Most sustainable electrical setup

[Dockhead]

Originally Posted by Pizzazz

We have through the cycles discussion a few times. On one hand, we have the manufacturer’s data that say, a typical golf cart battery would do 1,000 cycles at 50% discharge and half that at 75% discharge. So, in a way, it is similar to your fuel tank analogy, there is just so much chemicals in the battery.

Real life usage is less because there are other issues killing the batteries. High temperatures is a major factor, discharging them completely is pretty bad, running them dry (when the top of the plates are exposed) is really bad. I posted some charts a few posts ago. I have always been curious if the deep discharge is additive to these other factors or not. It is unclear. So, I totally believe that the typical battery that is cycles 25 times a year would die after 3-4 years but cycling them often has benefits as well. There are too many factors to consider.

I personally like the idea of $500 for replacing a typical 450AH battery bank. You can do it often, you can do it before going on a major multi year cruise and if you mess up (ie at the dock, someone knocks the power cord off while you are away), you can easily replace it. But that is me.

I will switch to Lithium when the cost goes down another 30% and probably for my next boat. It is a hard sell today but I see how it makes sense. For me the driving factor will be fast and efficient charge acceptance from the alternator so I will not need to install solar (hate the looks of it).

All very reasonable, just one point -- read MaineSail's article about real life cycle life of lead batteries, vs. ratings. He say 1000 "laboratory cycle" golf cart batteries will do 500 cycles only in absolutely ideal conditions, and that typical life is maybe 150 cycles. See: https://marinehowto.com/what-is-a-deep-cycle-battery/

[Dockhead]

Originally Posted by john61ct

My use of ROI in this case: the time period it takes for a higher outlay to break even compared to a shorter lived alternative.

Simplified example

Car Y costs 60K and might last 40 years, being a long time that is less certain, higher risk.

Car X costs 15K but only lasts 7 years. Being a shorter span, that is more certain.

In theory, buying Car Y gives the extra 12 years "for free" compared to buying Car X four times.

But that "profitability" on the higher up-front outlay is not in fact realized (ROI does not start) until those 28 years are up.

The much higher uncertainty of everything working out that long, means a rational funds manager or economist would radically discount the potential return.

I understand what you meant, but you are mangling financial concepts here. There is no "profitability" and no "investment" and no "return". A battery is not a car; it's a big bag of chemicals. It's a consumable. It's a current, not a capital expense. If you buy an extra big sack of flour at Costco, that's not an investment -- you're just buying ahead. The risk that you'll never need it or it spoils is higher, than with the smaller cheaper bag, but the cost per unit of the bigger bag is less, so you have to balance the cost savings against those risks and see how it looks to you. As to "radically discounting" the value of whatever it is you bought ahead -- that depends. Depends on the time value of money in your own particular financial world, on the certainty or uncertainty whether you will use it up, on the increased risk of its spoiling over a longer storage time. But with the regard to the last of those -- a well set up lithium bank with a good BMS should have an order of magnitude (or more) less risk of being prematurely killed even over 20 years, than a lead bank over 4 years, so this factor would merit a premium, not a discount.



In the case of lithium vs lead and the cost of a cycle -- even with the North American numbers posted, which I am still leery of -- even with Pizzazz's numbers which include the BMS -- the cost of a cycle is nearly half for lithium. In my case it's about 1/6.



And for a proper economic analysis of this you need to figure other costs associated with charging the batteries. In my particular case, the saving of generator hours by itself will pay for the bank in just a few years, never mind the huge extra cycle life. I've put more than 2000 hours on my generator in the last 10 years, costing me about €9000. I will save at least half of those hours with lithium, or more, saving me at least €450 a year. Just this factor alone will pay for the cells in 6 years -- not the DIFFERENCE in the cost of the cells, but the whole cost of the cells. Many cruisers will get similar results.


Every case is different, and a boat with a huge solar array will look very different, but the economic case alone (not getting to the improvements of usability and functionality) is compelling for many cruisers. Everyone of course will have to decide for himself, but he should be using correct information.

[warrior 90]

Originally Posted by john61ct

Not with a lead bank, if it's have been at all significantly drawn down, a very common mistake.

It takes at least 5-7 hours to get back to 100% Full.

No way you can trust a charge source to tell you when your bank is full,

you need to calibrate the stop-charge point (usually extending AHT longer),all charge sources will drop to Float by default way too early .

Resulting in a grossly shortened bank lifespan.

As I said, very common for noobs to make this mistake.

With a good sized, good matched solar system and by that I mean relation of consumers, battery size and solar charge capacity it will never been significantly drawn down because when there is a bad solar day You top off with the engine or Gen

Very common situation on boats of noobs

* all charge sources will drop to Float by default way too early
What are You going to do about it ?

Still better then cooking the batteries.

[warrior 90]

Originally Posted by john61ct

The size of your Starter is 100% irrelevant to how you get current from one circuit to the other.

Nothing to do with DCDC chargers specifically either.

> if You have decent solar it´s for topping of the house batteries only anyway or to prevent low discharge

Solar can be used for any need requiring energy input, not sure what you are trying to say there.

> Instead of 1 unit You could use 2, one with a very low rate for smooth cycling and the other bigger in case You need a boost.

Same here, current is pulled according to the need of the bank, you always want as much available as possible, at least with lead.


> So now there is no more direct connection of the alternator with the house bank and that will eliminate all the issues with 2 different types of batteries when charging with alternator.

Usually the alternator matches (close enough) one of the banks, so only one DCDC is needed for the other one.

Few would need to pay for a DCDC for just a Starter batt, cheaper to just buy one that suits the alt output, maybe replace it a little more frequently.

YOU MISSED IT

> but is very easy on cycling the starter battery

Starter batt does not get cycled, at all.

Originally Posted by Pete7

The point of not overloading an alternator is one of the reasons I don't have an external regulator fitted. The solution is to limit the demands on the alternator for large current with one of the those DC > DC battery chargers which also neatly limits the voltage.

I think we will end up with an engine start battery which then supplies the LFP. Not sure were to add the solar and mains BC at the moment, more studying needed.

Pete

While the starter battery is sized to the alternator capacity the LFP is not.
So with a DC > DC the high amp draw from the LFP is limited and will not overload the alternator.
Once starter battery is full a second DC > DC is connected in parallel to take optimum advantage of the alternators capacity but without the danger of over loading.
Once engine is stopped starter battery can keep on charging the LFP till desired state of charge of starter battery and if done with a low charging rate will be easy on cycling.

Why would I wanna to do this ?
Less components, more reliable, less wires, fuses and much less $$$$

[Pete7]

True, but the alternator is 60A. Sterling do a 30A and 60A B2B charger, I guess the 30A will do but two would mean the alternator running hard. Also need to think about how the solar can feed into this whilst the engine is running, perhaps two B2Bs is the answer, but expensive at £214 each though.

Pete

[warrior 90]

Originally Posted by Pete7

True, but the alternator is 60A. Sterling do a 30A and 60A B2B charger, I guess the 30A will do but two would mean the alternator running hard. Also need to think about how the solar can feed into this whilst the engine is running, perhaps two B2Bs is the answer, but expensive at £214 each though.

Pete

Don´t know the price right now but those DC > DC are the ones You are looking for.... fully adjustable.

https://www.victronenergy.com/upload...50-400W-EN.pdf

https://www.victronenergy.com/upload...L-ES-IT-DE.pdf

For the first stage choose a 10 - 15 amp. If the starter battery is in good shape it will recover very fast after engine has started.
Set the second one to once battery is full. 60 amp is a good size alternator. I would go for a total of less then 40 amps when they are both in parallel.
Once You stop the engine You go back to one and constant 10 - 15 amps won´t hurt the starter battery but is still a nice extension charge rate for Your LFP without putting starting capacity in danger.

Solar directly to LFP to share full load of consumers.

[john61ct]

warrior, you aren't grokking some essential concepts, leading to bad advice

There is no need to put a Starter on the DCDC output side at all. It is not dropping in SoC, does not actually "cycle" at all, is designed to just sit directly on alt output and will last many years just like that.

No need in **any** case to think about "first do this then do that" everything just gets charging current all at the same time no worries. The Starter batt is always full, and even if not, no waiting needed.

The ideal is to set up the alt with an external VR that lets you adjust the Volts and Amps rate, so that it is well suited to connect direct to House, no DCDC needed.

Then most any old combiner / VSR / ACR will take care of keeping Stater topped up, again no DCDC needed at all.

If the alt is left stock, output direct to Starter, then the DCDC is there to connect the engine circuit, alt as source outputting converted voltage and throttled current as desired to the House bank.

These DCDC can be stacked for greater amps, up to say 0.4C of the LFP Ah capacity, less in cold weather.

But all of them are left connected all the time, good ones will have their own internal VSR, others need one to be installed separately, or an old school IGN solenoid if appropriate.

But no one ever needing to do anything manual unless you want to, everything should just work automatically.

Originally Posted by warrior 90

While the starter battery is sized to the alternator capacity the LFP is not.

This is not a thing. Any size bank, any size alt combination desired, no problem.


> Once engine is stopped starter battery can keep on charging the LFP till desired state of charge of starter battery

A very bad idea and makes no sense the way phrased there.

Originally Posted by warrior 90

Once You stop the engine You go back to one and constant 10 - 15 amps won´t hurt the starter battery but is still a nice extension charge rate for Your LFP without putting starting capacity in danger.

Same again, very bad idea, no one should do this.

Unnecessarily complex, inefficient and risky, but most of all pointless not accomplishing anything useful, solution in search of a problem

Again, Starter needs no specific attention. LFP does not need further charging. If it did, should only be fed by an active charge source, never from any battery.

Transferring stored energy from any battery to another battery is not a thing, and always to be avoided.

[Pete7]

Originally Posted by john61ct

The ideal is to set up the alt with an external VR that lets you adjust the Volts and Amps rate, so that it is well suited to connect direct to House, no DCDC needed.

Wow, what happens when the LFP bank is full and the BMS says no more and disconnects leaving the alternator with nothing connected to it, fried diodes?

Originally Posted by john61ct

Transferring stored energy from any battery to another battery is not a thing, and always to be avoided.

Your post was difficult to follow but, B2B is the way Sterling recommend their LFP set up. Are you saying they are wrong? Seems the safe controllable option to me since it means the alternator charge can be limited, useful in a hot engine room which doesn't benefit from the cooling your LFP banks have in a building, you do have a LFP bank don't you?


Pete

[Dockhead]

Originally Posted by Pete7

Wow, what happens when the LFP bank is full and the BMS says no more and disconnects leaving the alternator with nothing connected to it, fried diodes?

When the LFP bank if is full, the charge source should be shut down, not disconnected. The disconnection is an emergency measure only; a backup in case something goes wrong and a charge source goes wild. The decision to end charging need not be made by the BMS necessarily; can be made in other ways. There are different approaches. For the extremely rare case when something goes wrong and the BMS disconnects the charge source, you need one of these: https://sterling-power.com/products/...tection-device, all of £47, unless you've wired the system so that the charge source remains connected to a lead battery.

Originally Posted by Pete7

Your post was difficult to follow but, B2B is the way Sterling recommend their LFP set up. Are you saying they are wrong? Seems the safe controllable option to me since it means the alternator charge can be limited, useful in a hot engine room which doesn't benefit from the cooling your LFP banks have in a building, you do have a LFP bank don't you?Pete

There are different ways to do this too. If your charge sources are connected first to a lead battery, like a start battery, then you can charge the lithium with a B2B. HOWEVER, they are very expensive and you can't get very big ones. You screw up the whole system if you can charge at 100 or 150 amps but you can only get 60 amps of that to the lithium. Using A B2B charger attached to lead simplifies control and safety but is not ideal if you have a high amp charge source and largish lithium bank. For a small lithium bank it might be ok.


There are other ways to control alternator charging; Balmar alternator regulator is a really good one, which can be connected to the BMS or other device to shut down or ramp down alternator output when needed. In my case, 100 amp * 24v alternator and presumably 300 AH * 24v of lithium, I will connect the alternator directly to the lithium and control it with a Balmar regulator. An alternative is the Sterling Alternator-to-Battery Charger, but this is expensive and again, can be limiting in terms of amperage.



The Balmar regulator (and probably some others) can also be used to derate the alternator where necessary, and if you are going to use a car-type rather than true heavy duty alternator, then this is essential with lithium. So an A2B charger is not indeed the only, and probably not the optimum way to do this.

[Bunji]

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?

Howdy guys, Hope your choices are as sustainable as this topic, Composting toilets are a great idea, Easy to make yourself, I diverted the pee straight out the side (1 inch through hole fitting) so we only have to deal with the poops. Also we’ve been using the ARB 12 volt fridge/freezers there more efficient / reliable than most the others Cheers

[warrior 90]

Originally Posted by john61ct

warrior, you aren't grokking some essential concepts, leading to bad advice


If the alt is left stock, output direct to Starter, then the DCDC is there to connect the engine circuit, alt as source outputting converted voltage and throttled current as desired to the House bank.

We never talked about anything else

> These DCDC can be stacked for greater amps, up to say 0.4C of the LFP Ah capacity, less in cold weather.

Has nothing to do with charge rate of LFP.
Subject is to protect the alternator from overload.

> But all of them are left connected all the time, good ones will have their own internal VSR, others need one to be installed separately, or an old school IGN solenoid if appropriate.
> But no one ever needing to do anything manual unless you want to, everything should just work automatically.

Did You read the Victron files I attached ?

Quote:Originally Posted by warrior 90 View Post
While the starter battery is sized to the alternator capacity the LFP is not.

> This is not a thing. Any size bank, any size alt combination desired, no problem.

The isssue with the alternator are the different types of battery
?¿?¿?¿? You aren't grokking some essential concepts, leading to bad advice


Quote: Originally Posted by warrior 90 View Post
Once engine is stopped starter battery can keep on charging the LFP till desired state of charge of starter battery

> A very bad idea and makes no sense the way phrased there.

Can You read ? I wanna take advantage of the capacity of the starter battery. I don´t need a full starter battery.
In this set up I need the starter battery because I wanna protect the alternator from overload caused by the LFP.

Quote: Originally Posted by warrior 90 View Post
Once You stop the engine You go back to one and constant 10 - 15 amps won´t hurt the starter battery but is still a nice extension charge rate for Your LFP without putting starting capacity in danger.

> Same again, very bad idea, no one should do this.
> Unnecessarily complex, inefficient and risky, but most of all pointless not accomplishing anything useful, solution in search of a problem

Very simple SET IT - FORGET IT

> Again, Starter needs no specific attention. LFP does not need further charging. If it did, should only be fed by an active charge source, never from any battery.

YES, IT DOES !!, and I hate the noise and wanna keep the engine run time as low as posible. I only need enough charge for the night . Starter battery is good enough for me. Next morning I have solar.

> Transferring stored energy from any battery to another battery is not a thing, and always to be avoided.

Who are You to say so ?
All depends on the design objectives of the system.


Originally Posted by john61ct View Post
The ideal is to set up the alt with an external VR that lets you adjust the Volts and Amps rate, so that it is well suited to connect direct to House, no DCDC needed.

[QUOTE=Pete7;3056580]
Wow, what happens when the LFP bank is full and the BMS says no more and disconnects leaving the alternator with nothing connected to it, fried diodes?

Yes, Wow + W O W , I am sure that happened more then one time.
I know of a case... just spent a fortune to upgrade 2x400amp Lithium, big alternator + Balmar external regulator+etc Victron Movies...etc. $$ etc.

But it did not only fry the diodes. It also cost him a new 200 amp Leece Neville alternator, $$$$ AUTSCH.
Of course all the components were new and still under warranty.
After endless $$$ phone calls with the experts... but only stories to save their bud.

Finally he gave up and bought a new alternator from his pocket.
How much did the party cost ?.......+ $$$ sitting in the marina ?


Originally Posted by john61ct View Post
Transferring stored energy from any battery to another battery is not a thing, and always to be avoided.

[QUOTE=Pete7;3056580]
Your post was difficult to follow but, B2B is the way Sterling recommend their LFP set up. Are you saying they are wrong? Seems the safe controllable option to me since it means the alternator charge can be limited, useful in a hot engine room which doesn't benefit from the cooling your LFP banks have in a building, you do have a LFP bank don't you?

Pete

Absolutely Right. Charge can be limited SET IT & FORGET IT.

KISS. No more issues with temp sensing, cooling fans and all the other fancy $$$ patches.