I have fried 2 charge controllers! Please help!!

[sunshine_eggo]

Okay, array checked. 10X 200W panels? 2S5P array.

A 40 (2S3P) and a 30 (2S2P) would be fine

60A would cut it the majority of the time.

STC ratings are for when the CELLS = 25°C. This is rarely the case unless it's cold outside. When it's 25°C outside, cells are typically 40-50°C. This notably reduces their output.

Panels typically only produce ~80% of STC rated power. Check the panel's NMOT or NOCT rating - that's a much more realistic performance number.

My array in AZ at 6500' elevation at an optimized fixed year round tilt rarely produces rated power, and I'm probably getting about 10% more sun than sea level because of less atmosphere.

 

[RVLiFe]

My vote is for two separate 40A or 60A controllers. Or if you can live with the inefficiency of only being able to ever get a max of 60A then go with one unit and wire it like you have above. If it works 90% of the time under 60 amps then why pay good money for a little extra output? You can always buy another one down the road i suppose. I’ve yet to see 200 watt output from those panels but I did come close when in Florida once.

EDIT: I like @sunshine_eggo recomendation a lot! I whole heartedly agree with his assessment. You will get all the power you need from that configuration.

 

[MushroomMan67]

My vote is for two separate 40A or 60A controllers. Or if you can live with the inefficiency of only being able to ever get a max of 60A then go with one unit and wire it like you have above. If it works 90% of the time under 60 amps then why pay good money for a little extra output? You can always buy another one down the road i suppose. I’ve yet to see 200 watt output from those panels but I did come close when in Florida once.

That is what I'm going to do RVLiFe. FINAL ANSWER!
I will be purchasing ONE of these and when $ allows will purchase a 2nd for better efficiency.

 

[MushroomMan67]

That's funny. That is the one I fried.

EPEVER has some 80A models. You could also buy 2X 40A.

I'm going with a single unit of this model at 60A. Then will move it up to a 2nd unit when $ allows.
You opened my eyes to a much better model (4-stage).

 

[sunshine_eggo]

That is what I'm going to do RVLiFe. FINAL ANSWER!
I will be purchasing ONE of these and when $ allows will purchase a 2nd for better efficiency. when I want to add more panels.

Revised.

I'm going with a single unit of this model at 60A. Then will move it up to a 2nd unit when $ allows.
You opened my eyes to a much better model (4-stage).

4 isn't necessarily better than 3. The fourth is "equalization," and that only applies to flooded lead acid (FLA) batteries. Most charge controllers offer this without calling it a 4th stage.

 

[MushroomMan67]

Revised.



4 isn't necessarily better than 3. The fourth is "equalization," and that only applies to flooded lead acid (FLA) batteries. Most charge controllers offer this without calling it a 4th stage.

I'll take it!
Now I have to better understand fuses for the solar. Will I need fuses if I'm connecting 5 panels in parallel to the single CC?

 

[sunshine_eggo]

I'll take it!
Now I have to better understand fuses for the solar. Will I need fuses if I'm connecting 5 panels in parallel to the single CC?

Yes. for 3 or more panels in parallel, over-current protection must be provided on each string.

A single MC4 fuse rated per the panel label per string (5) would suffice.

Alternatively, you could use a combiner box.

 

[MushroomMan67]

Yes. for 3 or more panels in parallel, over-current protection must be provided on each string.

A single MC4 fuse rated per the panel label per string (5) would suffice.

Alternatively, you could use a combiner box.

15 or 30 Amp each?

 

[MushroomMan67]

Yes. for 3 or more panels in parallel, over-current protection must be provided on each string.

A single MC4 fuse rated per the panel label per string (5) would suffice.

Alternatively, you could use a combiner box.

I am a little confused on one size of fuse.

 

[BradCagle]

They're calling "absorption" "float".

Again, I have this charger. My manual looks exactly like that.

It will charge to the float voltage and simply hold it there. I watched it do this to my AGM batteries every time I used it. They would never get fully charged.

It'll fully charge lifepo4, I have the ampinv 40a version of this. He can set the float to 3.45v per cell (27.6 i think he has 24v system right?), and it'll fully charge just fine.

I dont know the longevity of it, but it's pretty good

 

[MushroomMan67]

It'll fully charge lifepo4, I have the ampinv 40a version of this. He can set the float to 3.45v per cell (27.6 i think he has 24v system right?), and it'll fully charge just fine.

I dont know the longevity of it, but it's pretty good

That's what I thought. If I set it to the correct v all should be good.
However...I decided on this model. It's 4-stage so....all is good. Know I don't have to worry about it and I upped to a 60a so I can use 5 panels in parallel.

Nice video!
THANK YOU BRAD!!!

 

[Bud Martin]

It'll fully charge lifepo4, I have the ampinv 40a version of this. He can set the float to 3.45v per cell (27.6 i think he has 24v system right?), and it'll fully charge just fine.

I dont know the longevity of it, but it's pretty good

Thanks for the video.
BTW, do you have video on your ground mounted @5:05? Thanks!
BTW, I see your video about setting the system Voltage, but how do you set it the first time out off the box, I.E. if you have 24V batteries, will know to set itself to 24V instead of 12V so it will not blow up if the default is 12V, thanks!
Sorry, I know it is off topic.

 

[BradCagle]

Thanks for the video.
BTW, do you have video on your ground mounted @5:05? Thanks!

Yes

and

BTW, I see your video about setting the system Voltage, but how do you set it the first time out off the box, I.E. if you have 24V batteries, will know to set itself to 24V instead of 12V so it will not blow up if the default is 12V, thanks!
Sorry, I know it is off topic.

It'll give warning about battery high or low, just go into the settings and change the system voltage. I have a short video on it:

 

[Bud Martin]

Yes

and

It'll give warning about battery high or low, just go into the settings and change the system voltage. I have a short video on it:

Thanks!

 

[sunshine_eggo]

I am a little confused on one size of fuse.

It's not specified, so I'd go with 10A - well above the 5.XA short circuit current.

It'll fully charge lifepo4, I have the ampinv 40a version of this. He can set the float to 3.45v per cell (27.6 i think he has 24v system right?), and it'll fully charge just fine.

I dont know the longevity of it, but it's pretty good

The only downside to this is you need a 5+ hour absorption period at 3.45V/cell.

 

[hankcurt]

It's not specified, so I'd go with 10A - well above the 5.XA short circuit current.

I agree with sunshine_eggo that 10A fusing would be sufficient with a 5.83A short circuit current.

Per the manual, you are allowed to use no higher than a 15A fuse.

 

[BradCagle]

The only downside to this is you need a 5+ hour absorption period at 3.45V/cell.

While I've seen the videos about taking longer to charge. I do not see that in practice, maybe ever so slightly. But nothing like having to absorb for 5+ hours. LiFePO4 doesn't actually have an absorb, once it hits a set voltage that's pretty much it.

 

[Ampster]

LiFePO4 doesn't actually have an absorb, once it hits a set voltage that's pretty much it.

It most definitely has a Constant Voltage stage in which the voltage stays the same and current tapers. That is unless your charging source turns off when the set voltage is reached.

 

[MushroomMan67]

That's what I thought. If I set it to the correct v all should be good.
However...I decided on this model. It's 4-stage so....all is good. Know I don't have to worry about it and I upped to a 60a so I can use 5 panels in parallel.
THANK YOU BRAD!!!

I agree with sunshine_eggo that 10A fusing would be sufficient with a 5.83A short circuit current.

Per the manual, you are allowed to use no higher than a 15A fuse.

View attachment 109340

That's great! I can only find 15 and 30 amp. However, I'm sure 10A is out there.
Am I to assume they go between EACH panel?

 

[sunshine_eggo]

While I've seen the videos about taking longer to charge. I do not see that in practice, maybe ever so slightly. But nothing like having to absorb for 5+ hours. LiFePO4 doesn't actually have an absorb, once it hits a set voltage that's pretty much it.

Cell datasheets differ as do my own logged testing. LFP cells typically state full charge at 3.65V @ 0.05C tail current. At lower voltages, it's lower tail currents. There is always a at least a short absorption period to enable the current to fall from the initial to the tail.

Most of my testing was done with 0.4-0.5C charging. If you're only starting at a 0.1-0.2C charge, it doesn't take long to get to .05C or lower at absorption. I should probably qualify that 5+ hour absorption time as a combined bulk+absorption with a DoD criteria. Best is a tail current criteria.