What to use massive solar surplus on? - Page 1
Forum section: electronics / beginners

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: February 28, 2025, 10:51:14 am
content: Ironically I bought a 3rd, 100w panel for my van with the idea it would take me through the winter period.This turned out to be next to totally useless since I had next to 0 solar (average 0.01 kwh per day) through those dark months.I instead bought a dc-dc charger which allowed me to break my dependence on solar.This month now though the solar has suddenly jumped back to life in a big way.I am at close to full charge of my modest 105ah lifepo4 battery most days and we aren't even into spring proper yet, let alone summer.I only use about 240wh per day and so have a huge surplus.I have very modest electrical needs though and have not thought of what else I would really want to 'burn off' all this surplus solar.I only have a dc system so could get a small ac inverter and I am sure could drain it in no time with induction cooking/power tools.AC I am quite scared of thoough due to increased risk/care required and since there is no pressing need for it I am not really that interested in adding it to the system.Not sure what else this surplus energy could be useful for since I have my basics needs like, lighting, cooking, heating, laptop, small devices taken care of?

author: BeBuLamar
author_rank: Super Contributor
timestamp: February 28, 2025, 11:34:16 am
content: Reading several of your posts I am wondering if you live off grid that is you have no electricity from the ultiliies? You have to rely on solar and your van for electricity?

author: tunk
author_rank: Super Contributor
timestamp: February 28, 2025, 11:40:07 am
content: A 12V kettle?For your tea and hot water for washing your dishes?

author: BadeBhaiya
author_rank: Regular Contributor
timestamp: February 28, 2025, 11:42:43 am
content: Put a bucket of water under your desk and keep it at a comfy temperature all day long to soak your feet in.That's what I do to use up the excess solar power. Much better than letting it flow out and having the electricity company pay me a pittance per kWhQuote from: BeBuLamar on February 28, 2025, 11:34:16 amI too would like to know. 240Whr/day is extremely low.

author: thephil
author_rank: Regular Contributor
timestamp: February 28, 2025, 11:47:35 am
content: Use electrolysis to make Oxyhydrogen. You can later explode your RV with it.

author: Haenk
author_rank: Super Contributor
timestamp: February 28, 2025, 04:52:26 pm
content: Any solution anyone (or you) comes up with - is pointless, as the value of the excess power is next to zero. If you don't drain your main battery by normal use, another battery would have been my idea to use the power and make your power supply safe for maybe a couple of no-sun days. Still, that battery costs likely more money than a large 400W solar panel.

author: Bud
author_rank: Super Contributor
timestamp: February 28, 2025, 05:17:32 pm
content: Hate to say the obvious, but - crypto currency mining.

author: themadhippy
author_rank: Super Contributor
timestamp: February 28, 2025, 05:56:26 pm
content: led grow lamp for growing tomatoes in the van

author: Xena E
author_rank: Frequent Contributor
timestamp: February 28, 2025, 06:30:45 pm
content: Quote from: themadhippy on February 28, 2025, 05:56:26 pmTomatoes 🤨 ?

author: tooki
author_rank: Super Contributor
timestamp: February 28, 2025, 06:53:51 pm
content: Quote from: themadhippy on February 28, 2025, 05:56:26 pmWould it not be more efficient to just put a sunroof in the van? No conversion losses.

author: nali
author_rank: Frequent Contributor
timestamp: February 28, 2025, 06:59:02 pm
content: A ventilation fan to stop the van overheating on those hot sunny days.

author: Brumby
author_rank: Unknown
timestamp: March 01, 2025, 01:47:30 am
content: Lease the sides of your van for live advertising and run the displays from the excess power.Oh, wait .... "off grid" has the implication you won't be in many 'high traffic" areas...Scratch the advertising.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: March 01, 2025, 08:32:41 am
content: Quote from: BeBuLamar on February 28, 2025, 11:34:16 amQuote from: BadeBhaiya on February 28, 2025, 11:42:43 amThat is correct.Well I don't use much, what can I say?I listed what I use. Just a few 12v appliances. The diesel heater/cooker and laptop probably use the most.Quote from: themadhippy on February 28, 2025, 05:56:26 pmI had considered hydroponics actually but they are most useful through the winter months when there is least solar anyway aren't they? In summer I could just grow using the good old fashioned sun.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: March 01, 2025, 08:33:59 am
content: Quote from: Bud on February 28, 2025, 05:17:32 pmI think it is dead now for small timers isn't it? Has been since like 2011 or whatever when the 'ant-miners' and such came in.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: March 03, 2025, 09:41:57 am
content: Quote from: Haenk on February 28, 2025, 04:52:26 pmWhat do you mean the value of the excess is next to 0? Might not be much for people running power hungry AC stuff but that is a lot of excess power in my DC only world.As I only use about 20ah per day that is 80ah surplus and more since it is keeping it charged to almost full. Probably would go above if I were drawing more as the PV just trickles and turns off a lot of the time currently due to full charge of the battery.

author: Psi
author_rank: Super Contributor
timestamp: March 03, 2025, 09:52:11 am
content: I love how growing tomatoes and crypto mining are the most sane and potentially useful suggestions so far.

author: BeBuLamar
author_rank: Super Contributor
timestamp: March 03, 2025, 10:50:48 am
content: Quote from: electroniclearner820327 on March 03, 2025, 09:41:57 amIt's best to get more batteries as in the long term you really do not have a surplus.

author: Jwillis
author_rank: Super Contributor
timestamp: March 03, 2025, 05:36:39 pm
content: Don't do anything or as BeBuLamar suggests, add more batteries. Always having a surplus is better than a deficit. It also guarantees your storage is always fully charged which will extend battery life.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: June 20, 2025, 06:16:06 am
content: Quote from: BeBuLamar on March 03, 2025, 10:50:48 amCan you explain that?

author: RoGeorge
author_rank: Super Contributor
timestamp: June 21, 2025, 11:56:13 am
content: Quote from: electroniclearner820327 on February 28, 2025, 10:51:14 amCongrats for your new panels!The problem was never about how to harvest more energy. There is plenty energy around, solar or in other forms. The true problem always was about how to store the surplus, such that you can make use of it when you mostly need it.So far, the most efficient/easy energy storage is in chemical form. Breaking water as HO might be one thing, though prone to make boom, so that must be done very carefully.Or, you can use the extra electricity to drive 6h light cycles to grow chickens, and harvest their eggs.Or, maybe grow weed or vegetables indoors, with artificial lights, depending of where you live, dunno.

author: Seekonk
author_rank: Super Contributor
timestamp: June 22, 2025, 03:26:16 pm
content: Most people use hot water. I divert excess energy to do that. I have a 30 gallon tank just for laundry and do all cycles with hot water. Water stratifies easily making the top of the tank always hot. Many use less water than they think. I have a primary 2 gallon tank fed by a preheater. Even as little as 500WH of solar is enough to heat that. Nice having some hot water for hand washing and cleaning. I have taken good showers with just two gallons. Sorry, you will have to convert that to liters.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: June 22, 2025, 05:19:03 pm
content: Turns out I don't have too much surplus at all now.My last laptop was not charging and the new/old replacement I am now using takes up about 2x the power! Also got a fan cooling base which has 6x fans which will add to it.Lately I noticed that the battery would charge up to 0.7kwh of the 1.2kwh and this is in full sun days! So the current amount seems just about right with little to spare as that is not a large buffer at all and could imagine going into a shortfall quickly if there were a few cloudy days.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 24, 2025, 06:59:32 pm
content: A total of 3 100W panels does not seem much at all to live from. If I had a choice (I'm in a rental apartment, no garden and people living on top of me) then I would probably install a few kW of panels, and use the rest for water heating or cooking to reduce the other fuel costs.