Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 23-04-2018, 22:07   #121
Sponsoring Vendor

Community Sponsor
Cruisers Forum Supporter

Join Date: Apr 2006
Location: Port Alberni, BC Canada
Boat: Uniflite 31, 1973
Posts: 138
Images: 1
Re: Inverter/Charger Recommends

PFC or no, inverter-chargers are particularly sensitive to the input voltage waveform due to the designs that allow common components between the two functions. This also limits their charging power to about half the inverting power. Generators produce distorted waveforms under reactive loads, and the inverter-charger is very reactive. The effect is a chopped-off or flattened peak of the AC voltage. PFC reduces the effect on the generator and improves performance, but generators have a fairly distorted waveform compared to mains power to begin with. Heating loads are non reactive and the lower the proportion of reactive to total load the better the generator waveform will be, thus one will observe increased output capability when heaters are turned on. Generators with electronic regulators will perform best, capacitor regulation worst, and larger better than smaller.
__________________
Experience develops good judgment; bad judgement develops experience.
EngNate is offline   Reply With Quote
Old 16-05-2018, 17:40   #122
Registered User
 
TassieBloke's Avatar

Join Date: Sep 2006
Location: Melbourne AUS
Boat: Transpac 49
Posts: 124
Images: 3
Re: Inverter/Charger Recommends

Hi All,

Trying to get my head around the whole Inverter Combi thang...

I live on board just as a side note.

When I bought my boat, it had a 12V Mastervolt Combi in it, which subsequently blewup after 1 month After investigation by Mastervolt, they concluded that the dust build up inside has caused a short circuit on the PCB and that was that.

Fast forward 3 or so years, and now I am in a position to investigate replacing the Inverter.

Now to my question. The Victron and others advertise the Power Assist function. This is important for me as we are limited to a 240V/15A shore power supply. Is the power assist function truly that? If my current draw exceeds 15A, then will the Inverter will concurrently draw the deficit Amps from the house bank?

I have read the literature on the Victron Quattro in particular, and it seems to be slightly ambiguous. It mentions the power assist function, but then goes on to say that the switchover is essentially instant. This means to me, that if the current exceeds a certain amperage, then the Inverter will draw all power requirements (limited to Inverter size) from the house bank. I would have assumed the switchover to mean that if it is drawing off the housebank, and a external power source (genset, shore power) is detected, then the switchover to the new power source would be essentially instant. However, I could be completely wrong.

I guess the upshot of it all is to get the sizing of the Inverter right. If I can rely on 3.5kW from the shore power, and have a 3kW Inverter, then I theoretically have access to 6.5kW of power. Is this assumption correct?

Any input would be appreciated.
__________________

__________________
Just remember, Engineers built the Titanic, and Noah built the Ark
TassieBloke is offline   Reply With Quote
Old 17-05-2018, 04:17   #123
Registered User
 
transmitterdan's Avatar

Join Date: Oct 2011
Boat: Valiant 42
Posts: 4,535
Re: Inverter/Charger Recommends

You have it mostly right. If power assist feature is turned on then whenever the mains current passing through the combi unit exceeds a preset amperage the inverter will supply the extra amps drawn by the AC devices. It does not stop using the mains power. The combi just supply's the extra amps.

In configuring power assist mode you choose the maximum mains current (say 15A). You can draw that plus whatever the inverter can supply. The setting for max mains is not continuous as it is usually done via switches so probably it will have only a few possible choices.
transmitterdan is online now   Reply With Quote
Old 17-05-2018, 08:21   #124
Registered User

Join Date: Jan 2017
Posts: 7,254
Re: Inverter/Charger Recommends

Of course drawing massive amps from a weak bank may trigger an inverter cutout from voltage dropping.

High-amp chemistries like LFP and newer high quality AGM will have less voltage sag, but sometimes you just have to go with a higher capacity bank.

And any bank getting toward EOL will sag more over time.
john61ct is online now   Reply With Quote
Old 17-05-2018, 11:43   #125
Registered User
 
CatNewBee's Avatar

Join Date: Aug 2017
Boat: Lagoon 400S2
Posts: 1,236
Re: Inverter/Charger Recommends

Quote:
Originally Posted by TassieBloke View Post
Hi All,

Trying to get my head around the whole Inverter Combi thang...

I live on board just as a side note.

When I bought my boat, it had a 12V Mastervolt Combi in it, which subsequently blewup after 1 month After investigation by Mastervolt, they concluded that the dust build up inside has caused a short circuit on the PCB and that was that.

Fast forward 3 or so years, and now I am in a position to investigate replacing the Inverter.

Now to my question. The Victron and others advertise the Power Assist function. This is important for me as we are limited to a 240V/15A shore power supply. Is the power assist function truly that? If my current draw exceeds 15A, then will the Inverter will concurrently draw the deficit Amps from the house bank?

I have read the literature on the Victron Quattro in particular, and it seems to be slightly ambiguous. It mentions the power assist function, but then goes on to say that the switchover is essentially instant. This means to me, that if the current exceeds a certain amperage, then the Inverter will draw all power requirements (limited to Inverter size) from the house bank. I would have assumed the switchover to mean that if it is drawing off the housebank, and a external power source (genset, shore power) is detected, then the switchover to the new power source would be essentially instant. However, I could be completely wrong.

I guess the upshot of it all is to get the sizing of the Inverter right. If I can rely on 3.5kW from the shore power, and have a 3kW Inverter, then I theoretically have access to 6.5kW of power. Is this assumption correct?

Any input would be appreciated.
This is partlly true: yes, power assist will topp up the shore power - and no, you will not add 3500W with a 3000 Quattro, the 3000 are VA, continous power is much less, my Quattro 5000(VA) delivers only 4000W continous power, I guess the 3000VA device can provide only 2400W at 25C, 2200W at 40C and 1800W at 65C continous power.
CatNewBee is online now   Reply With Quote
Old 17-05-2018, 15:18   #126
Registered User
 
TassieBloke's Avatar

Join Date: Sep 2006
Location: Melbourne AUS
Boat: Transpac 49
Posts: 124
Images: 3
Re: Inverter/Charger Recommends

Thank you all for your replies. This was exactly the information that I needed

There is no intention to draw the load fully from the housebank, thus any 'top up' would be for a short duration.

I have found over the last months, that my maximum draw is around 240V/20A and ambient temps here would rarely exceed 40C, so a inverter rated at 3000VA should cover the deficit amply.

There is a 600AH flooded cell house bank, so even drawing for a longer duration at 240V/5A (12V/100A), all things being equal, I could draw for at least 2.5hrs before approaching the 50% DOD for flooded cells.

I guess ultimately I would move away from flooded cell to another chemistry, but that is a number of years away, so it is not vital that the inverter be fully compatible with LP or similar.

Thanks again
__________________

__________________
Just remember, Engineers built the Titanic, and Noah built the Ark
TassieBloke is offline   Reply With Quote
Reply

Tags
charger, men

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Coast Guard recommends boaters don't use New Pass Iin Sarasota, Fl. salty_dog_68 Atlantic & the Caribbean 1 05-04-2016 18:55
surveyor recommends... kim r Construction, Maintenance & Refit 1 27-09-2013 06:50
Opinions on this charger: BASSMASTER ProMariner Marine Battery Charger exranger Electrical: Batteries, Generators & Solar 6 30-11-2008 07:25
Webasto or Mikuni heater ? recommends davis911s Liveaboard's Forum 8 15-01-2008 17:52
AC charger smarter than the 3 stage "smart" charger? CSY Man Electrical: Batteries, Generators & Solar 64 30-09-2006 12:49



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 15:34.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.