31.2Kw Victron LiFePO4 Split System Install

[CalmSeasQuest]

Originally Posted by Pizzazz

It is a fascinating setup and definitely pushes the limits of what we are accustomed to on recreational boats. You have done a great job.

The counter argument is what exactly are you trying to optimize for? Capability to run the air con without the generator? Is it worth it to push all this current back and forth and the added complexity? I think at this level we are talking ship sized electrical systems. Wouldn’t a smaller, super quiet, 1800 rpm generator be enough? This is how ships go about it, one or two generators and that’s it. I have also fallen in this trap to keep investing in complex systems, etc. and every couple of years I slim down and simplify the systems on my vessel. At some point you need to balance the complexity vs. the expected utility.

SV Pizzazz

Thanks Pizzaz,

Design complexity is a valid concern (especially since we're out of space for any more blue boxes. ) The goals are multi-faceted; The ability to run AirCons sans GenSet and to optimize our charging processes (solar, Genset and alternator(s)), further reducing reliance on diesel and related maintenance.

Another part of the rationale - We'll be mostly live aboard in the Tropics post-COVID and I have a special needs child whose medical needs have a large influence. These upgrades significantly improve quality of life aboard without having a Genset running 24/7.

In retrospect, I think the system appears more complex on paper than in actuality. "Most" of the components would be needed in a similar sized best-practice single bank. I just split the AC and DC systems to gain redundancy.

[CarlF]

Amazing setup.

While mine is not nearly your scale, I have also struggled with the proper role of solar in a power hungry cruising lifestyle. I quickly decided that it was impractical to have enough solar to provide 100% of the needs indefinitely.

1) If you are running A/C, solar is not going to significantly reduce genset running time so don't worry about it. But that battery bank will certainly let you run the A/C at less than full power in the evening.

2) If not running A/C, then look at the solar as a way to extend the time between genset runs. On my boat I can anchor in the afternoon and go two nights at anchor without starting the genset (assuming reasonable sun). By the second morning after breakfast I either need an hour on the genset or get underway.

I calculated that adding more solar in the less than ideal locations available would not get me to a third day without the genset- so I didn't bother.

[CalmSeasQuest]

Originally Posted by CarlF

Amazing setup.

While mine is not nearly your scale, I have also struggled with the proper role of solar in a power hungry cruising lifestyle. I quickly decided that it was impractical to have enough solar to provide 100% of the needs indefinitely.

1) If you are running A/C, solar is not going to significantly reduce genset running time so don't worry about it. But that battery bank will certainly let you run the A/C at less than full power in the evening.

2) If not running A/C, then look at the solar as a way to extend the time between genset runs. On my boat I can anchor in the afternoon and go two nights at anchor without starting the genset (assuming reasonable sun). By the second morning after breakfast I either need an hour on the genset or get underway.

I calculated that adding more solar in the less than ideal locations available would not get me to a third day without the genset- so I didn't bother.

Thanks Carl,

I agree, solar is the weak link in the system and we'll never have "enough". I spent a lot of time looking for ways to add much more solar but came up empty. My initial plan was to add 3 more Sunpower X22 370W panels by extend the existing solar array further aft. After careful consideration, I wasn't comfortable adding that amount of weight; that far aft.

The remaining options are flex panels on the bimini and Port side coach roof. At best, probably an additional ~600W.

I've decided to wait and see how the existing system performs before making a decision about additional solar. The same applies to the addition of 24V/185A alternator(s).

[NaClyDog]

If you do enough sailing at decent speed, a Watt and Sea might pay for itself in a timely manner. That is on the wish part of our list for now.

[CalmSeasQuest]

Originally Posted by NaClyDog

If you do enough sailing at decent speed, a Watt and Sea might pay for itself in a timely manner. That is on the wish part of our list for now.

Agreed - The Watt & Sea and as a last resort; Wind Generator are on my research list pending how the system performs.

[NaClyDog]

I hope this isn't an imposition but could you keep this thread updated on your research and outcomes, please?


Cheers.

[CalmSeasQuest]

Originally Posted by NaClyDog

I hope this isn't an imposition but could you keep this thread updated on your research and outcomes, please?


Cheers.

Will do

[nebster]

Looks like a pretty nice design to me. You've covered a lot of bases.

Just a few comments/thoughts, for posterity if nothing else.

1. The autotransformer is actually a 32A imbalance device. (The 100A refers to its pass-through capacity on the 230V rails.) It will rebalance up to 32A, or somewhere around 28A continuously. That should be sufficient for your loads.

2. Your inverter-chargers being in your engine area will probably derate when it's warm. On the hottest days, when enclosure temps approach 115F, my units lose nearly 40% of their charging capability. (Perhaps you will be able to cool the room better.) It is a good idea to have quite a bit more inverting capacity than you expect to use, especially because demand is often highest when it's hottest outside.

3. If I were designing this system, I would probably stay with all lithium at 24V (or 48V) but in two or more banks each managed independently, plus a dedicated 12V supply for those loads. This simplifies the design and lets you apply more blue boxes of the exact same type to one, big battery. That either improves redundancy or reduces the number of blue boxes you need (although not necessarily the cost, since you'd end up with fewer, larger ones!).

3b. As you may have discovered, there's no way out of the box to combine the data from unsynchronized inverters onto a single Cerbo GX/VRM instance. This complicates reporting somewhat.

[CalmSeasQuest]

Originally Posted by nebster

Looks like a pretty nice design to me. You've covered a lot of bases.

Just a few comments/thoughts, for posterity if nothing else.

1. The autotransformer is actually a 32A imbalance device. (The 100A refers to its pass-through capacity on the 230V rails.) It will rebalance up to 32A, or somewhere around 28A continuously. That should be sufficient for your loads.

2. Your inverter-chargers being in your engine area will probably derate when it's warm. On the hottest days, when enclosure temps approach 115F, my units lose nearly 40% of their charging capability. (Perhaps you will be able to cool the room better.) It is a good idea to have quite a bit more inverting capacity than you expect to use, especially because demand is often highest when it's hottest outside.

3. If I were designing this system, I would probably stay with all lithium at 24V (or 48V) but in two or more banks each managed independently, plus a dedicated 12V supply for those loads. This simplifies the design and lets you apply more blue boxes of the exact same type to one, big battery. That either improves redundancy or reduces the number of blue boxes you need (although not necessarily the cost, since you'd end up with fewer, larger ones!).

3b. As you may have discovered, there's no way out of the box to combine the data from unsynchronized inverters onto a single Cerbo GX/VRM instance. This complicates reporting somewhat.

Hi Nebster,

This is great information some of which I was not aware of. Thank you very much for your post.

I was not aware of the lesser Autotransformer unbalance limits. I think we should be within the 28A.

I knew there would be some thermal loss on the Multis but I never thought it could be as high as 40%. I’m working on additional cooling for the port engine well (initially for a larger alternator) it we’ll incorporate the Multi cooling as a priority.

We’ve been working on the reporting solution and have come to the same conclusion. I was surprised and disappointed Victron didn’t allow for multi BMS systems reporting. I’m planning on using an existing Color Gx for the DC side and the new Cerbo and Touch for the AC side.

[nebster]

I've found adding extra fans to the inverter can help, to an extent. At some point the surrounding air just has to be cooler, though. That applies to the autotransformer as well; its design pushes the limits for its MCB given the size and convective airflow it has.

For reporting, I ended up assembling a custom dashboard downstream of the Victron screens. The bad news is that you have to do it to get everything joined together in one place. The good news is that Victron makes most of the data accessible via a variety of standard APIs.

[CaptainMCT]

Originally Posted by CalmSeasQuest

Greetings all,

I'm in the process of upgrading the solar and electrical systems on my 2019 Fountain Pajot Saba. After extensive research, I've settled on a somewhat "atypical" design to overcome some single-point-of-failure concerns. I'm new to LFP systems and would greatly appreciate any comments or suggestions offered.

SV Ghost Electrical System Overview
In researching LFP designs I was troubled to learn that an entire battery bank can be shut down by the BMS due to problems with a single cell. If a single battery bank were used, this could result in the vessel going dark. This was not an acceptable outcome. Instead I chose a design that provides redundancy and fault tolerance with automated fail-overs should a battery bank shut down for any reason. To accomplish this, we split the AC and DC systems.

AC Systems
The AC side consists of 1000AH @ 24V Victron LFP driving 2 X 24V, 3Kw-230V and 2 X 24V, 3Kw-115V MultiPlus charger inverters. The bank is maintained by shore power or a 13.5Kw Genset through a 100 Amp Victron Autotransformer (to prevent leg imbalance) and 1850W of Solar. The system is sized to allow us to operate about 20K BTU of AirCons overnight and occasionally throughout the day (i.e. meal prep), sans GenSet. Plans exist for the addition of a 180AH 24V alternator should; based on real world use and performance it be needed. This bank is responsible for the following potential loads,

• 6 AirCon Units – 60K BTU (3 @ 12KBTU, 3 @ 8KBTU fitted with SoftStarts)
• A theoretical maximum of 12Kw of combined 115V/230V inverting
• 280 Amps of 24V battery charging (6720W)
• 12V House Bank Charging - DC/DC 24V/12V @ 60 Amps
• Watermaker - Aquabase YK3 180 L/H (Alternate power source – Genset Primary ~2000W)

24V Fault Tolerance and Fail-Over Rationale
Should the 24V bank encounter a low voltage/SOC condition, the GenSet is configured to auto-start and auto-stop based on pre-programmed values.
Should the BMS shut down the 24V bank for any reason, all critical systems, (Navigation, windless, lighting…) continue to operate off the 600AH 12V bank. Additionally, the GenSet can be started to maintain all AC systems.

DC Systems
The DC system consists of 600AH of 12V Victron LFP. The bank is maintained by 60 Amps of 24V/12V DC/DC charging and the 2 engine alternators fitted with Wakespeed WS500 external regulators. This bank drives,

• All critical vessel DC systems including navigation, communication, autopilot, windless and lighting

12V Fault Tolerance and Fail-Over Rationale
Should the 12V bank suffer a BMS shutdown or low SOC, a relay routes all 12V loads to the Starboard 200AH AGM start battery. The start/fail-over AGMS are charged via individual 24/12 DC/DC chargers. The starboard battery is also charged by the GenSet Alternator (the Starboard engine shares the start battery with the GenSet.) This can also be paralleled with the Port side 200AH start/fail-over battery if needed.

European Power (230V/50Hz) Solution
For shore power use when in locations using 230V/50Hz power, a manually activated system diverts 50Hz shore power only to the pair of 24V/230V MultiPlus charger inverters which charge all battery banks and provides pass-through to the AirCons and watermaker. The 24V-115V MultiPlus’s operate in inverter-only mode supplying 115V service to the vessel.

System Components
Wherever possible we prioritized Victron components as we had extensive Victron equipment already onboard and to maximize interoperability.

5 X Sunpower X22 370W Solar Panels = 1850W (we're working on ways to install additional solar)
5 X Victron SmartSolar MPPT 100/50
5 X Victron 200AH 24V Smart LiFePO4 = 24Kw
2 X Victron 300AH 12V Smart LiFePO4 = 7.2Kw
2 X Victron BMS300200000 VE.Bus BMS
2 X Victron MultiPlus 24V/3000W/70A-50 120V
2 X Victron MultiPlus 24V/3000W/70A-16 230V
1 X Victron Autotransformer 120/240 - 100A
2 X Victron Orion-Tr Smart 12/12-30A (360W) Isolated DC-DC charger (Paralleled 12V House bank)
2 X Victron Orion-Tr Smart 12/12-18 18A Isolated DC-DC Charger (Start/Fail-over)
2 X 200AH 12V AGM Start/Fail-Over batteries
2 X Wakespeed WS500 12V External Voltage Regulators
2 X Sterling Power Alternator Protection Device for 12v (AP12D)
1 X Genset Autostart Functionality (Onan 13.5Kw)
3 X MICRO AIR - ASY-364-X07 EasyStart 3 Ton
3 X MICRO AIR - ASY-364-X36-IP EasyStart 3 Ton
1 X Victron - BPP900450100 Cerbo GX
1 X Victron - BPP900455050 Cerbo Display
2 X Victron - LYN040102100 Lynx Shunt VE.Can
2 X Victron - LYN060102000 Lynx Distributor
XXX PACER - 4/0 AWG Black/Red Battery Cable (more feet then I care to count)
Numerous Blue Sea Systems, Merlin Gerin and E-T-A Fuses, Relays, Switches and Breakers
Battery Tables Created Using 80/20 Extruded Aluminum

There are a few areas yet to be determined such as monitoring. We currently use a Color Control GX and are adding a Cerbo GX with the GX Touch 50 controller. The hope is to transition all to the Cerbo, but it is unclear if it supports multiple BMS.

Thanks again for putting up with such a long post - I truly appreciate your time and any comments or suggestions.

I see your boat often, which charter company? Charterhouse?

[CalmSeasQuest]

Originally Posted by nebster

I've found adding extra fans to the inverter can help, to an extent. At some point the surrounding air just has to be cooler, though. That applies to the autotransformer as well; its design pushes the limits for its MCB given the size and convective airflow it has.

For reporting, I ended up assembling a custom dashboard downstream of the Victron screens. The bad news is that you have to do it to get everything joined together in one place. The good news is that Victron makes most of the data accessible via a variety of standard APIs.

I ran a heat study (attached) on the Port engine well while we were still in the USVI's. Under sustained high RPMs it peaked at 117f and averaged ~92f. I was already planning on additional cooling to extend the cycle life of the 2X 12V LFP Batts. This would included adding a 4" exhausting vent line using a 24V blower. The 2X existing 3" vents line will serve as intakes.

Thankfully the 5X 24V LFPS are away from the engine heat, under the bunk in a well/air conditioned master stateroom.

[CalmSeasQuest]

Originally Posted by CaptainMCT

I see your boat often, which charter company? Charterhouse?

We ran crewed charters with Dream Yacht Charter in the Bahamas and VI's our first year. We were preparing to go cruising this year but COVID forced a delay.

Our present plan (subject to COVID) is to run one more crewed season in the VI's while waiting for a vaccine. Once the world opens up again, we move aboard and go cruising.

[ghrt]

Originally Posted by CalmSeasQuest

[...]

• The 2X 12V/300Ah batteries are also located in the Port engine well as is a 200AH AGM start/fail-over battery.
• The other 200AH AGM start/fail-over battery is located in the Starboard engine well.

I'd try to avoid hot spaces for bateries (either AGM or LFP). They like 25*C. An engine will go easily to 90*C.

[CalmSeasQuest]

Originally Posted by ghrt

I'd try to avoid hot spaces for bateries (either AGM or LFP). They like 25*C. An engine will go easily to 90*C.

Although the bulk of the LFP batteries are being located under the Master bunk, space limitations require some components live in the engine wells. The heat study done in the engine wells (shared a few posts above) show a max temp of 117f and an average of 92f. Although warmer than ideal it is within the operating range of the batteries.

We're adding additional powered cooling to lower ambient tempts to extend battery life cycles and improve the performance of the charger/inverters.