Inverters

[sotal]

I know generally inverters aren't the most recommended piece of hardware in a Bongo.

People expecting to run a bunch of microwaves and kettles etc and then draining the battery in seconds etc.


However we just purchased a cheap mini oven which is 240v. It is a 6L Elgento oven. It has got me wondering whether or not it would be worth trying an inverter with it.

It states that it is 220-240v 600w.

I'm wondering if it would be worth getting a relatively cheap inverter and just start the engine up to run it?

We have a LB and Split charge but at 600w I imagine the battery would drain rather fast?

Also the cheaper inverters are 'modified sine wave' it states they are not suitable for microwave ovens - would they be OK for a mini oven? It has a regular heating element at the top and at the bottom.

[jimmo62]

If it's just a regular resistive heating element (like a normal home oven) then the modified sine wave should not be a problem as there's no electronics to mess up....

600watts is going to be 50 Amps at 12V, allow a bit extra for losses in the inverter and cables. So your LB would be drained pretty quickly remembering that you should not really discharge below 50%. Not sure what the alternator can provide for long periods, you may find that even with the engine running the battery still discharges

If you are thinking of running the engine while the oven is in use, why not get a small suitcase-stype petrol generator instead which gives you lots more flexibility. 600W units are pretty cheap. It's a much simpler solution and you can use it away from the van as well.....

[sotal]

I've actually got a generator in the garage, just a smallish one - might be 1500w. We used it once with the caravan and found it too much of a pain. Heavy lump to keep shifting around, a bit smelly, a pain to start when it hasn't been used for a while (stale fuel etc!)

Haven't really got room for it anywhere, it has literally been used 2 times, I pulled it out to test it the other day but couldn't start it on the old fuel in it.


As far as I know the alternators are 90A units so should be able to sustain 50A (I am guessing there!) Plus the buffer of the battery. From the instructions the oven is supposed to heat quite quickly and due to the small space cooks quite quickly too. The timer on it only goes up to 15 mins max. So hopefully it wouldn't need to be on for too long at once.

[Tony x]

Do take a little care with inverters.
Remember their is no earth and there have been plenty of accidents - mostly on boats I gather.
So long as what you plug in doesn't require an earth then you should be fine.

[g8dhe]

Be aware that without air flow from moving there isn't a lot of ventilation / cooling going on in the alternator, so trying to pull a massive load from the alternator when stationery is not a good idea.....

[mikeonb4c]

Be aware that without air flow from moving there isn't a lot of ventilation / cooling going on in the alternator, so trying to pull a massive load from the alternator when stationery is not a good idea.....

I'd never thought about that. Maybe another benefit of a scavenger fan over-ride switch? I used mine to good effect in heavy traffic en route through London yesterday - kept engine bay temp down around 76 degrees as opposed to the high 80s.

[blobber]

Also the cheaper inverters are 'modified sine wave' it states they are not suitable for microwave ovens -

Never put an inverter in a microwave oven.......... it won't cook sine waves.

[g8dhe]

On a V6 the scavanger fan won't make much difference, as the alternator is front low drivers side above the mainstream from the scavanger as far as I can see.

[mikeonb4c]

On a V6 the scavanger fan won't make much difference, as the alternator is front low drivers side above the mainstream from the scavanger as far as I can see.

I think this where the undertray is intended to help the scavenging effect. The fan should promote flushing out of hot air through encouraging lower air pressure and a drawing in of air through the front opening of the undertray. Even though the alternator is not benefiting from direct forced flow over it from the fan, it ought still to benefit from inflow of cooler air and expelling of 'ambient' hot air from within the engine bay enclosure. Hard to assess extent without seeing the installation but. ...every little helps etc.

[sotal]

Decided that when we want to use it we will just use EHU!

Safer, easier and can pay for a fair few nights of EHU with the cost of a decent inverter.

[mikeonb4c]

Decided that when we want to use it we will just use EHU!

Safer, easier and can pay for a fair few nights of EHU with the cost of a decent inverter.

Very sensible. Inverter not really the solution for anything heavy duty IMHO.

[windywatson]

Hi, Heed others advice & don't get involved in trying to this type of set up with cookers & inverters. I'm an electrical/electronics engineer by trade & have had the privilege of working for a large motor home distributor as an habitation technician.
If you want to use an inverter, you will need to have more in reserve than the power of 1 leisure battery & due to high currents you will need substantial wiring too. Most set ups using inverters will have multiple batteries & in addition up rated alternators to help replenish them. There is a very good reason why electric hooks are so popular 240 v systems give you the energy you need at lower currents. Once you start to try and push 12v systems to deliver large amounts of energy the currents you need start to become very high. Steer clear of these types of systems unless you really want to spend money on good kit & more batteries etc. The money you will spend would buy you a smaller more compact generator or pay for you to stay on a site with elec hook up.

Cheers.

[Tony x]

Hi, Heed others advice & don't get involved in trying to this type of set up with cookers & inverters. I'm an electrical/electronics engineer by trade & have had the privilege of working for a large motor home distributor as an habitation technician.
If you want to use an inverter, you will need to have more in reserve than the power of 1 leisure battery & due to high currents you will need substantial wiring too. Most set ups using inverters will have multiple batteries & in addition up rated alternators to help replenish them. There is a very good reason why electric hooks are so popular 240 v systems give you the energy you need at lower currents. Once you start to try and push 12v systems to deliver large amounts of energy the currents you need start to become very high. Steer clear of these types of systems unless you really want to spend money on good kit & more batteries etc. The money you will spend would buy you a smaller more compact generator or pay for you to stay on a site with elec hook up.

Cheers.

I couldn't agree more - this is excellent info

This is a link to our solar panel and inverter set up:-
http://igmaynard.co.uk/bongo/forum/view ... 44&t=68033
We used 75 amp (about) for the cables that carry 12 volts from the battery to the inverters - great, thick copper affairs and not cheap.
If you like maths, heat produced in a wire is amps x amps x resistance.
What this means is that, if you halve the voltage, you get four times the heat produced in a wire for the same wattage.
This is why those overhead cables carry such high voltages - it's so the heat losses are reduced (and the fact they are AC rather than DC comes into it too)
If you want power for cooking etc, then you need a generator or a substantial setup. If you want power for small items - a charger, computor, maybe a tv and xbox affair, then an inverter will just about cut it if done well

[Alison01326]

I know you want to use your oven, now that you've bought it, but there are also stove top alternatives which would negate the use of a hookup. Firstly a pressure cooker - noisy and fills your Bongo with steam but can do a casserole in less than 10 minutes, or an Omnia stove http://www.omniasweden.com/

[sotal]

I like the idea of the Omnia, it just looks a bit restrictive with it's doughnut shape inside.

Off in the Bongo in a couple of weeks but will have EHU anyway now that it is a bit cooler so that we can have electric heating on.


In the summer we didn't really have any EHU as we didn't really need any. We didn't need heat and the battery did everything else we needed - we went out every day in the Bongo which recharged the battery. Coolbox on all day and off at night. So it was more for the summer - but we can have more BBQs in the summer!