12V Inverters

Hello. Does anyone have any experience with 12V inverters?

I’m just kitting out my new van and would like to install an inverter.

In my old van I had a 300W inverter, and it was as really not very good. It struggles to even charge a drill battery with a 180W charger.

I’m after a unit which will power an 800W microwave as the largest load. Do I need to oversize the inverter to deal with inrush currents etc, or is a 1000W unit likely to have sufficient capacity to run it?

Thanks.

Just take sandwiches for lunch instead

You will need far more than 1kW - microwaves are rated on the output power, an 800W one will use 1.2-1.5kW. Inrush will be huge - it's a big transformer and a capacitor inside.

You will also need a second battery to supply the inverter, using the vehicle battery is not an option for high powered loads..

Or get yourself one of these https://www.honda.co.uk/industrial/products/generators/inverter/specifications.html#eu22i

I bought a 3 kva model for my son, really the batteries were not big enough just 3 x 180 Ah but that was not the problem, it was a simulated sine wave which is really a square wave with an off between upper and lower waves, well not waves it was square wave. 3 kva at 12 volt = 250 amp which is a large fuse, so each FET had a 16A fuse, so 16 FET's and 16 fuses, sounds OK but to power share it used the resistance of fuses, theory may be OK but in practice they did not power share so as each fuse ruptured there was more power pushed through the remaining FET's until the expensive blue smoke came out, returned to China and got charged import tax to return it, new one arrived but there was nothing to tell you is a fuse ruptured so it seems it was going to go the same way, at which point the boat was sold, and new owner used a true sine wave inverter instead.

The problem is 3 x 180 Ah batteries are heavy, OK with a narrow boat, it weighs around 20 ton maybe more so an extra 4 cwt is nothing, however with a road vehicle that's a lot of weight.

There are special inverters that can add to a supply, so a very small generator with the inverter can run larger items, used with narrow boats, I would go to a narrow boat forum and ask on that, they are use to using the larger inverters and likely can suggest a tested unit which will not emit blue smoke.

I have the extra leisure battery and split charger on my old van which I’ll be transferring to the new one.

I’ll investigate more into actual power required and see if there’s lower power model available.

I have previously had a generator setup which worked great for the kettle and microwave, but it’s a pain to keep fuelled and the vapours make the van smell especially as the tank vents in warm weather as well as the fire risk, and also having to keep the doors open when it’s actually running, so I’d much prefer to go all electric if possible.

It’s a shame there isn’t an option for a PTO generator on the van that would be ideal.

Ex-employers company vehicle had 750watt output pure sine wave inverter, around 65Amps input. Was as big as we could get on a 12volt vehicle. Uprated alternator modded to provide higher output on idle, 120amp deep discharge batteries isolated to supply inverter.Used to power a Computer package before Laptops/in-car computers were available.

If you want higher wattages from an inverter in a 12v vehicle I will suggest you are for some expensive mods to your vehicle - 24 Volt conversion, additional (caravan style deep discharge) batteries, split charge bridge, possibly a high output alternator.

RF Lighting said:

I have previously had a generator setup which worked great for the kettle and microwave, .... and also having to keep the doors open when it’s actually running, .

Click to expand...

And you're still alive ?

Ready meal around 10 minutes at 750 watt output so 1 kW input so around 85 amp at 12 volt, so around 20 Ah used out of battery for 1 ready meal so yes theory can work, but the problem is recharging, we found with the narrow boat over night lights used very little from 3 x 180 Ah batteries but charging took time, and it needed a recharge time of around 12 hours to fully recharge, but we would only cruse for 8 hours, it is charging the battery which was the problem, even with stage chargers slowly the battery would become more and more discharged, so once a month my so needed to find some where with a hook up so he got around 16 hours extra charger with the 8 hours there and 8 hours after he got around 32 hours charging which would bring the batteries back up.

So you would need to be able to charge batteries over night as well as on the vehicle, we don't drive for anything like 8 hours, caravan uses have found solar panels are far better than split charging even using the sterling pulse inverter charger, problem we realised is cost, yes with solar panels and stage inverter charger we could maintain the caravan leisure battery, but it was for the amount we used the caravan cheaper to use sites with hook-up. The battery only really needed for motor mover.

We have considered an inverter generator for the odd time we are not on a site with hook-up, but in the main we use gas, we need a battery to pump water and for lights, no gas lights in modern caravan, and for ignition of fridge and central heating fan, and water heater ignition so we do need a battery, a 75 Ah will last us with care around 3 days, lights is the big drain, I have a very small inverter around 150 watt which will work PC, and also one built into the 12 Ah jump starter, but rarely used, the 12 Ah jump starter will charge from cig lighter output, so that is out back-up, once main battery exhausted that will keep things running until we find a site with hook-up.

But look at small inverter generator and compare with our jump-start pack, and not much difference, inherited jump start pack, when it goes will replace with inverter generator.

for good quality true sine wave inverters, take a look at the Victron range.

By the way, you can get 12v microwaves.

I had a 2kw continuous , 4kw surge inverter on a van, running a cheap 240v microwave. It worked ok but obviously you had to have the engine running.
Gas stove or ghille kettle is easier!