diy solar

diy solar

I have fried 2 charge controllers! Please help!!

sunshine_eggo said:
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.
Click to expand...
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?
 
MushroomMan67 said:
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?
Click to expand...

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.
 
sunshine_eggo said:
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.
Click to expand...
I am a little confused on one size of fuse.
 

Attachments

  • IMG_1428.jpeg
    IMG_1428.jpeg
    305.4 KB · Views: 2
sunshine_eggo said:
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.
Click to expand...

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
 
BradCagle said:
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
Click to expand...
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!!!
 

Attachments

  • Renogy 60A.png
    Renogy 60A.png
    345.1 KB · Views: 2
Last edited:
BradCagle said:
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
Click to expand...
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.
 
Last edited:
Bud Martin said:
Thanks for the video.
BTW, do you have video on your ground mounted @5:05? Thanks!
Click to expand...
Yes
and

Bud Martin said:
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.
Click to expand...
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:
 
MushroomMan67 said:
I am a little confused on one size of fuse.
Click to expand...

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

BradCagle said:
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
Click to expand...

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

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.
 
BradCagle said:
LiFePO4 doesn't actually have an absorb, once it hits a set voltage that's pretty much it.
Click to expand...
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 said:
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!!!
Click to expand...

hankcurt said:
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
Click to expand...
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?
 
BradCagle said:
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.
Click to expand...

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.
 
MushroomMan67 said:
Am I to assume they go between EACH panel?
Click to expand...
You only need to fuse the wires coming from each string of panels in series. So if you have a string of two panels connected in series, the positive wire from one panel and the negative wire from the other panel will be fused before they are joined with the wires from the other strings of two panels.

That is why people often use a combiner box where they bring the wires from each string of panels in to fuses and then combine them on one set of wires going to the charge controller.

However, you should fuse both the positive and negative wire coming from each string of panels.
 
hankcurt said:
You only need to fuse the wires coming from each string of panels in series. So if you have a string of two panels connected in series, the positive wire from one panel and the negative wire from the other panel will be fused before they are joined with the wires from the other strings of two panels.

That is why people often use a combiner box where they bring the wires from each string of panels in to fuses and then combine them on one set of wires going to the charge controller.

However, you should fuse both the positive and negative wire coming from each string of panels.
Click to expand...
I am going to draw up a diagram for 5 panel / parallel with fuses and get it over to you in the next 24 hours.
However, understanding that I will be doing 5 panel / parallel to my CC. How many fuses will I need and what amp? I am thinking 4 fuses at 10 amp?

I ask because I need to by them today in order to have them for the weekend when I go to the house.

I'm not ready to deal with a combiner box.
 
Ampster said:
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.
Click to expand...
Yeah, but it's not 5+ hours long. I charge my main 8kw battery bank to 3.43 per cell, and after it hits that voltage, the current tapers off over 30-60m

And even at 3.43v per cell my batteries fully charge. They 100% cycle every day, and run my crypto miners.
 
MushroomMan67 said:
I am going to draw up a diagram for 5 panel / parallel with fuses and get it over to you in the next 24 hours.
Click to expand...

MushroomMan67 said:
I am going to draw up a diagram for 5 panel / parallel with fuses and get it over to you in the next 24 hours.
However, understanding that I will be doing 5 panel / parallel to my CC. How many fuses will I need and what amp? I am thinking 4 fuses at 10 amp?

I ask because I need to by them today in order to have them for the weekend when I go to the house.

I'm not ready to deal with a combiner box.
Click to expand...
The 'String' is why I am getting confused. I am talking strictly parallel...no 'string' correct?
 
You must log in or register to reply here.

Similar threads

D
Mixing MPPT & PWM charge controllers 2 batteries
Replies
17
Views
317
DC_Ripple
D
S
My first system.
Replies
21
Views
661
spicoli
S
WorldwideDave
Dc breakers and inline MC4 fuse
Replies
6
Views
247
WorldwideDave
WorldwideDave
G
Very little PV input amperage ??
Replies
8
Views
192
garyr
G
G
First RV setup, 3x100w flexible Newpowa panels, Victron 100/30, Giandell 1500w inverter, 2x100ah AGM 12v batteries. Fuse / breaker / cutoff questions
Replies
3
Views
177
mikefitz
mikefitz

diy solar

diy solar
Back
Top