Cheapo Inverter

[Dave Payne]

I have a Victron inverter that handles my power usage nicely at the minute however the other half does like her hair dryer, and before you say tell her she cant use it, its not an option.

Also I fitted an electric oven when I was in the marina as I didn't think I would leave said marina, and I hate cooking with a gas oven and I don't really use the oven much, in the winter I prefer cooking on the stove.

Now ive left the marina and also ripped out the old gas oven I can either replace the new oven with gas or get a bigger inverter, 3000 watts will cover my needs.

Spotted some cheapo ones on the web and my thinking is, I fit one along side my victron, the victron runs in standby which looks after the fridge when I'm away from the boat, the cheapo doesn't and I don't think I would want to leave a cheapo one running when I was not on the boat, I would then have a chang over switch between the two so that when I am using the oven or the other half is using the hair dryer I can use the cheapo, then when done flick back to the victron.

Don't really want to be lugging around a genny either.

Cant really see any problems with BSC as long as I wire it correctly, use the correct dcable and a three way switch with an off in-between the two inverters?

[Robbo]

Electric Oven on batteries, don't you read this forum?  What's your power source for the oven?

[rusty69]

Blimey. 

Thought you were going to say my wife has a hairdryer and I fitted an electric oven. How can I use the oven to dry the wife's hair. 

2 minutes ago, Robbo said:

Electric Oven on batteries, don't you read this forum?  What's your power source for the oven?

The Mains probably 

[Dave Payne]

Run the oven from the batteries...

Its 2.5kw, so the very rare times I do use it, I use it for maybe 30 mins max, = 125 amp things out my batteries, I am fitting a fourth battery so will have 220 amp things available before they hit 50%.

LIke i said, I rarely use it, and in winter I cook stews, pies, jacket spuds, chilli on the stove, summer I bbq and eat fresh food cooked on the hob.

To be honest I don't even know why I'm bothering to fit it, but its there so I may aswell, plus the hairdryer is a must if the other half wants to spend time on the boat.

[mrsmelly]

It will be cheaper and less hassle long term to trade the wife in and get one who is lower maintainance. I used to have a high maintainance one but traded her in for the present one who doesnt even own a hair dryer. Much better option.

[Dave Payne]

4 minutes ago, mrsmelly said:

It will be cheaper and less hassle long term to trade the wife in and get one who is lower maintainance. I used to have a high maintainance one but traded her in for the present one who doesnt even own a hair dryer. Much better option.

Each to their own and all that, she likes to look good, and I like a women on my arm who looks good.

 

Makes me look better

[Robbo]

I would remove the oven and replace with a Combi oven then, at least you can do some microwaving and get some use out of it!   Can't help on the inverter choice tho, but you could run a separate AC loop for high powered items and just keep everything seperate.

 

PS, I'm also having a Combi oven, but I have a built in genny, if you do use it run the engine, and if end up doing it often get a high amp alternator.

Edited April 11, 2017 by Robbo

[Dave Payne]

Yes, was thinking of running a dedicated 240v socket from the inverter to the oven and a spare for the hair dryer actually, keep it simple!

Not a big user of microwaves either, have survived for near two years without one.

[Robbo]

21 minutes ago, Dave Payne said:

Yes, was thinking of running a dedicated 240v socket from the inverter to the oven and a spare for the hair dryer actually, keep it simple!

Not a big user of microwaves either, have survived for near two years without one.

If you have a dedicated consumer box for the other inverter for RCD/breaker then you could just run both inverters.   I would use different colour cable than your current AC and label appropriately so you never mix as that would be bad.

[Dave Payne]

Actually, just had a google of my oven and it says the below.

Energy Consumption Conventional (Main Cavity): 0.84 Kwh

https://www.thewrightbuy.co.uk/ignis-aks1400ix-stainless-steel-electric-single-built-in-or-under-static-oven

 

Inside the oven where these is a label with model number on and it says 2.5kw.

[Robbo]

7 minutes ago, Dave Payne said:

Actually, just had a google of my oven and it says the below.

Energy Consumption Conventional (Main Cavity): 0.84 Kwh

https://www.thewrightbuy.co.uk/ignis-aks1400ix-stainless-steel-electric-single-built-in-or-under-static-oven

 

Inside the oven where these is a label with model number on and it says 2.5kw.

That's 0.84Kwh,  that's like your journey distance is 84miles where the 2.5kw is the max MPH you can do in the journey.

[Dave Payne]

So how many watts would it use per hour, 840 or 2500 ?

[Robbo]

1 minute ago, Dave Payne said:

So how many watts would it use per hour, 840 or 2500 ?

The consumption over an hour is 850watt-hours,  the wattage it can use at anyone time is 2500watt,

watt-hours, Kwh is the equivalent of miles.   So it's 850wh taken from your batteries (per hour).

watts, kilo-watts, kw is the equivalent of MPH.  So it's 2500watts your inverter needs to supply at any one given time.

[Dave Payne]

Right, so the max I need is 2500 watts, a 300 watt inverter covers this.

It should pull 850 watt hours per hour its on, meaning 850/10 = 85 amp hours out my batteries?

[Robbo]

Just now, Dave Payne said:

Right, so the max I need is 2500 watts, a 300 watt inverter covers this.

It should pull 850 watt hours per hour its on, meaning 850/10 = 85 amp hours out my batteries?

Er no, you'll need at least a 2500watt inverter that can supply that for a good period of time.  It's not 2500watt peak, it could be using 2500watts for minutes until it gets to temperature. 

[Dave Payne]

sorry, meant 3000 watt.

[Robbo]

Just now, Dave Payne said:

sorry, meant 3000 watt.

Aye, that better, but make sure it can supply that, heat will reduce the wattage.   If you look at your Victron manual it says what it can supply at different operating temperatures.  Cheap inverters are more likely not to give this info tho.

[WotEver]

Madness...

[Chewbacka]

Putting aside the wisdom in running an oven from batteries.  You say you will rarely use the oven, in which case for the 15mins it takes to heat up using 2500W ( so about 250A and about 65AHrs ) you could run the engine at say 1500rpm to share the load between the alternator and the batteries - though it depends upon the size of alternator that you have.

I would also give you a couple of warnings.  Some cheap inverters claim to be continuously rated for x watts, but when you read the specs they warn you not to exceed more than about 75% of x for more than a few minutes.  The second point is that 2 inverters - unless special (expensive) with a link cable - will not be in phase and so the voltage between the 2 live outputs will vary rapidly between nothing and about 500V peak, so think about keeping the sockets well apart etc.  Personally I would not do what you are going to do.

[cuthound]

If you use two inverters then you need to keep the outputs (sockets fed from each one) 2 metres apart, or only have one swinched on at any time, which may not be practicable if one is feeding the fridge. 

This is because the output waveforms of each inverter will not be in phase. If you get yourself across them it could be a 440 volt shock, not a 240 volt one.

[Robbo]

What Victron model inverter do you have now?

[tomsk]

8 hours ago, mrsmelly said:

It will be cheaper and less hassle long term to trade the wife in and get one who is lower maintainance. I used to have a high maintainance one but traded her in for the present one who doesnt even own a hair dryer. Much better option.

I'd favour an efficient source of heat.

[nicknorman]

2.5kw is about 250A from the batteries. Even with 4 this is a very fast discharge. I think they will struggle to keep this up even for 30 mins without the voltage getting too low for the inverter. And as the voltage drops, so the inverter will pull even more current. And then the batteries will need a whole heap of recharging. Electric oven on a boat is a REALLY BAD IDEA unless you have a large built in quiet generator and huge batteries.

[MtB]

On 12/04/2017 at 00:30, nicknorman said:

2.5kw is about 250A from the batteries. Even with 4 this is a very fast discharge. I think they will struggle to keep this up even for 30 mins without the voltage getting too low for the inverter. And as the voltage drops, so the inverter will pull even more current. And then the batteries will need a whole heap of recharging. Electric oven on a boat is a REALLY BAD IDEA unless you have a large built in quiet generator and huge batteries.

 

It's not like you Nick, to understate your case....

[Ange]

Tell your missus that hairdryers dry out her hair - giving up the hairdryer was the best thing i ever did for my hair, i was stunned by how much better its condition was when we lived aboard and i let it dry naturally.

I'm back in a house now and haven't used the hairdryer that came out of storage a year ago.

(Yeah i know she won't believe me but it's worth a try )

Edited April 12, 2017 by Ange