Electricity for Boonie
We have upgraded the van's electric power and I will go into a bit of a detail regarding some of the choices we made and why. Please keep in mind I'm not an electrical professional and this is based on research I have done and testing will need to happen (on the road, here's hoping!) - if you are interested to see how it worked out I will post a follow up to this to show what needed improvement, what worked and what didn't. If you want the short and curly version I have a link to the video at the bottom of the page.
When we purchased the van it came with 2 solar panels on top - we didn't know what power they output and were not inclined to disconnect them entirely and see if it still had its label underneath (especially since they are 10 years old now). We purchased an OHMMeter and checked the Volts & OHMs coming in from the solar panels. Using this we could find out the Watts. So based on the below math each panel is about 60 watts of maximum input per hour on a sunny day:
Volts - 20
Ohms - 3
Amps = 6.666 (Volts / Ohms)
Watts = 133 (Volts x Amps)
The van originally had 1x 120AH 12V leisure battery to run the lights, water pump and fridge. We also wanted to add an inverter so we can use AC power to run our appliances for the kitchen, laptop etc. Quickly adding up the numbers we realized this one battery would not be enough for our needs (plus there is also a % loss of power when converting DC to AC with an inverter). To work this out we looked at the watts required on all of our device chargers and added them together (some items are listed in Amps so you need to convert this to Watts to calculate easily later on - Volts x Amps = Watts). In the below image you can see an example of Kate's phone charger, it has 5 Volts & 2 Amps = 10 Watts.
So adding up all our devices together it came to around 204 Watts - this is continuous, meaning per hour. If you look at the battery we have you can quickly figure out (120 AH x 12 V = 1440 Watts) that 1440 Watts / 204 Watts gives you about 7hours - and its not recommended you use more than 50% power on these batteries (so really we have 3.5hours of constant use). So it was simple enough to decide we would double the power and add another 120AH battery... However if we spend the entire day in the van 7 hours might not be enough, or even to get us through 3 days of average use. Now we factor in the solar panels - they are inputting 133 Watts maximum on a good day for maybe 6 hours in summer - that's only 780 Watts so we would really need a generator if we have a few bad days of weather or high power usage. We dont really have the space for a generator nor did we want to add more expensive equipment or else we would have decided already at this point to replace the solar panels, solar converter and put in 2 large 240AH batteries (already hitting 1000 Euro for this installment if we do it ourselves plus working out how to deal with the current state of the wiring - which is a mess). So Kate's uncle suggested we connect the Vans Motor battery to the 2 leisure batteries installed and when we are driving we can use the alternator to charge all batteries - hooray! So this is what we have done: The motor battery connects below the engine with the yellow wire below and then into the battery bay beneath the seats, and has its own big red switch to disable or enable the connection so that when the vans engine is off we can disconnect the connected power - so they don't over charge or flatten the motor battery using power in the van.
We were going to get a 300 Watt power inverter (its recommended to get what you need), however later we decided on a 600 Watt inverter as we realized we might want some additional items to use in the kitchen and even a small hand mixer can use up to 500 Watts. We also have a fuse that goes in between the orange breaker switch and the positive terminal on the inverter which is 40AH (which in hindsight should actually be 80AH Ill explain below). I did my initial calculations based on the 300 Watt inverter and forgot to update this:
300 Watt inverter @ 600 Watt peak on a 12V battery
80% of 600Watts for a safety margain (so you dont actually hit the peak)
480Watts / 12 = 40AH
Now you can see why 80AH would have been more effective:
600 Watt inverter @ 1200 Watt peak on a 12V battery
80% of 1200 Watts for safety margin
960 / 12 = 80AH
Ill update this if I blow the fuse, at least its quite easy to replace and not so expensive. Remember, im not an expert - you can learn from my mistakes :D
You are looking at the reverse of the breaker switch (orange switch), the right side is where all the main items in the van connect to, lights, fridge etc. The left side is the direct power where the batteries all connect, so even if that breaker switch is turned off I can still charge the batteries with the alternator if I have that red switch enabled.
We will be installing a battery meter next so I can gauge exactly how much power is remaining in the batteries so we dont over/under charge them - safety is important people!
You can see what I mean about the wires being in a bit of a mess:
So we added a lid, and now it looks pretty! (well almost, maybe some paint will help)
If you are interested to see how this all worked out ill be posting a second video and post to follow this up, so hold on to your chairs! If you also want some more information to work out your own power needs you can visit some of these websites below:
Calculate Solar Panel Amps:
https://homeguides.sfgate.com/calculate-amps-solar-panel-79495.html
http://www.altenergy.org/renewables/solar/DIY/solar-panel-testing.html
OHMMeter symbol guide:
http://www.themultimeterguide.com/multimeter-symbols-guide/
When we purchased the van it came with 2 solar panels on top - we didn't know what power they output and were not inclined to disconnect them entirely and see if it still had its label underneath (especially since they are 10 years old now). We purchased an OHMMeter and checked the Volts & OHMs coming in from the solar panels. Using this we could find out the Watts. So based on the below math each panel is about 60 watts of maximum input per hour on a sunny day:
Volts - 20
Ohms - 3
Amps = 6.666 (Volts / Ohms)
Watts = 133 (Volts x Amps)
The van originally had 1x 120AH 12V leisure battery to run the lights, water pump and fridge. We also wanted to add an inverter so we can use AC power to run our appliances for the kitchen, laptop etc. Quickly adding up the numbers we realized this one battery would not be enough for our needs (plus there is also a % loss of power when converting DC to AC with an inverter). To work this out we looked at the watts required on all of our device chargers and added them together (some items are listed in Amps so you need to convert this to Watts to calculate easily later on - Volts x Amps = Watts). In the below image you can see an example of Kate's phone charger, it has 5 Volts & 2 Amps = 10 Watts.
So adding up all our devices together it came to around 204 Watts - this is continuous, meaning per hour. If you look at the battery we have you can quickly figure out (120 AH x 12 V = 1440 Watts) that 1440 Watts / 204 Watts gives you about 7hours - and its not recommended you use more than 50% power on these batteries (so really we have 3.5hours of constant use). So it was simple enough to decide we would double the power and add another 120AH battery... However if we spend the entire day in the van 7 hours might not be enough, or even to get us through 3 days of average use. Now we factor in the solar panels - they are inputting 133 Watts maximum on a good day for maybe 6 hours in summer - that's only 780 Watts so we would really need a generator if we have a few bad days of weather or high power usage. We dont really have the space for a generator nor did we want to add more expensive equipment or else we would have decided already at this point to replace the solar panels, solar converter and put in 2 large 240AH batteries (already hitting 1000 Euro for this installment if we do it ourselves plus working out how to deal with the current state of the wiring - which is a mess). So Kate's uncle suggested we connect the Vans Motor battery to the 2 leisure batteries installed and when we are driving we can use the alternator to charge all batteries - hooray! So this is what we have done: The motor battery connects below the engine with the yellow wire below and then into the battery bay beneath the seats, and has its own big red switch to disable or enable the connection so that when the vans engine is off we can disconnect the connected power - so they don't over charge or flatten the motor battery using power in the van.
The black box you see above the red switch is the Solar Charge Converter - which regulates the power from the solar panels into the battery.
We also have a breaker switch (orange below) that disconnects the two leisure batteries entirely for when we want to do any electrical work such as when we added the power inverter.
300 Watt inverter @ 600 Watt peak on a 12V battery
80% of 600Watts for a safety margain (so you dont actually hit the peak)
480Watts / 12 = 40AH
Now you can see why 80AH would have been more effective:
600 Watt inverter @ 1200 Watt peak on a 12V battery
80% of 1200 Watts for safety margin
960 / 12 = 80AH
Ill update this if I blow the fuse, at least its quite easy to replace and not so expensive. Remember, im not an expert - you can learn from my mistakes :D
We will be installing a battery meter next so I can gauge exactly how much power is remaining in the batteries so we dont over/under charge them - safety is important people!
You can see what I mean about the wires being in a bit of a mess:
So we added a lid, and now it looks pretty! (well almost, maybe some paint will help)
If you are interested to see how this all worked out ill be posting a second video and post to follow this up, so hold on to your chairs! If you also want some more information to work out your own power needs you can visit some of these websites below:
Calculate Solar Panel Amps:
https://homeguides.sfgate.com/calculate-amps-solar-panel-79495.html
http://www.altenergy.org/renewables/solar/DIY/solar-panel-testing.html
OHMMeter symbol guide:
http://www.themultimeterguide.com/multimeter-symbols-guide/
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