Do I connect a load to charge controller or battery?

Leboy001

New Member
Joined
Sep 25, 2021
Messages
4
Hi total noob here, but I have googled without much success
Which probably means I'm googling the wrong thing.

I am in the design phase of making a solar power station for camping with lifepo4 cells. The plan is to have a couple of 12v cigarette plugs and usb ports attached to a fuse box and for now at least not have any inverter.

Should I connect the 12v load to the mppt charger controller or the battery directly? Or does it not matter which?
 

Rednecktek

Photon Sorcerer
Joined
Sep 8, 2021
Messages
2,012
Location
On a boat usually.
Your loads should connect to the battery.

Your charger should connect to the battery

Your battery is the heart of the system, everything connects to it. Your battery is capable of providing the power whenever you need it. If you connected a load to the charge controller, it would only provide whatever power was actively being generated by your panels, which would be pretty useless in the dark. :)
 

Jordi

Solar Enthusiast
Joined
Oct 13, 2020
Messages
213
Hi total noob here, but I have googled without much success
Which probably means I'm googling the wrong thing.

I am in the design phase of making a solar power station for camping with lifepo4 cells. The plan is to have a couple of 12v cigarette plugs and usb ports attached to a fuse box and for now at least not have any inverter.

Should I connect the 12v load to the mppt charger controller or the battery directly? Or does it not matter which?
The mppt controller should have 3 paird of ports; one for the panel, one for the battery and one for the load. Let everything flow through the controller; this is the safe advice. The controller has to be compatible with the same panel and battery voltage. The output to the load will be the same of the battery. The professionals here will also suggest a fuse for the battery circuit to avoid co-circuits and fire.

Connecting the load directly to the battery is doable when you want a higher load than the mppt controller can handle. But then professionals won't recommend because you can basically discharge the battery to deep and the mppt controller is unable to stop it. Result is possible damage of the battery life.

My opinion is that you can use the battery directly If you are present and know for sure your load and consumption isn't too high (eg. vacuum clean 10 minutes). But as standard setting, don't do.
 
Last edited:

pierre

Somewhere down South
Joined
Dec 21, 2019
Messages
913
Consider something like this. I build lithium batteries into these cases for camping and offroad activities. Very useful and convenient.
I agree with Jordi above. The SCC will disconnect the load when the battery reaches a certain discharge level. Connected directly to the battery might lead to a total discharge level. You can however connect directly to battery if your load current exceeds the max output rating of the SCC but you will have to manage it.
 

Attachments

  • Case 1.jpg
    Case 1.jpg
    101.4 KB · Views: 4
  • Case 2.jpg
    Case 2.jpg
    74.2 KB · Views: 4
Last edited:

Rednecktek

Photon Sorcerer
Joined
Sep 8, 2021
Messages
2,012
Location
On a boat usually.
Note that the "Load" ports on most basic controllers are pretty worthless, I know mine top out at 60w/5a so the only thing I use those ports for is the motion detector lights in the utility room so I can see what I'm doing when I get there at night and can turn everything else on.

Being a beginner, I would HIGHLY recommend starting out with some cheap deep cycle batteries from Wally World or the like. You're going to learn a lot and you're going to make mistakes. Building a battery from scratch is a pretty advanced step and you really don't want to risk burning up the expensive stuff right out the gate.

We call all the money we spend getting things wrong "Tuition", the cost of learning. :)
 

pierre

Somewhere down South
Joined
Dec 21, 2019
Messages
913
Note that the "Load" ports on most basic controllers are pretty worthless, I know mine top out at 60w/5a so the only thing I use those ports for is the motion detector lights in the utility room so I can see what I'm doing when I get there at night and can turn everything else on.

Being a beginner, I would HIGHLY recommend starting out with some cheap deep cycle batteries from Wally World or the like. You're going to learn a lot and you're going to make mistakes. Building a battery from scratch is a pretty advanced step and you really don't want to risk burning up the expensive stuff right out the gate.

We call all the money we spend getting things wrong "Tuition", the cost of learning. :)
I only use Victron stuff and cannot comment on other makes. You make very good points.
 

Rednecktek

Photon Sorcerer
Joined
Sep 8, 2021
Messages
2,012
Location
On a boat usually.
Oh, don't get me wrong, Victron is the top shelf stuff, but my last name isn't Musk or Bezos. :)

Start small, start cheap, start simple. Replace things as your needs grow, don't be afraid to break something every now and then. Just don't burn down the house, the wife gets cranky about that. :)
 

pierre

Somewhere down South
Joined
Dec 21, 2019
Messages
913
Oh, don't get me wrong, Victron is the top shelf stuff, but my last name isn't Musk or Bezos. :)

Start small, start cheap, start simple. Replace things as your needs grow, don't be afraid to break something every now and then. Just don't burn down the house, the wife gets cranky about that. :)
The Victron stuff is the one brand freely available here in ZA and pricing better than in North America. The Dutch like us more ;)
 

rmaddy

Full-time Solar-powered Trailer Life
Joined
Nov 16, 2019
Messages
3,735
Location
USA
Keep in mind that only a small subset of the Victron solar charge controllers have load terminals.
 
Top