Most sustainable electrical setup

[Dockhead]

Originally Posted by john61ct

Make that electric.

You don't want to **have to** run the engine for hours every day, and the 12V compressor type is 99.99% of the market now, much more reliable and easier to get serviced.

More reliable? Where do you get that information?


Engine driven freeze plate refrigeration is actually a good solution on a small and low power boat. You don't run the engine for "hours every day"; a properly designed system can freeze the plate in less than an hour, and you generally do this when you are running the engine anyway for other reasons. I have never owned a boat with this system, but I've chartered a few and I was very pleased with it. It dramatically reduces daily electrical power usage.



That being said, most of us don't really have a problem finding enough power for electric refrigeration either; that's what I've always had. But in a pinch, where it is desirable to reduce electrical power consumption, because you can't quite fit enough solar, or whatever, this can be a great solution. Refrigeration is by far the largest power user on most cruising boats and even more now that we all use LED lighting; at anchor with nav gear and pilot shut down, the reefers might account for 2/3 of your daily consumption. This can be a very big deal.

[donradcliffe]

Good advice on the fridge, but it will be your biggest electricity consumer.

Computers have a vast range of power consumption, from the 15 amps mentioned above to 1 amp for a netbook, or even less for a tablet. It is hard to find out what each draws, but it is worth your while to do so.

Here in the States, the best batteries for a boat your size are a couple of golf cart GC2 batteries in series, but YMMV.

More solar is better, but on a 34 ft boat I'd try to put in a minimum of 400 watts. The rigid panels last for 20 years, while the flexible ones are gone in 1 or 2.

[alansmith]

Through this process of asking questions and reading you will become informed. There are so many permutations. Please take the time to read a very good author on marine electrical. His website ‘ Marinehowto.com. Go under electrical and plink away.

[boatpoker]

Originally Posted by alansmith

Please take the time to read a very good author on marine electrical. His website ‘ Marinehowto.com. Go under electrical and plink away.

Not just "good". Rod is simply the best there is.

[alansmith]

When living in a boat year round you have to have a balance between charging systems. If it is raining for days on end... your solar won’t give you even 20 % of sunny weather.

[Rorzech]

Originally Posted by pallantejm

My partner and I were wondering what the best / most affordable options would be for our electrical setup.

We would like to optimize our electronics usage to ensure battery power to:

- 2 laptops
- 2 phones
- Mast lights
- Anchor winch
- Electric bilge pump
- Thru-hull depth sounder/transducer

We plan on getting a 3-way fridge but would mainly rely on propane. The oven and stove would also rely on propane.

Cabin lights would be portable LEDs.

Previous owner installed a macerating toilet w/electric flush but considering switching over to compost toilet instead.

Currently have 12V Starter battery for the engine and the 130 A/H Deep Cycle battery is dead (will need to replace). Due to the dead battery all electrical systems on the boat do not work (besides the starter).

Do not have solar panels (what would the recommended wattage be?)

What would the ideal electrical setup be for the above requirements and would anyone have a ballpark figure as to how much it would cost to install?

My advice is forget the 3 way fridge ! You can thank me later.Get a nice little LiFePo4 battery bank 300Ah @ 24 Volts and 4 300 watt solar panels and a Victron inverter 2kW to 4kW and an Electro Dacus 120 amp MPPT 24V controller. The battery bank should weight about 80 lbs and supply all the power you need. A 3 foot tall electric fridge now a days only sucks about 50 watts, only when its on. With this system you could get and use an induction hot plate instead of playing with and paying for propane. Now you have a real electrical system that will give you all the power you need, and not have to be worrying about it all the time. No filling batteries with distilled water or other PITA stuff. Get er done !

[OneHullPaul]

I wouldn't decide anything until you have spent a few hours listening to Jim Cote from Pacific Yachts on YouTube. The best free marine education I have found online to date. Good luck!

[GreenWave]

Originally Posted by donradcliffe

Good advice on the fridge, but it will be your biggest electricity consumer.

Computers have a vast range of power consumption, from the 15 amps mentioned above to 1 amp for a netbook, or even less for a tablet. It is hard to find out what each draws, but it is worth your while to do so.

Here in the States, the best batteries for a boat your size are a couple of golf cart GC2 batteries in series, but YMMV.

More solar is better, but on a 34 ft boat I'd try to put in a minimum of 400 watts. The rigid panels last for 20 years, while the flexible ones are gone in 1 or 2.

One note on batteries... depending on the type you will/shall have proper venting set-up for these. I have seen very few boats that actually accomodate this properly. Hence an AGM set-up is often utilized to avoid that problem.

[HankOnthewater]

I am sure you got the message to remove the LPG fridge..... all content of previous posters are correct in my opinion.

My previous boat came with such fridge. Apart from government regulations etc. common sense is that these fridges need a lot of ventilation to the outside air and to do that on a sailing boat ...... virtually impossible, see attached pic of the standard vents used on campervans for these kind of fridges..... Furthermore, because of the flame heating the fluid, the fridge needs to be upright..... not possible whilst sailing, and using such fridge on 12 Volt.... you will only do that once, because it draws constantly around 10 amps, is not controlled by a thermostat, so battery will be flat soon!
Yes, on that boat I removed that 3-way fridge after 1 year.

[OneHullPaul]

Yeh, don't bring regular lead acid on a boat, even sealed. Some sulphuric acid will escape and slowly eat it's way into your bilge and any keel bolts. AGM gives you 50% usable capacity via 30% with regular lead acid. You can drain down to 30% with AGM or 20% for thousands of discharges if you can spring for firefly's. In rough numbers for a group 31.

$125 Lead Acid
$250 AGM
$500 Firefly

I would be sure to invest in a balmer high output alternator with 3 stage regulator.

I would also strongly suggest hydro. Even my old bought used aquair is 100w 24 hours a day when towed behind so the equivalent of a 300-400 watt solar power in energy delivery when on passage.

[Gtstricky]

Originally Posted by OneHullPaul

I wouldn't decide anything until you have spent a few hours listening to Jim Cote from Pacific Yachts on YouTube. The best free marine education I have found online to date. Good luck!

+1
He has enough info in his videos to get you credit at some community colleges

[Pizzazz]

Since the discussion evolved into battery type arguments (it always does), there is nothing more economical that good old lead acid batteries. You can discharge them down to 20% for 400-500 cycles which will give you 2-3 years of useful life for $100/battery. You only use AGMs if you need to mount them in weird positions. Ignore what others say.

Lithium is better but not economical at 7x the cost. People will say you should only discharge wet cells to 50% but then you will get double the life. Big deal. You can easily replace the batteries every two years. We have had so many discussions on this.

SV Pizzazz

[Dockhead]

Originally Posted by Pizzazz

Since the discussion evolved into battery type arguments (it always does), there is nothing more economical that good old lead acid batteries. You can discharge them down to 20% for 400-500 cycles which will give you 2-3 years of useful life for $100/battery. You only use AGMs if you need to mount them in weird positions. Ignore what others say.

Lithium is better but not economical at 7x the cost. People will say you should only discharge wet cells to 50% but then you will get double the life. Big deal. You can easily replace the batteries every two years. We have had so many discussions on this.

SV Pizzazz

We have had so many discussions on this, so why do you keep posting wrong information?


No one on here uses the drop-in Victron lithium batteries intended to let you use lithium in a lead-acid system without modifications, which cost 7x what the cheapest lead batteries do.


The serious approach to using lithium, as discussed in our various threads on here, is to use prismatic cells with correctly adapted electrical system.


These currently cost, at full retail, premium Winston cells, from EV Power in Europe, €4.53 per nominal ah @ nominal 12v (https://www.ev-power.eu/Winston-40Ah...IDE.html?cur=1) ex VAT. Usable capacity is 85% of nominal so you pay €5.33 per usable ah.


Premium gel batteries like Rolls cost €3.63 per nominal ah or €7.26 per usable ah, ex VAT, so more expensive than lithium. Rolls Batteries | Wind & Sun


Cheap golf cart batteries like Trojan T105 (my favorite lead battery) are a much better deal at €1.49 per nominal ah or €2.98 per usable ah, so are cheaper than lithium to buy, but since they last 3x to 4x less long, they will be more expensive in the long run IF you cycle your batteries enough to wear them out (not everyone does). https://www.batterymegastore.co.uk/trojan-t-105-x2.html




So the economics of lithium are incorrectly described with that misleading phrase about 7x the cost. Different people will experience the economics differently, and so will make different choices:


1. If you are rarely off grid and rarely cycle your batteries fully, then lithium doesn't make economic sense (but you might still prefer them).

2. If you are mostly off grid and cycle your batteries hundreds of times a year, then lithium almost certainly makes economic sense (independent of the huge operational advantages).

3. In between will be in between -- count for yourself.

4. If you already have a boat which is already set up for lead acid, it may cost you a boat buck or two to convert it to use prismatic lithium cells, which may or may not tip the economic scales for your particular use case.

5. Most people will be making this decision with economics not the first in priority criterion anyway. Saving money with lithium will just be a bonus and not the main motivation, compared to the very great advantages in operation.

[john61ct]

This OP does not sound like they're currently a great candidate for an LFP system, neither OTS packaged nor climbing the DIY learning curve.

Bit New Zealand will have its own market factors, very different from Europe / UK and certainly the US in the relative economics of the choices on offer there.

Local advice for a good value true deep cycling lead solution to get them through the next 4-7yrs with a minimum up front investment for now, would IMO serve them best.

This one issue is maybe 20th in a prioritized list of decisions to be made, lets not let that tangent overwhelm the main thrust of the thread.

[Dockhead]

Originally Posted by john61ct

This OP does not sound like they're currently a great candidate for an LFP system, neither OTS packaged nor climbing the DIY learning curve.

Bit New Zealand will have its own market factors, very different from Europe / UK and certainly the US in the relative economics of the choices on offer there.

Local advice for a good value true deep cycling lead solution to get them through the next 4-7yrs with a minimum up front investment for now, would IMO serve them best.

This one issue is maybe 20th in a prioritized list of decisions to be made, lets not let that tangent overwhelm the main thrust of the thread.

Well, he can decide for himself. Every case is different, and he just needs information on the basis of which he can make that decision.


If he's technically apt and is starting from scratch I would say on the contrary he's a very good candidate for lithium. it sounds like he plans to be off grid most of the time, so that's already an indicator that lithium would be good for him. If on the other hand he's conservative and doesn't want to dive too deep into it, which is also fine, then he should be quite happy with a bank of Trojan T105's or similar golf car batteries. Both of these systems will work well and both are reasonable in cost.



All we can do is lay out options, and it does not serve him to mislead him with ridiculous statements about the cost of this choice. I have given an accurate picture applicable at least in Europe; that will be a good start for him to do his own research on what is available in his own market.


I disagree that he's automatically a good candidate for lead. If he's building the system from scratch, he might well be wasting his money on lead-oriented infrastructure and system architecture which he will throw away if he converts to lithium later.