What safety devices do I need with my solar system?

[poot_traveller]

I have a LiFePO4  battery (12V/100AH), a MPPT controller (with no screen), an invertor, and of course a solar panel (160 Watts).

I work full time, so five days a week I have to leave my solar system unattended while it charges during the day, that means if something goes wrong I won't be there to disconnect the battery. 

The instruction manuals that came with the controller and battery are quite overwhelming. Both manuals basically say my van is going to catch fire if I get one thing wrong. So I wish to know if anyone can recommend some safety devices to use with my solar system to prevent overcharging, under charging, low voltage, high voltage, and any other type of charging or voltage that isn't suppose to be going on?

 

[LoveCareThinkDo]

The instruction manuals that came with the controller and battery are quite overwhelming. Both manuals basically say my van is going to catch fire if I get one thing wrong.

The manuals are just covering their butts. LiFePO4 is about the safest you can get (https://www.batterystuff.com/kb/articles/battery-articles/lithium-battery-overview.html). I live in my van full-time, with my LiFePO4  battery right under my head. I pay no attention to it at all. I am perfectly safe. If you have the Battle Born battery, you couldn't damage it if you tried. The internal electronics protects it.

You will need three breakers: One on the positive lead from your panels. One on the positive wire from your charger controller to your battery. And one between the positive terminal of the battery and all the rest of your DC powered stuff. That's as much detail as I can (or will) get into in a written post. I'm a former electronics technician and I still just relied on Northern Arizona Wind and Sun to tell me what size breakers I needed. I'm too lazy to do the math. What size you need depends entirely on your exact setup. Don't let anyone just throw numbers at you without them knowing the gauge or length of your wires, or the amount of current flowing through each part of your system.

Right now, the only person I would trust to do those calculations for you is JiminDenver. But he does this for a living, so it really wouldn't be considerate to ask him to do those calculations for free.

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[LoveCareThinkDo]

Oh yeah, if you have a decent MPPT charger controller, IT is supposed to, you know, control the charging of the battery and prevent damage. Contact the manufacturer of both the controller and the battery and ask them what settings to use for your battery.

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[poot_traveller]

[quote pid='465316' dateline='1567675124']
I don't know anything about electricity except I know it can kill.

I'm not sure what you mean by saying you rely on the wind and sun to give you the size of the breakers you need (I didn't even know what a breaker is until I googled it), but I assume you purchased a bunch of breakers and did trial & error. 

Ill set up my solar system first and put the breakers on last and see which ones work the best.  Thanks
[/quote]

EDIT: @LoveCareThinkDo - This site is a bit buggy and I'm not able to quote your post but obviously I'm replying to you.

 

[poot_traveller]

Oh yeah, if you have a decent MPPT charger controller, IT is supposed to, you know, control the charging of the battery and prevent damage. Contact the manufacturer of both the controller and the battery and ask them what settings to use for your battery.

Sent from my SM-T510 using Tapatalk

Yeah I know it's suppose to do that but I don't trust a controller alone to do that.  Same reason you have breakers on your system, a controller by it's self can't be trusted.

 

[AuricTech]

Northern Arizona Wind and Sun is a store. There's a link to their online forum in my .sig file.

As for circuit breakers/fuses, you size them to protect your wiring. To help figure out what size wiring to use, my .sig file also includes a link to an online Voltage drop calculator.

Hope that helps!

 

[poot_traveller]

Oh, what a odd name for a store.

Anyway, I think you have to already know the wire size for that calculator, as it's a calculator for voltage drop.

 

[highdesertranger]

to your original question put a breaker on the solar feed and flip it off when you are not around for days. Lithium doesn't need to be charged everyday like lead/acid does.

as for breakers, DC breakers are usually one way breakers. meaning they only work in one direction. so putting one on your solar feed is fine but putting one on your battery isn't because the electricity is flowing one way when charging and the other way when discharging. use a fuse.

also use quality components. marine stuff is top of the line, car audio stuff is usually the bottom of the line.

highdesertranger

 

[regis101]

What brand MPPT ?

 

[tx2sturgis]

If you bought a good brand name MPPT controller it should be very reliable and will not try to overcharge your lithium battery. Also, the BMS in the battery should protect from over and under charge, and extreme temps. All of those components are made to operate un-attended. This assumes they are good quality and were installed correctly. A shoddy installation and/or super cheap no-name components might not be the best idea in your situation.

 

[poot_traveller]

to your original question put a breaker on the solar feed and flip it off when you are not around for days.  Lithium doesn't need to be charged everyday like lead/acid does.

as for breakers,  DC breakers are usually one way breakers.  meaning they only work in one direction.  so putting one on your solar feed is fine but putting one on your battery isn't because the electricity is flowing one way when charging and the other way when discharging.  use a fuse.

also use quality components.  marine stuff is top of the line,  car audio stuff is usually the bottom of the line.

highdesertranger

OK thanks, I'll look into getting a DC circuit breaker for the panel to controller wiring.

 

[poot_traveller]

What brand MPPT ?

Fazcorp MPPT Solar Charge Controller 30A 12/24V MC-Series

https://fazcorp.co.nz/products/mppt-solar-charge-controller-30a-1224v-ml2430-1

 

[poot_traveller]

If you bought a good brand name MPPT controller it should be very reliable and will not try to overcharge your lithium battery. Also, the BMS in the battery should protect from over and under charge, and extreme temps. All of those components are made to operate un-attended. This assumes they are good quality and were installed correctly. A shoddy installation and/or super cheap no-name components might not be the best idea in your situation.

I don't know what would be considered a good brand, but I have a fazcorp controller; https://fazcorp.co.nz/products/mppt-solar-charge-controller-30a-1224v-ml2430-1

 

[poot_traveller]

Could I use fuses instead of circuit breakers? The reason is because installing fuses seems the easier option.

I'll just need to grab three fuses, whack em on, and I'm done. Beats trying to find what size/type/etc circuit breaker I should use.

 

[highdesertranger]

yes fuses are fine. highdesertranger

 

[highdesertranger]

I know I said fuses are fine. I should have added checked the specs for the fuse and the voltage of what you want to fuse. I had to use a breaker on my solar feed because of the high DC voltage. fuses aren't rated for that high DC voltage. most DC components top out at 48 volts. highdesertranger

 

[poot_traveller]

OK this sounds good, thanks. 

Installing a solar system is getting less harder. Before it looked overwhelmingly hard.

 

[wayne49]

"wind & sun" is not an odd name for a purveyor of off grid energy generation solutions.

 

[poot_traveller]

"wind & sun" is not an odd name for a purveyor of off grid energy generation solutions.

The way he worded his sentence, combined with the oddly named store got me confused.

"Northern Arizona Wind & Sun" is an odd name for a store imo.

 

[CityWoman]

"Northern Arizona Wind & Sun" is an odd name for a store imo.

I'm not familiar with the store but, going by its name, I'd say they sell products and/or services related to harnessing the wind and sun for energy. Seems like an apt name to me.