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[Applause] [Music] hi everyone jeff cote here with another session of votingtechtalk.com so we've got a question from jack jack asks jeff i purchased two 170 watt flexible solar panels for my boat can you recommend a controller volts and amps i watched your 2018 boat show video where you talked about installing a fuse between the controller and the battery what size type of fuse should i install all right two questions not too bad so first things first when you're sizing a solar controller for a solar panel or a series or parallel solar panel what you want to think about is a few variables you want to think about you know what is best basically going to be the battery voltage is going to be 12 volts 24 volts is it 32 volts is it 48 volts that's going to matter so first thing is for most of us it's going to be a choice between 12 and 24 right the other voltages are not going to matter that much to most of us but know what your battery voltage is because most solar controllers are actually sized for a specific battery voltage and they don't allow both although some controllers do but you got to figure that out all right first so you know your battery voltage then you want to know what is the maximum wattage right that's going to come into the solar controller and now the maximum wattage it could be two panels in series or it could be two panels in parallel right now of course the voltages are going to be different depending if you add the panels in series or in parallel but the wattage won't you still need to add the wattage right so if you've got 270 watt panels you have a 340 watt solar array and if you've got two 170 panels in parallel you still have a 340 watt rate now this is key because when you size a solar controller you're going to size it for the maximum wattage that is coming into for that solar array right and so in this case you're looking for a solar control that's going to allow up to 340 watts input so that's another one now you take that and then the other thing too that's important there's also this maximum input voltage right so not all solar arrays right some solar arrays have different input voltages because not all solar panels have the same voltage and there's going to also be another variable that's important is what is the maximum solar voltage now that's important because if you add the two panels in series the voltage will actually in this case double if you did three it would be three times but if you add the panels in parallel the voltage is going to stay the same the current is going to go up and that's an important factor for sure and that's going to come in in wattage right and there's going to be limitations on the maximum amperage that come in but you're not going to affect the overall high voltage so if i had a boat with two 170 watt solar panels it doesn't matter if it was wired in series or in parallel what i probably would recommend to look at popular choice and it's not your only one because there's a lot of choice out there the one we use the most is probably the victron 100 slash 30. right that's the one we generally use the most for these situations and there's a model that comes with bluetooth and there's one that doesn't and if you're looking at doing more anything other than the vanilla or standard settings in your controller one option is to actually buy a controller that has bluetooth with built-in and then you can use your app to control and to commission and also monitor your solar array some of us don't care for that to be honest not everyone does and some of us are going to buy just a bluetooth dongle and change it every time we configure every controller and if ever we want a monitor solar a cern solar controller then we plug in the bluetooth dongle in it so it really depends on how much of the monitoring you're going to do and if you're going to do very little then it might make sense to buy a bluetooth dongle to do multiple controllers or if you only have one controller then it's probably going to make more sense to just go ahead and buy the blue the controller with bluetooth within because it's going to be about the same price as without plus the dongle so that's what i would do and that's a great question now the other second part was where do you install the fuse between the controller and the battery well the fuse should be installed at the positive post of the battery or at the positive unswitched distribution of the battery meaning a place that is always connected to the battery because a charger circuit which a solar panel is or solar controller needs can be connected not on the load side i.e after the switch but before the switch so it has to be on switch it has to be always on and so that's why you're going to see in a lot of diagrams they've got the the little fuse connected right on the battery post now it doesn't have to be on the battery post in a lot of our boats including my own and certainly a lot that we've worked on we're going to be always installing a positive unswitched distribution and what you're looking for that is you want to make sure that that distribution right does not is always always on so even if you turn the switch on or off on your boat your source selector switch that positive distribution is always on and that's where you would actually bring your solar controller connection to and you would put that fuse right there at the start of your positive unswitched distribution or directly on your positive post of your battery so thanks for asking the question jack and good luck for all of you tackling solar on your boats i want to thank you for watching this video don't forget to subscribe if you want to get more of this cool content and also check out our website if you've got questions that are unanswered we've actually taken the time to answer quite a few questions and you might be surprised to find the answer right there on our website so thanks again