12v power only in Motorhome

Burns1 · Member

12v power only in Motorhome

Aus-Kiwi · Guru

I would go with 400 watt with Aa little reserve for cloudy days etc it doesn't use too much of your roof space ., Just over 30 amp supply .

Dougwe · Chief one feather

Welcome to the gang Burns1, enjoy here and out in the playground.

Not only Solar is important in that situation but IMO the size of battery power is just as important. Solar keep things charged only but the battery/s are what powers things, through that inverter, i.e. your fridge.

I run with 450w Solar on the roof of my van with 2x110amp batteries. I also have a seperate 120w panel I can use on the ground to follow sun when stationary if needed. The 120w is wired in separately to the main system to a separate regulator.

My fridge is a 185lt fridge freezer, 240v, 12v, Gas. If I had a 12v only I would run with 2x120amp batteries minimum.

I am sure the people with better knowledge than me on this matter will be along soon.

Good luck with it all and keep safe on the roads.

Edit......typo (or bad eyes :) )

-- Edited by Dougwe on Monday 11th of January 2016 09:31:39 AM

Peter_n_Margaret · Guru

Burns1 wrote:
..............(or it says it has a 1000w inverter included.

You need to get someone who knows what they are looking at to assess the whole of the electrics.

The 'inverter' mentioned above is possibly a 240V supply that is powered from the batteries.

It is not possible to analyse what you have and give reliable advise 'remotely' unless what you have can be described accurately.

If you have sufficient solar and an adequate charge connection to the house batteries from the alternator, it is not essential to be able to plug into 240V power.

We have no ability to plug into 240V, but can camp indefinitely and run our 12V compressor fridges and other accessories.

Cheers,

Peter

oldtrack123 · Guru

Peter_n_Margaret wrote:
Burns1 wrote:
..............(or it says it has a 1000w inverter included.
You need to get someone who knows what they are looking at to assess the whole of the electrics.
The 'inverter' mentioned above is possibly a 240V supply that is powered from the batteries.
It is not possible to analyse what you have and give reliable advise 'remotely' unless what you have can be described accurately.
If you have sufficient solar and an adequate charge connection to the house batteries from the alternator, it is not essential to be able to plug into 240V power.
We have no ability to plug into 240V, but can camp indefinitely and run our 12V compressor fridges and other accessories.

Cheers,
Peter

A BIG ditto to above smile

PeterQ

Aus-Kiwi · Guru

Yep he says he has house batteries . More tech info .,

PeterInSa · Guru

Re (12v/240v fridge/freezer but this one has only 12v to the FF.)

A friend has set his Mh up to run the compressor frig only on 12v. Has 3 x 110amp Deep cycle batteries and solar panels on the roof. If batteries are getting down due to overcast weather, just starts up his Honda 20I generator and uses his 5 or 6 stage battery charger to top up the batteries.

Peter

Burns1 · Member

Ok. I see I need a bit more info and I have a bit more. I have found that it has 2 house batteries.(I'll find out size) The 1000w inverter goes to 240v for charging computers,phones and using small appliances. Will find out more.

Also, can you run the van for 1/2 hr to charge batteries??

-- Edited by Burns1 on Monday 11th of January 2016 11:47:32 AM

Aus-Kiwi · Guru

If batteries are going flat ? They are old.. Or you need more solar . Charging off alternator is mainly a helper as often house batteries are a distance away from regulator . Meaning the voltage drop will effect battery charge efficiency . Being a motorhome I suggest solar is way cheaper, more efficient, doesn't rely on 240v support .. Better to fit the latter solar regs with 3 or so stages of charge that adust charge to battery condition also .. Don't skimp on wire size ..

mickm · Veteran Member

You need to know the average useage of the FF at its worst i.e. On freezer mode with the compressor running. If it is a smallish 40L fridge it should be about 2-3A if it is a bigger 70L fridge it might draw 5A. A portable 120W suitcase solar setup (as available on evilBay) should input about 7A which will run the bigger fridge for about 6-10 hours during the day in summer. The rest of the time you are in debit mode. You do not mention the size of your battery banks but if you have a 100Ah battery which means you have 50Ah to play with before you flatten the battery as 12.2V is 25% capacity. So in the dark hours using 5A you have 10 hours before you are in strife and your freezer becomes a fridge and you are on the slippery slide cold wise.

Disclaimer. There are so many permutations and combinations to the equation that giving a precise answer is impossible.

One thing is certain, there is not a snowflakes chance in hell that the batteries would last 4 days.

if you are to run solely on 12V, why the inverter. It makes more sense to have a battery charger so that you can plug into 240V if available to recharge the batteries. The alternator will never completely recharge the batteries.

Alchemi

-- Edited by mickm on Saturday 30th of January 2016 04:17:47 PM

mickm · Veteran Member

Don't know why I typed 4weeks when I meant 4 days.

sorry

Jaahn · Guru

Burns1 wrote:
Ok. I see I need a bit more info and I have a bit more. I have found that it has 2 house batteries.(I'll find out size) The 1000w inverter goes to 240v for charging computers,phones and using small appliances. Will find out more.
Also, can you run the van for 1/2 hr to charge batteries??
____________________________________________________________________________________________________________--

Hi,

People have asked for more info and that is needed for a sensible answer.

However to answer your question above about running the van to charge, yes and no !! Yes it can charge the batteries IF IT HAS BEEN SET UP TO DO SO AND DEPENDING ON THE ALTERNATOR SYSTEM. More information again required. No to 1/2 hour, probably more time required ??

It was said that the alternator can never charge the batteries completely ! That depends too, they certainly can but may not. I can run forever on my alternator.

The 1000 watt invertor is probably much oversize and may be a liability. Depends on the installation and the actual uses for it. 150 watt may be better.

Jaahn

-- Edited by Jaahn on Sunday 31st of January 2016 12:40:47 AM

Burns1 · Member

Thanks for all the excellent replies.I've learnt a lot already. As sure as a battery will go flat, my wife will change her mind, and it seems we are heading in a different direction ATM. But that of course doesn't mean we will not arrive back at this point again soon. So your help won't be in vane. Thanks again.

baysidetas · Veteran Member

You need to keep every thing in balance.

It is no good having a large battery capacity if you do not have the ability to recharge them in a reasonable time be it by solar panels, a generator or the vehicle engine.

Conversely it is no good having a large solar system if you do not have the capacity in your battery system to accept that charge.

And then you need to consider how much of a heavy power user you may be.

I would differ from Jaahn regarding the invertor; a over time a 300W unit is is almost certain to prove inadequate.