Inverters

[MauriceMynah]

I have a 350w pure sinewave inverter at the moment, but before the winter I think I might need more than that. My options are one big one or multiple small ones.

I'm never going to run anything hefty from them, but I wondered which was the better option. If I were running a phone charger from a 2kw inverter, would that use more or less power than running that same charger from the 350w inverter? 

Edited to add...

Does it harm an inverter to be left on with nothing running from it? 

Does an inverter use much power when not doing anything? (but turned on  of course!)

[petersjoy]

Hi John, I always charge the phones from a 12v socket with a usb adaptor in, think that is better than using an invertor for that.

[annv]

Hi I would suggest a inverta/charger from Sterling Products if you google there site for info you will see why theirs have a stand by setting along with working with no battery's connected if you remove over stand down period but still want to use power. John

[Cheesey69]

The only inverter I’ve got is to run the telly, and that don’t use much power around 2.5amps

the rest runs on the 12volt. 
I have shore power that runs a charger and a range of sockets. 
I find I don’t really need any more inverters because there is nothing else that needs 240. 
I can only think you must want a microwave but the mrs just waits until we have shore power 
I am going to put in solar just to give my battery bank more legs. 

[Oddfellow]

I wouldn't recommend anything from Sterling. Thrown away way too many Sterling inverters to want to go down that route again. 

Different inverters have different idle power draws. There's no easy answer to this one.

However, your inverter max power rating will have little or no difference to the power drawn from the batteries with just a phone charger. However, this is a remarkably inefficient way of charging a phone which requires a 5v DC supply. What you're doing is multiplying your 12v DV supply by 20 time and creating an alternating frequency on it which takes power to achieve and immediately dropping that to 5V dc with the phone charger which is 7v DC less than you started with. This makes zero sense. 

Install USB charging ports and have done with that. 

 

 

[BroadAmbition]

I wouldn't recommend anything from Sterling. 

Really? - That's surprising as all our electrical kit, the inverter, 12 and 240v chargers, battery management system, monitor / control panel are all Sterling products and have been providing sterling performance for over fourteen years now

Griff

[Vaughan]

17 hours ago, Oddfellow said:

I wouldn't recommend anything from Sterling.

I don't know about Sterling but I certainly agree with the rest of your post. It is easy to buy a 12 volt charging lead for a mobile phone or other appliances - they are available in motorway service stations. Much easier and the phone usually charges a lot quicker.

You can count on around 10% loss every time you convert current from one thing to another.

[MauriceMynah]

I could have used my nuclear toothbrush as an example rather than a phone charger. The toothbrush needs a pure sinewave 240v input to start the nuclear reaction but only draws .000007 of an amp.

That is to say would a powerful inverter draw  the same amount of juice from a battery as a less powerful one when on the same load.

[grendel]

MM I think that a lot depends on the inverter, some will draw the same basic amount when in standby as when running (plus the load), others will have a standby mode where they drop to a low current until a signal tells them to fir up and get to work, its just a case of finding the specification that suits you best (or turning off the inverter when you are not using it.)

[oldgregg]

If you're thinking about replacing your inverter then it might be worth looking at an inverter / charger such as the Victron MultiPlus range.

With that setup, you can have a 240v circuit for sockets etc that runs from whatever power source is currently available and a separate 'shore power only' circuit for your immersion heater etc.

You can also throttle the current available to the sockets to ensure the batteries always get a good charge without maxing out the 16 amp supply. 

They aren't all that cheap, but if you're using the boat a lot then it might be a good investment.

As for charging electronics, I always try to use 12V chargers where possible.

[petersjoy]

1 hour ago, MauriceMynah said:

I could have used my nuclear toothbrush as an example rather than a phone charger. The toothbrush needs a pure sinewave 240v input to start the nuclear reaction but only draws .000007 of an amp.

That is to say would a powerful inverter draw  the same amount of juice from a battery as a less powerful one when on the same load.

Yes I killed 2 toothbrush chargers before realising it was the cheaper 150w inverter that did it.

Recently bought one of these https://www.amazon.co.uk/gp/product/B076P9PGX3/ref=ppx_yo_dt_b_asin_image_o03_s00?ie=UTF8&psc=1

Looks a well made unit, have used it but not for the toothbrush yet, stuck to mains for topping those up.

[grendel]

I even use a 12V-19v DC-Dc converter for running a laptop when aboard, it basically cuts out the conversion to 240V AC all in the plug in part, works fine and hammers the battery less than an inverter.

[Oddfellow]

2 hours ago, MauriceMynah said:

I could have used my nuclear toothbrush as an example rather than a phone charger. The toothbrush needs a pure sinewave 240v input to start the nuclear reaction but only draws .000007 of an amp.

That is to say would a powerful inverter draw  the same amount of juice from a battery as a less powerful one when on the same load.

Approximately the same. It is the load ON the inverter that dictates the load on the batteries, not the max watt output of the inverter. 

[Oddfellow]

36 minutes ago, grendel said:

I even use a 12V-19v DC-Dc converter for running a laptop when aboard, it basically cuts out the conversion to 240V AC all in the plug in part, works fine and hammers the battery less than an inverter.

There is a lot to be said for this.  My latest laptop as a whopping 230W power supply. Are there any such DC-DC devices that will cope with this at a reasonable cost? 

[grendel]

6 minutes ago, Oddfellow said:

There is a lot to be said for this.  My latest laptop as a whopping 230W power supply. Are there any such DC-DC devices that will cope with this at a reasonable cost? 

a good question, my laptop is only 90W so the 120W converter I use is plenty big enough

[grendel]

well after doing some quick research, it seems 120W is about the best commercially available off the shelf, but I do see that one could be made, as I have found examples of dc-dc converters that can be parallelled together to ratings of 2.8kw (that would hammer your batteries I must say) so a 230W model should be possible to construct from commercially available components. that said the 120W one could be used to charge the laptop while switched off and boost the useable time even while switched on

[CambridgeCabby]

Removed by op

[annv]

I have had exemplary service from all the Sterling Products that i have used, and have found it difficult to get Vectron items repaired unless  returned to Holland, Sterling do a same day repair if presented to them before 10 o'clock, thy also give technical advise over the phone. John

[MauriceMynah]

4 hours ago, Oddfellow said:

Approximately the same. It is the load ON the inverter that dictates the load on the batteries, not the max watt output of the inverter. 

Thank you. That was the question I wanted answered

[petersjoy]

On 12/07/2021 at 10:24, petersjoy said:

Yes I killed 2 toothbrush chargers before realising it was the cheaper 150w inverter that did it.

Recently bought one of these https://www.amazon.co.uk/gp/product/B076P9PGX3/ref=ppx_yo_dt_b_asin_image_o03_s00?ie=UTF8&psc=1

Looks a well made unit, have used it but not for the toothbrush yet, stuck to mains for topping those up.

Just a quick update, these inverters have been £47 on amazon for ages, just reduced to £35 today. i've ordered another one just now, far better than a cheap modified sine wave one.