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smartsolar-usr asked

MPPT 75|10: Should I rather connect my devices to "Load" output or to a Bus-Bar together with Battery to "Battery" output?

Hi there, I am setting up my MPPT 75|10 SmartSolar charge controller for use together with a 12V Battery and two devices that work on 12V and require about 50W in total. I am furthermore using a 110W Solar Panel (max. Voltage: 18.27V, max. current: 6.03A). Let's get to my question.

I was advised to connect my devices and the battery to the charge controller by connecting two bus bars (for + and -) to the battery output of the controller and all devices and the battery onto these bus bars. I am however now realizing that there is a Load output where I could connect my devices to. So I am wondering if I should rather connect my devices directly to "Load"? What is the advantage and disadvantage of each method? Is it safer to connect directly to Load?

An insight to this would be very much apprechiated, thanks in advance!

PS: I also understand German ;)

MPPT ControllersLithium BatterySolar Panel
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kevgermany answered ·

Grüsse

Firstly the load output of the MPPT allows you to set a minim battery voltage in the charge controller. At that voltage it stops the battery discharge. So it's useful for battery protection.

Up to you whether you connect loads there or to the battery.

With only two users, unless you intend to expand later, there's little point in going to the expense of busbars. Just make sure you have an isolator or removable fuse on the battery positive. And fuse the loads properly.


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David avatar image
David answered ·

There is one situation where you should not use the Load output of the Solar Controller ... where any of the loads have a momentary/initial surge.

The Load outputs have no surge capability and if you exceed the rated output the Load disconnects and you will lose all power (so a compressor fridge for example should not be connected that way for example).

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smartsolar-usr answered ·

Vielen Dank @kevgermany! In that case it makes more sense for me to use the load output. I don't necessarily need a busbar... it's just a way to distribute the current between the different components. I do not fully understand your suggestion of using a fuse for the battery, since it should be protected from overcurrent through the Charge Controller, or am I wrong? Would be thankful if you could elaborate on this!

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kevgermany avatar image kevgermany ♦♦ commented ·
Ideally you need a way of disconnecting the battery without removing the leads. Good for emergencies, maintenance. Removable fuse or isolator will provide this.

Any short circuit on the positive wires to the battery will draw from the battery and so inline fuses to prevent more serious damage are a must.

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