Solar panels, batteries & off grid stuff
Discussion
with solar... every watt is a prisioner and you look to conserve as much as you can.
So first thing you do is look at your loads. What power and what voltage are you operating at ?
You will get the most efficient operation to try and run everything you can at your main DC bus voltage which is generally the same as your battery system. this make it so much eaiser and it means that you remove as much of the wastage as what you can. to convert 12/24/48v dc to 230v takes some doing, and then if your taking watts that can soon mount up... a 1kw load at mains is around 1000/230 or around 4.3 amps and with losses and running current on the inverter that dc draw at 24v... would be.... around 55A or so... at 12v thats over 100A !
so first rule to eck out your solar is use mains to top up if you can, and use gas for cooking and heating.
So first thing you do is look at your loads. What power and what voltage are you operating at ?
You will get the most efficient operation to try and run everything you can at your main DC bus voltage which is generally the same as your battery system. this make it so much eaiser and it means that you remove as much of the wastage as what you can. to convert 12/24/48v dc to 230v takes some doing, and then if your taking watts that can soon mount up... a 1kw load at mains is around 1000/230 or around 4.3 amps and with losses and running current on the inverter that dc draw at 24v... would be.... around 55A or so... at 12v thats over 100A !
so first rule to eck out your solar is use mains to top up if you can, and use gas for cooking and heating.
ruggedscotty said:
with solar... every watt is a prisioner and you look to conserve as much as you can.
So first thing you do is look at your loads. What power and what voltage are you operating at ?
You will get the most efficient operation to try and run everything you can at your main DC bus voltage which is generally the same as your battery system. this make it so much eaiser and it means that you remove as much of the wastage as what you can. to convert 12/24/48v dc to 230v takes some doing, and then if your taking watts that can soon mount up... a 1kw load at mains is around 1000/230 or around 4.3 amps and with losses and running current on the inverter that dc draw at 24v... would be.... around 55A or so... at 12v thats over 100A !
so first rule to eck out your solar is use mains to top up if you can, and use gas for cooking and heating.
OP wants to be "off grid". He might struggle to top up from the mains. So first thing you do is look at your loads. What power and what voltage are you operating at ?
You will get the most efficient operation to try and run everything you can at your main DC bus voltage which is generally the same as your battery system. this make it so much eaiser and it means that you remove as much of the wastage as what you can. to convert 12/24/48v dc to 230v takes some doing, and then if your taking watts that can soon mount up... a 1kw load at mains is around 1000/230 or around 4.3 amps and with losses and running current on the inverter that dc draw at 24v... would be.... around 55A or so... at 12v thats over 100A !
so first rule to eck out your solar is use mains to top up if you can, and use gas for cooking and heating.
Give this place a call or drop them an email. Ask for Ryan, he will give you some good ideas and design you a system for your needs.
https://www.portablepowertech.com/
ruggedscotty said:
with solar... every watt is a prisioner and you look to conserve as much as you can.
So first thing you do is look at your loads. What power and what voltage are you operating at ?
You will get the most efficient operation to try and run everything you can at your main DC bus voltage which is generally the same as your battery system. this make it so much eaiser and it means that you remove as much of the wastage as what you can. to convert 12/24/48v dc to 230v takes some doing, and then if your taking watts that can soon mount up... a 1kw load at mains is around 1000/230 or around 4.3 amps and with losses and running current on the inverter that dc draw at 24v... would be.... around 55A or so... at 12v thats over 100A !
so first rule to eck out your solar is use mains to top up if you can, and use gas for cooking and heating.
This. The first port of call is to work out what you want to run and the shape your system around that, not starting with the solar and batteries and then working back. Otherwise you may end up with way too much or too little. So first thing you do is look at your loads. What power and what voltage are you operating at ?
You will get the most efficient operation to try and run everything you can at your main DC bus voltage which is generally the same as your battery system. this make it so much eaiser and it means that you remove as much of the wastage as what you can. to convert 12/24/48v dc to 230v takes some doing, and then if your taking watts that can soon mount up... a 1kw load at mains is around 1000/230 or around 4.3 amps and with losses and running current on the inverter that dc draw at 24v... would be.... around 55A or so... at 12v thats over 100A !
so first rule to eck out your solar is use mains to top up if you can, and use gas for cooking and heating.
For example, compile a list of what you need to be 'off grid'. It's different for all of us. Many motorhomers may be happy with their fridge running from gas and no hairdryer. I can't use a gas fridge as I'm off grid for longer than a gas bottle lasts, and I need the fridge to operate in extreme temperatures which gas fridges can't do. Because of that my version of off grid has to have a 12v compressor fridge and all the expense and solar needed to run it.
Start by making a load sheet detailing what you want to run, the quantity, amps, voltage, wattage and hours you expect to use it. From that you can size your battery and from that you then need to size your solar so they're large enough to replenish the batteries in the environment you intend to use them. There's no point having huge batteries that you can't recharge. From that you can work out the cost and from that you can tweek it if it's too much by going back to your load sheet and marking things as a priority.
There's a great video here explaining how to size your set up and it includes a load sheet in the description. If you fill it in an post here we can discuss and help you make a system that best fits.
https://youtu.be/Ji18lY2rtUI
Going through this at the moment.
We have a Pajero with a roof tent. Main car starting battery and a 80ah deep cycle under the bonnet. The starter battery is left alone. When go camping I link up another 120ah battery in the back to give us 200ah of battery storage.
These are charged by the alternator when driving and a solar panel when stationary all via DCDC charger.
I do have a 120 watt solar blanket, but am starting to doubt it's output. Looking at a better quality 300 watt solar panel. I would rather oversize it for winter duties.
It would be nice to have a fixed panel but our car isn't a dedicated camping setup so not ideal.
Another thought was to fit another 120 ah battery in the back to total 320ah, but my DCDC charger is limited to 25 amp, so would take a while to charge although doable. I could also upgrade to a 40 amp unit, but I believe having a more substantial panel will solve my issues.
We run a 40L fridge and LED strip lights in the awning and tent. USB chargers for phones. Pretty low draw really.
We have a Pajero with a roof tent. Main car starting battery and a 80ah deep cycle under the bonnet. The starter battery is left alone. When go camping I link up another 120ah battery in the back to give us 200ah of battery storage.
These are charged by the alternator when driving and a solar panel when stationary all via DCDC charger.
I do have a 120 watt solar blanket, but am starting to doubt it's output. Looking at a better quality 300 watt solar panel. I would rather oversize it for winter duties.
It would be nice to have a fixed panel but our car isn't a dedicated camping setup so not ideal.
Another thought was to fit another 120 ah battery in the back to total 320ah, but my DCDC charger is limited to 25 amp, so would take a while to charge although doable. I could also upgrade to a 40 amp unit, but I believe having a more substantial panel will solve my issues.
We run a 40L fridge and LED strip lights in the awning and tent. USB chargers for phones. Pretty low draw really.
Gingerbread Man said:
Going through this at the moment.
We have a Pajero with a roof tent. Main car starting battery and a 80ah deep cycle under the bonnet. The starter battery is left alone. When go camping I link up another 120ah battery in the back to give us 200ah of battery storage.
These are charged by the alternator when driving and a solar panel when stationary all via DCDC charger.
I do have a 120 watt solar blanket, but am starting to doubt it's output. Looking at a better quality 300 watt solar panel. I would rather oversize it for winter duties.
It would be nice to have a fixed panel but our car isn't a dedicated camping setup so not ideal.
Another thought was to fit another 120 ah battery in the back to total 320ah, but my DCDC charger is limited to 25 amp, so would take a while to charge although doable. I could also upgrade to a 40 amp unit, but I believe having a more substantial panel will solve my issues.
How do you link up your second leasure battery to the 80a one under the bonnet ?
We run a 40L fridge and LED strip lights in the awning and tent. USB chargers for phones. Pretty low draw really.
We have a Pajero with a roof tent. Main car starting battery and a 80ah deep cycle under the bonnet. The starter battery is left alone. When go camping I link up another 120ah battery in the back to give us 200ah of battery storage.
These are charged by the alternator when driving and a solar panel when stationary all via DCDC charger.
I do have a 120 watt solar blanket, but am starting to doubt it's output. Looking at a better quality 300 watt solar panel. I would rather oversize it for winter duties.
It would be nice to have a fixed panel but our car isn't a dedicated camping setup so not ideal.
Another thought was to fit another 120 ah battery in the back to total 320ah, but my DCDC charger is limited to 25 amp, so would take a while to charge although doable. I could also upgrade to a 40 amp unit, but I believe having a more substantial panel will solve my issues.
How do you link up your second leasure battery to the 80a one under the bonnet ?
We run a 40L fridge and LED strip lights in the awning and tent. USB chargers for phones. Pretty low draw really.
SS427 Camaro said:
Gingerbread Man said:
Going through this at the moment.
We have a Pajero with a roof tent. Main car starting battery and a 80ah deep cycle under the bonnet. The starter battery is left alone. When go camping I link up another 120ah battery in the back to give us 200ah of battery storage.
These are charged by the alternator when driving and a solar panel when stationary all via DCDC charger.
I do have a 120 watt solar blanket, but am starting to doubt it's output. Looking at a better quality 300 watt solar panel. I would rather oversize it for winter duties.
It would be nice to have a fixed panel but our car isn't a dedicated camping setup so not ideal.
Another thought was to fit another 120 ah battery in the back to total 320ah, but my DCDC charger is limited to 25 amp, so would take a while to charge although doable. I could also upgrade to a 40 amp unit, but I believe having a more substantial panel will solve my issues.
How do you link up your second leasure battery to the 80a one under the bonnet ?
We run a 40L fridge and LED strip lights in the awning and tent. USB chargers for phones. Pretty low draw really.
We have a Pajero with a roof tent. Main car starting battery and a 80ah deep cycle under the bonnet. The starter battery is left alone. When go camping I link up another 120ah battery in the back to give us 200ah of battery storage.
These are charged by the alternator when driving and a solar panel when stationary all via DCDC charger.
I do have a 120 watt solar blanket, but am starting to doubt it's output. Looking at a better quality 300 watt solar panel. I would rather oversize it for winter duties.
It would be nice to have a fixed panel but our car isn't a dedicated camping setup so not ideal.
Another thought was to fit another 120 ah battery in the back to total 320ah, but my DCDC charger is limited to 25 amp, so would take a while to charge although doable. I could also upgrade to a 40 amp unit, but I believe having a more substantial panel will solve my issues.
How do you link up your second leasure battery to the 80a one under the bonnet ?
We run a 40L fridge and LED strip lights in the awning and tent. USB chargers for phones. Pretty low draw really.
So the only place for this was the boot, or infact the 3rd row of seats position that sit under the boot floor.
I added this battery in parallel. 40amp fuse under the bonnet, ran twin cable to the boot (you could just run a positive and earth it to the body in the rear, but I ran both). Then another fuse at the rear. I then finished with an Anderson plug so to allow easy removal.
If I had one bank of batteries. I would have the DCDC charger in the rear by the batteries and have the batteries all in a row.
I have points off of the second battery for the fridge, an Anderson plug on the tow bar for a trailer power hook up, then an Anderson on the bull bar for the solar input. Another plug on the roof rack rails for the awning and roof tent to plug into.
I'm in Australia, so nearly every ute or 4x4 here has some.kind of camping bias!
I used a Redarc 1225 DCDC charger under my bonnet. They can come with a solar input or just plain dual battery management off of the alternator.
I believe that if you fix solar panels permanently to the top of your vehicle, not all units (like my Redarc) allow the use of house panels. I believe using a house panel to be a cheaper alternative and other units allow that. Not a big issue for me as I haven't room for a fixed setup.
If you go fixed, that's helpful as always charging when parked in a carpark, but also useful to be able to plug in a moveable solar panel setup also for if you camp in the shade.
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