Newb here looking for some wisdom :)

lukew

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Jan 4, 2018
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Hi guys. So myself and the partner have just finished up converting a MWB Vauxhall Movano into a motorhome and have just booked our ferries to Santander for early next month.

What I was hoping for was some general advice on our current electrical set up.

We are hoping to mainly camp off grid as we travel down to the algarve and at present have:

1 x 200w solar panel > 2 x 85ah deep cycle batteries > PSM3 unit >

This will feed into a 1500w inverter for use with occasional laptop/phone/camera charge and then the 12V system which will run our Waeco CRX 50 fridge (1.3 Ah/h), LED lights, water pump, and our occasional Eberspacher D2 diesel heater (hopefully wont need this in the algarve!)

So for those of you who are seasoned off grid campers, how does this sound for keeping us juiced up? Is it adequate? Not looking to spend more than 2-3 days without moving on to another spot.

Appreciate any responses :)
 
Jan 29, 2017
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Welcome, looks okay to me but I think the inverter might be over size, be careful that its switched off when not in use as they can have quite a high residual current. Also dont know about the fridge requirements, 1.3Ah/h sounds modest but its every hour. The heater might take a bit more than you think, it'll be cold in the Algarve in the evenings and possibly rainy and on the way down but then you will be driving most of the day so presume that the alternator will bring up the batteries. Watch out for the steady discharge of batteries in parallel if thats what you have done. I prefer to switch one in and one out
Have a good trip,

Mike & Ann

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Apr 27, 2008
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Your biggest user of 12v is your fridge using by your figures 32Ah per day. This alone will flatten your batteries to 50% in a couple of days. Dont let them get below 50% as this will damage them. Your solar panel will easily replace this in the summer but will struggle in the winter even in the Algarve. I should look at fitting a b2b charger to maximise the charge you will get from driving. Also worth looking for 12v chargers for your stuff rather than using an inverter which is quite inefficient.
 
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lukew

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Jan 4, 2018
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Thanks for the replyies guys!

Welcome, looks okay to me but I think the inverter might be over size, be careful that its switched off when not in use as they can have quite a high residual current. Also dont know about the fridge requirements, 1.3Ah/h sounds modest but its every hour. The heater might take a bit more than you think, it'll be cold in the Algarve in the evenings and possibly rainy and on the way down but then you will be driving most of the day so presume that the alternator will bring up the batteries. Watch out for the steady discharge of batteries in parallel if thats what you have done. I prefer to switch one in and one out
Have a good trip,

Mike & Ann

The batteries are set up in parallel as advised by our auto electrician. By steady discharge, im assuming you mean no heavy loads dragging it down in one go?


Your biggest user of 12v is your fridge using by your figures 32Ah per day. This alone will flatten your batteries to 50% in a couple of days. Dont let them get below 50% as this will damage them. Your solar panel will easily replace this in the summer but will struggle in the winter even in the Algarve. I should look at fitting a b2b charger to maximise the charge you will get from driving. Also worth looking for 12v chargers for your stuff rather than using an inverter which is quite inefficient.

I was advised by the electrician who helped fit out the van to get the 1500w inverter. It would just power 2 UK plug socket oulets we have fitted into the wall. Im not sure there are 12v chargers to charge a 60w Macbook pro?
I haven't come across b2b chargers so will look into this for sure, I know we have a split relay charge for when we are on the move at the moment.

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TheBig1

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personally, i see the battery bank as being way too small for off grid camping in the winter. the 200w of solar is just not able to keep up with the drain. the inverter is capable of flattening the batteries in minutes when in full use
 
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lukew

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personally, i see the battery bank as being way too small for off grid camping in the winter. the 200w of solar is just not able to keep up with the drain. the inverter is capable of flattening the batteries in minutes when in full use

What would you see as a suitable set up for off grid?
thanks

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TheBig1

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Nov 27, 2011
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200-300ah of batteries, 300w solar and a b2b charger to boost charge from the engine
personally have 480ah topped up by 360w solar and a 50amp b2b powering a 2200w inverter. with no good sun, we run the engine for 2 hours every 3-4 days. but we run a special piece of breathing equipment every night to keep me alive
 
Jan 29, 2017
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When you connect two batteries in parallel, even if they are identical then eventually the characteristics change, they develop different voltages at any one time, this means that one tries to charge the other and then the reverse happens and slowly down they go.
You said that you would move every couple of days and you dont mention a tv . also you didnt say just how many hours a day you will drive between camps. The inverter is much bigger than you need just to charge a computer and phones, you sure you havent got daft plans for a kettle off the inverter, that would really kill the batteries!
When all's said and done , just go and enjoy yourself but I should take a mains lead with you and treat it all as a learning curve. You probably will be able to stop"off Grid" but sites and hookup can make life a lot easier if the the sun goes in.
 
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lukew

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200-300ah of batteries, 300w solar and a b2b charger to boost charge from the engine
personally have 480ah topped up by 360w solar and a 50amp b2b powering a 2200w inverter. with no good sun, we run the engine for 2 hours every 3-4 days. but we run a special piece of breathing equipment every night to keep me alive

Thanks for the info. The solar electrics were wired to have an additional panel added in if needed... so would another 85ah battery in series with the other 2 + an extra 100w panel be wise before we set off? As this is our first build and first trip, I really dont want to be caught out whilst we are out there.

Also do you recommend any b2b charger? Started looking into them now but I can only see them really starting around the £350 price range. Ouch!

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lukew

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Jan 4, 2018
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When you connect two batteries in parallel, even if they are identical then eventually the characteristics change, they develop different voltages at any one time, this means that one tries to charge the other and then the reverse happens and slowly down they go.
You said that you would move every couple of days and you dont mention a tv . also you didnt say just how many hours a day you will drive between camps. The inverter is much bigger than you need just to charge a computer and phones, you sure you havent got daft plans for a kettle off the inverter, that would really kill the batteries!
When all's said and done , just go and enjoy yourself but I should take a mains lead with you and treat it all as a learning curve. You probably will be able to stop"off Grid" but sites and hookup can make life a lot easier if the the sun goes in.

Ha, no plans for a kettle! We have a gas hob fitted. Certainly no TV or any other appliances. Was mainly 240v required for charging the laptop and camera batteries really.
Hmm, I will go back to our electrician on the inverter size and question him.

We plan to do at least 2/3 hours driving between sites and no longer than 2/3 days at each site.

I was hoping that my set up would be sufficient but getting worried that I've underestimated things here
 
May 31, 2015
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1 x 200w solar panel

Quick fix , is to use a 100w portable unit , that at least will give ya 300w .

i see the battery bank as being way too small for off grid camping in the winter.

I share that opinion .

1500w inverter

Personally , i would leave that alone as much as possible , unless your on hook up .

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Jan 19, 2014
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You will be ok with what you have when the days start getting longer. We use pretty much what you've got, a compressor fridge, no lap top but small TV. Our panel is 150w and charges the battery at over 9 amps in full sun.
I fitted a NASA BM1 battery monitor last year and it's a great bit of kit, it shows:

Battery voltage.
Charging amps (& estimated time to fully charged)
Discharging amps (& estimated time to flat)
Battery percentage charge.
AH remaining.
AH used (or charged) since last reset.
Starter battery voltage.

Best 100 quid I've ever spent (y)
20171028_141317.jpg
 
Jan 29, 2017
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Also fitted the Nasa BM1 unit many years ago. It really has helped me to know whats going on with regard to battery charge state and loads. Think our panel is 80 or 100 watt and in full, blue sky, sun we can see 6amps but thats only when the battery is low. Amazing how it drops away with the slightest bit of cloud.
The second panel would be a great insurance but I think you should just go and enjoy all the work you have done. The inverter will work just dont leave it switched on when not in use. I had a 1200watt one and downsized to 150w, enough for essentials, mostly we charge from the 12v
If you are going to drive for 2/3 hours every few days I am sure the alternator will do the job providing the wiring is good quality between the two batteries
Mike & Ann
PS dont forget that mains lead, there are cl's with hookup!

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May 31, 2015
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I know we have a split relay charge

Another thing i would mention is spare fuse's for the relay charger . I also have one fitted to my small van and it's constantly knocking the fuse out for no reason . My guess is it's the surge of power when i start the van .
 
Nov 12, 2014
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Your best bet is to only run the invertor when you are driving and charge everything then. We have 2*110ah batteries and no solar. We arrive with everything (including a backup battery bank for the phones) fully charged. With TV, fire stick and heating (gas but blown air) we can do 2 days and still have over 12v from our battery.

We don't charge the laptop when we are off grid unless driving.
 

grasscutter

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Jan 29, 2017
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Also, I would be sure to take even a basic digital Voltmeter, it will enable to to see if and what is going on. If you cant interpret the results then someone on here should be able to help. Attached is something I picked up on here, I think. It will at least give you a clue. And dont forget the earlier advice, dont take the batteries below 50% charge unless you really, really have to.
Best wishes

Mike

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Feb 9, 2008
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Hi and welcome. I think you will be fine. The inverter is a bit of a worry? if your only charging/running lap top's tablets phones etc, then it's way to big. I do all that with a 350 W inverter. Solar Panel id fine when you have sun and 8-10 hour days but even in winter you will get 6 hours minimum although will be quite overcast on the Algarve at this time of year. Your fridge is another problem. You might need to get on lecce every so often. You will soon know when you get down there and figure it all out.
 

maxi77

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Even in the winter there is a lot of sun in the Algarve, you can tell the ones on a short break as they all wear t shirts and short whilst those of us who came in October are well wrapped up and the locals are in puffa coats and big boots. I would bin the big inverter and replace it with a smaller say 250 watt full sin wave unit. Switch mode chargers cab be upset by anything else. You should have no difficulty in finding 12 volt chargers for your laptop and phones and if the camera has a USB charger then that as well. Running a compressor fridge with 170AH is perhaps light considering the solar will not give you a top up every day. So more battery and a bit more solar would be better.
 
Apr 27, 2016
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If you are mostly just charging your macbook, phones etc, I would go for a 150 watt Pure Sine Wave inverter rather than a 1500 watt Modified Sine Wave inverter. You can you can wire it in permanently with a fuse, but it's small enough to plug in to a cigarette lighter socket if you prefer.

https://www.maplin.co.uk/p/maplin-12v-pure-sinewave-150w-inverter-a71jw

People on here generally disagree about Pure Sine wave (more expensive but better for electronic devices and some motors) and Modified Sine Wave (cheaper but OK for lights, heaters, drills etc). My view is, PSW for small electronic devices.

I've found that if it doesn't specifically say PSW or Pure Sine Wave in the description, it is almost always the cheaper MSW (Modified Sine Wave) type.

so would another 85ah battery in series with the other 2 + an extra 100w panel be wise before we set off?

Just double-checking - I presume you meant in parallel. In series is not a good idea.

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Feb 9, 2008
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People on here generally disagree about Pure Sine wave (more expensive but better for electronic devices and some motors) and Modified Sine Wave (cheaper but OK for lights, heaters, drills etc)
With respect! I believe that is incorrect. I'm of the view that almost all members on here who own an inverter know the difference between PAW & MSW and have chosen the correct type for their application. Then again I could be wrong.......but I think not.
 
Jun 4, 2016
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Hi and welcome :)
Perhaps have a small trial trip to see how your new van gets on off grid, and I cannot recommend a battery monitor high enough so that you can monitor exactly what is using how much, and how your batteries are really behaving.

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