Solar and Battery bank build

[Jbradley15]

Disclaimer: I'm new here and all of the things I am doing is with limited wits and knowedge of how solar systems and how energy systems in general work. Any help is greatly appriciated.

Hey all, I am just finishing purchasing a Wauquiez Amphitrite 43 and since the batteries are trashed for the power bank (and the engine power) I have found myself in a position that I am able to design a new battery system and will be using a combination of alternator power and solar power to maintain and charge these battery banks.

Heres what I am thinking:

I would like to use two to four Renogy Deep Cycle AGM Battery 12 Volt 200Ah for the main battery bank and two Optima Batteries 8004-003 34/78 RedTop Starting Battery for the engine power.

side note: I will be having children sleeping above the battery banks so FLA is out of the question for me.

I'm a little shaky on the voltage regulators etc and I will be doing more research on how to charge these batteries correctly, I read AGM and SLA can have serious issues if they are overcharged and would like to prevent that while using a large brushless alternator such as this one (https://www.discountstarterandaltern...single-2spool/) when the solar power doesn't keep up or when I need to top the batteries (wikipedia said once every three months will preserve battery life on AGM batteries, please tell me if thats wrong).

I am okay with arduino and raspberry pie and am considering using these to create a voltage and amperage regulator, I still need to learn more about what exactly these batteries need to build something like this. I might just buy a regulator depending on price and system fit.

So I'm a bit shaky on all of this but mostly the solar arrays and I have a pretty specific set of perameters I will be needing to deal with. Since everything on a sailboat is a compromise I will just list the "perfect" solar panel syetem and start compromising from there.

- great surface area to power ratio (smaller is better)
- flexable would be nice but I don't want to reduce effiency if possible
- strong enough to be constantly exposed to bouncing around on waves and wind with the boat
- waterproof (obviously)
- able to survive a few years of exposure to salty air
- either be easily moved yet still secure or try to eliminate the problem of bad amperage with partial shading (this is a major focus)
- and I want to be able to fix it when I break it (I will break it)

I have found out that partially shading a solar panel can cause MASSIVE amperage drops whe even a small area of the panel has been shaded. Im figuring that this is caused by the way the panels are wired (PLEASE CORRECT ME IF I'M WRONG). I have also considered mounting solar cells encapsulated in some sort of resin to a canvas cloth (maybe 24" X 24") with some form of quick disconnect to a power grid and slide in edge supports (cut down broom handles or something) to create a removable frame and be able to fold the panel for better storage while we are under way.

In a feeble attempt to save money and design the panels with alternative wiring (shading problem fix hopefully) I am planning on building the panels myself. I will keep you guys updated on how this project goes.

[Jbradley15]

some friendly folks on reddit have changed my mind about power storage, I now believe that LiFePO4 batteries are superior in every way to any lead acid technology. I am specifically looking at this sokbattery https://www.sokbattery.com/products/...ifepo4-battery with this charger for my battery bank setup?

I specifically like this one just because its cheap(ish), carries a support team / warranty, its serviceable and (although its currently out of stock) appears easier to buy if I ever needed to increase my power bank size than the chinese cells that a lot of people seem to be using.

I'm thinking that 206 AH would be enough but I'm confident that I can buy another one to easily double my storage.

My inverter is a Prosine 2.0 and I believe that will be sufficient, no need to spend money there and the alternator also seems to be acceptable in quality so I'm going to try to save some money there also.

It's gonna take a while for this battery to show up so I have some waiting to do.

[cr180]

First, full disclosure, my experience is Florida and Bahamas cruising. Two thoughts,
1) Solar power in your region may be iffy, and
2) Ask how many Reddit folks that have convinced you LiFePo battles are superior have actually cruised? Think the LiFePo technology has enormous potential, but expensive and maybe not proven by those of us who cruise. Have had decades of experience with Trojan T105 batteries. Never let me down. Take a look.

[MerMike]

I'm pretty sure there is no reliable way to use drop-in LiFePO4 batteries in a marine configuration and maintain reliable protection for your alternators. With no communication between the battery BMS and the rest of your system, a disconnect commanded by the BMS will damage the diodes in your alternator if it happens while under load.

I understand there are devices like the Sterling BatteryProtect. What I don't know, and remain suspicious of, is whether such a device can be continually relied on. I'm thinking not.

There are 2 paths that are known to work. One is a DIY battery pack with an external BMS, that works in concert with the alternator voltage regulation, either directly though a protocol like CanBus, or through relays that drop the field before disconnect. In both cases you can receive alarms prior to the disconnect.

The other path is through a battery system that has a BMS built in that performs the communication function. Lithionics is the one that most readily comes to mind. Victron also makes such a system but it works only with their equipment.

I'm certainly interested in hearing how this might be accomplished with a level of reliability that satisfies me, but I have not seen a solution yet.

[Jbradley15]

Originally Posted by MerMike

I'm pretty sure there is no reliable way to use drop-in LiFePO4 batteries in a marine configuration and maintain reliable protection for your alternators. With no communication between the battery BMS and the rest of your system, a disconnect commanded by the BMS will damage the diodes in your alternator if it happens while under load.

I understand there are devices like the Sterling BatteryProtect. What I don't know, and remain suspicious of, is whether such a device can be continually relied on. I'm thinking not.

There are 2 paths that are known to work. One is a DIY battery pack with an external BMS, that works in concert with the alternator voltage regulation, either directly though a protocol like CanBus, or through relays that drop the field before disconnect. In both cases you can receive alarms prior to the disconnect.

The other path is through a battery system that has a BMS built in that performs the communication function. Lithionics is the one that most readily comes to mind. Victron also makes such a system but it works only with their equipment.

I'm certainly interested in hearing how this might be accomplished with a level of reliability that satisfies me, but I have not seen a solution yet.

thanks for the input, I have found some other issues with the formentioned charger. The main one was that it only supports a 25 amp charge from the solar array or the alternator which would make the solar panel hard to find a with low volts and then I would have to run them parallel and use much heavier guage wire, all of which I dont like.

Instead I think I'm going to go with a renogy rover 40 amp charge controller which would be dedicated to solar (and wind if I decide on that later) and then run a dedicated DC-DC charger like this https://www.fisheriessupply.com/prod...50-400w-en-pdf. Another benefit of this renology charger is that I can add a bluetooth adapter and have that wirelessly run to my computer with data recording so I can see a problem before it becomes a problem.

I am happy with the internal yet serviceable BMS in the battery, if it ever failed it looks like it would take almost no time to replace. If this wasnt servicable I probably would want to build my own battery with an external BMS.

dedicating a customizable DC-DC charger appears to be a winning solution to what you had said and the other problems I have found.

The massive discharge rate, huge amount of cycles and the safety of the LiFePO4 batteries are really attractive to me. The cost of the battery is about $1000 and comes with a pretty good warranty. $1000 for 206 AH is pretty reasonable when you take into account that 164 amps are available compaired to using AGM 6v batteries (also should be charged carefully) running at 200 AH each I would have to buy and store 4 of them and due to the discharge rate of 50% on an AGM giving me about 200 AH of useable energy. I would be lucky to get that battery pack for less than $1000 and the weight and space savings on LiFePO4 are also very attractive to me.

I'm not trying to discredit anyone, just showing some of my research.

I'm probably wrong about most of this but I haven't figured out why yet.

[MerMike]

The Victron DC-DC chargers can also be paralleled, which will be necessary as they deliver only 30A of charging per spec. If you take out 150A, that's 5+ hours to return it to the bank with a single charger.

Make sure you install them in a well ventilated area, as they get warm at max output.

Edit - one more note, unless you're using them as isolated power supplies, you can use the non-isolated versions, which are about $20 cheaper.

[foggysail]

Originally Posted by cr180

First, full disclosure, my experience is Florida and Bahamas cruising. Two thoughts,
1) Solar power in your region may be iffy, and
2) Ask how many Reddit folks that have convinced you LiFePo battles are superior have actually cruised? Think the LiFePo technology has enormous potential, but expensive and maybe not proven by those of us who cruise. Have had decades of experience with Trojan T105 batteries. Never let me down. Take a look.

Agree with you about your T105s although very pricey around here. I recommend Sam's Club IF there are any in the area for East Penns for cost. For what I paid for 8 of them at a Sam's, I think they were priced as a loss leader.

[lmxr]

Originally Posted by Jbradley15

[...]Hey all, I am just finishing purchasing a Wauquiez Amphitrite 43 and since the batteries are trashed for the power bank (and the engine power) I have found myself in a position that I am able to design a new battery system and will be using a combination of alternator power and solar power to maintain and charge these battery banks.

Heres what I am thinking:

I would like to use two to four Renogy Deep Cycle AGM Battery 12 Volt 200Ah for the main battery bank and two Optima Batteries 8004-003 34/78 RedTop Starting Battery for the engine power.

side note: I will be having children sleeping above the battery banks so FLA is out of the question for me.

Understandable about not wanting to sleep above batteries! I've heard that CO alarms are also sensitive to LA battery gassing. Installing one very close to the batteries might provide an additional level of safety. Not sure whether the RedTops still live up to their name.

I'm a little shaky on the voltage regulators etc and I will be doing more research on how to charge these batteries correctly, I read AGM and SLA can have serious issues if they are overcharged and would like to prevent that while using a large brushless alternator such as this one (https://www.discountstarterandaltern...single-2spool/) when the solar power doesn't keep up or when I need to top the batteries (wikipedia said once every three months will preserve battery life on AGM batteries, please tell me if thats wrong).

AGM is indeed rather sensitive to overcharging (same for Gel), far more than FLA. SLA is somewhat in between. Overcharging occurs when the chargers stay too long in the absorption phase. Many chargers advertise their special voltages, but what you actually need is smart logic that transitions to the float phase at the right moment.

The Victron SmartSolar MPPT chargers are really nice in this regard as they offer a lot of programming freedom (far more than just voltages, also absorption time limits, tail current etc.), can talk to each other over Bluetooth such that they synchronize their charge phase and can talk to a battery voltage sensor such that they base their charge phase on the actual battery voltage and not the distorted voltage at their own output. The VE.Direct protocol is open-source so you can easily interface them with a RPi or so if you desire so. They are a bit pricey but you also get something in return.

What kills LA batteries is the sulfation that occurs when they are not fully charged. This occurs very rapidly. Topping up every three months is the very least one should do. One ought to fully charge LA batteries at least once a day.

I am okay with arduino and raspberry pie and am considering using these to create a voltage and amperage regulator, I still need to learn more about what exactly these batteries need to build something like this. I might just buy a regulator depending on price and system fit.

Nice project. In case you haven't yet stumbled on it, this open-source project might provide some inspiration: https://arduinoalternatorregulator.blogspot.com/. Now and then second-hand Balmar regulators pop up for very reasonable prices.

So I'm a bit shaky on all of this but mostly the solar arrays and I have a pretty specific set of perameters I will be needing to deal with. Since everything on a sailboat is a compromise I will just list the "perfect" solar panel syetem and start compromising from there. [...]

It is indeed always a compromise. Some people prefer flexible panels that they carry around the boat. I've the impression those panels spend quite some time inside the boat where they generate little power. I prefer hard panels that are installed such that they can stay outside all the time as I don't like to adjust my day to carrying solar panels around. YMMV.

We studied our boat carefully to see where there is space for panels and then selected suitable panels. We felt that a few hundred Watt-peak (Wp) delivered a significant contribution. A quick picture search on your boat model (nice yacht BTW!) turns up a few locations for hard panels, such on a hard top, on a davits or on the rigid stern railing. It is a sailboat so do take into account where you'll have to be while handling the sails! The hard top might not be that preferable in that regard.

Residential solar panels have shown to do perfectly fine in the marine environment as long as they are supported sufficiently. They also tend to be rather affordable. They are large but they also generate a lot of power if they are unshaded. Smaller panels can be found in RV shops. For the technology you'll want monocrystalline as these generate considerably more power for the same surface area (but generally are also more expensive for the same power). We didn't bother with 'marine grade' as it seems to correlate mostly to the price tag and not to any actual difference in materials, workmanship or design.

I have found out that partially shading a solar panel can cause MASSIVE amperage drops whe even a small area of the panel has been shaded. Im figuring that this is caused by the way the panels are wired (PLEASE CORRECT ME IF I'M WRONG). [...]

Indeed! Excellent observation. Many panels try to address this issue using several strings that are put in series with a bypass diode or put in parallel. Shingled panels come to mind. In the end shading is something we have to live with, I'm afraid.

In a feeble attempt to save money and design the panels with alternative wiring (shading problem fix hopefully) I am planning on building the panels myself. I will keep you guys updated on how this project goes.

While it is your choice what you spend your time on, with such a beautiful yacht I'm afraid I would prefer sailing over building solar panels. I doubt you'll be saving any money and I also doubt they will perform better, yet feel free to prove me wrong. Building something that holds its own in the marine environment is achievable but is not easy. Salt water is a bitch. BTW if you haven't yet be sure to check out the marinehowto site: https://marinehowto.com/. He wrote one of the landmark articles about lithium batteries on boats.

[Jbradley15]

I have ordered the batteries and they should be arriving today, I went with the SOK Battery marine 206 AH batteries https://www.sokbattery.com/products/...ifepo4-battery which have a nice warranty and great reviews. I will let you guys know how it turns out.

I'm signing the final acceptance offer today and should be able to fully tackle this project withing the next few weeks.

[Jbradley15]

I decided I would categorize this build in a few different posts in the correct forums, if you would like to see my lithium power bank build check out this.

https://www.cruisersforum.com/forums...ld-257503.html

I will start posting back here when I get back onto the solar thing.