Greetings and Introduction

[Viking65]

Hello all, my name is Lars and I'm new to the forum and new to solar/LiFePO4.

Two projects on the horizon - a small scale system for my pocket trawler boat to replace the old AGM batteries and even older charger. It's a nicely done system with labeled and nicely run wiring, but time for an upgrade. Maybe 400 watts of solar on the hardtop, 200 Ah of LiFePO4, and the associated bits to hook it all together. I do have an onboard 3.5kw generator and a Balmar alternator on the Yanmar diesel, so plenty of capacity to produce electricity from diesel fuel, but all of that makes noise. Long term for the boat might include switching to something like the 11kw Vetus electric inboard, big 48v battery bank and more solar. Short term is just an upgraded 12v house bank with perhaps 2000w inverter, charger, solar controller, and whatever else is needed to make it all work and be safe. Fancy displays are fine, but not required.

Second nearer term project is an emergency backup battery system for the fall hurricane system here in Florida (summers in Michigan). Just enough to run the fridge and a few lights for a few days with some temporary solar and a small Honda portable generator to top off when needed. This one I think I'll build from the cells up, while the boat will get commercial/retail equipment since it will be left unattended but powered-up for long stretches.

Any recommendations on the hardware for the boat would be very welcome. Inverter, charger, solar controller, how to connect the alternator/start battery into the system. Lots to learn.

Lars

 

[robbob2112]

Hello and welcome

Below is the normal order of things -- there are a number of basic systems listed in my answer thread that would work for your backup project easy.

For the boat you want to use the ABYC rules and top tier quality stuff -- Generally Victron is designed around that sort of use. Others will work, but for a boat out on the water you want something with redundancy and as few ways to let the moist air in as possible.



Standard Blurb

Don't spend any money, until you have planned out the entire system. An eraser is cheap, but returns can be costly.

Planning

1. Energy Audit - what do you have to power?
2. Size the inverter for your maximum instantaneous demand (including surges).
3. Size the battery for how long you want power, when the sun isn't shining.
4. Size the PV to cover the loads and recharge the battery, when the sun is shining for your area - most in the US use 4hrs or 5 hours a day of sun
5. Trying to use old equipment you already have usually costs more in design compromises than just selling it and doing it right.
6. READ the site - every question you have has probably already been asked - if you have special circumstance - start your own thread.

Design planning

1. Use drawio to design your system if the instructions didn't include a design you can use. https://www.drawio.com/
2. Tilt angle - your latitude is your year round tilt angle - in my case the 5/12 roof pitch is around 22 degrees so is a summer time tilt. My winter tilt is somewhere around 42 degrees - but they would act like a sail and tear my roof off if tilted that far.
3. Don't forget temperature when calculating panel voltage - my 335w panels mounted at 42degrees on the side of the house deliver 408w in winter at 36 degrees.... at 9 degrees it delivers 430w... The voltage increase is similar with an increase in current.

Installing

1. Use https://pvwatts.nrel.gov/pvwatts.php - put in your address and the rest to see how many hours a day of sun
2. Use this when you mount your panels to get the wind and snow loads - https://ascehazardtool.org/
3. Buy quality tool when you do - the cheap stuff is generally inferior and will make bad connections
4. Remember you are dealing with lethal current and voltage - use safety equipment
5. If you are unsure about anything ASK - there are many experts in different fields willing to answer your questions