diy solar

diy solar

Solar on Winnie View 2014J?

srssrs

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Joined
Nov 16, 2021
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22
Hello,
A newbie to this forum but have been digesting many posts regarding RV solar installation and, of course, many of Will's YouTube videos.
I have ordered 3 - 210w. panels from HighTec solar in Indiana and will be building 2 - LifePo4 280ah batteries to be installed in place of the stock lead acid batteries. I am also considering the EpEver 20 amp 12v/24v charge controller with MT50 remote. Is this appropriate for my 630w. of panels and how should I wire the panels? I would like to have gone with 4 panels but really only have room for 3. I am considering a 3000w. pure sine wave inverter and will also add an automatic transfer switch, a smart charger for lithium, a DC-DC converter, etc. I am undecided yet on these items. I will rely primarily on solar, will occasionally use shore power and an on-board diesel generator if needed. I am interested in any and all comments and suggestions you may have regarding my planned installation.
Thank you.....Steve
 
Please post a picture of the sticker on the back of the panels.
Also post a product link to the EpEver solar charge controller you are considering.
When you say dc-dc converter I suspect you want to run a 24 volt system, confirm?
 
2x 12volt 280ah batteries = 7168 watt hours
2x 24volt 280ah batteries = 14336 watt hours

630 watts of panel at 100% efficiency will take over 11 hours to charge your 12 volt setup and over 22 hours to charge your 24 volt setup.
100% efficiency is not going to happen.
The panels will be flat and since you have 3 you will either have to run them in parallel or 3 in series(if the charge controller will allow it).
I'm going to make a very rough guess of 50% efficiency.
That means the charge times double.

Now for the load side.
3000 ac watts / .85 conversion factor / 24 volts low cutoff = 147.058823529 service amps
147.058823529 service amps / .8 fuse headroom = 183.823529412 fault amps

3000 ac watts / .85 conversion factor / 12 volts low cutoff = 294.117647059 service amps
294.117647059 service amps / .8 fuse headroom = 367.647058824 fault amps

That means at 12 volts each battery+bms must be able to handle 147.058823529 amps continuous
That means at 24 volts each battery+bms must be able to handle 73.529411765 amps continuous

Both voltage options are achievable.

Hope this helps you with the scale and proportion of things.
 
Last edited:
Below are the specs of the panel. I will be running a 12v. system. 2- Lifepo4 280ah. x 12v. batteries in parallel? Here is a link on the charge controller: https://www.amazon.com/dp/B081JWQLS...olid=2NNU9WEMF64I6&psc=1&ref_=gv_ov_lig_pi_dp
Thinking it may not be adequate as it is only 20 amps. The DC-DC converter would be to protect my alternator. Perhaps I am not correct on this?


Temperature coefficient of Voc: -0.33% °C
Temperature coefficient of power: -0.23% °C
Temperature coefficient of Isc current: ±0.05% °C
NOCT (nominal operating cell temperature): 45 ° C (± ° C)
Maximum Power Output:
215 Watts
Max Operating Voltage (Vmpp):
20.03Volts
Max Operating Current (Imp):
10.76Amps
Open Circuit Voltage (Voc):
23.72Volts
Short Circuit Current (Isc):
11.44 Amps
Module Efficiency:
>18.7%
 
Below are the specs of the panel. I will be running a 12v. system. 2- Lifepo4 280ah. x 12v. batteries in parallel? Here is a link on the charge controller: https://www.amazon.com/dp/B081JWQLS...olid=2NNU9WEMF64I6&psc=1&ref_=gv_ov_lig_pi_dp
Thinking it may not be adequate as it is only 20 amps. The DC-DC converter would be to protect my alternator. Perhaps I am not correct on this?


Temperature coefficient of Voc: -0.33% °C
Temperature coefficient of power: -0.23% °C
Temperature coefficient of Isc current: ±0.05% °C
NOCT (nominal operating cell temperature): 45 ° C (± ° C)
Maximum Power Output:
215 Watts
Max Operating Voltage (Vmpp):
20.03Volts
Max Operating Current (Imp):
10.76Amps
Open Circuit Voltage (Voc):
23.72Volts
Short Circuit Current (Isc):
11.44 Amps
Module Efficiency:
>18.7%
Ok assuming your solar charge controller is "tracer 2215BN".
That SCC only supports max pv input power of 260 watts.
An important detail that I can't find in the product description is what the max pv voltage the solar charge controller can manage.
Since its limited to 260 watts it will take over 27 hours at 100% efficiency to charge your batteries.
 
Also I can't find the tracer 2215BN on EpEver's website.
 
Since you are running a 12 volt system you don't need a dc2dc converter.
Did you mean dc2dc charger perhaps?
 
Are your panels going to be mounted flat and how bad is the shading in your destinations? That would help deciding on using a parallel or series arrangement and also help size the controller. I would suspect a 40 amp controller may be sufficient.
 
Thank you for the replies SmooJo and Whinny. All that is helpful. My panels will be mounted flat but am considering using tilt mounts. The AC unit on top could shade slightly but that is why I am considering being able to tilt slightly.

I am not locked into that charge controller so if there is another that you might like for various reasons, I would consider it.

Is wiring all 3 in series advisable? Will I be able to find a fuse to handle that OK?
Is that the most efficient way to charge my batteries? I was thinking if I had 2 - 280ah Lifepos in parallel, that would equal 560 ah. Is this correct? I am trying to fit the new batteries in a limited space under the step well where there were 2 - group 24 lead acid batteries.
 
Is wiring all 3 in series advisable?
If shading is going to be an issue probably should do 3 in parallel.
Will I be able to find a fuse to handle that OK?
No fuse is required for 3 in series.
You should have a means of disconnect though.
Is that the most efficient way to charge my batteries?
What way are you referring to?
I was thinking if I had 2 - 280ah Lifepos in parallel, that would equal 560 ah. Is this correct?
That is correct.
 
Thank you. I was also thinking the 3 should be in parallel. That way if one was shaded, it would not affect the other two, and therefore it would be more efficient than having the 3 in series. What would be your choice for the charge controller?
 
Thank you. I was also thinking the 3 should be in parallel. That way if one was shaded, it would not affect the other two, and therefore it would be more efficient than having the 3 in series. What would be your choice for the charge controller?
I will let someone more knowledgeable suggest an scc for you.
 
If I wire these panels in parallel, can someone suggest a solar charge controller you might consider and what type of wiring connectors would I purchase to connect all three? Thank you.....Steve
 
If I wire these panels in parallel, can someone suggest a solar charge controller you might consider and what type of wiring connectors would I purchase to connect all three? Thank you.....Steve
@srssrs did you start your plan with an energy audit?
How did you determine...
That you prefer a system voltage of 12 volts?
That you require a 3000 watt inverter?
That you require that you need 14336 watt hours of battery capacity?
 
I did a 180 AH LiFePO4 conversion on my '07 Navion. Our chassis should be similar. Are you sure 2 x 280 AH batteries will fit under the steps? Originally I wanted to get 8 180AH cells under the steps. That wouldn't fit without major metal re-working. I get along fine with 180AH, 12V. I have a 2500 W inverter to (only) operate the microwave. It takes about 160 - 150A. Otherwise all electronics operate off of 12V. I haven't used my generator since going with LiFePO4.

I recommend using series solar panels. When installing panel bypass diodes, series is more efficient in shady conditions. No fuse is needed between panels and charge controller, just a disconnect switch. A dc/dc (alternator) charger is good. Probably don't need more than 30A.
 
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