Would solar be effective in the midwest?
Would a 200 watt solar panel keep a single 100ah lifepo4 charged during a midwest Iowa winter/December ? I use about 50 ah per day , I found a online calculator that said 50ah is about .65kwh I be...
Forum Discussion
50 amp-hr at 12v is 600w-hr (actual voltage may modify the results a bit but not enough to drastically change the answer).
General assumption is you get 4-5 times the rated wattage in watt-hours...ie: 200w panel will get you 800-1000w-hr in a day.
On the surface sounds great. Problem is there are several mitigating factors.
- Winter in the north, the angle of the sun and shorter days will reduce panel output.
- Cloudy days (more common in winter) will reduce panel output.
- Snow on the panels will kill most of the output.
- Charging systems are not 100% efficient, so even in ideal conditions, expect to lose some.
Unlike Lead-Acid batteries which are typically kept above 50% discharge to avoid damage, Lithium can run down to around 20% with little risk, so 100amp-hr translates to around 960w-hr of usable power if you start fully charged. Depending on age and abuse, you may no longer have 100amp-hr batteries.
For your usage, I would want at least 50% more solar to make up for the losses from the theoretical output (maybe 100% more...300-400w of panels). Then I would want to double the battery bank as you will get multiple cloudy days from time to time. 1920w-hr will give you 3 days in a row of cloud cover before you run out.
Alternatively, you can keep a small generator and an eye on the charge state. If the bank gets too low, crank up the generator for an hour or two and give them a boost (preferable to go thru the onboard AC to DC charger as most generator 12v outlets don't put out a lot of amps).
PS: Be careful reading the replies as many people are mixing up units.
General assumption is you get 4-5 times the rated wattage in watt-hours...ie: 200w panel will get you 800-1000w-hr in a day.
On the surface sounds great. Problem is there are several mitigating factors.
- Winter in the north, the angle of the sun and shorter days will reduce panel output.
- Cloudy days (more common in winter) will reduce panel output.
- Snow on the panels will kill most of the output.
- Charging systems are not 100% efficient, so even in ideal conditions, expect to lose some.
Unlike Lead-Acid batteries which are typically kept above 50% discharge to avoid damage, Lithium can run down to around 20% with little risk, so 100amp-hr translates to around 960w-hr of usable power if you start fully charged. Depending on age and abuse, you may no longer have 100amp-hr batteries.
For your usage, I would want at least 50% more solar to make up for the losses from the theoretical output (maybe 100% more...300-400w of panels). Then I would want to double the battery bank as you will get multiple cloudy days from time to time. 1920w-hr will give you 3 days in a row of cloud cover before you run out.
Alternatively, you can keep a small generator and an eye on the charge state. If the bank gets too low, crank up the generator for an hour or two and give them a boost (preferable to go thru the onboard AC to DC charger as most generator 12v outlets don't put out a lot of amps).
PS: Be careful reading the replies as many people are mixing up units.
