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The one limitation I see is lithium is very much optimized for deep cycle use. It is almost the opposite of the heavy duty starting battery. Where you might get 800 cold cranking amps out of a big starting battery, lithium has a common limitation of 1 amp per amp hour, except for surges. My 60ah lithium is limited to 60a continuous draw.

Here is a part of the product description from a 100 ah Battleborn.
"100 amp continuous output with a 200 amp surge output - 30 seconds 1/2 second surge output for higher loads"

I have priced out a 200 amp hour lithium battery back for my electric sail boat and the batteries alone are $10,000. Could you post a link as you have found a cheaper source that I would be interested in. Dennis
I am interested in who is charging you $10k for 200ah worth of lithiums? Generally speaking unless you get a group buy or build your own Lithium goes for about $10 an amp hour, so 200ah should be $2,000. Unless your electric boat has some crazy proprietary thing going on and they are charging a 500% premium. I am also wondering how they can power an electric motor. Is it 36v or even higher?
 

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I am still confused with the 800 amps vs amp hours. Deep cycle batteries including lithium are rated in amp hours. So 8, 12 volt 100 amp hour batteries in parallel are a 800 amp hour system. But to try to get an 800 amp load out of this system would impossible.
If you wanted a larger bank like 800Ah, paralleling 8x 12V drop-ins is not the way to do it.

As for the C-rate discharge possible the inaccessible circuitry inside is a bottleneck long before the cells / chemistry.

8C may very well be entirely possible for most quality cells, but is not conducive to good longevity, and if course could only last a few minutes.
 

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If you wanted a larger bank like 800Ah, paralleling 8x 12V drop-ins is not the way to do it.
How would you do it build your own bank with individual cells?

As for the C-rate discharge possible the inaccessible circuitry inside is a bottleneck long before the cells / chemistry.

8C may very well be entirely possible for most quality cells, but is not conducive to good longevity, and if course could only last a few minutes.
What about 2-3c is that too much to ask? I know the lithium is there to maximize longevity as well as other beneficial attributes. Would short periods of 2-3c take such a toll on the battery, they put circuitry to prevent that?
 

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All LI chemistries have no problem acting as a Starter battery.

A tiny unit compared to lead can crank ut a lot higher current and longer. They are the norm for performance motorcycles these days, and jumper packs even for large OTR diesel engines.

The only issue is design, if a BMS is involved it must permit the short burst of very high current.

And cost, pretty silly spending 8-15x more for such a trivial task.

Also in sub-zero temps, lead will likely go a bit lower and still discharge well enough

while LFP must be pre-warmed, certainly for charging, or be damaged, even destroyed.

My 60ah lithium is limited to 60a continuous draw.
Strictly a drop-in design choice, nothing to do with the chemistry.
 

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What about 2-3c is that too much to ask? I know the lithium is there to maximize longevity as well as other beneficial attributes. Would short periods of 2-3c take such a toll on the battery, they put circuitry to prevent that?
Even though John has been saying this, I'll make it explicit - this is a limitation of the drop-in battery design itself, not a general limitation of lithium batteries. In other words, the manufacturers of the branded drop-in batteries made that limitation because they could use cheaper parts and hide them away. If you want more from a battery, stay away from the likes of Battleborn, etc.

A system from companies like Victron or Lithionics will not have this limitation.

The CALB datasheet, for example, shows continual 2C operation as within spec.

Mark
 

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What about 2-3c is that too much to ask? I know the lithium is there to maximize longevity as well as other beneficial attributes. Would short periods of 2-3c take such a toll on the battery, they put circuitry to prevent that?
Short bursts are no problem, longevity might be reduced a bit if done frequently, but we're talking a tiny percentage of many thousands of cycles.

In propulsion use cases 15C or higher is very common when acceleration is needed.

Buying cells to create your own bank is trivially easy.

And implementation of the 3-4 protections required, balancing methods etc

in short, BMS functionality

can be performed by a collection of OTS components, or by buying "a BMS", or manually by a knowledgeable and diligent owner

or some combination of all three.

But I'm not getting into the detailed specifics here, too much disagreement even among experts, really a can of worms, too many self-interested parties protecting their rice bowls.

But really not rocket science, there are hundreds of examples out there, the cruisersforum.com threads and MaineSail's post on marinehowto.com are good starting points.
 

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A system from companies like Victron or Lithionics will not have this limitation.

The CALB datasheet, for example, shows continual 2C operation as within spec.

Mark
Thanks for the info guys. I have a 60ah Bioenno battery in my portable pack. Its 1c limitation only affects me in terms of not being able to power a larger inverter. Just doing my homework for knowledge's sake and a future system.

How would batteries in a parallel bank affect C rating? Can you get 200 amps out of a 2x100 ah batteries in parallel?
 

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The one limitation I see is lithium is very much optimized for deep cycle use. It is almost the opposite of the heavy duty starting battery. Where you might get 800 cold cranking amps out of a big starting battery, lithium has a common limitation of 1 amp per amp hour, except for surges. My 60ah lithium is limited to 60a continuous draw.

Here is a part of the product description from a 100 ah Battleborn.
"100 amp continuous output with a 200 amp surge output - 30 seconds 1/2 second surge output for higher loads"



I am interested in who is charging you $10k for 200ah worth of lithiums? Generally speaking unless you get a group buy or build your own Lithium goes for about $10 an amp hour, so 200ah should be $2,000. Unless your electric boat has some crazy proprietary thing going on and they are charging a 500% premium. I am also wondering how they can power an electric motor. Is it 36v or even higher?
Yes, the electric motor is 48 volt, so it would take 8, 12 volt, 100 amp hour batteries. 2 sets of 4 in series to get to 48 volts and than parallel to double the ah. The ah add in parallel and voltage adds in series.
Most people with electric motors on sailboats, me included use the individual batteries as they are much lighter to deal with than a 48 volt 200 amp hour pack and take up basically the same footprint with the advantage of placement in smaller areas to better utilize space. You can scatter them around.

Price?, you had not realized that I use 48 volts so I need 8 instead of 4 to get to 200ah at 48 volts. The price you said brings it to about 8k, plus truck fright. I may have rounded up a little high. The batteries are connected to the Variable Frequency Drive (VFD) and motor by way of 2-0 (double 0) cables. The price I have seen for the Battle Born batteries is about $950 each. These are the only ones that I was considering.

If interested you can go to the Battle Born site and check out the set ups by Sailing Delos (house battery set-up) and Sailing Uma (electric motor set up)

I probably added confusion to the thread with the higher voltage and higher amp load. But the 800 Amp system lead me down the rabbit hole.

Delos is the first link and Uma is the second



Dennis
 

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Can you get 200 amps out of a 2x100 ah batteries in parallel?
Yes, with the caveat that the draws on the individual batteries must be the same. For example, 100A from each would be within spec, but 120A from one and 80A from the other may cause the first to shut down, which would quickly shut down the second.

Mark
 

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Yes, with the caveat that the draws on the individual batteries must be the same. For example, 100A from each would be within spec, but 120A from one and 80A from the other may cause the first to shut down, which would quickly shut down the second.

Mark
Starting amp draw on a typical car is around 400 amps. So you can get it out of 1, 12 volt battery. But not for very long.
 

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Perhaps it is worth getting what I need through a local retailer who will honor the warranty. Is it worth the extra 2 grand to have a local dealer with spare parts in stock and within 50 miles or so of me, and not go through all the research and doubt if where I'm purchasing my batteries is a reliable supplier?
Any thoughts?
One thing I question is does the local supplier have a set of batteries sitting on the shelf waiting for warranty replacement? Or do they carry LifePo batteries even available for retail sales?

I have been trying to spend more money locally recently trying to support the locals in these economic hard times, turns out local businesses are up 40% this summer. I am still trying to give less to Bezos and more to locals.

The weird thing is the 10 year warranty on some batteries, that really changes things but do they swap it out on the spot prorated or do they have to ship it back from whichever island you are on at the moment and wait for it to be opened and tested before determining how to warrant it?

I would guess the real advantage for buying locally is if you get a bad battery right off the bat or it fails in short order.
 

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I dont play around at the ends and have no bms, not looking for max capacity
EV routinely tests max capacity at both ends
Do you have a LifePo setup? I am interested to know how you manage it without a BMS?
 

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Do you have a LifePo setup? I am interested to know how you manage it without a BMS?
The cells are stable, not running wild
I check the batteries each time a thread like this pops up.
In Jan there was something like .004v max difference between cells.
I have 8 180 ah cells, 4s2p
This morning, before sun started in on the panels, max diff was .003v...3 year mark

They seem to manage themselves. Again, i dont play on the ends
Why was bms not thought necessary before lfp batts...eh?
 

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Why was bms not thought necessary before lfp batts...eh?
Because you did not pay $1000 per 100ah battery before. Also, you can get a good estimate of lead based battery health and state of charge by monitoring the voltage, the Lithium battery does not give the same indications.

I understand where you are coming from and i have a single LifePo battery without a BMS, but just added a Coulomb meter for some extra knowledge and to monitor what is going on with my power pack.
 

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How would batteries in a parallel bank affect C rating? Can you get 200 amps out of a 2x100 ah batteries in parallel?
In principle yes, doubling Ah capacity cuts the C-rate in half.

But again, with a proprietary enclosed pack since that seems to be what you mean, it all depends on their specific circuitry, it is a design limitation that varies per product

nothing to do with the cells themselves.

Just talking bare cells, paralleling multiple strings is not a good idea in general, certainly one pair for redundancy should be OK maybe three not too bad, I would not go past that.
 

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Try to find any suppliers of LFP units "local" to you before you talk about what you "prefer".

As I stated, North America has a very thin distribution/reseller network in anything Lithium.

Usually for cells you need to self-import from China.

AFAIK with these drop-in assemblers, they only sell direct, and freight charges within the US for large quantities can often be higher than the shipping charges from China.

With the 'rona now, delays are the problem, what used to take 3-6 weeks can now be 4-6months, and shipping charges going up, potential tariffs.

At some point buying from Europe will become competitive.
 

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..... Also, you can get a good estimate of lead based battery health and state of charge by monitoring the voltage, the Lithium battery does not give the same indications.
....
I dont understand...indications
I check cell voltage with a multi meter. Thats all
 

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Even though John has been saying this, I'll make it explicit - this is a limitation of the drop-in battery design itself, not a general limitation of lithium batteries. In other words, the manufacturers of the branded drop-in batteries made that limitation because they could use cheaper parts and hide them away. If you want more from a battery, stay away from the likes of Battleborn, etc.

A system from companies like Victron or Lithionics will not have this limitation.

The CALB datasheet, for example, shows continual 2C operation as within spec.

Mark
Mark, so could the Victron 12 volt 200 ah LIfePo4 be put in a series of 4 without issue to get a 48 volt bank? Of course it is still $8k but the less wiring. Four batteries vs 8. Dennis
 

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If you are going to pay for Victron, follow their recommendations for your target voltage and Ah capacity.


Find a good dealer with experience in your use case. Otherwise you are getting all the hassles of DIY without the cost savings!

___
Propulsion is an entirely different arena from House bank storage

really should not be mixed up in the same thread.

Same with drop-ins compared to LFP generally, just leads to too much confusion.
 

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Mark, so could the Victron 12 volt 200 ah LIfePo4 be put in a series of 4 without issue to get a 48 volt bank? Of course it is still $8k but the less wiring. Four batteries vs 8. Dennis
I'd consult Victron for that. They sell "drop-ins" now as well as externally monitored battery systems. It is very likely the externally monitored batteries could be, but the drop-ins may not.

Mark
 
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