Lithium Upgrade Design - Input Required

[Artemon]

Originally Posted by UFO

I have just started the process of getting my head and very limited knowledge of marine electrical systems around a Lithium upgrade to my dying battery bank. Don't worry I have a very good marine electrician who will install it all for me when I am ready, but I want to get a better understanding of the system myself in advance of this - I have read marine how to and Nordykn Design pages, but I am still hazy about the overall setup.


Following is a rough layout of my initial idea - All input is welcome.

I can see that you have designed a nice system. You use the AGM as a buffer for the lithium bank. No further protection for alternators needed. What is the double smart relay? Is it a way to seperate loads from chargers? What model are you using since most of those relays are for less than 10A if I understand correctly.

[undrsol]

Check out “Freely Roaming” on YouTube. Great tutorial with sources, prices, theory, etc. you can build a 280ah for about $650 and have the exact same components (better even) than name brands

[rma]

Originally Posted by undrsol

Check out “Freely Roaming” on YouTube. Great tutorial with sources, prices, theory, etc. you can build a 280ah for about $650 and have the exact same components (better even) than name brands

I think you've missed the last dozen posts on this thread advising on why exactly NOT to do this.

If you think "Freely Roaming" can offer anything valuable to the design and installation of a marine lithium system, then I think you have more homework to do. Consider reading through this entire thread first.

Sorry if this comes across as harsh. It's just frustrating to see people always try to take the shortcut to understand a complex topic and even more frustrating when others recommend that very shortcut.

[dstraton]

I went through the Lithium upgrade on my Seawind 1160 in 2012. I described the process here. https://psyberspace.com.au/lithium.html

The system worked flawlessly, and I believe remains fine 9 years later.

In your travels, you will come across people who appear to want to make you anxious, and encourage you to complexify your system. I came to believe that if a system was so complicated that I couldn’t easily troubleshoot and/or over-ride it in an emergency, that my security would be decreased, not increased.

[rma]

Originally Posted by dstraton

I went through the Lithium upgrade on my Seawind 1160 in 2012. I described the process here. https://psyberspace.com.au/lithium.html

The system worked flawlessly, and I believe remains fine 9 years later.

In your travels, you will come across people who appear to want to make you anxious, and encourage you to complexify your system. I came to believe that if a system was so complicated that I couldn’t easily troubleshoot and/or over-ride it in an emergency, that my security would be decreased, not increased.

I appreciate your keep it simple philosophy. In the case of LiFePO4 on board, the system can be quite simple and easy to troubleshoot. However, a complete, proper, and safe installation is complex. Note that complex doesn't mean incomprehensible.

Does your insurance company know about the lithium aboard your Seawind? Do they know there is no BMS aboard?

I'm glad to hear it has worked for you for so long.

We all take the risk we're willing to take.

[undrsol]

Originally Posted by rma

I think you've missed the last dozen posts on this thread advising on why exactly NOT to do this.

If you think "Freely Roaming" can offer anything valuable to the design and installation of a marine lithium system, then I think you have more homework to do. Consider reading through this entire thread first.

Sorry if this comes across as harsh. It's just frustrating to see people always try to take the shortcut to understand a complex topic and even more frustrating when others recommend that very shortcut.

It seemed to me that the person on that channel provided a pretty comprehensive description of his system design and was pretty fastidious/safety conscious. Granted, it was not not as complex a system as some have discussed on this thread but did incorporate multiple charging sources and guards against overcharge, cells becoming unbalanced, etcetera. Worth a look for people curious about designing a relatively simple system

[UFO]

Originally Posted by Artemon

I can see that you have designed a nice system. You use the AGM as a buffer for the lithium bank. No further protection for alternators needed. What is the double smart relay? Is it a way to seperate loads from chargers? What model are you using since most of those relays are for less than 10A if I understand correctly.

I have updated the design since then - See attached image.


The Smart relays each take 120A (2 per relay so 240A) and are controlled by a BMS.


https://123electric.eu/products/123smartrelay/


Decided against those in the end.


To an earlier post, yes I have 3 x Engine/Generator start batteries and would also have a 200Ah AGM - This whole circuit with Generator, Engines, chargers, Start Batteries and AGM are currently in place (except there is currently 800Ah AGMS).


The plan is to leave it in place but add the lithium with some changes to the Charge and Load Bus as the attached diagram shows

[fakinx]

Originally Posted by UFO

I have updated the design since then - See attached image.


The Smart relays each take 120A (2 per relay so 240A) and are controlled by a BMS.


https://123electric.eu/products/123smartrelay/


Decided against those in the end.

Good thing to do if you’re not planning to use them. Not that it’s anything wrong with them more that manufacturer clearly states they are not disconnecting at exact same time so current can be more that 120A rated.
Been there scraped that.
IMHO there is a need for one emergency contactor for cutting off complete bank in case everything else fails. Yes, it’s about 100€ additional cost but for a very very rare situation when something is really off it could be a battery savior.
I had one occasion when my MPPT failed producing 26V instead 14V with my current LA (that thing still puzzles me since PV is on 54V). I noticed that when on a swimming ladder and felt some electricity through my body. Luckily there was no damage (current into battery was very low) but could ruin something if it went on unnoticed. And MPPT was Victron 75/15 at the time so even high-end equipment can (and will) fail at some point. That episode meant immediate upgrade of my system with CCGX and remote control via VRM portal.
Just for an example...
Personally I think 3 layers of protection is needed but that’s just me. Of course someone could go with less (without BMS even) but that would be... hmmm, very very very bad example of engineering.

[fakinx]

And just a note on BP220:
Using it in front of an inverter which can draw in excess of 220A alone not to account normal home use is a bit underestimated. You should seperate loads or be very aware of your usage not to exceed 220A load.
Of course you’ll be fine with some 1,6kVA inverter or similar but that’s about it.
If we’re talking 12V system that is.

[Nate24]

Originally Posted by rma

Walbee, thanks for sharing this. In the interest of adding to this discussion as a whole I want to highlight the last communication in the thread you shared. This is still a developing industry (at least for marine applications) and there are no engrained standards yet. We know the attributes of lithium chemistries and their advantages and constraints in marine installs but a universal standard has not yet been defined. It is because of this that I make the following point:

I want to strongly advise others interested in lithium aboard to not take any design or intallation advice from the above youtube videos or others. I have seen a lot of content on the `Tube by people who at best state half-facts and at worst misrepresent themselves as experts and actually advise the use of cheap/unsafe systems/components. It should also be noted, that many of the videos out there come from the "VAN LIFE" crowd, where a lithium battery disconnecting from the system may be an inconvenience or where an electrical fire may mean an insurance claim. On a floating vessel, loss of electrical power could have much more serious consequences, and an electrical fire poses a substantially higher risk of loss of life.

These consequences require a system that is much more complicated than these YouTubers would have you believe. If you are going to attempt such an install, make sure you have done your own independent research (i.e. far beyond watching a few videos) and know exactly how your system works and how it can fail. Complete system failure is not an option on an ocean-going vessel (or even for one tied to a dock 95% of the time). You need to be fully confident in the system, this also means that you cannot rely on manual shut offs. By the time YOU, a human, knows something is wrong, it is too late to remedy the situation. All disconnects need to be automated by a sophisticated BMS. The Daly BMS mentioned in the "Cheaper than AGMs" video is total crap. Look at the size of the cables coming out of it, do you really think those cables can handle 120A for more than a couple of seconds? Moreover, that BMS will make your lithium bank act like a "drop-in" lithium in that it can only disconnect itself from the system. It cannot distinguish from an HVD or an LVD event. This is also problematic and requires a unique system design so that unregulated charge voltage will not bypass the disconnected lithium and destroy all the electronics on board.

I do not mean to insult anyone or imply that they haven't fully done their homework. I just want to make it clear to anyone who finds this thread in the future and is maybe just getting into lithiums to reach out beyond the YouTube content and be safe. Take everything you read with a grain of salt and remain skeptical. If it sounds too good to be true, it most definitely is!

Good advice. Jim also works with ABYC to help investigate and write the standards. He has selflessly helped countless folks work through electrical issues of all kinds on their boats. His replies posted here are part of a longer chain in response to the same type of discussion posted here. It therefore, by necessity, leaves out some of the questions and discussions that lead up to his comments. The discussion on MTOA was initially centered on being able to achieve a lithium battery system that would be within the realm of cost associated with WLA batteries.

With apologies to him if I got what he was teaching throughout these posts wrong, here was my take on his final points. His advice as the discussion moved to its end point is that unless you are planning a long term association with the boat in question, that the payback is not there yet. As “most” trawlers are not true Water boats">blue water boats, nor sailboats, some of the advantages of a lithium system just does not currently offset the costs to have the setup designed for the safety, reliability, and service needed for the trawlers being discussed. Of course, if folks have a different use case, or the budget, then more power to them.

So, I think he and you are directly in line with guidance on these systems.

I really like your setup and may use it to develop my own system. If you don’t mind telling us, what was the total cost of your investment, and was it your labor, or did you pay to have it installed? Also, with your permission, I would like to send your pdf of the system you have to Jim. I think he would enjoy looking through it.

[rma]

Originally Posted by Nate24

So, I think he and you are directly in line with guidance on these systems.

I really like your setup and may use it to develop my own system. If you don’t mind telling us, what was the total cost of your investment, and was it your labor, or did you pay to have it installed? Also, with your permission, I would like to send your pdf of the system you have to Jim. I think he would enjoy looking through it.

Thanks for the compliments!

Please feel free to share, that's why I posted it! I hope my setup helps others design their own systems or at the very least provides some insight into the design constraints of lithium battery installations. There are some slight differences in my final design that deviate from the diagram I posted but the overall concept is the same. The differences include powering the Cerbo GX from the load disconnect of the BMS and the chassis ground on the inverter is much larger than it appears in my diagram (the main wires to the inverter are 3/0, the chassis ground is 2/0).

It's a bit hard to delineate the "total" cost as some of these components I already had or were part of the solar system and I won't add those in.

The (2) Victron Smart LiFePO4 12v 160Ah batteries were ~$3200
Victron VE.Bus BMS $118
Victron Cyrix-Li-Charge ~$75
Victron BP-220 ~$140
Victron Cerbo GX ~$295
Victron Orion Smart B2B DC-DC charger 12-12/30 ~$230
Victron SmartShunt 500A ~$130

So all of this was ~$4188

I designed and installed the entire system myself. Nordkyn Design is a great place to start, then once I had a real grasp of system design, I was able to design a system that would work with the available charge sources on my boat. The Victron component manuals are loaded with useful information, I'd recommend diving into those before making any commitments.


Another major expense:

I built my own dual-DC bus distribution "panel" to accommodate the wiring. This included building my own busbars from 3/8" 7000 series aluminum. Each bus is 1.5" wide, drilled and tapped for 5/16" aluminum bolts, washers, lock washers, and nuts. The busbars were sized up accordingly to comparable copper busbars (aluminum has ~67% the conductivity of copper). I needed 6 massive busbars so building my own was the only cost-effective option. In total, the aluminum busbars and materials to build my distribution panel were about $50. Even with copper (which I may redo in the future depending on how well this lasts), it would only be $90 (but don't underestimate how long it takes to drill and tap everything!). If I were to build this panel with Victron or BlueSea busbars the price would've been around $750.

Also, awhile back I bought 100' of Ancor 3/0 marine cable for my windlass. I had about 35' leftover for this project. This can add up to a serious expense if you don't have the appropriate wire on hand. Buying this kind of cable in bulk worked out to ~$3/foot which is an absolute steal.

Keep in mind there are lots of other components that I had to buy:
Thermal breakers, fuses, cable lugs, data cables, breakers, heat shrink, etc.
This stuff really adds up.

My intent is to write all of this up in a detailed blog post on my website. I'll include lots of photos of the build and final installation as well as complete wiring diagrams. However, I probably won't get around to this until the summer...too many projects this spring. I'll be sure to post a link on this thread when I get around to it.

[Artemon]

Thank you for the contribution. Well thought out and quite realistic in executing it.
At some point, I would greatly appreciate a more detailed of the dual bus bar for charges/loads. I understand the overall concept but as always the devil is in the details.
Thank you in advance
Yianni

[Nate24]

Originally Posted by rma

Thanks for the compliments!

Please feel free to share, that's why I posted it! I hope my setup helps others design their own systems or at the very least provides some insight into the design constraints of lithium battery installations. There are some slight differences in my final design that deviate from the diagram I posted but the overall concept is the same. The differences include powering the Cerbo GX from the load disconnect of the BMS and the chassis ground on the inverter is much larger than it appears in my diagram (the main wires to the inverter are 3/0, the chassis ground is 2/0).

It's a bit hard to delineate the "total" cost as some of these components I already had or were part of the solar system and I won't add those in.

The (2) Victron Smart LiFePO4 12v 160Ah batteries were ~$3200
Victron VE.Bus BMS $118
Victron Cyrix-Li-Charge ~$75
Victron BP-220 ~$140
Victron Cerbo GX ~$295
Victron Orion Smart B2B DC-DC charger 12-12/30 ~$230
Victron SmartShunt 500A ~$130

So all of this was ~$4188

I designed and installed the entire system myself. Nordkyn Design is a great place to start, then once I had a real grasp of system design, I was able to design a system that would work with the available charge sources on my boat. The Victron component manuals are loaded with useful information, I'd recommend diving into those before making any commitments.


Another major expense:

I built my own dual-DC bus distribution "panel" to accommodate the wiring. This included building my own busbars from 3/8" 7000 series aluminum. Each bus is 1.5" wide, drilled and tapped for 5/16" aluminum bolts, washers, lock washers, and nuts. The busbars were sized up accordingly to comparable copper busbars (aluminum has ~67% the conductivity of copper). I needed 6 massive busbars so building my own was the only cost-effective option. In total, the aluminum busbars and materials to build my distribution panel were about $50. Even with copper (which I may redo in the future depending on how well this lasts), it would only be $90 (but don't underestimate how long it takes to drill and tap everything!). If I were to build this panel with Victron or BlueSea busbars the price would've been around $750.

Also, awhile back I bought 100' of Ancor 3/0 marine cable for my windlass. I had about 35' leftover for this project. This can add up to a serious expense if you don't have the appropriate wire on hand. Buying this kind of cable in bulk worked out to ~$3/foot which is an absolute steal.

Keep in mind there are lots of other components that I had to buy:
Thermal breakers, fuses, cable lugs, data cables, breakers, heat shrink, etc.
This stuff really adds up.

My intent is to write all of this up in a detailed blog post on my website. I'll include lots of photos of the build and final installation as well as complete wiring diagrams. However, I probably won't get around to this until the summer...too many projects this spring. I'll be sure to post a link on this thread when I get around to it.

Thanks for the writeup. The 2/0 cable for the ground on the inverter is one of the most commonly missed installation issues. People think the ground is only for AC current, but in fact has to be able to carry the amp load from a DC short.

I too have about 30 feet of 4/0 I will be able to use when get around to putting this together. Thanks for the use of the chart!

[carstendenmark]

Wooh, now you guys scare me off a bit !
When just converting a sailboat to electric propulsion, with shore power and solar, I guess the system setup would be much more simple ?


When a potential boat buyer reads this thread, he may think that a degree in electrical engineering is necessary to deal with such a system...

[Nate24]

Originally Posted by carstendenmark

Wooh, now you guys scare me off a bit !
When just converting a sailboat to electric propulsion, with shore power and solar, I guess the system setup would be much more simple ?


When a potential boat buyer reads this thread, he may think that a degree in electrical engineering is necessary to deal with such a system...

It is new technology. A really interesting subset of having a boat. Finding solutions that work for this somewhat economically helps solve one of the biggest issues in boating, improved power management.

Mistakes can be costly, both in treasure and safety, so intense discussions of the various options become necessary.