Started a new project

[Simi 60]

Not all the bits are here yet but making a start.

End result will be 3 batts @ 24v X 280ah lifepo4
Each with its own 200amp BMS
Each with its own 200 amp marine rated battery fuse
Total of 840ah usable @ 24v.
Pretty much double what we have prior.

 

[GoneDiving]

Following

 

[O C Diver]

Looks like a very nice upgrade!

Ted

 

[Larry M]

What’s the physical footprint of the new batteries? It looks like you’ll be gaining some room.

 

[sean9c]

It's so interesting to realize that amps aren't heavy.
Following along

 

[Simi 60]

What’s the physical footprint of the new batteries? .

Each cell is 175mm x 72mm x 207mm H - Plus stud height
Makes the block I am doing around 350mm x 400mm (13.7 inch x 15.7 inch) if including the compression frame which will be 17mm marine ply and threaded rod

It looks like you’ll be gaining some room.

Losing it

The vertical space where the current batteries are (8 x 220ah AGM), each slot is too short to run the 8 cells made into a normal rectangular shaped battery

I will be putting these on a plinth on the other side of the bulkhead in what was the old cold-room and where the inverter charger is
Valuable wine storage space lost

I will access what to do with the old batteries after I have the new ones up and running - there are bound to be several that are still OK

They will all likely stay onboard, weight is good, we still have the dead battery bank from when we first bought the boat down there

 

[Simi 60]

Chinglish instructions for that BMS are doing my head in
8 cells and 22 wires and gems like this in the instructions

 

[healhustler]

Also intending large LiFePo4 bank for solar & house only. Will be keeping the 8D’s for as long as they last for starter, windlass and thruster. Who knows what battery tech may be taking over next. Following.

 

[O C Diver]

Just as a curiosity, when building banks of Lithium batteries, do they not recommend spacing between batteries to dissipate heat while charging? Recently replaced my Trojan T-105s with Firefly batteries. They were pretty adamant about maintaining spacing and allowing heat to dissipate from the bottoms.

Ted

 

[GoneDiving]

Just as a curiosity, when building banks of Lithium batteries, do they not recommend spacing between batteries to dissipate heat while charging? Recently replaced my Trojan T-105s with Firefly batteries. They were pretty adamant about maintaining spacing and allowing heat to dissipate from the bottoms.

Ted

Its by no means unanimous but many recommend the opposite, ie compression, especially at high discharge rates.

Given low cells internal resistance and 840ah, current would have to be very high to create significant cell heating. I suspect most of the temp rise actually comes from cables, connecters, converters etc rather than the cells themselves.

 

[GoneDiving]

Its by no means unanimous but many recommend the opposite, ie compression, especially at high discharge rates.

Given low cells internal resistance and 840ah, current would have to be very high to create significant cell heating. I suspect most of the temp rise actually comes from cables, connecters, converters etc rather than the cells themselves.

I stumbled upon this comparison between rigid and flex busbars. The thermal discussion starts at 20:00

https://youtu.be/7y1apti8N5M

 

[Simi 60]

Compression frames made and assembled
This is two out of three
The 3 BMS have had all connections done and waiting on the Noalox to turn up from US so I can connect the busbars and BMS

Noalox used because terminal posts are aluminium and, we don't have anything like it in Oz.

 

[Comodave]

I put the Lithium batteries in our last boat for the house bank. I used copper bars to join them instead of cables. Used heat shrink to insulate the bars in case a tool would get dropped on them. Much cleaner install and also made the entire bank solid as a rock.

 

[Simi 60]

Just as a curiosity, when building banks of Lithium batteries, do they not recommend spacing between batteries to dissipate heat while charging? Recently replaced my Trojan T-105s with Firefly batteries. They were pretty adamant about maintaining spacing and allowing heat to dissipate from the bottoms.

Ted

These EVE cells, the new version I have reckon they can get 6000 cycles if compressed vs 2500 cycles if not so sayeth the manual.

Thats something silly like 15 years and 75% capacity

 

[GoneDiving]

These EVE cells, the new version I have reckon they can get 6000 cycles if compressed vs 2500 cycles if not so sayeth the manual.

Thats something silly like 15 years and 75% capacity

Looks good ??

I read the manual as 6000 Vs 2500 cycles being driven by 45 Vs 25° ambient temp rather than compressed vs uncompressed.

What max charge and discharge current do you expect?

 

[Simi 60]

With the gear we have we rarely see more than100amps going in but if we fired up the Genset while solar was smashing it we could get closer to 200 amps, maybe.

Going out we usually never see much more than 25amps out or 40amps out if doing hot water , desal or running off a brew (never at same time) and a cloud goes over and usually I'll shut the offender down or start Genset if it looks like doing it for any sort of time.

I may consider another victron 5000/125 multiplus alongside our current one so as to go electric galley (not convinced) and some more panels ( so cheap) but more that our current one is 5+ years old trouble free and...........(reaches out and touches wood)

 

[Simi 60]

I read the manual as 6000 Vs 2500 cycles being driven by 45 Vs 25° ambient temp rather than compressed vs uncompressed.

There is that as well
Moving this bank into the old insulated cold room, under the inverter charger
But without a couple of tonnes of ice it still gets around 30c in summer after running the engine all day

Might look at some sort of insulated blanket for the doorways, one from ER to void space (where old batts live) and void space to cold room.
Have had some of our wine supply not as happy as it should be due I guess, to warmth.

 

[Mischief Managed]

Any thoughts about keeping the old batteries in the mix and connecting the new batteries to them through DC to DC converter(s)? All charging (except the DC to DC) could take place on the new batteries and all loads could be powered by the old batteries. You'd get all the advantages of efficient charging of the LFPs and double your battery bank for just the cost of DC to DC converter(s) until the old bank is worn out (which would take a really long time since this design would maintain a high SOC on the old batteries the vast majority of time).

 

[Tator]

following

 

[Simi 60]

Any thoughts about keeping the old batteries in the mix and connecting the new batteries to them through DC to DC converter(s)? All charging (except the DC to DC) could take place on the new batteries and all loads could be powered by the old batteries. You'd get all the advantages of efficient charging of the LFPs and double your battery bank for just the cost of DC to DC converter(s) until the old bank is worn out (which would take a really long time since this design would maintain a high SOC on the old batteries the vast majority of time).

All sounds terribly inefficient and convoluted, not to mention expensive.

The LFP bank is already double the size of the old bank
The old bank is worn out that is why it is being replaced
The old bank was always at a high SOC, never went below 80%, always at 100% by midday yet is failing after 5 years.

 

[catalinajack]

What is the warranty on all these lithium batteries? All you folks jumping on the lithium bandwagon I thank you for being beta testers. The jury is out on whether these things are worth the investment. For the time being I will stick with tried and true flooded lead acid batteries. They just plain work and give me all I need for my use profile. I do understand that, in some limited circumstances, they can be a good functional option but that still doesn't answer the question of longetivity. Good luck guys.

 

[catalinajack]

All sounds terribly inefficient and convoluted, not to mention expensive.

The LFP bank is already double the size of the old bank
The old bank is worn out that is why it is being replaced
The old bank was always at a high SOC, never went below 80%, always at 100% by midday yet is failing after 5 years.

So, your new lithium bank - how long will it have to last in order to equal the cost of your five-year lead acid bank replaced every five years? In other words, what is the payback period. Will it even last that long? How do you know that it will?

 

[GoneDiving]

All you folks jumping on the lithium bandwagon I thank you for being beta testers..

I regard my DIY dive scooter lithium battery as a test bed. Built in 2005, it still gives me ~6x the old battery's run time after much more aggressive charge and discharge cycles than a house bank. Exactly how much, I don't know because I stopped monitoring it years ago. It just works, no maintenance required.

The jury is out on whether these things are worth the investment. For the time being I will stick with tried and true flooded lead acid batteries.

As is your right. However, find me someone who installed lithium and returned to lead. ?. There are many power sources now where you simply cannot buy lead any more. Even NiMH is becoming rare.

I'm not suggesting that lithium is for everyone but as availability and cost improve it can be a valid option for many.

 

[Simi 60]

So, your new lithium bank - how long will it have to last in order to equal the cost of your five-year lead acid bank replaced every five years? In other words, what is the payback period.

Replacement with half decent AGM 880 ah (440ah usable) was going to cost around $6000
The LFP cells and BMS cost around $5000 but I get double the usable ah and in theory as much as 4 X the life

Also bear in mind that LFP lifespan is usually worked out on cells dropping to 80% usable capacity

‘In standard environment, and for 1C cycles, we can get from the chart the below life cycle estimation for LFP :
3 000 cycles at 100% DoD
4 500 cycles at 80% DoD
10 000 cycles at 60% DoD
etc.
It should be noted that following the number of completed cycle, the batteries still have a nominal capacity > 80% of the original capacity.’
https://www.powertechsystems.eu/home/tech-corner/lithium-iron-phosphate-lifepo4/

Will it even last that long? How do you know that it will? <Snip>
All you folks jumping on the lithium bandwagon I thank you for being beta testers

The chemistry has been around for 20+ years now and they have been consistently punching well above their weight

I think the beta testers were the ones playing with them in the 2000's, we are well past that point now and getting into the next lot of technology.

 

[catalinajack]

Replacement with half decent AGM 880 ah (440ah usable) was going to cost around $6000
The LFP cells and BMS cost around $5000 but I get double the usable ah and in theory as much as 4 X the life

Also bear in mind that LFP lifespan is usually worked out on cells dropping to 80% usable capacity





The chemistry has been around for 20+ years now and they have been consistently punching well above their weight

I think the beta testers were the ones playing with them in the 2000's, we are well past that point now and getting into the next lot of technology.

"Replacement with half decent AGM 880 ah (440ah usable) was going to cost around $6000".

Holy smokes. Eight Trojan FLAs totalling 900 ah can be had for about $1,700 in the U.S. In my opinion, except when watering FLAs is difficult, AGMs offer nothing for a huge price. Yes, LFP has four times the life, in theory. As I said, still in beta. Yup, LFP is double the usable, if one needs it, but I do not. The point I was trying to make is that LFP, for all its challenges in getting them set up, and their expense, and their unproven long-term viability, is a good choice for few boaters.

 

[Simi 60]

"Replacement with half decent AGM 880 ah (440ah usable) was going to cost around $6000".

Holy smokes. Eight Trojan FLAs totalling 900 ah can be had for about $1,700 in the U.S. In my opinion, except when watering FLAs is difficult, AGMs offer nothing for a huge price. Yes, LFP has four times the life, in theory. As I said, still in beta. Yup, LFP is double the usable, if one needs it, but I do not. The point I was trying to make is that LFP, for all its challenges in getting them set up, and their expense, and their unproven long-term viability, is a good choice for few boaters.

Trojans here are more expensive than AGM if doing ah to ah is same voltage.
I'm guessing you are quoting 12v pricing?

And LFP is well proven, how many decades of reliability do you need in a product before you deem it a safe bet?

Have you progressed past 1970's cars yet?
Seatbelts, airbags?

Geez and I thought I was a Luddite. (-;

 

[Comodave]

I don’t see LiFePO4s as a beta. They are proven. They offer many benefits and do have some constraints but IMO they are worth it. Life and usable capacity aside what about the ability to pack in a huge charge in a short time? It is for everyone to make the choice for themselves but I wouldn’t fault for someone’s choice for or against them. Just be happy for the improvement in his boat.

 

[catalinajack]

I don’t see LiFePO4s as a beta. They are proven. They offer many benefits and do have some constraints but IMO they are worth it. Life and usable capacity aside what about the ability to pack in a huge charge in a short time? It is for everyone to make the choice for themselves but I wouldn’t fault for someone’s choice for or against them. Just be happy for the improvement in his boat.

Dave, I am not faulting anyone's choice. In fact, I acknowledged that, for some folks, lithium is a good choice because of their particular circumstances. In my opinion, I do not see that they offer much to the far majority of boaters, those that do not stay away from shore power more than a day or two at a time or are constrained by space availabilty as I recall you are, for example. Those that believe that they will see a payback over time, well, that there is some worth. The real question, one that I believe is unanswered, is how long will they, in fact, last. We won't know that until a bunch of first users have had them for more than 10 years. If they do not last as long as the manufacturer's represent the payback may not be there. Still, some users may not care considering the space aspect and the useable amphours. I wish you all luck with your choice. Every use case is different. Solutions are best tailored to particular use cases.

One last thought - what about fire danger? If a lithium battery causes a fire on a boat, the boat is doomed. No fire suppresion system is able to squelch a lithium battery failure. There are more than a few examples of Teslas catching fire. They burn, very hot, until the batteries' energy has all been used. There are examples of Teslas burning for as long as 20 hours. I read of one case where a fire department used 65,000 gallons of water just keeping the wreck contained. The chances of such happening are indeed very low but when I think of so many boaters who worry about clogged filters offshore and the need for dual Racors, this danger seems, to me, to be a bit more concerning. If a lithium bank goes tits up, it will get so hot that it may melt right through the bottom of the boat.

 

[catalinajack]

Trojans here are more expensive than AGM if doing ah to ah is same voltage.
I'm guessing you are quoting 12v pricing?

And LFP is well proven, how many decades of reliability do you need in a product before you deem it a safe bet?

Have you progressed past 1970's cars yet?
Seatbelts, airbags?

Geez and I thought I was a Luddite. (-;

I am not a luddite. I just have a different opinion but we all know that Simi's boat has the best solution for everything. Just wondering, do you have Vacuflush heads? Now there's a bit of ancient technology that has a documented history of reoccuring problems. And there are more than a few guys on this forum who want nothing to do with electronically controlled engines for obvious reasons. Are they luddites also? You are showing your condescending arrogance again.

 

[Simi 60]

I am not a luddite. I just have a different opinion.

An opinion based on what reality?
As I said, LFP is pretty much old tech now and proven to be very reliable
If it wasn't reliable they wouldn't use it in hospitals, remote installations, busses, UPS, military, etc etc

but we all know that Simi's boat has the best solution for everything.

Really?

Just wondering, do you have Vacuflush heads? Now there's a bit of ancient technology that has a documented history of reoccuring problems

Nope

And there are more than a few guys on this forum who want nothing to do with electronically controlled engines for obvious reasons

I am one of them

Are they luddites also?

As I said, I pretty much consider myself to be one

You are showing your condescending arrogance again

And you are showing your total lack of humour
You did see the smiley face at the end of my luddite comment right?