12V inverter (1 Viewer)

[Starspirit65]

Hi i'm new to MHs only had mine for 4 weeks and still kitting it out it's a Marquis Starspirit 2004.We are going to be using it off grid for most of the time, and i've just bought two Banner Energy bull 110ah batteries can anyone recommend a good 12v inverter please?
We will be using TV, microwave,Laptop, hairdryer etc, and camera chargers.

 

[Richard n Ann]

Finest money can buy: Studer AJ series

Decent quality: Victron

Or for a gamble the Chinese cheapos, our Meind one is good but they vary.

 

[Stealaway]

You will need a pure sign wave if you need it to work a micro wave

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[Richard n Ann]

The microwave will absolutely hammer the batteries, if you can manage without and use gas the batteries will live longer.

Ann uses the babyliss "Big Hair" hair dryer it's got 350w and 750w settings which are more battery kind. She didn't buy it for the low wattage she likes it anyway

 

[peterc10]

No point in having two batteries and an inverter unless you have something to replace the power you will be using. So the first question is how much solar will you be getting? And you will probably need to get a B2B charger as well.

The wattage of the hairdryer will probably decide what sized (in watts) inverter you will need. We have a cheap 2000/4000W modified sine wave inverter from Amazon that is only used for my wife's hairdryer and that has worked OK for the last 6 or 7 years. Don't know about microwaves because we do not have one in the motorhome. We rarely use the one in our house so that is no loss to us. As others have said use gas for cooking and heating otherwise your batteries will be flat in no time.

Using an inverter for low voltage DC appliances like TVs, laptops, phones cameras etc etc is very inefficient. Much better to get 12V adaptors for them and install some 12v power points.

 

[two]

I'd forget the microwave (and save a lot of weight), then go for 1kW pure sine wave (PSW) inverter.
I've used MSW inverters successfully but some electronics don't like them. We had hair straighteners that wouldn't work, for example, and an e-Bike charger. PSW assures you of not damaging things unnecessarily.
Batteries have a modest, finite capacity. Try to avoid using inverted 'mains' power as if you were at home and prefer 12V chargers if you can get them.

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[jezport]

Just used a travel kettle in our van, but only use it when its sunny. Kettle takes around 700w while my solar was putting 104w back in. Kettle takes around 4 minutes to boil. So if I worked it out right my battery would be back to full in around 25minutes as long as the sun stays out. Wouldn't use it at night for anything that heats.

 

[two]

I don't think (Lead-Acid) batteries like being exercised heavily.
So even brief rapid discharges may impact the number of cycles a battery can perform.
Lithium seem to be much more tolerant but I wouldn't take advantage of that characteristic.
It is good to replenish what you remove as soon as you can.

 

[scotzsue]

We are about to replace our quest travel kettle think it is about 600w have had it for some time but it recently started switching itself on if left plugged in and last time I used it it tripped our electric. It has been disposed off, we do have another small travel kettle but we like a nice mug of tea in the morning and it only does one mug. Thanks for the reminder.

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[RogerIvy]

We all use Giandel pure sine. Work really well and not that expensive.

 

[Lenny HB]

With only 210an of batteries you will have enough power for a small travel hairdryer. If you want your batteries to last you should limit the discharge to the C5 rate which would be 42 amps.
A 1000 watt inverter allowing for inverter inefficency running at 1000watts would draw 90 amps.

 

[autorouter]

You should note that the battery capacity varies, depending on how fast you discharge it. This battery, discharged over 20 hours, gives 100Ah. When discharged at a slower rate, over 100 hours, its capacity is 110Ah. These are known as the C20 and C100 rates. When discharged at a faster rate, for example with an inverter, their capacity will be less.

These batteries are the wet (flooded) type, and I imagine will be better than other technologies like Gel or AGM when coupled to an inverter. However they will still be stressed, so best to stick to short bursts of power like a microwave, hairdryer or coffee machine.

When choosing an inverter, it's tempting to consider big inverters like 3kW or even 5kW, and that's what you would choose for an off-grid house. Unlike batteries, where bigger is always better, there is a downside to high power inverters. To calculate the battery amps, divide the watts by the battery volts, and add 10% for inefficiencies. A 2000W inverter will draw 2000/12 = 167A, plus 10% makes it over 180A. That would stress the batteries even if you had twice as many as your 200Ah bank.

The no-load battery drain for a big inverter can be substantial, and you'll need to switch it off when not in use to avoid flattening the batteries. Choose an inverter that's just big enough for the job you want it to do. Also a smaller inverter will be kinder to the batteries when it's running.

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