Greetings all,I apologize if this subject is covered elsewhere, but I couldn't find it if it is. :)Will a 510 watt solar system, (such as Keystone), be enough for Boondocking lights, tv, fans, and coffee maker/microwave? I would not be trying to run A/C or fridge.I know atmospheric conditions and an individuals usage are all variables, but was curious given "average" conditions.Any input would be much appreciated, and it's nice to be here. :)

The solar panels are only part of the equation. You will also need a big enough battery bank and inverter to run things like a microwave and coffee maker but yes 510 watts should be enough to meet those demands. Microwave and coffee maker do consume a fair amount of amperage but only for a short period so overall impact isn't great. The other loads like fan, lights (use led) and TV don't consume a lot of power unless you are using them frequently.As you point out quality of sunlight will play an important role in battery state of charge. If you have no back up power supply such as a generator you may have to moderate the use of your electrical devices to keep the battery from being overly discharged during periods of cloudy skies.

Generally yes 500 watts will run those items fine. Go easy on the coffee/microwave for best results. I assume it will come with four batteries to drive a 2000 watt inverter.

Usually 500 solar will do it all but the proof is determined by doing an energy use servey (either actual use or desire use) which helps you determine how many battery amp hours you need. That number helps you determine the solar watts...1 amp hour to 1 solar watt is common but don't be afraid of 1 to 1 1/2. Then you can match a controler. Use BIG wire.

Thank you so much!I believe the system, (Keystone and KZ), come with 1300 watt inverters, but I was already thinking a 2000 watt would be a worthwhile upgrade.Knowing that 500 watts with moderation will work, is huge, again I thank you both! :)

Prylosis wrote:Thank you so much!I believe the system, (Keystone and KZ), come with 1300 watt inverters, but I was already thinking a 2000 watt would be a worthwhile upgrade.Knowing that 500 watts with moderation will work, is huge, again I thank you both! :)Make sure you go with a pure sine wave inverter. Appliances like microwaves can struggle with a modified sine.

Solar system | Good Sam Community

17 Replies

allen8106
Explorer
Jan 06, 2020
I run 520 watts with 240 AH of battery capacity and by morning our capacity is down to about 70%-75% running my wifes CPAP, the refrigerator on propane, charging phones and running the furnace which runs on 12 volts.

By 1:00 - 2:00 pm the batteries are back to 100% when tilted.
StirCrazy
Moderator
Jan 02, 2020
i have 480 watts of solar a 200 watt inverter and 4, 6v - 235ah batteries. with this set up I can go camping in the fall (temps getting down to about 45 at night) leave the furnace running 24/7 use the led lights, let the kids watch a movie every night, use the coffee pot in the am (kiureg) and a little more. every night the batteries will be full before bed. so if you watch it you will be fin as long as you have the batteries. I would sugest four good 6v deep cycles.

Steve
CA_Traveler
Explorer III
Jan 01, 2020
pianotuna wrote:
HandyBob is dated and highly opinionated.
Agreed but he has opinions to think about.

He was (and I assume is) spot on about the Quartzsite solar dealers. I talked to both of them and walked.
pianotuna
Nomad III
Jan 01, 2020
HandyBob is dated and highly opinionated.
CA_Traveler
Explorer III
Jan 01, 2020
BTW Given those Evergreen specs a MPPT controller with a 10% efficeincy loss will significantly out perform a PWM controller across all temperature variations. It's not the controller but the panel voltage.
CA_Traveler
Explorer III
Jan 01, 2020
Prylosis wrote:
Thank you. Yes, I've been looking into a four battery set-up, and possibly 650 watts. That would require a minimum 40 Amp MPPT controller, but would probably go with a 50 Amp.

I previously found this article which seems very informative, but a little too much for me to get my head around.
https://cuernoverdesolar.files.wordpress.com/2012/12/318sab-solar-install2.pdf
OMG!!!

I looked at the links Evergreen panel specifications (for reasons not related to this thread) and was stunned. The NOTC spec for the panel is Vmp = 15.6V. While this is the MPPT power point is suggests a rather low voltage for PWM. What is the voltage at lower levels of radiation like down to 200 Wm2?

Correct me if wrong but how is this panel ever going to charge a battery at 14.8V with the wiring loss??? Not going to happen! More like 13+.

This voltage is consistent with the STC spec of a low 17.6V.

First 12V panel I've seen with 108 cells which suggests 4x27 cells, ie 27 cells in series rather than the common 36 cell panels which tend to run 19V.

Be careful about what you read on the internet and yes I'll include my own posts.
CA_Traveler
Explorer III
Jan 01, 2020
Kits are fine but more costly normally. I choose 60 cell panels and MPPT controller which cost the same as equivalent 12V panels and PWM. MPPT performance is better and since most panels have bypass diodes the shade tolerance is also better.

Recommend you first install a battery monitor about $200 and use it to evaluate your usage not to mention it's value with solar. I used mine to evaluate every DC load. ie Turn off all charging then turn a light on/off and note the difference in battery amps, etc. Plus a decent monitor will also track your daily usage battery SOC etc.
naturist
Nomad
Jan 01, 2020
Prylosis wrote:
Thank you. Yes, I've been looking into a four battery set-up, and possibly 650 watts. That would require a minimum 40 Amp MPPT controller, but would probably go with a 50 Amp.

I previously found this article which seems very informative, but a little too much for me to get my head around.
https://cuernoverdesolar.files.wordpress.com/2012/12/318sab-solar-install2.pdf

500 watts of solar panels would probably support around 250 AH of batteries just fine. Obviously 250 AH suitability for boon docking depends on usage. Given that 80 AH is all you get on a small trailer straight from the dealer, and that carries most folks overnight, 250 AH will probably do ya.

If you had 650 watts of solar panels, a 40 amp MPPT controller would be a stretch, certainly inadequate if those panels ever reached peak output on a 12 volt system. I have a 40 amp controller, and it says 520 watts max on 12 volts, or 1040 watts on a 24 volt system.

I have found a lot of really helpful solar advice on Will Prowse's web site, at http://mobile-solarpower.com, as well as his youtube channel at https://www.youtube.com/channel/UCoj6RxIAQq8kmJme-5dnN0Q.
Prylosis
Explorer
Jan 01, 2020
Thank you. Yes, I've been looking into a four battery set-up, and possibly 650 watts. That would require a minimum 40 Amp MPPT controller, but would probably go with a 50 Amp.

I previously found this article which seems very informative, but a little too much for me to get my head around.
https://cuernoverdesolar.files.wordpress.com/2012/12/318sab-solar-install2.pdf
pianotuna
Nomad III
Jan 01, 2020
It depends on your situation. For full time 500 watts may be a little on the light side.

If you are part time--then 500 is more than adequate, assuming a large battery
bank.

I'd consider an mppt controller and do a series/parallel installation.

Do an energy audit.

This web site may help: https://freecampsites.net/adding-solar/