Occasional off grid electrical advice please.

S

Sue26

Joined
Mar 29, 2021
Posts
147
Likes collected
100
Funster No
80,058
MH
Swift 696
Hello. We have a 2015 swift 696 that has an 80w solar panel on the roof and we have an 80w portable panel which we fix to the leisure battery when off grid. The longest we have been off grid for so far is 3 nights. We could do more and longer off grid camping but other half is working and needs to recharge his laptop. We also have a few other small items that we would like to recharge such as phones, toothbrush, portable radio etc. Rather than buy a collection of adapters/leads, would a small inverter plugged into the 12v socket be the best way to make us less reliant on EHU?
We have 1 wet cell leisure battery (110ah I think).

Thanks in advance.
 
Sort by date Sort by votes
Sue26 said:
Hello. We have a 2015 swift 696 that has an 80w solar panel on the roof and we have an 80w portable panel which we fix to the leisure battery when off grid. The longest we have been off grid for so far is 3 nights. We could do more and longer off grid camping but other half is working and needs to recharge his laptop. We also have a few other small items that we would like to recharge such as phones, toothbrush, portable radio etc. Rather than buy a collection of adapters/leads, would a small inverter plugged into the 12v socket be the best way to make us less reliant on EHU?
We have 1 wet cell leisure battery (110ah I think).

Thanks in advance.
Click to expand...
get a lithium 110ah batt and one of these i charge my laptop with this

Amazon product ASIN B072V5LKWM
Billy
 
Upvote 0
Thanks for responses. We do currently use a powerbank for phones but I was thinking whether the small inverter would be more flexible for laptop and other small electrical items. I will look into the small inverter like billy192 mentioned as it seems more flexible for our needs.
 
Upvote 0
A small inverter plugged into the 12V socket will be OK for low power items. How can you tell? The 12V socket will have a fuse, limiting it to something like 15A, or 10A if you are unlucky.

That means the maximum power you can draw will be 12 x 15 = 180W for a 15A fuse, and 12 x 10 = 120W for a 10A fuse. You will lose about 10% of power due to the inverter inefficiency, so that makes it about 160W or 110W.

So as long as the devices you plug into the inverter don't go above that power, the fuse won't blow. The device should have a power rating on the label. If not you can work out the power by taking a pair of voltage and amps values and multiplying them. For example a laptop charger with output of 19V 3A will consume a power of 19 x 3 = 57W. Plus about 10% for inefficiency, so that's about 65W.

If you regularly use 300W from a 300W inverter, you'd need to wire it direct to the leisure battery, with a suitable fuse. It's quite feasible to do this, lots of people have a small inverter wired to the leisure battery.

You need to know that an inverter has a small continuous power drain even with nothing plugged in, which can be significant if you are trying to get a battery to last for a few days off-grid. So make sure the inverter has a switch, and switch it off when not actually in use.

I use 12V laptop adapters and USB adapters that plug into 12V cigarette-lighter-style sockets.

Subscribers  do not see these advertisements

 
Last edited:
Upvote 0
Just to add to the above. Fit your own switch which disconnects the 12v supply. The switch on most inverters doesn't actually switch it right off.
 
Upvote 0
We're on the last day of a 3.5 week holiday off EHU on the same site so no engine charging.
We have 115 watts solar and 2 X 100ah lead acid leisure batteries.
We run a small inverter (300 watts continuous, 600 watt peak) wired direct to the batteries to power the mains TV and charge a cordless vacuum.
We only have one 12v outlet in the hab, to which I have attached a double USB charger via a clipsil plug to charge phones, tablets etc.
Batteries have not been below 75% even with a couple of rainy days on the trot, and we have been fully charged by lunchtime most days, late afternoon if we've used more electric than usual or if we've had a couple of poor days sun wise.
With 160 watts solar ( compared to our 115 watts) I would fit a second leisure battery, to cover periods of poor sun and due to inverter inefficiency run what you can from 12v.
If you're light electric users, like us, you could be ok off EHU for several weeks.
 
Upvote 0
We've got a small inverter, fitted before we bought the van, and have to say it is very rarely used - I think the last time was charging my electric razor which I'd forgotten to do before leaving home. Everything else is now on 12v, I've fitted a couple of extra cigarette lighter type sockets for the bigger needs and carry a couple of USB converters for phones etc.
200w solar panels, two 110amp leisure batteries, Sterling B2B charger plus battery master to keep the cab battery charged, we've never got close to running out of power, even parked up for two weeks at a time. We never bother with hookups if we stay on sites unless it's included in the site fee but generally don't stay on sites anyway (not a FLT, just don't feel like paying for things I don't want/need).
 
Upvote 0
Thank you all.
We currently have 1 12v socket in the hab area and I'm not sure of its rating (van currently in storage). The detail in all your responses is just what I had hoped for and it is most useful.
I think I need to look what options I have to power what I need to via the 12v socket before going down the inverter route.
(y)thanks again.

Subscribers  do not see these advertisements

 
Upvote 0
More and more gadgets are 5v usb powered now wevegot 6 usbs in our van and 2 12volts covers most stuff
 
Upvote 0
Sue26 said:
Thank you all.
We currently have 1 12v socket in the hab area and I'm not sure of its rating (van currently in storage). The detail in all your responses is just what I had hoped for and it is most useful.
I think I need to look what options I have to power what I need to via the 12v socket before going down the inverter route.
(y)thanks again.
Click to expand...
Sounds like my Swift.
I also only have one 12v socket in my hab.
It says max "4 amps" so I can't run much off it.
 
Upvote 0
Sounds like I need to call up at storage site to check out the max amps of the 12v tv socket. If it's only 4a max I may need a complete rethink of this little project!
 
Upvote 0
I'm pretty sure my 12v socket was meant to run a 12v TV as it's next to the aerial socket, hence only being 4 amps.
 
Upvote 0
My advice don't fit an inverter unless you really need 240v. Finding a way around using 240v and restricting yourself to 12v products will almost always result in longer battery life.

If you do need one, chances are you'll need a Pure sine for the toothbrush. I did, till I found a great OralB that charged via USB. It's rare you can't find a 12v option of most items in your van. Something like this will charge cameras, phones and, ipads and laptops, all without investing in an inverter.

Amazon product ASIN B004G6W8U4

Subscribers  do not see these advertisements

 
Upvote 0
Ah thanks. Mine will probably be the same then as it is next to the tv point. Back to the drawing board I think...
 
Upvote 0
We already have a 240/12v tv. My thought was to be able to use the socket for items other than the tv.
 
Upvote 0
If it's just the laptop then something like this will do the job. I regularly use one for mine and it's fine. Its also a lot lower powered than this - only 50watt if I remember correctly. Had it for 10 years.

This also has usb...

Amazon product ASIN B0111YIFK0
 
Upvote 0
Thanks for all your input. I will check out the load rating on the 12v tv socket and update you how I decide to move forward with this.
Sue

Subscribers  do not see these advertisements

 
Upvote 0
Sue26 said:
Thanks for all your input. I will check out the load rating on the 12v tv socket and update you how I decide to move forward with this.
Sue
Click to expand...
Hi Sue

Did you go further with this? I have the same MH and am just exploring Leisure batterys and Solar recharging etc
 
Upvote 0
Crim said:
Hi Sue

Did you go further with this? I have the same MH and am just exploring Leisure batterys and Solar recharging etc
Click to expand...
If your only requirement is charging laptops and the like then the simplest answer is one of these or similar:


They are now readily available up to 100 watts. I have one each in car and Moho.
Not sure what your exact requirements are but going off the OP's list you can charge almost any modern laptop with a USB C socket (I charge both my old personal Dell XPS13 PC and my work HP this way leaving the mains charger at home). Equally you can charge a phone obviously and I don't bother with a separate radio. I either use that in the cab or more commonly stream stations from my phone.
The electric toothbrush is a bit more problematic but using an EHU every 5 days or so should solve that?
If you require something to charge Ebike batteries then the sort of inverter suggested is likely to be your friend.

Alternatively consider something like a EcoFlow Delta 2 or similar (and a portable solar panel if you wish) if you have other mains equipment like a coffee pod machine or hair dryer that you want to power. But if doing that get in quick while Black Friday bargains are still around!
 
This site contains affiliate links for which MHF may be compensated.
Upvote 0
Crim said:
Hi Sue

Did you go further with this? I have the same MH and am just exploring Leisure batterys and Solar recharging etc
Click to expand...
Hi.
We bought a small inverter (300w I think) and attach it direct to a spare leisure that we occasionally take with us although we've only used it once.
In August we did 5 days off grid with the limited solar and battery capacity we have. This was at a festival and our usage was quite small really as we didn't spend a lot of time in the moho and the sun was shining most of the time. We have done 3 days previously when our demand was greater and the weather not so sunny. We could have done more with a little juggling of appliances.
Hope this helps.
 
Upvote 0
We use one of these, 300W Pure Sine Wave Inverters) wired permanenly (via a 30 amp fuse) close to the leisure battery.


As it has a very low standby current draiin, we mostly leave it on 24/7, but if can be switched off on the inverter which avoids the high current surge (charging the capacitor) which you get with an external switch.

P.S. The fan is not very quiet, so I relaced it with an ultra quiet 5 volt fan which is now plugged in to the USB ouput of the inverter itself.

Subscribers  do not see these advertisements

 
This site contains affiliate links for which MHF may be compensated.
Upvote 0

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Join us

Log in

Already a member? Log in here.

Latest journal entries

Back
Top