 litre diesel engine.
One the issues moving to house lithium (say LiFePO4) is that the chemistry is completely different, so ACR's shouldn't be used.

We are moving to lithium for house.
Is there any reason, apart from cost, not moving to 100% lithium and getting a new lithium starting battery too?
This could mean getting rid of starter entirely and just using house, or could mean still having a separate battery - how does one measure CCA requirements into a separate battery or to make sure the house battery can handle starting loads?

Lastly, if the house is the only battery, how can you properly fuse the house bank? Normally the positive from the starter battery terminal is unfused, and the positive line for everything from the house bank is fused. Are there fuses which can be switched off just when starting?

 

[sbman]

I'm interested in this at some point as well. My Detroit 671's want 1200-1400 CCA which means dual group 31s or an 8D. Getting something much smaller and lighter to do the same job would be wonderful.

That said, I haven't seen any LiFEPO4 batteries that have a CCA rating, they all seem to be deep cycle, rated in Ah and the built in BMS usually limits them to 100-200 amps output. The automotive Lithium battery replacements that have a CCA rating and are common are Lithium Ion which I don't think I want on the boat.

If someone is aware of an LiFePo4 battery that is good for use as a starting battery, I'd be very interested.

To answer your original question mcarthur, if you were using a house bank to start your engine, then you could just run a wire from the house bank to the starter, unfused as is normal and then a different wire up to your house bank battery switch and fuse system. Another issue might be if you have a shunt on the house bank's negative for a battery monitor which would probably need to be bypassed for starting purposes. I don't think I'd want to use a Lithium house bank for starting purposes, personally.

 

[jungpeter]

To answer your original question mcarthur, if you were using a house bank to start your engine, then you could just run a wire from the house bank to the starter, unfused as is normal and then a different wire up to your house bank battery switch and fuse system. Another issue might be if you have a shunt on the house bank's negative for a battery monitor which would probably need to be bypassed for starting purposes. I don't think I'd want to use a Lithium house bank for starting purposes, personally.

Ignoring all the ancillary issues regarding using lithium battery chemistry(s) aboard a small boat, that's an OK suggestion, as long as you include another battery SWITCH (ideally outside the engine room) on that separate feed to the main engine starter as well. You don't want a runaway (stuck) starter with no way to disconnect it from its power source.

Regards,

Pete

 

[sbman]

Ignoring all the ancillary issues regarding using lithium battery chemistry(s) aboard a small boat, that's an OK suggestion, as long as you include another battery SWITCH (ideally outside the engine room) on that separate feed to the main engine starter as well. You don't want a runaway (stuck) starter with no way to disconnect it from its power source.

That is a good idea and an additional feature that would be welcome. Most older boats did not have on/off switches for the start battery. Boaters should have a reliable set of cable or bolt cutters available for emergency use on board and easily accessible to use in a variety of unpleasant situations.

I've had a diesel generator that had the stuck starter issue (and it wasn't starting, just cranking with no way to stop it) and the emergency solution was to grab the emergency cutters and cut the cable. A switch would have been a lot nicer.

 

[mcarthur]

Thank you both - good additions to the plan should it move ahead:
1. run the starter direct of the (unfused) terminal.
2. make sure there's a switch in that circuit rated for "lots" .


The example chargers I'm talking about are something like the Noco GB70. From examples of use, they can certainly start a 6L diesel so they must have a decent CCA although I can't find an actual number.

I've seen lithiums advertised that have quite different discharge C's: from 0.5C to 2C (continuous). So I'm assuming things like the Noco's are high C discharge, mimicing the high CCA idea.

Probably a better question therefore is how can one choose a lithium house bank size and type/manufacturer (discharge C) that can also start a particular diesel? Either by size (3/6litre) or CCA/MCA.

 

[diver dave]

...

That said, I haven't seen any LiFEPO4 batteries that have a CCA rating, they all seem to be deep cycle, rated in Ah and the built in BMS usually limits them to 100-200 amps output. The automotive Lithium battery replacements that have a CCA rating and are common are Lithium Ion which I don't think I want on the boat.

If someone is aware of an LiFePo4 battery that is good for use as a starting battery, I'd be very interested.

....

Relion has a starter battery, the HP series. But, watch the ratings. Invest wisely; I toured a $7m boat yesterday that had a devastating Li battery fire. I do trust that brand, and have 3 myself.

 

[Delfin]

I can buy a relatively small starter lithium battery that can put out enough CCA to start a 6 litre diesel engine.
One the issues moving to house lithium (say LiFePO4) is that the chemistry is completely different, so ACR's shouldn't be used.

We are moving to lithium for house.
Is there any reason, apart from cost, not moving to 100% lithium and getting a new lithium starting battery too?
This could mean getting rid of starter entirely and just using house, or could mean still having a separate battery - how does one measure CCA requirements into a separate battery or to make sure the house battery can handle starting loads?

Lastly, if the house is the only battery, how can you properly fuse the house bank? Normally the positive from the starter battery terminal is unfused, and the positive line for everything from the house bank is fused. Are there fuses which can be switched off just when starting?

FWIW....I installed 600 amp @24vdc LFP a few years ago, and left the LA starter battery in place. Believing that continuous charge of the LFP, even at low voltages, is less desirable than episodic charge/deplete/re-charge. So, when underway, alternator output goes to the LA starter bank, then when we get to an anchorage, I bring the LFP online for house requirements. The selection between the two banks is via the existing battery isolation rotary switches plus the relay in the BMS controlling the LFP bank. When at the dock on shore power, starter bank on, LFP off. When LFP is depleted, and we get underway, starter bank off, LFP online. When LFP is charged and underway, LFP offline, starter bank online.



You can certainly use LFP for a single house/starter bank, but if you already have an LA starter bank, why remove it?


Folks can spend a lot of money to introduce fully automated systems, but given the seconds per cycle it takes to manage my batteries as described above, my time on the boat would have to be worth a whole lot of money to justify doing things differently.

 

[mcarthur]

FWIW....I installed 600 amp @24vdc LFP a few years ago, and left the LA starter battery in place. Believing that continuous charge of the LFP, even at low voltages, is less desirable than episodic charge/deplete/re-charge. So, when underway, alternator output goes to the LA starter bank, then when we get to an anchorage, I bring the LFP online for house requirements. The selection between the two banks is via the existing battery isolation rotary switches plus the relay in the BMS controlling the LFP bank. When at the dock on shore power, starter bank on, LFP off. When LFP is depleted, and we get underway, starter bank off, LFP online. When LFP is charged and underway, LFP offline, starter bank online.

Thanks for the thoughts.

We will also be having large solar, so the input is pretty continuous (during the day), not just alternator when moving.

You can certainly use LFP for a single house/starter bank, but if you already have an LA starter bank, why remove it?

One of the reasons is weight, and another is ability to VSR/ACR which you can't do with different chemistries. The first is of course boat dependent - we would save 100kg just from the started LA's! Having different chemistries can still be done using a DC-DC converter rather than ACR/VSR, but since we're going to an externally regulated alternator anyway, we won't need the LA starter to stop the diodes popping (another reason to keep a LA someone in the system so the alternator can stay in).

 

[mcarthur]

Relion has a starter battery, the HP series. But, watch the ratings. Invest wisely; I toured a $7m boat yesterday that had a devastating Li battery fire. I do trust that brand, and have 3 myself.

Thanks for that, I'll look at the Relion's but that's not a glowing reference about them

I was listening to Nigel Calder and Jeff Cote the other day, and I'd love to see more LiFePO4 options with a UL 1973 rating

 

[Jeff F]

Thanks for the thoughts.

We will also be having large solar, so the input is pretty continuous (during the day), not just alternator when moving.



One of the reasons is weight, and another is ability to VSR/ACR which you can't do with different chemistries. The first is of course boat dependent - we would save 100kg just from the started LA's! Having different chemistries can still be done using a DC-DC converter rather than ACR/VSR, but since we're going to an externally regulated alternator anyway, we won't need the LA starter to stop the diodes popping (another reason to keep a LA someone in the system so the alternator can stay in).

Consider keeping LA staring battery and using a small DC-DC charger to charge it from your house bank. Direct the alternator charge to the house bank. Problem solved.

I use Optima Red Top starting batteries that deliver 800 CCA and weigh less than 20 kg. It's hard to make a compelling case for the lithium alternatives for starting IMO.

 

[diver dave]

Consider keeping LA staring battery and using a small DC-DC charger to charge it from your house bank. Direct the alternator charge to the house bank. Problem solved.

I use Optima Red Top starting batteries that deliver 800 CCA and weigh less than 20 kg. It's hard to make a compelling case for the lithium alternatives for starting IMO.

I agree. And this is also my set up. Use chemistry technologies to their advantage.

 

[mcarthur]

Oh that's good about the Optima Red!
We have 2000 CCA at the moment in 2xVarta dual purpose, total 90kg; the engine starter requirement is for 535amp SAEJ537 and I'd say the 2000 CCA is way more than actually needed, but I don't know by how much!
The DC-DC is a good idea with the Optima though...

 

[Simi 60]

Our house bank is dying a slow death after 5 years of 24/7 usage with big loads.

Looked at Lp4 that we'd have to build ourselves but it would have to be a guaranteed 20 years to make it comparable in $$ value to the service we got from our cheap AGM.

 

[Delfin]

Our house bank is dying a slow death after 5 years of 24/7 usage with big loads.

Looked at Lp4 that we'd have to build ourselves but it would have to be a guaranteed 20 years to make it comparable in $$ value to the service we got from our cheap AGM.

You might see other reasons to go LFP than longevity once you start using a bank that charges in 1/3 the time and maintains 13/26 vdc until 85% discharged.

 

[sbman]

The example chargers I'm talking about are something like the Noco GB70. From examples of use, they can certainly start a 6L diesel so they must have a decent CCA although I can't find an actual number.

I've seen lithiums advertised that have quite different discharge C's: from 0.5C to 2C (continuous). So I'm assuming things like the Noco's are high C discharge, mimicing the high CCA idea.

Probably a better question therefore is how can one choose a lithium house bank size and type/manufacturer (discharge C) that can also start a particular diesel? Either by size (3/6litre) or CCA/MCA.

The jump starters like the Noco are Lithium Ion chemistry, not LiFEPO4. With a capacity of less than 8Ah, the cells in them are being pulled at 100C or greater during a start.

Here is a teardown video of an '4000 amp' NOCO jumpstarter:

All commercial Lithium starting batteries that I have seen are also Lithium Ion. I would not want a large battery made up of that chemistry on my boat.

I don't even like to have the ones in my phone/laptop on board, they do have a lot of protections built in against overcharge and such, but it's not foolproof and occasionally laptops and phones do catch fire. They are also found in Tesla vehicles which also occasionally catch fire.

LiFEPO4 chemistry does not perform well for extremely high discharge, and it is also far less reactive than LiON, which is why it is less prone to catching fire, but also makes it less suitable for putting out very high amps for short periods of time.

 

[Simi 60]

You might see other reasons to go LFP than longevity once you start using a bank that charges in 1/3 the time and maintains 13/26 vdc until 85% discharged.

Maybe, but trying to get the financier to part with $15,000 vs $3000 is a hard ask.

Plus the $15000 LFP I have to wait for gear to arrive from China and then build myself vs the $3000 drop in AGMs installed in a couple of hours

 

[mcarthur]

The jump starters like the Noco are Lithium Ion chemistry, not LiFEPO4. With a capacity of less than 8Ah, the cells in them are being pulled at 100C or greater during a start.

Here is a teardown video of an '4000 amp' NOCO jumpstarter:

Thanks sbman

 

[Delfin]

Maybe, but trying to get the financier to part with $15,000 vs $3000 is a hard ask.

Plus the $15000 LFP I have to wait for gear to arrive from China and then build myself vs the $3000 drop in AGMs installed in a couple of hours

You probably have already factored this in, but you need half or slightly less the total Ah with LFP vs. AGM. If you're mostly at docks with power, LFP doesn't make sense. If you're at anchor a lot, so need to generate the power used, reduced genset run time is also a savings. Bottom line, trading charging time of 4+ hours vs. 2- hours, plus steady high voltage delivered throughout a cycle makes the additional cost worthwhile for us.

 

[Helmsman]

Oh that's good about the Optima Red!
We have 2000 CCA at the moment in 2xVarta dual purpose, total 90kg; the engine starter requirement is for 535amp SAEJ537 and I'd say the 2000 CCA is way more than actually needed, but I don't know by how much!
The DC-DC is a good idea with the Optima though...

Having a lead acid battery as part of the system helps protect against an alternator failure caused by a BMS LFP battery shut off when reaching over or under charge while running. Cheap, fairly reliable insurance offset (only partially) by the increased cost outlay of the DC-DC.

 

[Simi 60]

You probably have already factored this in, but you need half or slightly less the total Ah with LFP vs. AGM.

Was working on a 400ah@24v system vs the 880ah @ 24v AGM we have

If you're mostly at docks with power, LFP doesn't make sense. If you're at anchor a lot, so need to generate the power used, reduced genset run time is also a savings. Bottom line, trading charging time of 4+ hours vs. 2- hours, plus steady high voltage delivered throughout a cycle makes the additional cost worthwhile for us.

Haven't seen a marina berth in 5 years and also have 2500 watts of solar on top so genset time is pretty low anyway

 

[Barking Sands]

Just an FYI- Dakota Lithium just came out with a 60AH Lifepo with 1000CCA. They are currently $599. https://dakotalithium.com/product/d...r-starter-deep-cycle-lifepo4-battery-1000cca/

 

[Simi 60]

You probably have already factored this in, but you need half or slightly less the total Ah with LFP vs. AGM. If you're mostly at docks with power, LFP doesn't make sense. If you're at anchor a lot, so need to generate the power used, reduced genset run time is also a savings. Bottom line, trading charging time of 4+ hours vs. 2- hours, plus steady high voltage delivered throughout a cycle makes the additional cost worthwhile for us.

Ok, I have swayed the financier somewhat
And jumped down the build an LFP rabbit hole over the last few days and seen that yes I can get a result for an acceptable price but I have done my head in.

Are you prepared to share details of this 600ah setup you have please?

 

[Delfin]

Ok, I have swayed the financier somewhat
And jumped down the build an LFP rabbit hole over the last few days and seen that yes I can get a result for an acceptable price but I have done my head in.

Are you prepared to share details of this 600ah setup you have please?

I didn't have time four years ago for another DYI project when I installed my bank, so bought two 24vdc 300 Ah Lithionics with their BMS. Since I had a 24vdc 1250 Ah AGM plus 2 x 200 Ah 12vdc 8Ds for the starter, plus an auto latching relay between the two banks and a Balmar 624 VR, I just left the starter bank as is, and removed the relay, then added 3 x 30 amp 24 vdc Sterling chargers to supplement the 140 Ah alternator on the CAT, detuned to 100 Ah.


This allows me to treat the LFP bank like a fuel tank - use, recharge and reuse, rather than have it on the receiving end of charge current all the time.



I programmed the Balmar VR to suit the LFP. Operationally, this is how the banks are used:


At the dock on shore current - LFP BMS switched offline, which isolates the bank, usually at around 65% charge, which is better for LFP than storing at full charge, and the rotary battery switch for the starter ON. So charge current from shore power goes just to the starter bank.


Underway to anchorage - LFP BMS on, rotary switch for the starter bank OFF. This recharges the LFP at 100 amps via the alternator, but if I want to speed it up, I'll start the Genset, which adds another 90 Amps to the charging current. If I really want to charge quickly, I'll switch on the Sterling chargers and now have around 280 amps charging. The charge acceptance rate of LFP is linear, so will accept whatever I send its way, only tapering in the last 5 minutes or so. I watch the voltage on the existing Xantrex Link 20. When the voltage teachers my target - 29 vdc -, I switch On the rotary for the starter bank, and the LFP BMS Off, as well as the Genset and the Sterlings, if on. Now alternator current is running to the LA starter batteries.


Crossing oceans - LFP BMS Off, and everything running off the alternator and starter bank.


At anchor - run the LFP down to 25% or so, then recharge at 190 Ah with Genset and Sterlings. Two hours is usually plenty of time, during which we make water, bake, do laundry, etc to take advantage of the genset time.


And just FYI, but we start the CAT 3/4 of the from the LFP, so I have no idea why that should be a concern. Hope that helps.

 

[Simi 60]

I didn't have time four years ago for another DYI project .

Thanks for the reply.
Only way we will justify it here is a DIY

Can convince the financier to stump up for 600ah@ 24v of GBS
Could probably get her to buy 800ah and that's comparable in price to 880ah of Victron AGM.
https://www.evlithium.com/GBS_Battery/1066.html


I'd prefer Winston's but they are quite a bit more $$ for quite a bit less ah.

 

[robtx]

Relion has a starter battery, the HP series. But, watch the ratings. Invest wisely; I toured a $7m boat yesterday that had a devastating Li battery fire. I do trust that brand, and have 3 myself.

Was it a Li fire or a LiFePO4 fire? If it was a LFP fire, how did they manage that? A physical puncture?

 

[diver dave]

Was it a Li fire or a LiFePO4 fire? If it was a LFP fire, how did they manage that? A physical puncture?

I dont know that answer. But i do know that it happened around 10 years ago. I suspect more modern battery electronics is in use now.