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Will this fry my solar charge controller?

jeffc2021

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I have 3 solar panels, each rated at 49.4 V open circuit voltage (more specs here) and a 40a MPPT SCC with a rated 150 V max input (here). However according to the specs, the MPPT is rated 138 V at standard testing conditions at 25 °C.

I want to wire all three panels in series so I can minimize the amount of wiring, fuses, and connectors I have to buy, but will this be too much voltage? I would have 3 x 49.4 V = 148.2 V going into the charge controller, which is below the 150 V rating but not 138 V rating at STC. Also, I've tested each of my solar panels to have an actual 45 V, so would this add up to 135 V and be okay?

If not, how would you arrange the panels?
 
Very good possibilty of frying your controller. With those panels, you could run them in parallel. You would somewhere in the 24 amps and 49 volts.
 
Very good possibilty of frying your controller. With those panels, you could run them in parallel. You would somewhere in the 24 amps and 49 volts.
does this mean I'll have to get fuses for each solar panel too? Since if I parallel all 3, I would have a short circuit current of 3 * 10.49 = 31.47 amps if one of the panels shorts?
 
Not for just 3 panels. Guessing that your 3 panels on a perfect day may produce less than 1000 watts? No real reason to fuse each panel.
 
Not for just 3 panels. Guessing that your 3 panels on a perfect day may produce less than 1000 watts? No real reason to fuse each panel.
Are you suggesting that I don't need to fuse at all? And why would my panels produce less than 1000 watts on a perfect day?
 
Yes, if your panels ever get colder you'll over volt your SCC and let out the magic smoke.

I'm guessing this is a 48v system? Otherwise you're going to need a lot more than 40a.

Parallel and inline fuses on each panel would do you well. You can either face them all south for ALLTHEWATTS at noin, or you can spread them SE/S/SW for some wattage all day long.
 
Yes, if your panels ever get colder you'll over volt your SCC and let out the magic smoke.

I'm guessing this is a 48v system? Otherwise you're going to need a lot more than 40a.

Parallel and inline fuses on each panel would do you well. You can either face them all south for ALLTHEWATTS at noin, or you can spread them SE/S/SW for some wattage all day long.
I'm doing a 24v system for my box van conversion. Thanks for the suggestion but they will be flat on the roof.
 
Yes, it will be over paneled and that should be fine according to the specs of the MPPT (3120W max PV array power). Can you elaborate on what the shading issues are?
 
Shading would be if there was a branch overhanging a panel or a cloud passing over a panel. If the 3 panels are in parallel and a shadow falls over 1 panel, the other 2 still work fine.

If you had the 3 panels in series and a shadow fell over a panel, the whole string gets nerfed.
 
Are you suggesting that I don't need to fuse at all? And why would my panels produce less than 1000 watts on a perfect day?
You may fuse as much as you would like. As far as fusing, i was referring to each panel not a master fuse on the circuit. You need to have one master fuse from the panels. Also, i did not see your panel specs and guessed that your panels are rated between 300 and 400 watts per panel. With shading, proper direction, proper degree slope, perfect 90 degree angle to the sun, time of day, heat vs cool temps, new vs used panels- yes it is a good possibility that you will be less than 1000 wats on the three panels that you have.
 
Your panels are rated for 400W. Three would produce around 1.2kW into the SCC. That particular model (4215BN) can only handle about 1kw input at 24V.

SCC may be able to handle 20% tolerance, but don't count on it. Bottom line, it's not in spec.

1658670074657.png
 
Your panels are rated for 400W. Three would produce around 1.2kW into the SCC. That particular model (4215BN) can only handle about 1kw input at 24V.

SCC may be able to handle 20% tolerance, but don't count on it. Bottom line, it's not in spec.

View attachment 103912
Actually, on a 4215 BN at 24 volts, you can over panel up to 3120 watts as long as you do not go over the 150 volts.
 
Your panels are rated for 400W. Three would produce around 1.2kW into the SCC. That particular model (4215BN) can only handle about 1kw input at 24V.

SCC may be able to handle 20% tolerance, but don't count on it. Bottom line, it's not in spec.
Yes agreed with GLC's comment above - it should be in spec according to the manual. I also mentioned earlier that this SCC can over panel up to 3120 watts. But it will only output a max of 1040 watts, even if the input from the PV is higher. In the user manual from the Amazon product page:

1658723632617.png
 
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PV panels do not push the power into the SCC, the SCC pulls power from panels up the maximum spec it needs to charge the battery.
I.E. your car battery has 600 cranking Amp, so when you turn on your car radio, does the battery push 600A into your car radio? No.
 
PV panels do not push the power into the SCC, the SCC pulls power from panels up the maximum spec it needs to charge the battery.
I.E. your car battery has 600 cranking Amp, so when you turn on your car radio, does the battery push 600A into your car radio? No.
Right, the SCC pulls power from the PV, and so the same amount of power is being transferred from the PV to the SCC. Which part are you responding to or what's your point?
 
I have 3 solar panels, each rated at 49.4 V open circuit voltage (more specs here) and a 40a MPPT SCC with a rated 150 V max input (here). However according to the specs, the MPPT is rated 138 V at standard testing conditions at 25 °C.

I want to wire all three panels in series so I can minimize the amount of wiring, fuses, and connectors I have to buy, but will this be too much voltage? I would have 3 x 49.4 V = 148.2 V going into the charge controller, which is below the 150 V rating but not 138 V rating at STC. Also, I've tested each of my solar panels to have an actual 45 V, so would this add up to 135 V and be okay?

If not, how would you arrange the panels?
Yes sir.. French fries
Excess voltage is a hard no. Cold weather raises voltage. Cc aren't tolerant of voltage as they are amps
 
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