Inverter size (3 Viewers)

[Richard n Ann]

I had a cheap 150W that freaked out on on laptop even though it should work in theory. I then bought a 300W pure sine wave and use it safely for laptop ( because same laptop freaked out the decent 12V->19V unit I have ) and ebike chargers and anything else.

The small loss of going 12v->240v-19v just isn't worth worrying about in the real world.

An inverter is the right solution for you.

Here is one I quickly spotted....

Or one like this, the FINEST MONEY CAN BUY!... Because you're worth it

 

[Lenny HB]

Sorry to bump the thread but am cosidering using a small 600w microwave just to warm things up (2x110a LB+ 80 solar.)-what size pure sine inverter would I get away with?

1500 watt would probable be OK anything smaller likely to trip out on startup current which can often be twice the rated power. Bigger expensive microwaves often use inverter technology and only draw about 30% more on start up.

 

[autorouter]

A. Pay installer to fit 2x 12v Hab sockets and buy 3 or 4 transformers
or
B. Pay installer to fit 150w Inverter and use the plugs I've got

My choice would be A: Pay installer to fit 2x Hab sockets. Specify that both are capable of taking 15 amps each.

You can run a 150w pure sine wave inverter from one of the 12V sockets (takes about 13 amps max). Higher power inverters are too powerful to run from a 12V cig-lighter socket, and need to be wired into the battery or use high-power connectors.

A 150w inverter does not use 150w all the time. If you plug in a 65w charger it will draw 65w from the 12v supply, plus an extra 10% or so to allow for conversion losses. So that's about 72 watts, and the current from the 12v supply will be 72/12 = 6 amps.

In the future you can get 12V items like USB-type phone/satnav chargers and laptop charger.

For information, a 90w 19v laptop charger will be fine as an alternative to a 65W 19v charger. It supplies only the amps that the laptop requires. Basically make sure the voltage is correct. The amps will look after themselves, as long as the charger is capable of providing the required amps and watts.

The downside is it is likely to be bigger and heavier than a 65w supply, and probably a bit more expensive too. It is however also capable of charging laptops that demand higher amps and wattage.

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[Wandering vagabond]

1500 watt would probable be OK anything smaller likely to trip out on startup current which can often be twice the rated power. Bigger expensive microwaves often use inverter technology and only draw about 30% more on start up.

Spot on post

In reality a lot of microwaves actually take nearer double the rated power and those with digital controls will only run on pure sine wave ... on my narrowboat i have a victron bvm 702 so can see the amps draw as it happens ... my digital 850watt microwave running through a 3kw sterling pure sine inverter has been known to draw nearly 200 amps!

Rick

 

[Guigsy]

I had a cheap 150W that freaked out on on laptop even though it should work in theory...

I've got a small'ish non-sinewave invertor. My laptop will charge fine on it, but it sends the touch pad nuts every 30 seconds.

 

[hilldweller]

but it sends the touch pad nuts every 30 seconds.

Is it worth the risk continuing to lose it ? How much is your laptop and more important it's contents compared to a new inverter ?

I have a 19V/12V supply which amazed me running the laptop through it, the ammeter showed a really serious rise every time the hard drive was accessed, they certainly gobble current.

Which is why it's better to go past the theoretical minimum and have some spare for a better laptop or bigger ebike.

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[Guigsy]

Is it worth the risk continuing to lose it ? How much is your laptop and more important it's contents compared to a new inverter ?

Totally agree. I thought it was a software issue at first. When I realised that it was only happening while I was charging, I stopped. I am risking charging the laptop while it's totally shutdown though. And only when I really need to.

 

[Rollin]

Another thing to be aware of when buying an inverter, is they usually give an efficiency rating, typically from 85% to 95%. However the gotcha here is that this rating is the optimum efficiency of the inverter, which will be achieved when drawing around 70% of the inverter's maximum rating.

This is mostly because the inverter will draw a certain amount just by being switched on. For larger inverters of 1000W and above, this operating power can be 15W or more, while a 200W unit could be as low as 5W.

So ideally choose an inverter with no more than about 50% more power output than you're going to need.