Could I get away with only solar power for my power needs?

devonian

Member
Joined
Apr 5, 2020
As the title says. I have mounted a 300w solar panel on my ford transit (or am just about to) conversion and am wondering if I need to bother with a split charge system as well (not going campsite electric hookup as want to be 100% off grid). Now I shall probably be investing in an efficient compressor fridge and my cooking and heating is gas and diesel respectively so that just leaves electric for powering mobile phone charges, LED lights, roof vent and perhaps a laptop. What do you think?
 

david.c.hall

Active Member
Joined
May 16, 2016
Location
Irnham, South Lincolnshire
Your fridge will probably use 45 to 60 Ah per day.
In the winter, depending on where you are your 300 watts could perhaps only give 20 Ah to 40 Ah.
You don't say what LB you have , which can help out on dark winter days, but it will still need to be recharged possibly by running the engine.
But basically it is unlikely that 300 watt is enough solar.
Which is why we have an LPG tank and a 3 way fridge
David
 

devonian

Member
Joined
Apr 5, 2020
Sorry I'm not sure what LB is? If you mean batteries I have 2 brand new 110 ah lead acid batteries.

But to be clear you think the only stumbling block would be fridge usage in the winter?
 

Sandbagsid

Member
Joined
Sep 16, 2019
Why not have a split charge system at least you could run the engine and know all batteries will get a charge. On the issue of the fridge they will flatten a battery quicker than anything as they draw so many amps an hour. If you are only relying on solar then I think in the winter your gonna have a problem. Just my opinion.
 

david.c.hall

Active Member
Joined
May 16, 2016
Location
Irnham, South Lincolnshire
Sorry! LB is just the usual abbreviation for Leisure Battery as opposed to VB for Vehicle Battery.
Yes, the fridge is going to be the biggest power user and the batteries will (depending on the fridge) only run the fridge for a max of 2 days without top up from solar or from running the engine ( assuming that you plan on using some sort of 'split charge' system off the Vehicle alternator.
I should perhaps explain that your 2 x 110 Ah batteries will only give a total of 110 Ah available without damaging the batteries and even then Persistent discharging to 50% will shorten battery life considerably.
David
 

devonian

Member
Joined
Apr 5, 2020
Why not have a split charge system at least you could run the engine and know all batteries will get a charge. On the issue of the fridge they will flatten a battery quicker than anything as they draw so many amps an hour. If you are only relying on solar then I think in the winter your gonna have a problem. Just my opinion.
I do have a votronic battery to battery charger which I can use, but I was just thinking I could save it for another camper build if I did one and just use that for that campers power (and probably not have a fridge in it) but looks like I need it for this camper if I want to have a fridge and use it all year.
 

BigStevie

Active Member
Joined
May 17, 2017
Location
Highlands
A split charge is straight forward and well worth fitting. As others have mentioned, even the most efficient compressor fridge will eat through you leisure batteries.
 

devonian

Member
Joined
Apr 5, 2020
A split charge is straight forward and well worth fitting. As others have mentioned, even the most efficient compressor fridge will eat through you leisure batteries.
Yes I think I will get a cheapo old style split charge just for topping up the battery and then I can save my votronic b2b for if I do another van conversion.
 

BigStevie

Active Member
Joined
May 17, 2017
Location
Highlands
If you spend an extra few quid you’ll get a split charge unit that not only keeps your leisure batteries topped up from the engine, but will also keep your vehicle battery topped up from the solar...
 

Roadrunner

Active Member
Joined
May 29, 2016
Location
Glengormley
My comp fridge will run 48 hrs on two 90ah batteries no bother,solar useless 4/5 mths of the year,stating the engine is useless as it will take at least a 40 mile drive to recharge all the batteries including the engine one.
 

WildVan

New Member
Joined
May 9, 2020
In my view split charge relays do not charge your leisure batteries enough, even on a long run.

Use the Votronic and do it right first time. I use a Sterling but have a Votronic mppt. No hesitation using a Votronic if I did it again, they make nice kit.

I ski trip in the van for a week, no problem running a fridge and heater 24/7. We have had great weather though so the 100w solar did the trick. On one trip a drive to the supermarket topped up the batteries enough for the week.

Everybody is different but running out of power is a bummer, so give your batteries the best care they can get.

I always mains charge the batteries once a month if at home in the winter.
 

CamperJack

New Member
Joined
Apr 28, 2020
My van is a 2013 and I recently read that on modern vans (including mine) a split charge relay doesn't work. Something to do with variations in the battery voltage as you drive and echo settings in modern cars. Basically the relay is activated to start charging the leisure battery when the voltage of the starter battery reaches a set point. But in modern cars the voltage goes up and down while driving and so the relay cuts in and out. Or something like that.

The best option, so I read, is a battery to battery charger. I plan on installing one in my build. Sad news is they are a little more expensive than split charge relays. I think they are about £150 for a 30A model. But if the relay doesn't work there's no point comparing the two.

Well worth the money IMO. I'd hate to be stuck away from home in bad (cloudy) weather with a flat leisure battery with no way to charge it. Nice to be able to go for a blast up the motorway to charge the battery if I'm not getting enough from the solar. Having a plan B is always handy. And you can't count on Great British weather being all that great, can you? I adore Lakeland for example but some weeks / months there are very overcast and wet!

In my case I also have this mad idea about going to northern Norway. I bet solar isn't great there either...
 

devonian

Member
Joined
Apr 5, 2020
My van is a 2013 and I recently read that on modern vans (including mine) a split charge relay doesn't work. Something to do with variations in the battery voltage as you drive and echo settings in modern cars. Basically the relay is activated to start charging the leisure battery when the voltage of the starter battery reaches a set point. But in modern cars the voltage goes up and down while driving and so the relay cuts in and out. Or something like that.

The best option, so I read, is a battery to battery charger. I plan on installing one in my build. Sad news is they are a little more expensive than split charge relays. I think they are about £150 for a 30A model. But if the relay doesn't work there's no point comparing the two.

Well worth the money IMO. I'd hate to be stuck away from home in bad (cloudy) weather with a flat leisure battery with no way to charge it. Nice to be able to go for a blast up the motorway to charge the battery if I'm not getting enough from the solar. Having a plan B is always handy. And you can't count on Great British weather being all that great, can you? I adore Lakeland for example but some weeks / months there are very overcast and wet!

In my case I also have this mad idea about going to northern Norway. I bet solar isn't great there either...
I shall be installing a votronic b2b charger relatively soon as like you say they are the best option and a decent power source, I also read that they charge up agm batteries quicker than standard ones not sure if thats true.
 
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