New Inverter / Charger

[john61ct]

Originally Posted by Mikado

I converted both my house and starter banks to 24V

It may be helpful if you explained why?

[Macgregor 26X]

On a small boat, which I would guess yours is not, 12v is probably the norm beacause there maybe one engine starter battery at 12v and maybe one or two house batteries, wired in parallel, also to produce 12v. The engine's alternator will likely be able to charge either the engine battery or the house batteries. The ancient way of doing this was to have a knob which you manually set to where you wanted the engine's alternator to send its charge to.

Modern systems use a VSR -Voltage switch relay, which usually gives priority to charging the engine battery and the switches to the house batteries. There are also two-way VSR's which are used for instance where there is a solar system or onshore system feeding an inverter with a battery charger. This can look in either direction of what's charged-up already and then switch on the other circuit.

The moment that you have a mixed system of 12v and 24v, charging becomes a headache.

The single advantage I can see of having everything at 24v is that feeds to high powered sine wave inverters need wires half as thick. That's it, but I'm sure folks with experience of larger boats will wade-in :-)

[alansmith]

Mr Wells, a couple of days ago Stu posted up one of the more valuable links I have seen in quite awhile. It is called something like Electrical Systems 101. There are many many articles written for people who have low levels of knowledge and confidence in electrical systems to those that are much educated and experienced. So, Stu, is, in my book, blunt and direct, but his advice is on the mark. It is one of those things ...do you like a pleasant and cheery doctor who knows jack shizzle about medicine...or do you want the crusty grouch who will get you well? In my opinion, Stu is a guy who knows his stuff and can be trusted to send you in the right direction. I just wish he would come down here and set my boat up correctly...but sadly the state of California banned him to a higher latitude for a spell. Smile....

[CareKnot]

Hi everyone, semi amateur here asking forgiveness in advance. Please consider condescending to a level I can understand.

I am a coastal Cruiser. My electrical usage is very modest, mostly centered around a laptop and required navigational Electronics. I have a 32 foot sailboat that came with two Walmart (yikes!) marine Start batteries.

A source for deep cycle marine batteries has recently been made available to me and I have room below the cabin sole for adding 4 additional group 24 batteries. I also own a couple a battery isolators, a 12v high output alternator (in addition to the alternator already on my Yanmar 2QM20) and 2 extra battery switches.

The boat will either be on shorepower or be charged from the alternators. Solar and wind come later. To say that I'm on a tight budget is a ridiculous understatement.

My assumption is to keep the Start battery bank completely isolated in order to reduce load balancing problems. I expect that they will deteriorate quickly and thereby exacerbate load imbalances.

I expect to add a small inverter (less than a thousand Watts) and a winless and a water pump/sprayer to help manage and clean my ground tackle.

Any suggestions vis-a-vis configuration, considerations and pitfalls would be greatly appreciated.

[CareKnot]

Oops, I'm sorry. Should I have started a new thread?

[Stu Jackson]

Originally Posted by alansmith

Mr Wells, a couple of days ago Stu posted up one of the more valuable links I have seen in quite awhile. It is called something like Electrical Systems 101. There are many many articles written for people who have low levels of knowledge and confidence in electrical systems to those that are much educated and experienced. So, Stu, is, in my book, blunt and direct, but his advice is on the mark. It is one of those things ...do you like a pleasant and cheery doctor who knows jack shizzle about medicine...or do you want the crusty grouch who will get you well? In my opinion, Stu is a guy who knows his stuff and can be trusted to send you in the right direction. I just wish he would come down here and set my boat up correctly...but sadly the state of California banned him to a higher latitude for a spell. Smile....

alan, thanks for the kind words, but you are confusing THE TWO STUS!!!

StuM is a highly qualified and knowledgeable electrical boat system advocate.

Neither he nor I "condone" lack of specificity and the use of incorrect terminology. He has written a valuable thread on this very forum about amps/amp hours and amps per hour that should be basic for anyone discussing electrical systems. Unfortunately, it isn't, but that shouldn't preclude him from correcting mistakes, sometimes glaring ones. And those glaring misuses of basic terminology usually (but not always) indicate someone who could use more time spent studying those basics.

All of us know electricity isn't easy, but none of us was born an electrician. We want to help, but it is so much easier when the question makes sense, and if not, it should be incumbent to identify where it doesn't and make recommendations for correction.

But we can't always be (re)writing basic electrical books on a forum for folks who start questions. They should be able and required to do their own homework and research on that.

It's like folks who keep asking "How long will it take for me to get to A from B?" without telling us how fast they can go or far it is, and then saying they can go 20 knots per hour!!!

I'm other "other Stu" and here's my 101 - I have to find StuM's amps topic and add it.

Electrical Systems 101 Electrical Systems 101

[Stu Jackson]

Originally Posted by CareKnot

Oops, I'm sorry. Should I have started a new thread?

Would be helpful. Or ask a moderator to move it. Thanks.

[StuM]

Originally Posted by rwells36

https://www.victronenergy.com/upload...alancer-EN.pdf

60'

From the link:

The problem: the service life of an expensive battery bank can be substantially shortened due to state of charge unbalance. One battery with a slightly higher internal leakage current in a 24V or 48V bank of several series/parallel connected batteries will cause
undercharge of that battery and parallel connected batteries, and overcharge of the series connected batteries. Moreover, when new cells or batteries are connected in series, they should all have the same initial state of charge. Small differences will be ironed out during absorption or equalize charging, but large differences will result in damage due to excessive gassing (caused by overcharging) of the batteries with the higher initial state of charge and sulphation (caused by undercharging) of the batteries with the lower initial state of charge.

Oh, you mean "charge balancing", not "load balancing".

That extract only talks about multiple batteries connected in series/paralleel (the way you are proposing to connect yours) or connected in series. As does the whole Battery Balancer linked document.

There is nothing there which raises any concerns about a 12V system comprising 12V batteries in parallel.

Your concern about "load balancing", which apparently is your only reason for proposing a major conversion of your electrical system, is a complete non issue.

Just go ahead and get someone who knows what they are doing to hook up your new batteries in parallel with appropriate wiring and fusing/isolation switches.

[StuM]

Originally Posted by robbievardon

Am I wrong or are 4 X 6 volt batteries = 24 volts?

If connected in series, they are 24 Volts. If connected in parallel, they are still 6 Volts.

[StuM]

Originally Posted by rwells36

I forgot stu, this forum is for !intelligent!questions only. I'll be sure to take some classes before asking next time.

No, this forum is to many things including seeking advice/assistance. The best advice I can give in light of the OP's questions is for him to learn the basics before messing around with 900Ah of 12 volt batteries.

They can destroy his boat or kill him if he doesn't know what he is doing and messes it up.

[StuM]

Originally Posted by rwells36

I forgot stu, this forum is for !intelligent!questions only. I'll be sure to take some classes before asking next time.

Thank you. That may well save your boat or your life.

[StuM]

Originally Posted by alansmith

Mr Wells, a couple of days ago Stu posted up one of the more valuable links I have seen in quite awhile. It is called something like Electrical Systems 101. There are many many articles written for people who have low levels of knowledge and confidence in electrical systems to those that are much educated and experienced. So, Stu, is, in my book, blunt and direct, but his advice is on the mark. It is one of those things ...do you like a pleasant and cheery doctor who knows jack shizzle about medicine...or do you want the crusty grouch who will get you well? In my opinion, Stu is a guy who knows his stuff and can be trusted to send you in the right direction. I just wish he would come down here and set my boat up correctly...but sadly the state of California banned him to a higher latitude for a spell. Smile....

You're thinking of the other Stu. And he's not such a crusty grouch as me.

[StuM]

Originally Posted by Stu Jackson

I'm other "other Stu" and here's my 101 - I have to find StuM's amps topic and add it.

Electrical Systems 101 Electrical Systems 101

Here it is: http://www.cruisersforum.com/forums/...ml#post1933764

The other other "other Stu".

[rwells36]

Originally Posted by StuM

> I have a concern about load balancing

Care to explain what you understand by "load balancing" and what your concern is?

> wire in parallel 2 sets of 4 batteries wired in series. Thus having 24 volt

That will give you 48 Volts, not 24 Volts.


> if I am inverting 24v instead of 12v do I get the Ah cut out by going to 24v in some way?

The answer to that question is yes, you get less Ah drawn by the inverter but at higher voltage, so the total power (Watt hours) drawn doesn't change.

> I suppose I just get more watts nut not more watt hours?

That statement is not just incorrect, it reveal a major lack of understanding of what Watts, Volts and Amps are. It just doesn't make sense at all.

If you have to ask these questions, you need to learn a lot more about DC electrical systems before doing anything with your current setup.


> I have 24v 1000 watts of solar

I assume that you have several nominal "24Volt solar panels", presumably wired in parallel. What sort of charge controller do you have?

MPPT Victron Energy 150/70 12/24/48 70 with (3) LG 315W 33.2Vmp 9.5A 60 Cell panels.

Also, charge balancing (not load balancing as I incorrectly referenced) was intended as a subsequent question; though an article often referred to at www.smartgauge.co.uk/batt_con.html seems to answer that question.

Note that "24 Volt solar panels" do not put out 24 Volts. They will generally have a rated/operating voltage of around 36 Volts with an open circuit Voltage of around 45 Volts.

For your information, I have 1000 Ah of 12V AGM batteries in my house bank (plus separate starter batteries for each engine) and 800W of solar, have no problems with "load balancing" and wouldn't consider switching to a 24V system.

I'm planning for 8 12v AGMs (Group 31) @ 116A each (116 x 8 for 928 Ah). Is there a limit to safely wiring these solely in parallel fashion?

I too have separate starter (24v) batteries for each of the two engines and a 12v 2500 watt 130A charger / inverter for the house bank.

Having both 24v and 12v aboard has yet to cause any problems (past 3 years). Then again, no changes have been made during that time either.

[Dockhead]

Originally Posted by CareKnot

Hi everyone, semi amateur here asking forgiveness in advance. Please consider condescending to a level I can understand.

I am a coastal Cruiser. My electrical usage is very modest, mostly centered around a laptop and required navigational Electronics. I have a 32 foot sailboat that came with two Walmart (yikes!) marine Start batteries.

A source for deep cycle marine batteries has recently been made available to me and I have room below the cabin sole for adding 4 additional group 24 batteries. I also own a couple a battery isolators, a 12v high output alternator (in addition to the alternator already on my Yanmar 2QM20) and 2 extra battery switches.

The boat will either be on shorepower or be charged from the alternators. Solar and wind come later. To say that I'm on a tight budget is a ridiculous understatement.

My assumption is to keep the Start battery bank completely isolated in order to reduce load balancing problems. I expect that they will deteriorate quickly and thereby exacerbate load imbalances.

I expect to add a small inverter (less than a thousand Watts) and a winless and a water pump/sprayer to help manage and clean my ground tackle.

Any suggestions vis-a-vis configuration, considerations and pitfalls would be greatly appreciated.

An intelligently asked question, which besides that, is not in any amateurish.

First of all, you don't need an inverter to power a laptop. Far better to buy a car charger for it, and power it with 12v. Is there anything else you wanted to power with an inverter?

If all you need to power is marine electronics and a laptop, then you don't need to do anything expensive. I suppose you also have lighting, fresh water pump, etc., no?

I doubt that you will need four Group 24 batteries for such modest house needs, but a good way to figure it out is like this:

Work out a power budget for amp-hours you will consume during whatever period you would like to not charge batteries. Add a healthy margin of error.
Do you have LED lighting? On a small boat, the biggest bang for the power buck is getting rid of all incandescent lighting, including nav lights. The nominal capacity of the bank should be at least about 4x that amount (usable power is usually about 50% of nominal when new, so you get a 50% reserve like this, which you need in any case for future additional equipment, deteriorating batteries, etc.).

If you can fit them, the cheapest and best deep cycle batteries are golf cart batteries from Costco, preferably 6 volt (wire in pairs for 12v). Two of them will probably be enough for you.

Use separate shore power battery chargers for this bank and the engine start battery. You need only a small one for the engine start battery; the other one should be about 20% -- 25% of nominal capacity of the bank.

Alternator charging is the tricky part. The best solution is separate alternators for start and house banks, with a heavy duty alternator for the house bank. This is expensive (mostly because of the extra pulleys and mounts) and not really needed for a setup like yours, but then you face the problem of how to split the charge.

For this, you can use a diode isolator, but I don't like these, because they can only provide the same charge profile to both banks, and obviously the optimum charge profile for start and house banks is not going to be the same. Much better is an echo charger or some other kind of battery-to-battery charger. So you can leave the alternator connected to the start bank, then charge the house bank from the start bank. I like the Sterling one:

https://sterling-power.com/collectio...ttery-chargers

I think this might even obviate the need for external regulation, as the normal "dumb" regulator of a standard alternator will feel the charger like a load, and feed it. But you should read up on alternator regulation and decide for yourself.

Last thing to think about is how to monitor the state of charge of your batteries. Never let them get below 50%! I'll state my opinion very briefly -- forget amp-counting battery monitors. If you have a spare couple hundred bucks, buy a Merlin SmartGauge. Otherwise, buy a cheap digital voltmeter and wire it very carefully directly to the battery terminals, make up a chart of SOC vs voltage UNDER LOAD. See: https://marinehowto.com/under-load-b...oltage-vs-soc/.

Good luck, and let us know how you get on.