Might already be covered but head is spinning - charging system!

[jkimbu]

Updated drawings to reflect two 30a input lines.

One flaw I see here is based on my observation that currently all the charger output and inverter outputs "appear" to be on line #2 only from the ammeters on the panel. I only ever see current on the line #1 ammeter when the line #1 non-inverter loads are active.

And if that's the case, there's no way I ever get 5000W of power onto all the inverter circuits without borrowing from the batteries. Which I guess is OK on shore power... but the current Xantrex SW 3000 does have this 'feature' where I have to energize *both* the input lines for it to function (it says it right in the manual and everything). So in the event that there's only a single 30A shore circuit available, right now I cannot do anything with that at all except run non-inverted loads (on either line #1 or #2, depending which inlet I connect to the shore). Which in my case means choosing between aircon (line #1) or refrig/battery charging (line #2).

Definitely would like to think of a way I could alternate between running the aircon and the fridge if I only have a single 30A input available that doesn't involve swapping the cable coming into the boat!

Cheers!

[smac999]

your first drawing only had DC in it. my first comment was on DC only.

the reason the inverter charger has 2 inputs. is so one input can be used by the charger (the 3000w probably uses 20a charging) and the other is the pass through to the loads. so if you use 2 30a inputs to one charger, you can still run 30a of loads while the charging is running.

if you only use one line, you are limited to 10a of loads when charging fully. if you exceed the 10a, the charger will claw back so the 30a main does not blow. this is a function of inverter chargers


if you are trying to feed one 30a line to both chargers, which you keep wanting to do. just the 2 chargers on will probably exced 30a. and they will not claw back because they don't know how much the other one is using. so one shore line will be both chargers and some inverter loads, and the 2nd line is only some inverter loads. not balanced.

if you run one line to each inverter charger. each charger can then draw 15-20a from each line, and allow the rest to go to loads. each charger will claw back if too much inverter panel loads are used on that line. and the main breakers will not blow. if you have draw on non inverter loads it will not know, and can not claw back properly. the victrons are better at this.

none of your drawings show all the AC wiring. you will need 4 separate neutral buses. this is important.

this complete separation avoids any issues with GFI dock breakers or if you update to ELCI breakers. you're existing shared line will not work with these. nor will stacking 2 new inverters. because the neutrals will get rejoined after the inverters for proper shared stacking. the first pic is not inverter stacking, it is 2 compleatly separate units.

if a dock only has 1 30a plug. buy a 30A Y cable. then you can run the whole boat. you will have to turn the chargers down.

the manual showing a house panel and 30a single pole hot only breakers is much different then a boat with double pole breakers coming form 2 different sources.


the inverter only has a single N input. so in your current line sharing setup your line 1 and line 2 neutrals must currently be joined as in 2nd pic? this will trip ELCI or GFI breakers. you can not do this.

[jkimbu]

Ahhh... thanks now I understand where the disconnect came from! Thanks!

Originally Posted by smac999

your first drawing only had DC in it. my first comment was on DC only.

Yeah none of the drawings were ever supposed to be detailed with respect to the AC side at all at this point.

Originally Posted by smac999

the reason the inverter charger has 2 inputs. is so one input can be used by the charger (the 3000w probably uses 20a charging) and the other is the pass through to the loads. so if you use 2 30a inputs to one charger, you can still run 30a of loads while the charging is running.

Yep, I confirmed that with Xantrex today - I was under the impression I had to power both of those lines to get anything to work, but apparently not... I'll double check at the boat tomorrow.

Originally Posted by smac999

if you only use one line, you are limited to 10a of loads when charging fully. if you exceed the 10a, the charger will claw back so the 30a main does not blow. this is a function of inverter chargers

Concur.

Originally Posted by smac999

if you are trying to feed one 30a line to both chargers, which you keep wanting to do.

Never meant to imply that I wanted to do this at all. Just wanting to be prepared for the case when I only have 1 30A available... Never thought I could connect it to two chargers.

Originally Posted by smac999

if you run one line to each inverter charger. each charger can then draw 15-20a from each line, and allow the rest to go to loads. each charger will claw back if too much inverter panel loads are used on that line. and the main breakers will not blow. if you have draw on non inverter loads it will not know, and can not claw back properly. the victrons are better at this.

As I've said, the downside of one line per inverter charger, from the inverter side, is that I have to commit to which loads come from which inverter, limiting flexibility a little bit but not a show stopper. I'll look into the Victrons, since I need a new control panel for the SW 3000 anyway, and if I cannot find one on ebay I'll have to bite the bullet....

Originally Posted by smac999

none of your drawings show all the AC wiring. you will need 4 separate neutral buses. this is important.

Yep - never meant to imply the AC drawings were complete at all, just conceptual.

Originally Posted by smac999

if a dock only has 1 30a plug. buy a 30A Y cable. then you can run the whole boat. you will have to turn the chargers down.

Well not *the whole boat*, only 30A worth of the boat. Heck on a hot summer day I can use up 20+ amps on aircon alone!!! The Y cable for those times when there's only one 30A available is a good idea - I'll see if there's a Smartplug version.

Originally Posted by smac999

the inverter only has a single N input. so in your current line sharing setup your line 1 and line 2 neutrals must currently be joined as in 2nd pic? this will trip ELCI or GFI breakers. you can not do this.

The present inverter (SW 3000) yes only one N... and yes I can see that the two inputs were out of phase that could pose a definite problem! The boat came to us wired that way... so I definitely have to resolve that.

Thanks again for the patience... I had originally only been thinking about the DC side as it's the battery swap and addressing charging the genset battery that I am focussing on next. I'll definitely look into the AC side in more detail!

Cheers!