Multiple Chargers and power source

[Seevee]

Can we discuss multiple battery chargers?
First, often we see multiple power sources/chargers working at the same time on the same bank.
Example: When the engine is running the alternator is charging the batteries, and with the generator on, it's charging the same batteries thru the charger. No issue
How about a shore power that powers a charger which charges the batteries. And a generator powering a different charger, both charging the same batteries.


But you can't use the shore power AND the generator to charge the same batteries thru one charger.


So, what's the protocol and limitations with multiple power sources and/or multiple chargers or combinations?


=====
I currently have a 110-15a power supply to a small charger to top off the batteries, and occasionally will have the engine running also charging, AND occasionally have the generator running and charging (all at the same time), without an issue. However, there is only one power source to each charger (or alternator) that is supplying the batteries.


Comments?


(also posted on MTOA)

 

[BruceK]

Have had simultaneously, engines running so alternators operative, solar operational, genset powering battery charger on( really on to power salt water washdown pump). No known ill effects, but interested in other experiences.

 

[Taras]

Important to know what type of batteries you have. Flooded for example can only accept a certain amount of charge. Lithium can accept a much greater amount of charge current..... too much current charge in the wrong battery type will fry them.

 

[tiltrider1]

I have a 150a charger and a 40a backup charger. If batteries are low I’ll run both at the same time. Today’s battery chargers are smart enough to back off as the batteries start to reach full charge. Alternators are the same so no problem adding them to the same mix.

 

[BruceK]

Important to know what type of batteries you have. Flooded for example can only accept a certain amount of charge. Lithium can accept a much greater amount of charge current..... too much current charge in the wrong battery type will fry them.

I figured the controllers of each of the various chargers, even run concurrently, would detect and react to charge level in batts, whatever type of battery. But different chargers, different sources, running concurrently, might fight each other. Let`s hope one of the electrical guys chimes in to be sure.

 

[Seevee]

One question I have: Can I run ONE charger that has two sources of power?
That could be an issue.


One power source would be a small dock power cord, 110v15a and the other would be the generator.

 

[NWSeadog]

Seevee - Unless the charger has two separate source inputs for the 110AC then NO you can not connect the output of your generator and the shore power together. You would probably damage your generator.

 

[jleonard]

Once you choose generator power from your panel it cuts out shore power.
So are you hot wiring the battery charger so the gen switch doesn't cut it off?
I used multiple chargers often on my Albin. I would run the generator and that would power the shore charger, PLUS I would plug in a Sears car battery charger into an outlet and add 10 amps from that unit. But all powered from the generator.

 

[C lectric]

DO NOT INTERCONNECT TWO SOURCES OF AC INPUT POWER or you will blow something.
I have seen people do that with the consequence of destroying, usually, the generator.
One will become a DEAD short to the other unless the Frequency and waveform of both are EXACTLY matched with each other AND kept in time.

Yes, there are small gens such as the Hondas and Yamahas that can parallel two units but there is an interconnection between that the inverters monitor to match waveforms. Without that they two would be damaged.
You already have enough comments about various DC sources.

I don't have a gen. but use solar and often leave the panels operating while the engine is running. The only time in the season I disable the panels is when
the potential of rough water is present and the panels MUST be put away.

 

[Seevee]

DO NOT INTERCONNECT TWO SOURCES OF AC INPUT POWER or you will blow something.
I have seen people do that with the consequence of destroying, usually, the generator.
One will become a DEAD short to the other unless the Frequency and waveform of both are EXACTLY matched with each other AND kept in time.

Yes, there are small gens such as the Hondas and Yamahas that can parallel two units but there is an interconnection between that the inverters monitor to match waveforms. Without that they two would be damaged.
You already have enough comments about various DC sources.

I don't have a gen. but use solar and often leave the panels operating while the engine is running. The only time in the season I disable the panels is when
the potential of rough water is present and the panels MUST be put away.

C,
I didn't think there was any way to have multiple AC sources feeding one charger.... doesn't make sense.
But we have multiple sources charging the batteries thru different chargers or alternator. Is there a limit or a point where it becomes excessive?


For example, I could see two alternators, a generator thru a charger and a totally separate charger thru shore power all charging the batteries. Now, each charger/alternator does have its own smart regulator.


======
But the issue I have at hand is:


I need a simple way to charge the batteries from a 110v15a house circuit. If I hooked that house current directly to the charger that the gen uses, I'd need a "either/or" switch. Does someone make such a switch that can be mounted in a breaker spot in the panel? The big switch for the gen/shore power would be very hard to install (no space).



Another thought is to just get another charger. Would get perhaps a 120 to 150a charger for the generator, and use the older smaller 60a charger for the 15a shore power, to keep the batteries topped.


The issue is that there's no 220v/50a service at my dock.

 

[Seevee]

Once you choose generator power from your panel it cuts out shore power.

So are you hot wiring the battery charger so the gen switch doesn't cut it off?

No, not the case.

I used multiple chargers often on my Albin. I would run the generator and that would power the shore charger, PLUS I would plug in a Sears car battery charger into an outlet and add 10 amps from that unit. But all powered from the generator.

That's what's on my current boat right now, except the smaller charger is a marine smart charger and is powered by 15a shore power, both charging the battery when the generator is running.

On my new boat, I only have one charger, but guess I'll need a switch for the 15a shore power so it's either gen or shore...not both, which I understand.

Thx!

 

[Seevee]

One more question, with a shore 15a line to the charger....


Is there any reason I couldn't just wire the above 15a line to the shore power side of the main "shore or gen" switch? I would never have a case where I'd use both the 15a and shore 50a at the same dock.

 

[Bacchus]

I have a transfer SW in my panel that selects shore or gen and a similar one that connects bus 1 &2 when using only one 30A shore cord.
Why would one of those work if used to supply the charger with either gen power of 15A shore?
If you were at the dock and hooked up to 50A for your main power you could plug the 15A cord in aboard using any convenient outlet. That atheist would be a work around and eliminate 2 sources connected w/o a transfer sw.

One related question I have always wondered about with shore charger running off gen while underway...
Won't the alternator sense high V put out by the charger and cut back / off alt output as would be the case when battys are full to prevent constant overcharging by alt?

 

[tiltrider1]

C,
I didn't think there was any way to have multiple AC sources feeding one charger.... doesn't make sense.
But we have multiple sources charging the batteries thru different chargers or alternator. Is there a limit or a point where it becomes excessive?

Excessive is a personal opinion. The battery does not care as long as all the charging sources are smart enough not to over charge.

For example, I could see two alternators, a generator thru a charger and a totally separate charger thru shore power all charging the batteries. Now, each charger/alternator does have its own smart regulator.


======
But the issue I have at hand is:


I need a simple way to charge the batteries from a 110v15a house circuit. If I hooked that house current directly to the charger that the gen uses, I'd need a "either/or" switch. Does someone make such a switch that can be mounted in a breaker spot in the panel? The big switch for the gen/shore power would be very hard to install (no space).

Yes there are such things but it would take two breaker slots and require a lock device.

Another thought is to just get another charger. Would get perhaps a 120 to 150a charger for the generator, and use the older smaller 60a charger for the 15a shore power, to keep the batteries topped.

This would be your simplest solution


The issue is that there's no 220v/50a service at my dock.

David

 

[ranger58sb]

Another thought is to just get another charger. Would get perhaps a 120 to 150a charger for the generator, and use the older smaller 60a charger for the 15a shore power, to keep the batteries topped.

The issue is that there's no 220v/50a service at my dock.

We eventually had two 115V chargers directed at one of our battery banks; original was 40A, and the new one was 60A. Individual breaker for each charger on the AC panel, worked fine. I didn't usually need to use both chargers at once (especially when on shore power for any length of time), but it was theoretically faster to use both when recharging batteries at anchor.

What would it take to get 220V/50A service at your dock? When we moved to our last marina, their electrician just swapped the existing two 30A lines to a single 50A, apparently no big deal, not even any cost to me.

-Chris

 

[koliver]

One more question, with a shore 15a line to the charger....


Is there any reason I couldn't just wire the above 15a line to the shore power side of the main "shore or gen" switch? I would never have a case where I'd use both the 15a and shore 50a at the same dock.

What is preventing you connecting to an external 15a line through your existing shore power hookup, using a 15 to 30 pigtail (I assume you already have a 30 to 50 pigtail for those docks that don't have 50)?

 

[Seevee]

We eventually had two 115V chargers directed at one of our battery banks; original was 40A, and the new one was 60A. Individual breaker for each charger on the AC panel, worked fine. I didn't usually need to use both chargers at once (especially when on shore power for any length of time), but it was theoretically faster to use both when recharging batteries at anchor.

What would it take to get 220V/50A service at your dock? When we moved to our last marina, their electrician just swapped the existing two 30A lines to a single 50A, apparently no big deal, not even any cost to me.

-Chris

Chris,
I don't have two 30a lines, which would be easy to convert to a 220v50a. I'd have to start over, because the conduit is not big enough for the wires. Probably in the few thousand range. And, 99% of the time, I really don't need that power. Just need the batteries topped off.


Seems like a second charger would be the simplest.

 

[ranger58sb]

Chris,
I don't have two 30a lines, which would be easy to convert to a 220v50a. I'd have to start over, because the conduit is not big enough for the wires. Probably in the few thousand range. And, 99% of the time, I really don't need that power. Just need the batteries topped off.

Seems like a second charger would be the simplest.

Well, FWIW... when we added the second charger... it was on the same 115V leg as the original charger. We just happened to have enough capacity to do it that way. 40A and 60A DC really only meant 4A and 6A AC, so it wasn't an issue...

Another possible issue for you, though... is whether the boat has an isolation transformer. I've read 240V/50A boats with isolation transformers can't get squat for power unless both legs are energized at at least 208V. That came up when guys in our owners club were trying to figure out how to charge batts while on the hard back in a storage lot... with only a few 115V plugs available. We didn't have that problem ourselves... but then again our boat was built the year before our factory started defaulting to installing isolation transformers in our boat model...

-Chris

 

[cafesport]

Im not sure what you are asking or trying to accomplish but
it sounds like you are wanting to improve your current charging setup’s speed of charge.

Unless you are recharging a lithium bank, throwing more or bigger chargers into the mix won’t reduce the amount of time it takes to reach full charge. If you do have a lithium bank you wouldn’t really want to keep it at full capacity anyway.

If you have AGM or Lead acid batteries, once they exit the bulk phase of their charging cycle, they only accept an ever decreasing amount of current. Multiple, or even bigger chargers will never speed up the charge acceptance rate. It’s the main reason many cruisers add solar panels. Outputting a couple of hundred watts for several hours to reach full charge makes no sense, no matter how small you size your genny. Best done on shore power or when running other big loads overnight on a genny.

 

[Seevee]

Well, FWIW... when we added the second charger... it was on the same 115V leg as the original charger. We just happened to have enough capacity to do it that way. 40A and 60A DC really only meant 4A and 6A AC, so it wasn't an issue...

Another possible issue for you, though... is whether the boat has an isolation transformer. I've read 240V/50A boats with isolation transformers can't get squat for power unless both legs are energized at at least 208V. That came up when guys in our owners club were trying to figure out how to charge batts while on the hard back in a storage lot... with only a few 115V plugs available. We didn't have that problem ourselves... but then again our boat was built the year before our factory started defaulting to installing isolation transformers in our boat model...

-Chris

On my current boat I have the isolation transformer, and the only way to charge the battery is:
1. Start the engine

2. Start the gen
3. Plug into shore
4. Or have a separate way to use a second charger or the primary charger powered directly from a 110/15a cord


I want the SAME thing for my new boat and looking for options. However, currently there's only one charger on the boat.

 

[Seevee]

Im not sure what you are asking or trying to accomplish but
it sounds like you are wanting to improve your current charging setup’s speed of charge.

Unless you are recharging a lithium bank, throwing more or bigger chargers into the mix won’t reduce the amount of time it takes to reach full charge. If you do have a lithium bank you wouldn’t really want to keep it at full capacity anyway.

If you have AGM or Lead acid batteries, once they exit the bulk phase of their charging cycle, they only accept an ever decreasing amount of current. Multiple, or even bigger chargers will never speed up the charge acceptance rate. It’s the main reason many cruisers add solar panels. Outputting a couple of hundred watts for several hours to reach full charge makes no sense, no matter how small you size your genny. Best done on shore power or when running other big loads overnight on a genny.

Cafesport,


See the above comment. Goal is to charge the batteries and keep them topped off at my dock, which does not have a 240/50a service (or two 30s out of phase). So I'm looking at a new separate charger or a way to power the current charger with 110v15a.

 

[C lectric]

One question I have: Can I run ONE charger that has two sources of power?
That could be an issue.


One power source would be a small dock power cord, 110v15a and the other would be the generator.

I think I misunderstood what you were asking which is what lead me to me reply.

I took the above to mean ONE charger at the same time from two different sources, A dockside connection AND a generator. NO which is why I replied the way I did. I saw that and it cost the guy two 3K gens. I had been asked to look at it and figured out this was what they had done. They did not understand what they were doing and bulled ahead.

You can use two different 120VAC power sources to power one charger but only one of the 120VAC source at a time, a generator OR a shore power connection.

 

[MacPhid]

If the current charger is hardwired to a breaker on board powered by shore power, perhaps disconnect the direct connection at the charger and install a 110v receptacle powered from the charger circuit. You could then wire a short pigtail with male plug to the charger and have it plugged into the new receptacle or unplug it and connect the 110v 15A extension cord when you're at your dock.

James

 

[Seevee]

If the current charger is hardwired to a breaker on board powered by shore power, perhaps disconnect the direct connection at the charger and install a 110v receptacle powered from the charger circuit. You could then wire a short pigtail with male plug to the charger and have it plugged into the new receptacle or unplug it and connect the 110v 15A extension cord when you're at your dock.

James

MacPhid,


That would work, but how about a simple switch that is an "either/or" switch. So you turn one on, it turns the other off.

 

[SteveK]

after 23 posts I still do not understand why multiple chargers or multiple power sources to charge are needed.

When engines are running, I presume there is no shore power and no need to run the gennie. When away from shore power and engines are off, the gennie can do the charging.

Each charging source I have known has built in regulation of some kind to avoid overcharging. So if you have two chargers working against each other they can be fooled into seeing the other charger as the battery level.

 

[Seevee]

after 23 posts I still do not understand why multiple chargers or multiple power sources to charge are needed.

When engines are running, I presume there is no shore power and no need to run the gennie. When away from shore power and engines are off, the gennie can do the charging.

Each charging source I have known has built in regulation of some kind to avoid overcharging. So if you have two chargers working against each other they can be fooled into seeing the other charger as the battery level.

Soo-Valley,
Simple answer: I need some way of charging the batteries at the dock, with a 110v source. Right now there is NO option to plug in the power.



No need to run two chargers, and that wasn't ever an issue.

 

[SteveK]

Soo-Valley,
Simple answer: I need some way of charging the batteries at the dock, with a 110v source. Right now there is NO option to plug in the power.



No need to run two chargers, and that wasn't ever an issue.

OK, others have asked why your normal shore cable cannot be used to feed this power, why you needed to add a separate one that will make it a complicated system to operate for you, never mind anyone else that may forget about it.
There have been enough threads about people with two 30 amp cables having issues. If all you want is 15A then run that through the existing input.

 

[MacPhid]

My understanding is that OP's dock is not in a marina, rather a dock at a residence. Only power available is a single 110v 15A circuit. While it may be possible to use adapters I suspect it would not be easy to get power into the boat through the 220v 50A connection.
Just my understanding of it of course.

James

 

[Seevee]

OK, others have asked why your normal shore cable cannot be used to feed this power, why you needed to add a separate one that will make it a complicated system to operate for you, never mind anyone else that may forget about it.
There have been enough threads about people with two 30 amp cables having issues. If all you want is 15A then run that through the existing input.

Soo-Valley,
Well, that's pretty much the plan, but the existing input is 240/50a only. So, I'll need a separate line to carry the 110/15a to the charger. And getting it there is still the issues.


However, after all the input, I believe an "either/or" switch that will have the normal ships power on one side and the 110/15 on the other, after which it would go to the charger.



Comments?




See schematic:

 

[SteveK]

If you cannot plug in the 50A anyway, then make an adapter to a 110. Power both legs of the 50Amp and control the feed by turning off breakers not needed.
Later on you may want 110 somewhere and can direct that feed.
BTW your schematic will work too, for me, just a hassle not needed.