[Tukemeister]

I am moving house very soon, the garage does not have electricity yet.
This will be done when the electrician does the some work for the gas combi boiler to be fitted in the garage. Which could be April / May.
Does anyone have any experience of Solar panels for Bike battery charging . If so what do I need to use or avoid.

[Bilgemaster]

I am moving house very soon, the garage does not have electricity yet.
This will be done when the electrician does the some work for the gas combi boiler to be fitted in the garage. Which could be April / May.
Does anyone have any experience of Solar panels for Bike battery charging . If so what do I need to use or avoid.

I cannot guess what they may be asking for them in Yorkshire or where they may best be found in the UK (where I seem to recall you hail from--You know, you really should  fill out your Profile's location section to make answers to such sourcing enquiries most relevant), but I have had great luck keeping my boat, RV and occasionally bike batteries tip-top with those ultra-cheapo 1.5 Watt solar panels like this one sold here in The Land of the Plastic Foon by Harbor Freight: https://www.harborfreight.com/15-watt-solar-battery-charger-62449.html currently asking just $15, though I've usually picked them up for much less on sale. There is what looks like pretty much the same model, though purporting to put out 2.5 watts (which should be fine too) on UK's eBay with free shipping for £14.99: https://www.ebay.co.uk/itm/384574517237

These smallish panels put out so little juice that one needn't run a voltage controller with them as one needs with more powerful options to keep from overcooking one's battery. At least for the lowbrow lead acid types of batteries I tend, these panels have long been an affordable "Goldilocks Solution". They also sell a little "Solar Power Connection Kit" for about $12, which might be handy for rigging a sort of extension cord into a powerless shed in order to hang the panel outside. I can confirm that both panels and cables are reasonably weatherproof.  See: https://www.harborfreight.com/solar-power-connection-cable-kit-63981.html

I've mentioned these handy solar gimcracks several times on the Forum. They may not be the best or certainly quickest solution for charging a dead battery, but they'll keep a decent one happy for years and years. Hell, I still have an old predecessor "puffy red framed" model of the breed that must be at least 15 years old that still pumps out an honest watt and a half.

[axman88]

A friend of mine got me involved in working on an off grid, standalone system in Kentucky.  He's been trying to convince me that panels can be had for 50 cents / watt, with quite substantial output.  From what I've seen, we aren't quite there yet, but close.

I think I'd spend a bit more than the little Harbor Freight panels, 1.5 watts at 24 volts is only 60 mA, and in practice, I think one would be lucky to see 2/3 of the rated output.  By my calculations, it would take a month of sunny days to bring a 12 A-hr motorcycle battery from 1/2 charge to full with one of these.

I think I'd start with something larger.  Maybe this 20watt kit:  https://www.amazon.com/Battery-Charger-Monocrystalline-Controller-Extension/dp/B091CYD2DH?th=1     Still pretty affordable at three times the price, but has 4.5 times the surface area of the little Harbor Freight gadget, and includes a controller.

What I'd really do, however, is put my money into a 10 or 12 gauge RV extension cord from my back porch.  That solution gives me lights, sound, and power tools, as well battery charging.  And this is what I did when my garage's underground power feed failed.  I would gotten away with it too, if I hadn't hung it from the clothesline to keep it from underfoot and under lawnmower.  As I found out from the document the building inspector left in my mailbox,  there are a lot more rules for "overhead power lines" than there are for extension cords.  Luckily, an easy fix, lying on the ground, and with the disconnection junction clearly visible so as to establish it's "temporary" nature, my 50 foot extension cord was entirely acceptable.

[Richard230]

I recently bought a portable folding solar panel from Amazon for around $160 on sale. It is rated at 50 watts, but the most I have been able to get out of it when placed outdoors in direct sunlight is 24 watts. Most of the time it puts out only 20 watts. But when I stick it in the sunlight that shines through my living room window I get 4 watts. 

[GlennF]

It will partly depend on your battery, lead acid batteries lose a lot of charge every month (will often be flat in 3 or 4 months) but some of the newer battery types are a lot better and need less charging when stored, however they can also need a different type of battery tender.

In terms of solar charging.

• There are quite cheap units available at auto shops specifically for trickle charging but they have minimal output and are unlikely to charge a fully depleted battery.
• the next step up, at several times the price, are the units designed for camper vans and RVs from camping shops. These often take the form of a "solar blanket" but can also be standalone panels
• then there are the things you fit to the roof and connect to a Tesla battery bank

The second sort is a good option if you are likely to go fishing and camping  a lot,  otherwise I would go for the highest rated model of the first type you get at auto shops

[Arschloch]

I recently bought a portable folding solar panel from Amazon for around $160 on sale. It is rated at 50 watts, but the most I have been able to get out of it when placed outdoors in direct sunlight is 24 watts. Most of the time it puts out only 20 watts. But when I stick it in the sunlight that shines through my living room window I get 4 watts. 

Kind of like the power delivery on the crank vs. the wheel on a motorcycle, just without a grip on the throttle.

[AzCal Retred]

@ #3: R230 - All you have to do is drive the panels up above the snow line, 16K - 19K feet and orient them at precisely 90 degrees to the sun at solar noon on a 30F ambient day...  
50% is about right in the real world, panels don't like heat & thick air too much. The good news is that there's no moving parts and service life runs 25 - 80 years. The only folks I've heard of overdriving their grid-tie inverter ratings are maybe a handful of folks "high" in the mountains of Colorado on rare clear, cold mid-summer days. For the 99% of us, a real non-issue. Here's an overview of panel types:

https://www.redarc.com.au/poly-vs-mono-vs-amorphous-know-the-difference

[Carl Fenn]

Yes l do, they keep battery charged if you buy the right one and hang it in window facing sun, you can also use charger and inverter if you have panel rigged to leisure battery and run power tools up to 500 watts.

[AzCal Retred]

My brothers ice fishing house in Wasilla, Ak. spends about 5 months parked on a back country lake with maybe 2-5 hours of near horizontal "daylight" on it's 60 watts worth of outside wall mounted amorphous silicon panels. They keep the Caterpillar battery charged up (and thus unfrozen...) between weekend visits just fine. All LED lighting, wood heat & propane camp stove take care of niceties. The panels just need to be able to supply more total watthours on average than you use from the battery. ( Gozinta > Gozouta  )

[GlennF]

Pretty much. Using a deep cycle gel battery or some such you have an ideal system for a weekender or fishing cabin.

[Richard230]

The fight between the Electric utilities and electrical unions and the solar power industry, vs. homeowners and environmentalists in California is really heating up, according to a long article in the business section of my newspaper titled "A fight over rooftop solar threatens California's goals", written by Ivan Penn and published by the New York Times. The article says that utilities don't want homeowner solar panels because "The more electricity they sell, the more money they make." The utilities are attempting to get the CA PUC to require a new monthly fee to be paid by solar homeowners of about $56 a month for the typical rooftop system.

The article says that the utility companies' proposal would increase the the electricity cost of the average solar rooftop system owner serviced by PG&E from $133 to $215 a month, according to the California Solar and Storage Association. "Many union members, an important constituency for Democrats, fear being left behind in the transition to green energy."

The solar industry argues that solar panels are no different than home insulation, installing energy-efficient appliances and other electricity-reducing improvements than installing solar panels on your home when it comes to reducing electrical demand - and the utility company's profit. 

[GlennF]

The fight between the Electric utilities and electrical unions and the solar power industry, vs. homeowners and environmentalists in California is really heating up, according to a long article in the business section of my newspaper titled "A fight over rooftop solar threatens California's goals", written by Ivan Penn and published by the New York Times. The article says that utilities don't want homeowner solar panels because "The more electricity they sell, the more money they make." The utilities are attempting to get the CA PUC to require a new monthly fee to be paid by solar homeowners of about $56 a month for the typical rooftop system.

The article says that the utility companies' proposal would increase the the electricity cost of the average solar rooftop system owner serviced by PG&E from $133 to $215 a month, according to the California Solar and Storage Association. "Many union members, an important constituency for Democrats, fear being left behind in the transition to green energy."

The solar industry argues that solar panels are no different than home insulation, installing energy-efficient appliances and other electricity-reducing improvements than installing solar panels on your home when it comes to reducing electrical demand - and the utility company's profit.

The issue in Australia is there is a lot of money to be made out of contracts building transmission lines, and extensive localised power pretty much eliminates the need for big lucrative transmission lines. 

Though there is a genuine issue with what to do with the surplus power during peak solar generation times.

The most amusing thing is listening to politicos use buzz word they do not understand - talking about base load power when they mean daily peak demand reserve for example.

[AzCal Retred]

GlennF covered it. Rooftop solar puts generation at the load, radically eliminating transmission demands. From the Utility perspective with rooftop PV, much system just load evaporates during peak (daylight residential HVAC & industrial load) time as it it self supplied. The model they prefer is the Solar farm suppliers (aka central generator) where they get paid handsomely to create & upgrade transmission from farmland where there was never any need before. Wheeling Fees, getting paid to bring in distant power over existing lines, is another lucrative income source. Making your own power locally rather blunts that.

Surplus power (curtailed; required to stop generating for Grid Stability reasons) can be readily stored with existing tech. Most countries have salt domes suitable for natural gas and/or hydrogen storage. P2G used "surplus" or "curtailed" power can readily drive commercially available electrolyzers, the resulting H2 is stored as blends in the natural gas system or in a salt dome (or oil well). Many countries are already piloting these programmes, which are understandably pushed back against and limited by existing energy suppliers. Every Kg of H2 displaces a Kg of natural gas sales, locally made power reduces wheeling fees.

Blending is a well traveled path, blends of 10% - 20% require no user hardware changes and provide actual utility grade energy storage. Blends allow existing "fossile generation" to do the stored renewable energy reconversion back to electrical energy.

Salt dome storage allows for a dedicated thermal cycle (or possibly even fuel cell) powerplant to put the stored energy back on the grid in a predictable manner.

Both P2G methodologies are about 40% overall efficiency. Curtailed Renewable power has no value and is lost if not stored. 100 MWHrs electrical curtailed become 40 MWHrs at "prime time". As Peak vs. Off-Peak rates can easily be 5x to 30x different, P2G gives renewables a better chance to participate in the market and provides grid stability. Making your own power reduces reliance on imported energy.

[Carl Fenn]

I think they have their uses for a small work shop or even garage, the latest panels give you 30% charge even in cloud 500 watts gives you enough for a pillar drill, grinder such like, LED bulbs only use a few watts, deep cycle leisure  batteries are a must but such a system is workable l used to use one. Of course you can make tea of run a heater but a gas camping stove will suffice for that.

[NVDucati]

The fight between the Electric utilities and electrical unions and the solar power industry, vs. homeowners and environmentalists in California is really heating up, SNIP...

GlennF covered it. Rooftop solar puts generation at the load, ...

Surplus power (curtailed; required to stop generating for Grid Stability reasons) can be readily stored with existing tech. Most countries have salt domes suitable for natural gas and/or hydrogen storage. ...

Salt dome storage allows for a dedicated thermal cycle (or possibly even fuel cell) powerplant to put the stored energy back on the grid in a predictable manner.

These two posts are extremely on target. If the world is serious about managing energy usage, it needs to make a bright-line distinction between stationary use energy and mobile use energy.
Buildings for factories and other stationary facilities, both public and private, can generate and store the energy it needs in situ. Mobile needs for transportation and non-permanent facilities have very different needs. Both involve storage. When compared, stationary energy use far exceeds mobile.
AzCal mentions salt domes and is right about the potential. For my money another major avenue for storage is compressed air. It is relatively easy to create and can be stored locally. A huge advantage of storing compressed air is low cost and safety. If it leaks, ... its just air. If it is penetrated, ... it won't ignite. It can heat or cool. It can run machinery. Any resultant exhaust emission is still just air, and cleaner filtered air at that. Even at the well understood efficiency loss, it can locally generate electricity.

It is obviously a big topic. But I don't see a lot of progress until the two usage models, stationary and mobile, are recognized and addressed separately.