2018 Frankia motorhome with Inverter

[Pete@Val]

What sort of equipment can we use on a 2000 inverter. We have two leisure batteries. Frightened we will flatten the battery quickly.

 

[autorouter]

The best use of an inverter is for high-power devices in short bursts. Here's an example.

A 700 watt microwave probably uses about 1000 watts of power while it is working on full power. To make the calculation easy let's say it's on for 6 minutes, ie 1/10 of an hour.

1000 watts will require 1000/12 = 83 amps at 12 volts, and allowing for inefficiencies let's call it 90 amps. Drawing 90 amps for 1/10 of an hour will use 90/10 = 9 amp-hours from your leisure batteries.

Your two leisure batteries are probably about 200Ah combined, and you're best only using 50% of that for longer battery life. So you have about 100Ah of usable capacity. So 9Ah for a microwave is fine, but obviously not too long or too often.

High power inverters are not very good for small loads for a long time, like phone chargers. An inverter has a small but definite power drain even when there's no load, sometimes even more than the drain of a phone charger. Best to switch off an inverter unless you are actually using it.

 

[funflair]

As important as what you can take out of your batteries is how you will put it back in, the example above is good and tells you that a microwave for 6 minutes doesn't use that much battery capacity and 200watts of solar would have that back in around an hour or two depending on the sun, a simple rule I work on is I can't see how it will go back in I think twice about taking it out, well certainly past 50% useable capacity.

Martin

 

[cmcardle75]

What sort of equipment can we use on a 2000 inverter. We have two leisure batteries. Frightened we will flatten the battery quickly.

You will. Give a list of what you had in mind to use, and we can suggest alternatives that are more friendly when off-grid. For example, ensure you have a TV running off the 12V, not off the inverter. Boil water in a kettle on the gas ring, rather than plugged in. Buy a 12V to 19V converter for your laptop. Many more possible examples.

 

[Pete@Val]

Thankyou I do that . What I would like to do is use a Ramoska cooking pot but it is 600 watts. Is this possible unsure

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[funflair]

Thankyou I do that . What I would like to do is use a Ramoska cooking pot but it is 600 watts. Is this possible unsure

Thats about 50 amps from your batteries so for an average cook of 40 minutes would take at least 35ah so quite a chunk out of most battery banks, and if you are cooking in the evening it will be the next day before you see it going back in from solar and it could take best part of all day if the sun doesn't want to come out and play.

I would do it but I know I have 320ah of useable lithium capacity and up to 30amps solar recharging.

Martin

 

[Richard n Ann]

Use gas, that's why it's fitted as standard. High power mains is just expensive hassle.

 

[autorouter]

What I would like to do is use a Ramoska cooking pot but it is 600 watts. Is this possible

It's a similar calculation. 600 watts from the inverter will draw 600/12 = 50 amps from the battery. I'm not sure how long the Ramoska would be on, but if it's 1 hour then you are taking 50 amp-hours from the batteries. That's half of the usable capacity of 100Ah. It's your call whether that's a good use of your battery power.

Do you have any solar panels? 200 watts of panel will probably generate 50Ah on a sunny day.

 

[funflair]

Use gas, that's why it's fitted as standard. High power mains is just expensive hassle.

Its only a hassle when you don't have it once you do its just expensive.

 

[Neilfg]

Can't fault the calcs above 600w for an hour 50amps.

But alot of devices do not draw the stated power all the time. We had a 1200w coffee machine it only drew 1200w whilst heating up to temp, out of the 14 minutes of use to make a coffee the full power was only for about 4 minutes the rest of the time maintaining temp and pump operating was a lot lower about 250w or less.

Perhaps get a plugin meter use the remoska and it will tell you the usage, still not perfect but cheaper than buying extra batteries when not necessarily needed . We did this kept me occupied for awhile testing everything from toothbrush charger to laptop

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[Pete@Val]

Thanks for your advice. Still nervous but plug in meter will be good

 

[autorouter]

Still nervous but plug in meter will be good

I think most average unmodified motorhome systems would struggle with a Remoska and a 2000 watt inverter, but if that's what you want, a few add-ons make it perfectly feasible.

I'd think that if you had 300 watts of solar, and maybe up the battery bank to 300Ah, that would do the job. Maybe a B2B charger to boost the charging from the alternator while driving, especially if you move on every couple of days rather than stopping for a week or two.

Many motorhomers, including myself, have done this and quite happily run a microwave, hairdryer, coffee machine etc without any problems.

 

[funflair]

Can't fault the calcs above 600w for an hour 50amps.

But alot of devices do not draw the stated power all the time. We had a 1200w coffee machine it only drew 1200w whilst heating up to temp, out of the 14 minutes of use to make a coffee the full power was only for about 4 minutes the rest of the time maintaining temp and pump operating was a lot lower about 250w or less.

Perhaps get a plugin meter use the remoska and it will tell you the usage, still not perfect but cheaper than buying extra batteries when not necessarily needed . We did this kept me occupied for awhile testing everything from toothbrush charger to laptop

Pretty sure the Remoska runs continuously, we have the smaller 400w.

M

 

[cmcardle75]

Thankyou I do that . What I would like to do is use a Ramoska cooking pot but it is 600 watts. Is this possible unsure

Whilst possible, it would require an absurdly overspecced system to do so successfully (probably well into four figures in terms of cost, and lots of weight in terms in payload). Electric cooking is best left for home or electric hookup, as electricity storage is expensive and not energy dense (either in volume or weight). Liquified gas (or diesel) is far cheaper to store than electricity and has massively greater energy density. This is why the vast majority of motorhome cooking is done on gas hobs, ovens, grills and BBQs.

You may find you get similar results using a cast iron dutch oven.

 

[TheDogMan]

you need lithium batteries, we don't use much gas as the solar panels keep them full, including electric toaster/ kettle, laptop, 2x ipads 2 x vaping cigs, dyson rechargeable Vac......

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[Stealaway]

There's no problems with running a 230v TV from an inverter. A 28" smart TV will only draw about 6amps. Easily recoverable with solar panels and less than half the price of 12v versions, even when you include the price of the inverter.

 

[Pete@Val]

Thanks everyone for your valuable advice. I think the inverter will
Be off until lithium batteries are fitted

 

[TheDogMan]

you need lithium batteries, we don't use much gas as the solar panels keep them full, including electric toaster/ kettle, laptop, 2x ipads 2 x vaping cigs, dyson rechargeable Vac......

Oh and 2 televisions one in the bedroom and one at the front

 

[Lenny HB]

Taking high current out of batteries reduces their life. Your Frankia probably has Gel batteries the recommendation for Gel is 20 amp max but in practice normally 30 amps that's for an 80a/h Gel So with 2 x 80 a/h batteries a max of 60 amps, allowing for inverter inefficiency you can use around 1050 watts at mains voltage. If you want to use the full power of your inverter it would be best to fit another couple of batteries.

 

[Pete@Val]

I am
Now wondering why they put an inverter in

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[cmcardle75]

I am
Now wondering why they put an inverter in

Some people have very specific usages. Most commonly this is hair dryers, which apparently are such a must for some people that it is "the hair dryer works, or I'm not coming!"

Many newbies are also enticed by the promise of using all their electricity guzzling home appliances, but then get taken quickly down to earth when they realise that they can only run them for 5 minutes.

Others have massive RVs with 1kW of panels on the roof and 1000Ah of lithium batteries and can actually pretty much do what they like!

 

[Richard n Ann]

Some people have very specific usages. Most commonly this is hair dryers, which apparently are such a must for some people that it is "the hair dryer works, or I'm not coming!"

Don't forget the straighteners they are equally important