Battery charger versus inverter

[jmcdboater]

I'm looking at buying a new (to me), vessel, which has a 40 amp battery charger. Does not have an inverter. Now I have never had an inverter, I know it converts 12 volt power to 110 power. If you have genset, which this vessel does, and a battery charger, how advantageous is having an inverter? I'm certainly not against adding one if it really makes sense. How much are they? This is going to be a liveaboard, so power consumption will be important. Thanks for all the help......

[cal40john]

This is a big it depends question. An inverter allows you to have 120 volt AC power without the generator running. If you have big loads you need a big costly inverter and a big battery bank. The current drawn out of the batteries is approx 10x that of the current listed on the AC appliance. Then you have to run the genset to charge the batteries, and the batteries take time to charge.

It's more efficient to use the genset usually, but if you want the quiet of not running the genset whenever you want 120 power then the inverter allows you to time shift when you run the genset.

[boatpoker]

The previous owner put a 3000 watt inverter in my boat, six years and I have never used. An inverter can cost from $50.00 to $5,000.00 (or more if you have to install new battery banks to feed them )to install and make things much more complicated. Many of them do not have a great history of reliability.

You need to educate yourself thoroughly on electrical systems before you spend money on stuff like this. It can get very complicated and a few quick questions on a forum ain't gonna do it.

[goboatingnow]

The previous owner put a 3000 watt inverter in my boat, six years and I have never used. An inverter can cost from $50.00 to $5,000.00 (or more if you have to install new battery banks to feed them )to install and make things much more complicated. Many of them do not have a great history of reliability.

Good quality invertors are very reliable, cheap Chinese junk isnt.

I find invertors very useful , I run 220V lamps ( SWMBO likes them !), its handy for low power mains devices etc. Prevents running generator for trivial mains devices.

for me 1000W-1500W is most useful , above that big batteries, and why ? , become more of an issue.

dave

[sailorboy1]

inverters are very useful, I wouldn't hesitate to replace mine with a new one if it were to stop working

[ranger58sb]

Relevant to the thread title... the battery charger (AC-to-DC converter) is pretty much mandatory, assuming you have batteries. Shorepower or the genset supplies the AC.

An -- additional -- DC-to-AC inverter may have some value, as others have said (e.g., quick hors d'ouvres at anchor, from quiet microwave without genset running)... depending on your own particular preferences, depending on your battery supply, etc.

Some inverters also include a battery charging capability (using AC supplied by shorepower or genset); many do not.

-Chris

[sdowney717]

I have 3000 watt 6000 watt surge 120 vac inverter made by Peak old world industries. It has a remote switch with led lights and auto shutdown if load is exceeded. It is a square looking thing, the old one which I shorted out accidently, was long rectangular. This new inverter is MSW BUT, it runs my microwave much quieter than the old MSW, so it is improved electronics.

I have a 6500 watt generator and it is nice to not have to run that for AC power underway. I had to get 3000 watt since I need to run my fridge-freezer and it is an AC only model. The inverter I have wired by way of 4 pole relay box into my boats electric system.
I have twin 30 amp power, so with 4 poles I can switch between gen-inverter-shore power easily using a couple toggle switches, no rotary expensive switch is needed.

close up of 4 pole double throw power relays




simplified schematic only shows 2 pole relays idea


box I welded from an old breaker box


wired into boat


One mod I made to these relays was spring pressure, even though they have 120vac coils, I lowered the spring pressure due to our marina voltage fluctuates low and caused the shore power relay to buzz.

My generator uses a sense voltage to sense power demand out on the load wires for autostarting. So I had to set the relays to be de-energized to allow the relay to conduct current from gen to load uninterrupted or I would loose that feature.
This means when plugged into shore power, the relay coil energizes and when shore power is off, relay de energizes for either gen or inverter.

At the helm area, I have 2 toggle switches.

One is on-off-on for generator with led lights
One is on-off for shore power
And there is the remote on-off switch for inverter.

[Mystic38]

If you buy a sizeable inverter/charger you can have say a 1500W inverter/75A charger..giving you a backup 40A charger.
This would be ideal for the microwave... running a generator for 60 seconds to heat coffee isnt my cup of tea... yes, its coffee..lol

Secondly, if you have a tv/dvd player/laptop etc... get a 150W inverter for $30.. far more efficient than running a large inverter to just watch tv.

[goboatingnow]

Easy enough to knock together an auto switching solution , using a few contactprs


Dave

[model 10]

Originally Posted by sdowney717

I have 3000 watt 6000 watt surge 120 vac inverter made by Peak old world industries. It has a remote switch with led lights and auto shutdown if load is exceeded. It is a square looking thing, the old one which I shorted out accidently, was long rectangular. This new inverter is MSW BUT, it runs my microwave much quieter than the old MSW, so it is improved electronics.

I have a 6500 watt generator and it is nice to not have to run that for AC power underway. I had to get 3000 watt since I need to run my fridge-freezer and it is an AC only model. The inverter I have wired by way of 4 pole relay box into my boats electric system.
I have twin 30 amp power, so with 4 poles I can switch between gen-inverter-shore power easily using a couple toggle switches, no rotary expensive switch is needed.

close up of 4 pole double throw power relays




simplified schematic only shows 2 pole relays idea


box I welded from an old breaker box


wired into boat


One mod I made to these relays was spring pressure, even though they have 120vac coils, I lowered the spring pressure due to our marina voltage fluctuates low and caused the shore power relay to buzz.

My generator uses a sense voltage to sense power demand out on the load wires for autostarting. So I had to set the relays to be de-energized to allow the relay to conduct current from gen to load uninterrupted or I would loose that feature.
This means when plugged into shore power, the relay coil energizes and when shore power is off, relay de energizes for either gen or inverter.

At the helm area, I have 2 toggle switches.

One is on-off-on for generator with led lights
One is on-off for shore power
And there is the remote on-off switch for inverter.

If you are going to show photos of you stuff you should not be usiing solid core house wire.

[boatpoker]

Originally Posted by goboatingnow

Good quality invertors are very reliable, cheap Chinese junk isnt.

I find invertors very useful , I run 220V lamps ( SWMBO likes them !), its handy for low power mains devices etc. Prevents running generator for trivial mains devices.

for me 1000W-1500W is most useful , above that big batteries, and why ? , become more of an issue.

dave

Google Xantrex inverter problems .... 200,000 hits

My stove is propane, I never have to run the generator for coffee in the morning.

[colemj]

Originally Posted by Guy

If you are going to show photos of you stuff you should not be usiing solid core house wire.

While I admit to not understanding the purpose of his post, I think that the use of solid wire for short jumpers across terminals is just fine in his application. I mean, we are talking what - 3" of wire to an adjacent relay terminal in a box that won't be flexing?

I don't understand why several of the wires have pulled out of their crimps, though....

Mark

[colemj]

Originally Posted by boatpoker

Google Xantrex inverter problems .... 200,000 hits

He specifically said "good quality inverters". You proved his point.

Mark

[Maine Sail]

Originally Posted by colemj

I don't understand why several of the wires have pulled out of their crimps, though....

Mark

Because crimping solid wire is like farting in church, you just don't do it..... It looks like he both crimped and soldered so very odd why it pulled out...

[model 10]

Originally Posted by Maine Sail

Because crimping solid wire is like farting in church, you just don't do it..... It looks like he both crimped and soldered so very odd why it pulled out...

Not to mention, it's not tinned so it will corrode, electrons travel on the outside of the wire and you only have 1 instead ofmaybe 18-20 and it kind of looks like more of the conductors are house wire too. Actually this is the best example of lousy wiring I could imagine.