What is a PV Combiner Box?

so this is a pv combiner box and today we're going to talk about what they do and how to use them very very simple device but people are intimidated because when you open them up there is a lot going on but all this device does is connect all of your solar panels to your inverter or solar charge controller so if you have multiple solar panel arrays in parallel the current will go up and you need to protect each string so having a fuse for each string and an over current protection device for each output is very important this combiner box also comes with a diode for protection so there's no back feeding from each string and we also have a surge protection device and these surge protection devices require a ground to dissipate the excess charge so over here we have a grounding bar so very simple device honestly all you do is connect some solar panels positive negative then you get a dc output positive negative and positive and negative that's pretty much it now let's talk about the fuses and the circuit breakers so the circuit breakers are for the parallel connection of all of these inputs so you can turn it on or off and that will control the dc output but these connections at the input for each individual string has their own fuse and each fuse is rated for 15 amps which is typical for a single series string you can easily replace these if something were to go wrong and the search protection device just works automatically in the diodes you don't have to do anything so it looks complex but there's no reason to be intimidated connect your solar panels connect your mppt and then turn the switch on and that's it everything else will work autonomously also this is a higher quality combiner box the connections are feraled as compared to other ones on amazon that are soldered and then they just screw them down some other youtube reviewers have actually found loose connections on those and that's why i never use them if you have parallel strings you should always have some form of over current for each and every individual string with smaller systems i'm fine just using inline mc-4 fuses also if you have a single series string connected to your system you do not need a combiner box and you do not need any form of over current protection this is very specific to parallel strings that are combined for a single or double input on an all-in-one system or for an mppt another benefit of combiner boxes is it organizes your wires so on the outside of your house cabin or rv you can have all of your arrays connected right here and right here to the fuses and you can have only two or four wires going out to your mppt or to your all-in-one system and it looks nice and makes your system look more professional now let's talk about how to size a combiner box depending on your array will determine what size of combiner box you need on this combiner box we have eight dc positive inputs and eight dc negative inputs and in the middle we have two dc outputs so each output can handle four parallel strings each so if you have an all-in-one system that can handle 4 000 watts on each mppt charge controller that means each breaker can handle 4 000 watts with those four inputs so 4 000 divided by 4 is 1000 watts so that means i can connect 1000 watts to each input and then have one breaker control a 4 000 watt input for the mppt and having two dc outputs is very useful for mpp solar or grow watt type inverters all-in-one systems that have two separate mppts but let's say you only have a single mppt or one solar input on your all-in-one system this is complete overkill and you do not need this many connections and over here we have a smaller combiner box so on this one we have a single dc output and four parallel string connection input and the typical surge protection device and the diodes so in this instance with this dc output we only have two conductors so we could put a thousand watts through each one if our mppt can handle 4000 watts so again very simple device just as the other one you have a grounding bar the diodes and everything else also these were provided by watts 24 7 which is a company i use to distribute all-in-one systems ian at that company does a great job and he got these specially made for his company and the build quality of everything that they sell is really nice i mean even this door is sealed everything is grounded properly this is a high quality unit especially compared to the units that they sell on amazon please check out the other reviews to see the fault points of those combiner boxes that's pretty much it a pretty simple device but very confusing at first i know if you're building your first solar system and you see these and all of these wires you're like uh oh what is going on but just look at the labels and follow the instructions it's very easy to use dc positive over here dc negative over here and then connect the output to your charge controller and that's all you have to do also ground it if applicable for your application anyways just a quick video on combiner boxes and i will talk to you guys soon bye

Channel: DIY Solar Power with Will Prowse

Views: 230,893

Keywords: off grid solar, will prowse, diy solar, rv solar

Id: XEK78TGOmbE

Length: 5min 36sec (336 seconds)

Published: Sat Jun 12 2021