Van Life: Solar & Off Grid Power Systems Explained

So in part one of our off-grid electrical system we shared with you the story of our search for the most reliable and powerful off-grid battery and why we chose to install 400 amp hours of Battle Born battery lithium So now that we have 400 amp hours of Battle Born battery ultra clean and safe power for our off-grid studio how the heck do we get energy back into the system? Well we have three ways to recharge our batteries on-grid, off-grid and on the move. So now you need a way to charge your batteries and when you're on the road fortunately you have an alternator. A 12-volt alternator can be applied directly to your lithium-ion battery bank in 12-volt configuration to charge it. There are many devices available to hook up an alternator to charge a second battery bank some as cheap as $20 but take it from us you'll never reach a hundred percent state of charge with these devices. If you're serious about off-gridding you'll need a way to provide your battery bank with a multi-stage charging profile but care must be taken to not overload your alternator. A lithium-ion battery can be charged so fast with such low resistance that it will basically max out your alternator and over time that could damage your alternator and shorten the lifespan of your alternator and you don't want to be stranded somewhere without your alternator. So a good solution for that is to control the current that comes from your alternator to the battery bank and your battery-to-battery charger is a great way to do that. So you have a 30 amp battery-to-battery charger which basically limits the current coming from the alternator to around 30 amps. So this device here is the Stirling Power 30 amp battery-to-battery charger. It's a multi-stage charging device which basically takes your current from your alternator and puts it into whichever kind of battery you have but be that lithium or a normal flooded lead-acid battery and speaks to it in exactly the voltages that it wants to be spoken to to ensure maximum life, maximum efficiency and also maximum charge rate. It's a really good piece of kit. We have this at 30 amps which is extremely conservative for most systems but our alternator is only 55 amps. This device ensures that we don't suck all of the power out of the alternator and it's still able to run and we can conserve basically duty cycle it in a certain way by not overloading it and only using a certain amount of power. There are much bigger devices available if you have a high output alternator you will be charging your batteries in no time at all. So for charging on the move cheap solenoids and voltage sensing relays only really give you about 80% state of charge for your auxiliary battery system. A multi-stage smart charging device is needed if you want to reach 100% state of charge. This is especially important if you have a newer vehicle with a modern alternator. Care must be taken not to overload the alternator particularly with fast charging batteries like lithium-ion. Now in all reality we're not going to be on grid all that often but in the situation where we're in a campsite and it's a cloudy day and we can't rely on our solar, which is epic by the way, we will be using a hookup. So this is designed to go into most UK campsites they have this type of connection it's IP44 rated so it's waterproof it's a 16 amp connection. In reality when we're parked outside someone's house we've just got standard access to a normal kind of plug top in a house we'll be using this adapter which we made up so this will go in here like so and then we can plug into any house in the UK. If we're not in the UK easy enough we just undo this change the plug top I've got a European one which will see us for quite a lot of the journey and then we can just get a local plug top wherever we are to plug into an electricity supply and run that into the combi up here. So from our 16 amp weatherproof socket on the outside of the van the twin and earth cabling connects through to an RCBO breaker and then onwards to this Stirling Power 40 amp global smart charger. The beauty about this device the Stirling Power 40 amp ProCharge Ultra is that it's a global charger it will accept electricity from anywhere any Hertz any frequency any domestic voltage and it will take that and convert it into a multi-stage charging profile for whatever type of battery you have which is great for overlanders like us because we don't know what kind of electricity that will come across and it basically takes that and keeps our batteries at a hundred percent state of charge when we are on grid when we're hooked up it will even load detect so if we happen to turn on any of our 12 volt systems including our inverter our fridge any of our pumps this thing will pick up the load and basically keep our batteries maintained at a hundred percent state of charge at all times. So this is a really cheap and efficient way to have a permanent hookup system. I will say if you're running AC units or anything that is requiring more than 40 amps you may want to look into a more hardcore AC hookup system but for small vans and small rigs this sort of thing is perfect. So for charging on the grid AC power supplies should be kept isolated by an appropriate breaker and kept separate from your onboard DC systems. A load detecting smart charger will allow you to remain hooked up to AC shore power. A global smart charger is only really needed if like us you are overlanding across borders. Now that means we can charge on grid and we can charge when we're on the move but what about charging off grid? When you're not driving you can still charge your batteries using the Sun and of course that's one of the huge benefits of lithium is that they can be charged in and recharged frequently and for a very long time and so when you're off grid solar is the perfect way to do this. So you need obviously your solar panels and then you need a solar charge controller. Due to the small size of our roof and our high power requirements for producing videos off grid we personally opted for rigid panels on the roof rather than the much more stealthy semi-flexible panels. Our panels are heavier for sure but they allow us to cover more surface area and hopefully at some point we will be able to tilt them which is particularly useful when you're traveling near extreme high and low latitudes and also during winter months when the Sun is lower in the sky. We have two fixed panels 250 watts on the rear and 120 watts on the front to give a combined total of a staggering 370 watts. For optimum performance we chose German monocrystalline cells which are better at handling high temperatures and also as they were from the same manufacturer and have the same date of production and exactly the same voltage they work extremely efficiently when connected in parallel together. The advantage of having these panels connected in parallel is that if part of the panel was shaded we'd only lose part of the power whereas if it was connected in series we would lose much more of the power if not all of it so when you're mobile and living in a van you are often shaded and you can't control that you might be under a tree so for van life parallel panels is the way to go. We've mounted our panels to our custom roof rack rails via aluminium brackets which we fabricated and mounted with a stainless steel fire door hinge on one side and a latch on the other side. We're yet to complete this tilting system so stay tuned for updates. So we have the Victron Energy Blue Solar 130 MPPT charge controller. Flippin heck why can't they call these things Boris or Steve or something? It'd be much easier. This thing does a really good job. This basically takes whatever voltage our solar panels can put out and converts it into exactly what our batteries want to see. These ones are currently tuned to speak to our Battle Born batteries in an appropriate voltage for the lithium-ion phosphate batteries. If you have anything above 150 watts of solar panels on your roof you can really benefit from having an MPPT charging controller like this one because it really maximizes your harvest and maximizes the output current so that basically translates to faster charging batteries particularly on days like this when there is partial cloud cover. Importantly it also has the ability to monitor your solar harvest by your smartphone which is really good for off-grid geeks like me. I have got zero watts of solar that's because I've got it turned off here at the breaker. If I flick that on, here we go, here's some solar coming in. 160 watts, 188, 203, 207, oh sorry I really geek out when it comes to solar. So that basically means we can see that a varying voltage is being pulled in because of the partial cloud cover today and that means the current is also changing. This device here will basically track the maximum power points and deliver the maximum current to the battery so we're getting currently 11-12 amps going into the batteries. You'll notice that we're currently in bulk charging stage which means our batteries have not yet reached a hundred percent state of charge. The other cool thing I can do with this app is I can see the history of how much solar we've harvested on each day. So here it shows when it's solid white that it's been in bulk charging all day which means we never reached a hundred percent state of charge and where it's kind of dark blue we have been in float which means we did reach state of charge. The maximum we've had in recent days is, let them know, we had a 940 watt amp hour, sorry, we had a 940 watt day. That's a pretty good yield. It must have been quite sunny that day. Look at that, we've got a 1.34 kilowatts, 1.34 kilowatts of power and we did reach float that day so that would have been a day that we were using our system quite heavily, probably editing on that day. Rest of the day is filming with our feet up. So now it's gone really cloudy and we've dropped down to 80 watts of solar. But what can you do, you know? Drive to Morocco, that's what you can do. Keep driving south, that's the solution. So for charging off the grid, monocrystalline panels are great for high-temperature environments. Parallel connected panels are best for van life and partially shaded situations. But remember, panels must be the same voltage to connect in parallel. MPPT charge controllers are beneficial when more than 150 watts of solar panels are being used. And being able to monitor your solar harvest isn't essential, but it sure is fun. You've probably seen one of these before. It's a 12 volt voltmeter to allow you to see what the state of charge is of your 12 volt system. It's quite typical in van life and RVs and things like that. Particularly with traditional lead-acid batteries, this is how you see your state of charge. But it's terrible! This is not the way to see your state of charge and I'll explain why. Imagine you spent all day off-grid depleting your batteries to, what can you get away with, 50%? Then you took a five-minute drive to the shops and it charged from your alternator at 14.4 volts all the way. You turn off your rig when you get there and the voltage slowly drops to around 13.6 volts. Great! The battery's charged. No it's not. The issue is you have to have your batteries resting for about 24 hours before you can truly see what the state of charge is. This is a very inaccurate way of seeing what the state of charge of your battery is. If you've got a lithium system you absolutely can't use one of these to see your state of charge. If you really want to know how much power you've got and how much longer you can stay off-grid, you're gonna need one of these. So this brings me on to my next favorite gadget that we've got. It's the Victron Energy BMV 700 shunt or battery monitor. This thing is not only necessary, it's awesome! So determining the state of charge of your battery bank is actually harder with a lithium bank and that has to do with the lower impedance. So it's a good thing but on the other hand over the charge cycle the voltage doesn't change much. So you're used to checking the state of charge just by checking the voltage of the battery bank and that's not the case with your lithium batteries. Because of that you need something a little bit more sophisticated to really get an accurate state of charge measurement and what that means is you need a shunt which measures the current going into and out of the batteries all the time. So in your system we apply the shunt on the negative battery terminal, we extract all of the current through that terminal and it gets distributed to the other batteries beforehand and what that allows us to do is when you're charging we measure the current going in, when you're discharging we measure the current going out and the Victron battery monitor that you guys have installed will basically keep track of all of that. You're counting electrons basically so rather than just measuring the voltage you're actually directly measuring the amp hours going in and out. It's a much more accurate way of keeping track. You can measure the voltage and see well am I empty or full or halfway but for a really accurate state of charge you don't you know not having to worry about relaxation or you know letting the battery sit to equilibrate a shunt based monitor is important. Because we can monitor every single amp of energy that goes into our battery and comes out of our battery we know exactly accurately the state of charge. That's really important when you've got a lot of investment in your off-grid system you need to know what your state of charge is so that you're not overworking your system and you know how long you can stay off-grid basically. This system allows us to monitor exactly the state of charge and right now we're at 99% state of charge. We are currently consuming 3.8 amps now we were about 12 amps of consumption with all of the things that are charging currently. We've also got some solar coming in but not enough solar to basically cover all of the debt that we've got on the system so we are net minus 3.7 amps at the moment. It also tells us how many days we've got remaining at this current draw so we could stay in for another two days almost three days at this current rate. But we'll have better solar soon this is going to fly up to 100% in no time at all. In fact just while I'm talking we've already gone into positive the sun's improved and now we're getting positive 24, 26, 27 watts of energy coming in from our solar. It's putting an extra power on top of what we're consuming with our devices charging. We can also see in the history what our deepest discharge was which was 208 amp hours which is roughly 50% of our system and it tells us the last time since the full charge which was about 30 minutes ago. So now it says we have got positive 10 amps coming in. We have infinite time remaining at this current situation with the solar. The bright sun that's now coming in through the window. This is a really cool system it's really good to be able to see what our actual state of charge is. This would be good even for people that don't have battle-borne batteries like we do but it's especially important if you do have a lithium-based system. So for monitoring your state of charge it is important to know the true state of charge for anyone who is serious about off-gridding and anyone who wishes to protect their investment in their off-grid electrical system. A battery shunt is the best way to accurately know your state of charge. We've got to give a huge shout out to Battle Born Batteries for not only completely relieving our battery anxiety but also helping us put together this incredible off-grid system. We were blessed to have the opportunity to hang out with Dennis directly and behind the business he is on a mission to drive down the cost of energy storage for everyone and that is pretty inspiring. On occasion during the summer whilst we've been testing this system we've woken to 100% fully charged batteries. All of our nighttime power consumption had been replenished by the morning sun before we'd even gotten out of bed. Amazingly we never once worried about being out of power. The scale of our system may be overkill for some small van weekend warriors but the base components are essentially the same no matter the size of the rig. We are extremely happy with this system. It has surpassed our wildest dreams and continues to perform incredibly. Also I've got to give a shout out to my dad for his help behind the scenes wiring this combi and making the finished studio look so darn professional. What a legend! Cheers dad! This is the system that we will use to create our travel series. Because of this system we will now be able to go off-grid, far off the beaten track and produce and edit our videos on site from anywhere in the planet. And that means that we will be able to share the experience with you of traveling around the world in this combi and basically bring you with us on the adventure. I hope you enjoyed geeking out with me guys. I've linked all of the equipment that we've been using down below and also a link to the diagram of our system and our guide to off-grid electrical systems which might be of interest to you if you're just getting into all of this. Also check out our build series if you want to see how our studio came together. Otherwise we'll see you in the next one when we hit the road.