Connecting 2 x 12v batteries, charge controller invertor and solar panel

[lellylel]

Hi everyone
Your help I desperately needed.
I currently have
2 x 12v 100ah batteries (which I will connect to together in series)
1 x 24v 3000w max output invertor
1 x 12/24v MPPT charge controller
1 x 240w solar panel
My question is does anyone have a drawing or diagram on how to connect everything together.
I have looked online but totally confused.

 

[sunshine_eggo]

That is not a MPPT controller. It is a known fake. It is a PWM controller. You never see USB plugs for charging on a MPPT.

With that controller, you MUST use 24V panels that typically have 72 cells with a Vmp around 36V. Your panel is a 60 cell panel. In moderate to warm conditions, that panel won't be able to reliably charge your battery. As heat increases, Vmp decreases. Vmp must be at least a little above voltage.

Will has several diagrams on his site.

 

[Mattb4]

There are plenty of simple PV setup charts on the 'net so giving you another is unlikely to solve your confusion. So let's go through the steps. From the PV panel there should be 2 wires with MC4 connectors. One is positive (+)and the other is negative (-). If there is no indication at the panel you will need to use a DMM (digital multi meter) to check for polarity. You will want to have at least a basic DMM in your tool box.

Typically solar (PV) wires to your SCC (Solar Charge controller) are color coded Red for positive and Black for negative. It is vitally important that you do not hook things up with the wrong polarity! Wires must be sized for the amperage and length of run. You will note on your panel a label giving it's specs for Voltages and Amperages. For working limit look a the Imp (7.95a). With this being pretty low you can easily get by with 12 AWG or 4mm PV wire.

Your SCC is a real low end PWM (the MPPT on it is a marketing lie as well as the 100a battery charge rating). It may work for awhile if this setup is intended as a learning experience. It requires you to hook up the battery to it first before hooking up the PV. This is in order for it to detect battery voltage. Your batteries need to connected in series (1pos to 2nd battery neg) and from the remaining 2 terminals to your SCC. Since teh maximum you are going to get from that one panel is the 7.95 charge to battery these wires do not need to be very large. I would insert a 15a fuse at least in one of these wires. Try to use proper battery lugs or ring terminals for hookup.

You two 100ah lead acid batteries in series makes a 24vDC 100ah battery. Typically you will not want to draw more than 1/2 of the total capacity during loading. They need heavy cable going to your 3000w inverter. Depending on the distance if it is short I would recommend at least 2 AWG . you will want a 150amp fuse between the inverter and the batteries. Once again use proper battery lugs and terminals and not teh spring clips from your images.

Hope this helps to get you going.

 

[mikefitz]

anyone have a drawing or diagram

RV Solar Power Blue Prints

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com

Ignore the two batteries on the left of the diagram. Your panel is the equivalent of the three shown.
Fuse to solar controller, 15 amps, 6mm2 cable
Fuse to inverter 150 amps, cable 25mm2
Cable joining batteries, battery positive to fuses, battery negative to inverter all at 25mm2. Controller negative cable 6mm2

Ideally use positive and negative buss bars as shown in this diagram,




Edit
As pointed out the panel has too low a voltage to work at maximum output, it will sort of work but the current will only reach the maximum in cool conditions. Advise adding a second panel in series and changing to a MPTT, Victron 100/20
Victron 100/20

 

[lellylel]

That is not a MPPT controller. It is a known fake. It is a PWM controller. You never see USB plugs for charging on a MPPT.

With that controller, you MUST use 24V panels that typically have 72 cells with a Vmp around 36V. Your panel is a 60 cell panel. In moderate to warm conditions, that panel won't be able to reliably charge your battery. As heat increases, Vmp decreases. Vmp must be at least a little above voltage.

Will has several diagrams on his site

'known fake', yes I saw a mention of that and conceded, I probably got what I paid for.
It worked when charging one 12v battery, but yes might struggle with two, even in our Spanish sun.
I will largely stick with my partners wiring for one 12v battery, done before setting off to work away
(will review diagrams on the site, thank you for those given, seen some that contradict each other, with Inverter coming from the controller).
It's just a temporary home, so been to charge phones etc... but it would be nice to run a fridge or if lucky, a freezer.
Will note to hook up the battery to it first/to detect battery voltage, once I add the second 12v battery in series with Terminal Connectors I got and a 150amp fuse, thank you.
Will consider adding a second panel in series and changing to a MPTT, Victron 100/20
Victron 100/20

Our biggest disappointment is the friend helping with supplying our little house, has twelve used Solar Batteries going wanting.
We imagined discarding our 100ah 12v for one of her lovely 1220ah ones with our current single 240w Panel. Even updating our 12v Inverter to a 24v one, on a kind neighbours advice.

Now we realise that we would need to move and use ALL twelve of the monster 2v Solar Batteries to reach 24v and cover the house with enough panels to hide it from even the Space Station.
Like Penicillin... we have given up understanding why we cannot use any of hers and just reluctantly bought a second 12v battery.

We might go 'Full Monty' if we are here longer, but right now, if feels like an enterprise that would give an 'Aspirin a Headache' Lol

 

[sunshine_eggo]

'known fake', yes I saw a mention of that and conceded, I probably got what I paid for.
It worked when charging one 12v battery, but yes might struggle with two, even in our Spanish sun.

It's not that it won't work with 24V. It's that the panel you have is bad for both 12V (Vmp too high) and 24V (Vmp too load) charging.

I will largely stick with my partners wiring for one 12v battery, done before setting off to work away

That panel with that controller on a 12V battery will never output more than battery voltage * Vmp or 14.4V * 7.95A = 115W, so you cripple the panel power by forcing it to operate at battery voltage rather than its Vmp.

Will note to hook up the battery to it first/to detect battery voltage, once I add the second 12v battery in series with Terminal Connectors I got and a 150amp fuse, thank you.

changing from 12 to 24V usually requires you completely reset and/or reprogram the controller.

Will consider adding a second panel in series and changing to a MPTT, Victron 100/20
Victron 100/20

That would be very effective

The 100 is 100V max (must include room for voltage increase due to cold weather and the 20 is 20A max OUTPUT, thus it will output:

20A * 14.5V = 290W on a 12V
20A * 29V = 580W on a 24V

Our biggest disappointment is the friend helping with supplying our little house, has twelve used Solar Batteries going wanting.
We imagined discarding our 100ah 12v for one of her lovely 1220ah ones with our current single 240w Panel. Even updating our 12v Inverter to a 24v one, on a kind neighbours advice.

You would need a very large amount of solar to properly charge the battery. Trying to charge 1220Ah with 240W guarantees the battery will degrade. You need to charge it with 61 to 122A (5-10% of the capacity). That would be a lot of solar.

Important to remember:

1) your solar power and sun determine how much energy you can use in a day.
2) your battery determines how long you can go between charges, and lead-acid batteries need to be fully charged regularly

This means that it doesn't matter how big your battery is. If you use more energy than the sun and your panel can supply on a daily basis, you will eventually run out of battery.

This means that batteries going dead doesn't mean more batteries are needed. It usually means more PV is needed.

Now we realise that we would need to move and use ALL twelve of the monster 2v Solar Batteries to reach 24v and cover the house with enough panels to hide it from even the Space Station.

not quite that much. You can probably get away with as little as 1500W.

 

[lellylel]

Thank you so much, for setting it all out.
Sure I will work it out.
Feel like lying down ???

 

[lellylel]

There are plenty of simple PV setup charts on the 'net so giving you another is unlikely to solve your confusion. So let's go through the steps. From the PV panel there should be 2 wires with MC4 connectors. One is positive (+)and the other is negative (-). If there is no indication at the panel you will need to use a DMM (digital multi meter) to check for polarity. You will want to have at least a basic DMM in your tool box.

Typically solar (PV) wires to your SCC (Solar Charge controller) are color coded Red for positive and Black for negative. It is vitally important that you do not hook things up with the wrong polarity! Wires must be sized for the amperage and length of run. You will note on your panel a label giving it's specs for Voltages and Amperages. For working limit look a the Imp (7.95a). With this being pretty low you can easily get by with 12 AWG or 4mm PV wire.

Your SCC is a real low end PWM (the MPPT on it is a marketing lie as well as the 100a battery charge rating). It may work for awhile if this setup is intended as a learning experience. It requires you to hook up the battery to it first before hooking up the PV. This is in order for it to detect battery voltage. Your batteries need to connected in series (1pos to 2nd battery neg) and from the remaining 2 terminals to your SCC. Since teh maximum you are going to get from that one panel is the 7.95 charge to battery these wires do not need to be very large. I would insert a 15a fuse at least in one of these wires. Try to use proper battery lugs or ring terminals for hookup.

You two 100ah lead acid batteries in series makes a 24vDC 100ah battery. Typically you will not want to draw more than 1/2 of the total capacity during loading. They need heavy cable going to your 3000w inverter. Depending on the distance if it is short I would recommend at least 2 AWG . you will want a 150amp fuse between the inverter and the batteries. Once again use proper battery lugs and terminals and not teh spring clips from your images.

Hope this helps to get you going.

Thank you.
My inverter came with its own cables.
My old inverter was a 1000w and I had a10amp fuse it.
Images attached.
Would I need a fuse or circuit breaker? And should pit on both the inverter and the soar panel?
I have drawn a diagram.
Any advice would be greatly appreciated

 

[Mattb4]

A 1000w inverter at 12vDC supplying it requires not only sufficient cable sizing from the battery but the fuse or breaker has to carry the amperage. 1000w/12vDC=83.33a So pretty much at least a 100w fuse if you intend to get the full power of your inverter. Do not confuse the SCC wires to/from the battery with the cable from your battery to the inverter. Those should be sized for the SCC charge amperage.

BTW. Your line diagram that includes wires from a 240vAC panel with (+) and (-) is inaccurate. AC has hot and neutral. DC has pos and neg. Never connect them together.

 

[lellylel]

A 1000w inverter at 12vDC supplying it requires not only sufficient cable sizing from the battery but the fuse or breaker has to carry the amperage. 1000w/12vDC=83.33a So pretty much at least a 100w fuse if you intend to get the full power of your inverter. Do not confuse the SCC wires to/from the battery with the cable from your battery to the inverter. Those should be sized for the SCC charge amperage.

BTW. Your line diagram that includes wires from a 240vAC panel with (+) and (-) is inaccurate. AC has hot and neutral. DC has pos and neg. Never connect them together.

My new inverter is max 3000w
I don't understand what you mean by my solar panel connection
Sorry for being dumb.

 

[lellylel]

Would this work?

 

[Mattb4]

Did not catch that you were using a 24vDC setup. The same rules applies W=VA therefor 3000w/24vDC =125a Most folks use 150a fuse and breakers.

Concerning your solar panels, they hook to your SCC (Solar Charge Controller). From your SCC it is wired to charge your batteries and should also be fused or have a breaker. Since your charge current is going to be what the SCC and panels can produce that wire and breaker are sized based on that amperage. You state you are using just 1 solar panel. At 30.2 volts it can produce 7.95a. Your batteries are going to need around 29vDC in order to be fully charged. So the maximum your SCC can feed the batteries are will just about be this amperage.

Edit: If this is just a learning setup you can just wing it without breakers and fuses so long as you understand to monitor it during operation and turn it all off when you are not around to watch it.

 

[lellylel]

Did not catch that you were using a 24vDC setup. The same rules applies W=VA therefor 3000w/24vDC =125a Most folks use 150a fuse and breakers.

Concerning your solar panels, they hook to your SCC (Solar Charge Controller). From your SCC it is wired to charge your batteries and should also be fused or have a breaker. Since your charge current is going to be what the SCC and panels can produce that wire and breaker are sized based on that amperage. You state you are using just 1 solar panel. At 30.2 volts it can produce 7.95a. Your batteries are going to need around 29vDC in order to be fully charged. So the maximum your SCC can feed the batteries are will just about be this amperage.

Edit: If this is just a learning setup you can just wing it without breakers and fuses so long as you understand to monitor it during operation and turn it all off when you are not around to watch it.

Thank you so much Mattb
So I need to have a fuse on the positive on the solar panel to the charge controller what size fuse?. Could I use the 10amp fuse I had on my old 1000w inverter (image attached) or would the fuse need to be higher?

And buy a 150amp fuse like the one I sent the image ? Will attach again to save you scrolling.

Thanks again

Did not catch that you were using a 24vDC setup. The same rules applies W=VA therefor 3000w/24vDC =125a Most folks use 150a fuse and breakers.

Concerning your solar panels, they hook to your SCC (Solar Charge Controller). From your SCC it is wired to charge your batteries and should also be fused or have a breaker. Since your charge current is going to be what the SCC and panels can produce that wire and breaker are sized based on that amperage. You state you are using just 1 solar panel. At 30.2 volts it can produce 7.95a. Your batteries are going to need around 29vDC in order to be fully charged. So the maximum your SCC can feed the batteries are will just about be this amperage.

Edit: If this is just a learning setup you can just wing it without breakers and fuses so long as you understand to monitor it during operation and turn it all off when you are not around to watch it.

 

[Mattb4]

No you do not need to fuse the wire from your solar panel. If you run more than two strings of panels in series than you would want to fuse.

 

[Mattb4]

Perhaps this guide here : https://www.renogy.com/learn-system-setup/ would help you.

 

[lellylel]

No you do not need to fuse the wire from your solar panel. If you run more than two strings of panels in series than you would want to fuse.

 

[lellylel]

Are great
So I just need to 150amp fuse for thr inverter to the 2 x 12v 100ah

 

[lellylel]

Perhaps this guide here : https://www.renogy.com/learn-system-setup/ would help you.

That's great thank you, makes it look nice and simple.
On watching the video I am guessing I should really get a 300amp fuse like the one attached
As my inverter is 3000w 24v

 

[lellylel]

That's great thank you, makes it look nice and simple.
On watching the video I am guessing I should really get a 300amp fuse like the one attached
As my inverter is 3000w 24v

Ignore that
Going for a 150amp fuse