Real life solar results

[naturist]

Just thought I’d post what I’m seeing. I have 400 watts of panels feeding 250 Ah (3000 watt-hours) AGM batteries. I ran them down fairly deeply, pulling 100 Ah of the 125 Ah feasible. Yesterday was rainy and fairly heavily overcast. So a little after noon I was getting around 25 watts from those panels. Today in bright sunshine I saw 378 watts.

I have established on several occasions that a good day will yield around 1600 watt-hours from those panels. For folks thinking about adding solar to their RV, I hope these numbers are helpful. The solar array, battery size, and intended power use must all be matched for best results. The usual battery trailer manufacturers put on units is the cheapest 80 Ah battery possible. If you find that battery adequate for your camping needs, you can probably make do with a 100-150 watt solar panel, as long as it is sunny. Rainy days, however, not so much.

I invite other folks with real life experience to share their numbers below so that we may help folks make up their own minds about what they might need.

[pianotuna]

theoldwizard1 wrote:

naturist wrote:
Just thought I’d post what I’m seeing. I have 400 watts of panels feeding 250 Ah (3000 watt-hours) AGM batteries. I ran them down fairly deeply, pulling 100 Ah of the 125 Ah feasible.

Pulling that much out of any type of lead acid battery will significantly reduce it's life.

By lithium next time.

He has 250 amp-hours--he used 100 amp-hours. That should be no problem with AGM.

Next time buy SiO2.

[naturist]

rlw999 wrote:

theoldwizard1 wrote:

Pulling that much out of any type of lead acid battery will significantly reduce it's life.

By lithium next time.

It really depends on how often he needs to deep cycle. Even at 80% DoD, he can get hundreds of cycles out of AGM's, so if he only deep discharges a few time a year, he may never see a payback on lithiums.

Pulling 100 Ah out of a 250 Ah battery is using only 40% capacity. Last time I looked, 50% is supposed to be the limit without damage. And we are talking about a true deep cycle battery, designed for solar applications, not a faux deep cycle "marine" battery.

[fj12ryder]

Thank you for the info.

[FLY_4_FUN]

400W of solar + pwm controller + cables/brackets $1000 CDN
2 x Kirkland 6v golf cart batteries $320
1800W modifies sine wave inverter powering 1/3 of the rv plugs $400

I could benefit from another pair of GC batts as I am topped off before noon and have less margin to use heavy loads. I rarely bring out our Honda 2000 unless its for microwave or other big loads. Very happy with my setup and it opens up so many off grid opportunities.

[Itinerant1]

valhalla360 wrote:
4-5 times the nominal panel rating in watts is what is normally assumed...so 1600w-h per day out of 400w of panels makes sense.

Overcast, small shadows, shorter winter days, etc...can really kill output.

This sounds pretty close. 1,280w flat mounted... late fall, winter, early spring I'll average 3.5kwh daily. Late spring, summer, early fall 3.5-7.5 kwh daily.

[Boon_Docker]

200 watts (roof mounted) of solar/MPPT controller.
Use on average 45-5O AH per day. Batteries (2-GC2) are back up to 100% by early afternoon with full sun.

[rlw999]

theoldwizard1 wrote:

Pulling that much out of any type of lead acid battery will significantly reduce it's life.

By lithium next time.

It really depends on how often he needs to deep cycle. Even at 80% DoD, he can get hundreds of cycles out of AGM's, so if he only deep discharges a few time a year, he may never see a payback on lithiums.

[theoldwizard1]

naturist wrote:
Just thought I’d post what I’m seeing. I have 400 watts of panels feeding 250 Ah (3000 watt-hours) AGM batteries. I ran them down fairly deeply, pulling 100 Ah of the 125 Ah feasible.

Pulling that much out of any type of lead acid battery will significantly reduce it's life.

Buy lithium next time.

[Old_Days]

We have 270 watts of solar with 2 group 27 AGM batteries, so far it has worked out really well. Just got back from a 7 day trip to the Tetons and never used the generator.

[fj12ryder]

How about some real solar total costs? I'm curious what it takes to put up that much solar. I won't do it, but am curious.

[PerryB67]

Our Escape came with a 170 watt panel on the roof and a GoPower PWM SCC. As long as we had decent sun it was fine, but shading would cause problems, plus the 170 watt is mounted on the back of the camper with about a 5 degree slope. Just don't camp with the panel facing north.

We have 260 ah's of SiO2 batteries.

We didn't want to worry about use, so I installed three 100 watt panels, and a Victron 100/30 SCC, so now have 465 watts in parallel on the roof (wired in parallel we lose 5 watts from the 170 watt panel, in series we lose 65 watts). We don't have a microwave (don't want or need one), and don't have an inverter (but want one for a toaster). We now have all the juice we need and an inverter for the toaster will be installed next!

Enjoy,

Perry

[madjack60]

I have 680watts of solar panels and 400ah of battery. Seems to serve well for my class.

[valhalla360]

4-5 times the nominal panel rating in watts is what is normally assumed...so 1600w-h per day out of 400w of panels makes sense.

Overcast, small shadows, shorter winter days, etc...can really kill output.