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Post Info TOPIC: solar controller where to install
Sarge9


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solar controller where to install
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My understanding is the solar controller needs to be as close to the battery as possible, do I have this right and what sort of loss are we talking.

Scenario is: Daughters Jayco poptop has a battery installed near the drivers side wheel arch under a bed, they are considering folding portable solar panels as the only draw is lights and TV (and maybe a water pump is dad installs it). If proximity is important then the controller will go under the bed too, but where to put the anderson plug?? out the side wall, but I see that as limiting the location of the portable panels which generally get put out in front of the van where they can be seen and easily moved. 

I dont understand the Jayco 12 volt management system. It seems to charge the battery whenever 240 connected or when travelling. I dont know if self senses, it does not auto change the 3 way fridge.

I guess my question is.... long leads between panels and solar controller (shortest lead to battery) or 3 metre lead between controller and battery and anderson plug up the front. 

My van has batteries and controller in the front boot.

I thank you for your expertise and experience.  



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Whenarewethere


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Just make sure you have thick enough cable between the controller & battery. Calculate the resistance for the total length + & -



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Are We Lost


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The cable between the controller and battery is the more important one. So keep that a decent size and relatively short.

With say an 8 gauge cable of less than 2 metres, your losses would be very low, unless you have a lot of portable solar. The cable between solar and controller is less important for 2 reasons:

  1. The solar panel output of around 18 volts is higher than the controller can use (assuming it is a PWM controller). So a loss of 1-2 volts does not matter.
  2. The higher the voltage, the less the loss due to cable capacity.

 



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Sarge9


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thank you for your responses, I intended using 6 b&s cable. I have used an online voltage drop calculator and assumed a 100 or 120 watt folding panel which apparently means about 6 amps.... drop of .30 over 20 metres. I thought it may have been more.
Nevertheless, Controller next to battery is easy enough, then an accessible anderson plug for the panels.

Cheers

Sarge

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Aus-Kiwi


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Yes the higher the voltage the less wire size required !! Being the length of wire counts also ! The closer to batteries the better . You may have to fit a link to fit all wires into ? If parallel multi panels ? To fit all the wire ! 18v or so over the distance is better than lower voltage after regulator!!

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Peter_n_Margaret


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The reason for having the controller close to the battery is not about power losses in the cables, it is about accuracy.
The solar controller is trying to control the voltage delivered to the battery to very accurate limits - like +/- 0.1V. If there is any voltage drop in the cables it can not do that. Firstly its reading of the battery voltage is incorrect and secondly the voltage it sends to the battery is wrong.
Cheers,
Peter

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OKA196, 4x4 'C' Class, DIY, self contained motorhome. 960W of solar, 400Ah of AGMs, 310L water, 280L fuel. https://www.oka4wd.com/forum/members-vehicles-public/569-oka196-xt-motorhome
 

 
swamp


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hit
Fit charge unit close to batteries ie within 2 mtrs . I mounted my unit in the front boot [Jayco camper ]. Batteries in front of wheel arch . I also mounted my battery isolator in the front boot with an AC switch for 240v charger .

I ran all batt [- ] cables to an insulated body mounted insulated power post ,then ran 6b&s from power post to isolator the back to battery negative

Solar controller mounted in front boot . Ran cables thru floor pos/neg towards draw bar mounted anderson plug for solar panel connection . Ran another 2 cables back rearwards thru cabin to battery .

Ando plug No50
All cable 6b&s

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Hylife


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most blankets now come with andersen style plugs and a controller.

YES, if possible, the best results will be if the controller is under the bed directly connected to the battery.



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