Lithium for the love of God

[john61ct]

Yes.

Discharge rate **much** higher, voltage sag much lower.

[john61ct]

Originally Posted by Oceansailor

And I wonder why in the hell Boeing engineers did not understand to use LifePO4 in the first place?

Aircraft, want to maximize energy density, thought their thermal protection was failsafe

[a64pilot]

Originally Posted by Oceansailor

And I wonder why in the hell Boeing engineers did not understand to use LifePO4 in the first place?

One word, weight.
Now it’s understood that an APU or even regular battery technology would have ended up weighing less with all the protection they ended up with.
But they were convinced that the battery technology had matured and was safe.

[a64pilot]

Originally Posted by a64pilot

One word, weight.
Now it’s understood that an APU or even regular battery technology would have ended up weighing less with all the protection they ended up with.
But they were convinced that the battery technology had matured and was safe.

When you push the limits of technology, sometimes you get bit.

[sailinglegend]

Originally Posted by exitstrategy

Hello All,

I have been reading and reading and reading all of these Lithium threads. Awesome stuff. But so much.

There really needs to be some sort of sticky thread with bullet points by this time.
Thank you,
-Erik

Anyone who has read all the Lithium threads and is still asking questions then maybe Lithium is not for them?

Yes they are fantastic, almost magic batteries, but you need to fully understand every aspect of 'Electrickery' if you are going to instal them - they are not plug and play.

New battery technology is developing fast so before Lithium batteries have paid for themselves there may be an even better, and much safer product to replace our very old Lead Acid technology.

LiFePO4 may not catch fire, but if you have a fire on board and they go up you will never put it out! In a car you can just stop and get out.

[john61ct]

Same with fuel, but big If.

IMO just fear mongering

[alaskanviking]

Originally Posted by exitstrategy

Thank you guys so much for clear crisp recommendations, and also thank all of you for all of your contributions in all of the other threads and blogs.

(Back from the relatively remote Ilets de Petite Terre, and now have some data roaming off my phone.)

Going LiFePO4 not new AGMs
I am definitely sold on the benefits of LiFePO4. @Navy_Davy the Carbon Foam batteries seem like a really good solution for upgrading lead, but I actually do want to have the full benefits of Lithium and I am enjoying the learning process.

Fully integrated solutions?
@OceanPlanet Bruce Schwab, JOHNMARDALL, I have much respect for your work and recommendations, and I have also studied Emerald Sea Life's installation on a sister Lagoon 450. I am sure these solutions are excellent. While I can afford a fully integrated-marine installation, I do not want to spend money that I do not need to spend. As I have already purchased a Xantrex FW3000 and 3 Outback 80s I believe I already have good sub-components to work with. And a DIY LiFePO4 project would push me to learn more about my boat – which is actually a major sub-goal of cruising for me. I will review again the OceanPlanet website when I get true WIFI and try to figure out what I am missing of the more integrated solutions. The MasterVolt website really didn't explain to me what you are buying.

DIY Solution High-Level

Handling Overcharging:

Solar:
As 44'cruising cat pointed out, the Outback 80s I have can be set to 13.8 bulk and 13.5 float so as to effectively turn off float charging after charging the batteries. This handles over-charging from solar.

Generator:
We also have a Onan generator that I now run once every couple of months, really to just keep it use. As the 2000 watts of solar cover all of our current needs as long as we stop the inverter for the laptops around 8-9pm. The generator output is coming into a Xantrex Freedom 3000 charger / inverter that has custom battery settings, and even a two-stage no-float mode. So, like the Outback I can program the charger to keep the Lithium safe. So even if we are starting and stopping the generator manually, if we are having an evening party and we are distracted we will not take the Lithiums above the knee for high voltage.

Alternators:
Finally, the alternators. We have the stock 80 amp alternators running into I believe under-sized stock Cristec 40 port & Cristec 60 stbd battery chargers. If we have the engines on, it is usually for the relatively short period of anchoring. If however we have decided to thumb nature and insist on motoring windward for hours and hours, then it seems like I have the option to shut-off the circuit breaker for these chargers. To do this safely, I turn off the engines, shut the circuit breaker, then fire up the engines again and continue to motor into the wind? But there is probably a more elegant voltage detecting relay device that I could put in here that would handle this automatically, as well as turn it back on!

This handles over-charging right? I do not need a diversion load setup? (Although my wife would love hot showers inside of the boat instead of the hanging camp shower )

Under-charging
This seems like not a problem to me. We already live under a low-voltage alarm regime with the current AGM setup. So there would be no difference to us for an alarm to sound and to respond. However, going a bit deeper. We are full-time cruisers and have yet to leave the boat overnight, but we will at some point want to leave the boat for a week or two. I would think that I would empty the fridge & freezers, turn them off. The inverter would be off, the bad-boy off. The only loads that I could think we would want remaining would be the bilge pumps, (possibly a light and some 12 fans). In the case of the bilge pumps I would rather drain the Lithiums down to 0% than to disconnect the bilge pumps. So it seems to me that low-voltage automatic cut-off is not required. I am most likely missing something? (Also I believe I am currently throwing away 300 amp-hours a day on the lead batteries, so as a practical matter, I do not see how I get to low-voltage unless I am filling SCUBA bottles - also below.)

What about my lead-acid starting batteries?
Besides the house battery bank, I have a starter battery for port, starboard and the generator. Can't I just leave them as-is and have them charged with the custom Lithium profiles above? Even if these are sub-optimal charging profiles, these are used just for start-cranking and by definition charge themselves as soon as they are used. But maybe I am confused and these 3 lead batteries are only charged by the dino-gas engines and I do not have to worry about the differing profiles.

Creation and Installation:
Alright so I buy quality cells from Winston, Sinopoly, CALB or A123.

Space & Size – this is easy, my battery bay is 15 inches tall so I do not even have to worry about laying them on their side. I could theoretically fit 20 cells of 400 ah each for 2000 ah at 12v! Wow that is a ridiculous amount of amp hours. Currently I believe I will go for about 700-900 amp-hours of Lithium. So space, no problem.

Then it comes down to reputable dealer, stock, shipping to St. Martin and then finally price. Would love current, specific recommendations. The various threads go back years and vendor performance changes.

So, assume that I buy 8x 400 ah prismatic cells to build a 2p4s 800ah house bank. This would take up less than half my battery bay and have room left over in case our energy consumption changes in the future. I see I can buy 0.8C for $466, and 1C for $508, it is a small price difference, but I have no known use for draining my batteries even at 0.8C, so I should just go with the 0.8C – correct? These would have a nominal cost of about $3800 from Lithium Batteries - Prismatic

I ship these 8 cells to St. Martin and buy/borrow a quality bench top power supply and perform the top-balancing that is well documented in several places.

While allowing these batteries to settle as long as possible (2-6 weeks), I build a compression case to hold these batteries and protect them from vibration wear and tear.

Day of Switch-Over
Change the power charging profiles on the 3 Outbacks and the Xantrex while still connected up to the Lifeline AGMs.

1. Shutoff all equipment.
   
2. Remove all equipment from the 12v socket receptacles.
   
3. Kill the solar via the circuit breakers.
   
4. Use the manual disconnect for the house bank
   
5. Use the manual battery disconnect for the 3 lead acid starter batteries
   
6. Disconnect the AGMs. Lift those heavy f*ckers out the stbd hatch.
   
7. Install the compression case for the Lithium
   
8. Install the individual Lithium cells, now in their final 2p4s configuration (do this at least once before day of install to be sure the bank is working as planned and fits into its compression case).
   
9. Connect the Lithium house bank
   
10. Verify voltages (DVM) and wiring (pretty much all the time.)
    
11. Manually re-connect the house bank
    
12. Check the voltage at the 12v socket receptacles.
    
13. Turn on something simple and cheap like fans, assuming that the fans are working and happy, start turning on equipment in escalating value
    
14. Once everything the house normally runs is up and running, start to verify charging is working well.
    
15. Manually re-connect the solar at their circuit breakers, verify the Outback is still on the current charge profile – maybe it got reset with the power off – so check again.
    
16. Verify that the Xantrex has its correct profile. Assuming that the house bank was at 50% SoC, before the Solar takes up, turn on the generator and have the Xantrex fill the lithiums, verify that it shuts off and not over charges. This should also be a good test of the Outbacks.
    
17. And done, I have a working lithium house bank.

I also have an unexpected benefit of this setup:
By using the Outbacks and Xantrex charge profiles, I still have the ability to re-install a lead house bank if for example I had a total failure of the Lithium bank in a remote Pacific Atoll with only some lead available on the supply ship.

The current draw-backs that I know of:

1. Relying on the pack-level voltage monitoring of the Xantrex and 3 Outback controllers, so after the initial balancing I would not have cell-level voltage monitoring. But I could address this by buying some more stuff (would appreciate suggestions) for these 8 cells.
   
2. No automatic low-voltage load cutoffs. The Outbacks actually have low-voltage option so I could isolate my lower priority loads to a bar to be automatically cutoff. The Xantrex already has a low-voltage setting for the inverter and this is practically the only thing that sends my house battery low right now. So I still feel like I do not need this.

Other Questions:
What are the smaller bits that I should buy at the same time as my order?

1. Bits?
   Some braided connectors? My own desktop power supply? A few more manual emergency disconnect switches? Heavy red&black cable (expensive on islands)? Terminals.
   
2. Induction Cooking?
   We currently use propane and butane for cooking gas. I like the idea of switching over, or at least having the option of using an induction cooktop. In daily use, what is your typical amp-hour usage for cooking by induction. And I assume that the Xantrex 3 kw inverter is strong enough? (If I know what typical induction amp-hour usage is, it might change my designed size to 1200 amp-hours of Lithium.)
   
3. Filling SCUBA Bottles?
   Does anyone have experience using a Baer Junior air compressor with the electric option? What does it take to fill an 80L tank? I have seen estimates of 220v @ 14 amps for 18 minutes = 77 amp-hours to 600 amp-hours. With our 2050 solar install, I have been averaging 700 amp-hours per day here in the West Indies. We have 3 divers on board and typically dive 2-3x a week. Fills are sometimes hard to get ashore. I would like to avoid a gas-driven compressor. If it took say 200-300 amp-hours per bottle, then a group dive is 600-900 amp hours. Our typical daily use about 430 amp-hours including washing clothes, ice and water-making. So, I believe I am currently throwing away ~300 amp-hours of energy every day. With planning it seems like I could keep our bottles filled off of solar/lithium/invert with careful use of each day's power generation. If not, I have the 5k generator to supplement the solar on a big fill day. Am I thinking about this wrongly?

Thank you again for everyone being so generous with their time and hard-won experience and skills.

-Erik

Hi,

I have been reading this thread with a lot of interest, as I am in a similar situation, and have found some of the solutions you are looking for.
First most people should acknowledge that not every battery is good for everyone. Second, for the most part there is two separate economic portions of this conversation. The initial cost, and the long term cost. Initial cost goes handily to 6v GC2 size batteries to get a decent size capacity. Long term maintenance, life, charging time with associated decreasing life of your engine/generator, weight etc. makes lithium the better choice.

Commercial lithium battery systems are not priced well enough for the market. Yes, they do put a lot of engineering into their products, to make a safe and reliable battery. However, a DIY system from someone who understands all the variables, dangers, and issues can be just as good or better. I really like the lithionics batteries. The cost of these batteries per capacity of the bank, plus the size does not fit my available space makes this solution not worth it to me at this time. Likewise, with the victron batteries. since I have a lot of Victron gear those are really attractive as they communicate and operate better together out of the box. The shape of the area does not allow for the quantity of these batteries that would give me the capacity I am looking for.

There are dangers with lithium, but that has been found to be mostly charging issues, overcharging/undercharging. This is the part where you must spend a lot of time looking into and figuring things out, as a small oops can be catastrophic. The second major fire related issue is simply the ability to but massive amperage through a dead short. If your wiring system isn’t up to snuff, or you took even a small shortcut it could easily burn your boat to the waterline. Lithium’s produce oxygen in these situations so once they catch it’s like burning magnesium and difficult to put out. Put energy and thought into fire suppression and containment, IE plan for the worse and hope for the best.

Someone posted about mixing a lithium and a lead bank. DON’T! your setting yourself up for overcharging and fire. It isn’t even ok to mix different chemistries of lead battery. Different charging and discharging voltages, with the lead typically being a higher voltage than lithium. If your charging the lead bank and your lithium is already full or close to it, an oops like accidently connecting them, or a programmable connecting relay that’s not quite right can overcharge the lithium’s (situation causing most of the fires). I’m not saying this can’t be done, but you must fully isolate the two banks and there are too many ways to have an issue.

Similarly, your alternator is a big danger with lithium. You have to have a programmable regulator set for the voltages on your specific lithium batteries. Depending on your wiring, is usually really bad to switch off your alternator while the engine is running. Fries alternators. Find a good programmable regulator and really learn what your specific lithium’s voltage limits are. Most charge to about 90-95% max voltage. Look at the VSR regulator it’s an Arduino based regulator that looks pretty promising, however I don’t have any practical experience with how robust it is. Another option is to use a higher voltage alternator like a 24v alternator for a 12v system, and feed it into a MPPT charge controller.

In order to isolate banks with two different chemistries, I contacted Victron and their MPPT charge controllers will work to charge a second bank from a house bank. This generally has to be a higher voltage feeding a lower voltage. I didn’t look at morning star or other brands. For instance, I have a 24v system, I can charge my 12v starting battery this way. These Victron MPPT controllers can also act as a power supply so you could use your 24v bank with a 12v charge controller as a DC to DC converter to supply your 12v equipment. Victron says on their site that this doesn’t work as well with really small loads, as the controller wont sense them necessarily. You can use this to set up a “buffer” battery. Use a MPPT controller to charge a single 12v battery, which feeds your circuit panel, loads are initially taken from the battery but the charge controller will see the drop and feed the system.

The BMS/No BMS debate likewise has been heated. Read an DIY EV forum to see how bad it can get. In general, even those that oppose BMS are coming around, as a lot of the fires are caused by overcharging. Spend your money and time finding a very good BMS that specifically works with your batteries and other components. Yes, you could manually charge your bank with a switch and a voltage meter. But everyone also monitors the electrolyte levels for their 6v wet cells perfectly. What happens is you get busy, or distracted, or it’s been a while since you were on the boat, and you forgot the exact voltages or procedures…

just as important the BMS will protect against too deep of a discharge which is just as dangerous, maybe more so than over charging. A good BMS will have high voltage isolation relay switches that can turn off the battery completely in case of overcharge or over discharge. Think of this as extra insurance for oops. Think about a refrigerator, water heater, or constantly cycling pump and the shore power connection gets shut off, for marina work ect. If a lithium drains all the way, it damages the cells. maybe they will all come back, maybe some will and one or two wont which is where the danger is and the potential to catch fire. With a few cells down, now your battery is at lower voltage, but your chargers are programmed to charge at the original higher voltage. The batteries now overcharge. A good BMS protects you from this issue, however you also must consider how your boat is wired and either turn off draining loads like this, or wiring them to the side of the inverter or inverter charger that cuts off in the absence of shore or generator power.

Most BMS’s use the CAN bus to communicate. There are differences between CAN networks however and you have to verify your equipment is compatible. Outback seems to be more compatible with a larger range of equipment. Victrons can bus is NMEA2k with a different connector, and I have only found a few units that are verified to work with my victron gear. REC BMS for sure, I have seen smart BMS working with a victron system and Color control on youtube, and I have heard that bactrium works, and Orion may work. It is possible with some BMS and equipment to use a signal and relay to indicate if it needs charging, or to stop charging, so you don’t have to have CAN necessarily. Your equipment will be different and you will have to get really knowledgeable. I also recommend after install you write up your own “manual” with this stuff, as you are not necessarily the only person operating or working on your boat. If you prescribe to a more manual system that must be closely monitored, that means you could forget things in between, or have difficulty in selling the boat later, as most people don’t want complicated stuff like that. The more automatic your system the better in that regard.

Your Bauer compressor and other high AC loads is possible with a big enough bank, but you really need to looking into your entire system for that. A 3000kva inverter is unlikely to do so on its own. If it’s a hybrid inverter that adds to the power coming off shore power (victron power assist function of its inverter chargers), a honda2k, or small generator you may be able to do it. the problem with the big AC motors is the startup current. It may run on 14amps @220 however it will need 30+ to start up which will overload your systems if your AC isn’t set up for it. Easy start devices will reduce this surge, but without oversizing your inverter and big upgrades to your AC system this may be a no go without a generator. I am looking at a 5kva+ size Victron inverter charger as I have a Bauer Oceanus 5hp compressor. Run time for an 80 scuba tank is somewhere in the 20-45 minutes for the Bauer junior. It is possible to run off a big bank, but we are talking about mandatory running the engine, or generator as it will suck up a lot of amp hours. Not impossible, I am doing this myself.

As far as the induction heating goes, again it is possible, but severly limits you. an electric oven i just see draining your bank completely. you either will have to have a really big bank or run your generator to use it much. thats a pain especially in a quite area. a Propane stove is easier to repair and maintain. there is a lot to be said about a good microwave. high power but only for a few moments. another possibility is an instantpot, or electric kettle ect I havent measured the loads from these devices but i suspect it must be better than an electric cook top. you could experiment with a single burner electric hot plate, and see if that works with your boat and bank.

V/R

Robert

[kmacdonald]

Originally Posted by Dave_S

Dumb question.........

When a lithium battery is at 20% is it's output the same as an AGM at 50% or at 20%

Will the lithium batteries run the electrics, start engines etc at 80% discharge.

In other words, is it functional at that level of charge.

Yes!!!!!!!!!!!

[alaskanviking]

Other lithium batteries – right now I am looking hard at the Tesla, Volt, and Leaf battery modules. This seems to be the cheapest per amp hour capacity. There are issues here, you can’t just toss one of these in your boat and go. A lithionics or victron commercial battery is around the $4-7K range for a 24v 200-250ah battery. Tesla (84KW) modules are 24v @ 220ah, and can be purchased from $900-1400 right now. The entire 16kw volt battery module can be purchased for $3-4k. the tesla’s have the most capacity for a given area. At ~24”X 11”X 3” a stack of 3 is close to the same as a big 8d battery, but would have 660AH’s. I should point out that you can’t simply stack these. EVTV does this in a wall mount system they make, however a boat is closer to a car, and will be bouncing and moving with the waves. There are little wires fusing the little cells of these modules on the top and bottom of these, a boat in swells, could generate a lot of force that could crush the batteries enough to short out or damage the modules. Even if a few cells get damaged the battery charge parameters change for a possible overcharge later., but worst case you have some dead shorts and potential fire, not a good thing in the weather that could cause this issue.

These battery modules are heavily engineered due to liability and legal issues from being in an auto. crashes have created battery fires. boats are not that disimilar with motion and vibrations. our solution to use these batteries is proper mounting and support. The EV folks recommend a metal case, solidly mounting the modules inside, separated by a good 1” or more with a layer of fire resistant material or insulation between. They also recommend to plumb in a CO2 extinguishing system, that is controlled by a temp sensor inside the case. In theory The CO2 will cool the batteries to the point where the cells don’t create their own oxygen. They also recommend plumbing in a saltwater feed with remote valve as a last ditch effort. in case of fire flood the cases completely. Depending on where this bank will be located, such a case must be waterproof if using tesla batteries because of all the exposed fuse wires inside the module. In my case I will be making a new bank on either side of the mast in the bilge. If water was in my bilge and got to the bottom of these modules it would short out the lower modules, and connect the positive and negative of the upper batteries to the water, shorting out the entire bank. This complicates a tesla install and makes it more expensive, not impossible. Volt or leaf modules have the terminals on top the same as a lead battery so that issue isn’t as bad – Note that lead batteries have that same issue here if they are submerged.

The Tesla modules have a slave BMS board already on them, that will save you a bit. Technically that is all you need but you won’t be able to monitor them. EVTV has a master BMS controller that interfaces with these modules. Unfortunately, while it does connect via CAN, I don’t believe the EVTV controller will talk to the Victron equipment. This means if I decide to use tesla modules, I will have to pull that board out and connect the wires to a new BMS, which complicates that install. The Volt and Leaf batteries need a BMS and you have to wire it up yourself, however their terminals are far easier to access.

Voltages could be a potential problem. Tesla modules range from 19-24v and are 22v at 70%. The volt batteries have 2 configurations for their modules, a 24v and a 48v. like tesla these are also lower than lead batteries. regular Lead acid/AGMs are around 11-13.5v and I have seen 14v before on some systems while charging. This means that some equipment may not be happy or work at all except when the bank is fully charged. Most Inverters should be ok, and motors generally shouldn’t be affected. A lot of equipment accepts a wide range of voltage. But you will have to look at the manuals and verify. Specifically look at the refrigerator systems. Their controls could shut off below a certain voltage regardless if there is enough capacity of the battery, that issue can affect any DIY lithium battery banks depending on how many cells you use.
It is possible to cut the metal plates connecting the terminals of a Volt battery and rewire to make a 48v module into a 24v, or a 24v into a 12v. this is complicated, and has some hazards, that I’m not certain I can recommend. It’s not for the uninformed, or most DIY installs. Unfortunately for the tesla and volt modules you cannot take the packs a part and reconfigure them for different voltages. The leaf modules can be taken apart and put together, allowing you to arrange for a bank that is closer to lead acid voltages. Look on you tube, there is a couple that put a large leaf pack into their RV and have a lot of info on such a build. They added modules so their pack ranges from ~48-51volts.

The tesla and volt battery modules have integrated water coolant/heating channels. This is an advantage over other lithium systems and chemistries in cold weather including the Prism cells. Lead acid batteries aren’t very good in cold weather charging either, but lithium cells will be damaged if you charge them below freezing. to clarify You can use the batteries, you can’t charge them. That means that in most systems you won’t be able to start the engine until the batteries are warmed up, because the alternator charge current. With Prism cells or leaf cells you can use electric blankets or mats, but the water systems are more efficient, and can also cool the batteries. Cooler batteries = less chance of fire. I was planning on getting a small 1-2 gallon water heater, and a small efficient pump in conjunction with temperature sensors. The Victron inverter chargers and the color control GX has programmable relays that can be used to turn on the cooling pump when charging or discharge currents exceed a set amount, or the batteries hit a certain temperature. This may not be needed for a boat system and it’s a bit more complicated than other systems, but ultimately I think it’s another safety feature that can be added, and essential for cold weather sailing areas. I am heading to the PNW later so this is a concern for me.

Originally my batteries were installed in the engine compartment. The PO moved them under the bed in the master stateroom, where they are difficult to access for maintenance and make the boat list to one side from the weight. He had a pair of ~5 year old AGM’s, however he didn’t upgrade the charger. The 30yo charger ultimately cooked the AGM’s. I changed to a 24v bank from 12v in 2010-2011 using 6v Cosco GC2 batteries. The higher voltage is worth it. it is more efficient as you essentially just doubled your wire size and reduced the resistance the battery sees. End result is the alternator, and new charger are more efficient and equipment uses a little bit less. Maybe 10-15% depending on what it is. Now that I’m looking to change batteries again, and due to upgrading my AC system I have been considering changing to a 48v system. I see autos, and more equipment moving to 48v. I suspect Diesel electric hybrid systems will be available in the next 5 years or so. So this means future proofing if I do so now, and put in a big 48v bank. The inverter would see a large drop in max amperage with 48v. There are 48v electric motors that are big enough to swap my diesel engine out, and there are 1-5hp 48v motors that could replace equivalent A/C and scuba compressor motors for an all DC system, but we are looking at a mostly DIY system at this point. I am on the fence as there isn’t a lot of 48v equipment, or 48v to 24v or 12v converters. There isn’t an easy conversion for my windlass or bow thrusters, so I would have to use a boost battery setup. There are a lot of 24v to 12v converters so staying with 24v is easier.

My boat isn’t necessarily power hungry, but I am not looking for a pure traditional vessel either. I have switched to all LED’s and more efficient equipment. I am doing major AC upgrades because of my scuba compressor. My main reason for installing a large a battery bank as I can reasonably fit is so I don’t have to use the engine, generator or shore power for as long as possible. I don’t want to listen to a motor if I can manage it. likewise sailing long stretches with navigation lights, radar, autopilot and other possible running systems. A big lithium bank will push recharging times far out. I am looking for close to 1000ah's. I also can take advantage of the Victron equipment and color control when away from the boat for longer periods and only keep them charged to 70% or so, as unlike my lead batteries now lithium doesn’t sulfate. The remote monitoring is handy too

V/R

Robert

[john61ct]

TL;DR

Yes a properly implemented LFP bank is expensive.

But it is the only safe chemistry other than the lead ones.

If you don't want to spend that much, just stick with lead.

One day properly engineered BMS and safety systems will exist for other LI chemistries, maybe even make repurposed EV packs safe enough.

But not yet, and likely not for years.

If you (think you) have the engineering skills and want to play mad scientist with just your own life and property, go for it, but don't endanger others.

[CatNewBee]

Originally Posted by alaskanviking

Hi,

....As far as the induction heating goes, again it is possible, but severly limits you. an electric oven i just see draining your bank completely. you either will have to have a really big bank or run your generator to use it much. thats a pain especially in a quite area. a Propane stove is easier to repair and maintain. there is a lot to be said about a good microwave. high power but only for a few moments. another possibility is an instantpot, or electric kettle ect I havent measured the loads from these devices but i suspect it must be better than an electric cook top. you could experiment with a single burner electric hot plate, and see if that works with your boat and bank.

V/R

Robert

Well, this is what I am doing, full induction cooktop, mid size convection oven, 4x1000Ah Winston cells, REC ABMS, 1650Wp solar, Victron MPPT 150/100, Victron Quattro 12/5000-220 100/100, Mastervolt MassSine 2000, both inverter can team up by power assist.

There is a backu generator 9kVA Onan.

Solar and LFP are sufficient for daily cooking, 3 fridges/freezers and 1x per day hot water (160Ah for 40l with 1200W heater) on almost sunny days, All day rain drains the battery by 200-300Ah at the end of the day by this usage, recharges to full the next day late afternoon if sunny. See separate post for details. Electric galley is doable.

I dont know what kind of sophisticated meals you are cooking and how long it takes, but it cant be too complicated with a 3 burner propane stove, the induction field can handle this probably too (up to 4 burner variable areas).

The battery yelds from full (3.65V cell voltage) to empty (2.9V cell voltage) 1300Ah (measured), what translates to 15kWh stored energy. That is a lot of juice. My daily consumption is between 4.5kWh and 6kWh.

[CatNewBee]

[sailjumanji]

So anyone have experience with the Mastervolt Ultra Lithium Ion series with integrated BMS and Masterbus communication? Having a Seawind cat built and their vendor is Mastervolt, with Mass Combi inverter/charger and SCM 60 MPPT control for solar. Cat with outboards, no generator, but 800 watts solar. Their standard battery is Mastervolt 270 amp-hr AGM. Option is two 225 amp hr. Owners report 80-100 amp hrs overnight drain. So 450 amp-hr AGM bank should be sufficient. Mastervolt makes a 360 amp-hr Ultra Lithium. Wondering what else I would need to change or add if going with the Ultra Lithium.

[alaskanviking]

Originally Posted by exitstrategy

What about my lead-acid starting batteries?
Besides the house battery bank, I have a starter battery for port, starboard and the generator. Can't I just leave them as-is and have them charged with the custom Lithium profiles above? Even if these are sub-optimal charging profiles, these are used just for start-cranking and by definition charge themselves as soon as they are used. But maybe I am confused and these 3 lead batteries are only charged by the dino-gas engines and I do not have to worry about the differing profiles.

The different chemistries have to be separated. Lead acid/AGM charge between 14.6 – 14.8V with a 13.6V – 13.8V standby voltage.
LiFePO4 have a nominal voltage of about 3.2V or 3.3V. lithium-polymer Li-Po batteries have a nominal voltage of 3.6V per cell. With Li-ion and LiPo batteries the recommended per-cell safety zone is usually between 3V (fully discharged) and 4.2V (fully charged) keep in mind 4.2v is your threshold and touching on overcharging. I have seen a lot of recommendations to only charge to a max of 3.8-4.0v per cell

So in reality this all depends on how many cells you use in a series string. 4 X 3.3v = 14.4v, or 16v charging to 4v per cell. This is on the low side for lead, but in theory would work. 3 cells = 9.9v, or 12v charging. This is too low to charge. Higher voltages are a little easier.

The next issue is the different charging stages. Bulk, Absorption, float ect. You don’t really need those with lithium, mostly charge at bulk until you hit your required max voltage than stop. That will mess up your lead acid start batteries which need the different phases. The lithium doesn’t need a float, although that gives you a safety factor when charging. The lead acid does need a float to maintain the charge. It may be possible that your charger has a separate ~5amp starter battery output, however I don’t know if that is programmable separately. I think its whatever the charger is set at.

With the 4 cell string in theory you could use a bank interconnect switch if your starter battery was dead. However, I believe a fully charged starter battery at 14.8v connected that way would “trickle charge” the lithium if you left the switch on, overcharging your lithium – potential fire hazard. Likewise, I don’t think you can use a voltage relay charger, or the same charger without a lot of potential issues

With a bank using any lithium chemistry I would separate the two banks completely. Lithium bank would charge via inverter charger or charger, solar, alternator ect. Start battery would get its own charger or trickle charger and in my case a MPPT solar controller between the two banks, as I have a 24v bank and a 12v starter bank. If its 12v to 12v, Sterling energy has a battery to battery charger, and for an emergency “my starter battery is dead” I would use a hidden interconnect switch, I think there are BEP or blue seas switches that use a key. I wouldn’t want this switch easily accessible, maybe mounted next to the starter battery in the eng compartment. I can see a scenario where a friend on board is trying to “help” get underway ect. As a boat may go to another owner at some point I would recommend a sign or tag that gives direction to not have it switched on when charging and only use when the starter battery is dead. Last thing someone needs is the liability and law suit from a lithium fire because the new owner didn’t realize the danger, and flipped the switch to charge like you would normally in some boats. Because of this last bit, it may be best not to connect an interconnect switch at all.

V/R

Robert

[alaskanviking]

Originally Posted by john61ct

TL;DR

Yes a properly implemented LFP bank is expensive.

But it is the only safe chemistry other than the lead ones.

If you don't want to spend that much, just stick with lead.

One day properly engineered BMS and safety systems will exist for other LI chemistries, maybe even make repurposed EV packs safe enough.

But not yet, and likely not for years.

If you (think you) have the engineering skills and want to play mad scientist with just your own life and property, go for it, but don't endanger others.

It’s not necessarily about the expense as it is the area its stored in and the capacity. The lower cost per area and per KW for the EV batteries is just a sweet extra. I haven’t ruled out LFP. I’m just looking at the possibility of using an EV battery due to the capacity I can get in a form factor that seems to fit my space better. I have been looking at commercial units to, although that seems to be a bit too ridiculous in price yet. Maybe in a few years’ commercial systems will have a reasonable price per KW and area.
However, it is not completely accurate to say LFP is the safest. it takes someone with better than average engineering skills to install a DIY LFP system, Designed and installed correctly you can use other chemistries. There are BMS’s that make these safe enough.
Honestly all batteries are inherently dangerous. lead cells can vent and blow up, any lithium can send massive amounts of current through a dead short or person in an instant. I’d even say that 12v lead are the most dangerous as there seems to be a sense of complacency and ignorance when regarding low voltage. I see some crazy wiring death traps, caused by owners doing their own electrical work, or pro’s taking short cuts. That’s far more dangerous to others. There was a power boat 5 slips away that had a 120/240 inlet catch on fire, while the owner was gone for several months. Luckily people were walking by when it happened and were able to cut power and put out the fire.
It’s a bit overboard to assume someone will automatically endanger others, as anyone that installs a new battery bank of any chemistry, or in reality does any electrical work, and doesn’t fully understand what they’re doing is a danger! That probably should include those that are knowledgeable but are not very spatially inclined, ie knowing where their body parts and appendages are / clumsy, or sloppy and leave stuff around while they’re working. I’ve seen and worked with both unfortunately.