Solar assisted streetlights - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: August 10, 2019, 01:45:19 pm
content: Hi,Obviosuly these need a battery. What sort of battery chemistry can handle being on top of a pole in the hot sun day after day and last a long time?Obviously to replace failures means getting up the pole.(unless the battery was at the end of a length of wire at the bottom of the pole..but that would need a custom pole....as opposed to one thats already there and being retrofitted.

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 10, 2019, 02:28:16 pm
content: Even at the bottom, in many regions in the world, that could get pretty hot especially during summer (think of the pole, constantly exposed to sunlight and being a pretty confined container since I guess it must be reasonably waterproof). A typical Li-ion battery would probably not last very long IMO. Of course, also think of cold temperatures during winter. Negative temperatures can also ruin some batteries.To get an idea about what kind of batteries are commonly used, here is a manufacturer:http://www.dyness.net/street-light-battery/It would seem that most of those batteries are still NiCd or lead-acid, which makes sense for those conditions. Lead-acid are commonly used in cars and work reasonably well over a pretty wide range of temperatures. They can take some serious abuse and will usually not explode.This company promotes and sells LiFePo4 batteries as a replacement. They would also be a much better fit than Li-ion batteries IMO (they are safer, can be used at higher temperatures and last for many more charge cycles).

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 10, 2019, 02:32:57 pm
content: This works and has been done, but is generally deployed in countries with a less than optimal power grid and undeveloped stretches of land where it's expensive to run cables through. Unfortunately these countries also tend to have lower average incomes and some people see the valuable batteries as a way of supplementing their income, rendering the street lights inoperable.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 10, 2019, 02:46:39 pm
content: From my research, NiMH seems to be the most tolerant of high temperatures of the common batteries in use. That's what I'm using for a backup pack inside a device that gets pretty warm.

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 10, 2019, 04:41:20 pm
content: Also have to worry about the cold in winter. -40's etc. Basically need a battery that can survive between say -40 and +40. Come to think of it what do they use in satellites? Those see pretty crazy temperature swings.The small solar patio lights you can buy do use NiMH and seem to do fine.

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 10, 2019, 04:59:49 pm
content: http://www.electrochem.org/dl/interface/fal/fal99/IF8-99-Pages25-30.pdf

author: Zero999
author_rank: Super Contributor
timestamp: August 10, 2019, 08:11:12 pm
content: The problem with high latitudes is the short winter days and in oceanic climates cloud is more of a problem, than low temperatures.

author: coppercone2
author_rank: Super Contributor
timestamp: August 10, 2019, 09:38:04 pm
content: I want to say LSD NiMH, I keep these in my car flashlight

author: coppercone2
author_rank: Super Contributor
timestamp: August 10, 2019, 09:41:18 pm
content: but keep in mind thishttps://en.wikipedia.org/wiki/Comparison_of_commercial_battery_types#Rechargeable_characteristicsit looks like lithium titanate is the only option for low maintence street lightsI have no idea what the hell nickle hydrogen isfor eneloop:Q. Does temperature have an effect on their performance?A. eneloop cells outperform alkaline and some other rechargeable batteries in freezing temperatures and perform well all the way down to -4 degrees Fahrenheit. Temperature does influence all battery performance including eneloop batteries. In extremely high temperatures batteries (including eneloop cells) can discharge at a more rapid rate.on the plus side, the power pole should cool quickly at night.. you can mount the batteries to a heat sink too

author: Cyberdragon
author_rank: Super Contributor
timestamp: August 10, 2019, 11:16:32 pm
content: We have these for parking lots in the US.

author: windsmurf
author_rank: Frequent Contributor
timestamp: August 11, 2019, 12:12:08 am
content: Nissan has a project to re-deploy used Leaf batteries for street lightinghttps://insideevs.com/news/337318/nissans-reborn-light-project-deploys-used-leaf-batteries/

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 11, 2019, 12:39:14 am
content: Quote from: Cyberdragon on August 10, 2019, 11:16:32 pmDo they get stolen?

author: coppercone2
author_rank: Super Contributor
timestamp: August 11, 2019, 02:05:55 am
content: we don't have insane thieves driving around in cherry pickers stealing lights here

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 11, 2019, 02:49:54 am
content: Quote from: coppercone2 on August 11, 2019, 02:05:55 amApparently copper theft including that of street lights is quite an issue so people going for relatively valuable batteries isn't a stretch.https://www.cnbc.com/id/100917758

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 11, 2019, 03:05:59 am
content: Shouldn't be that difficult to glue in the battery such that attempting to remove it will rip it apart and dump its electrolyte all over the thief.

author: Circlotron
author_rank: Super Contributor
timestamp: August 11, 2019, 03:11:56 am
content: Make the entire lamp, battery and solar panel into one glued-together unit like an iPad that has to be returned to the manufacturer just for a new battery.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 11, 2019, 03:13:56 am
content: Quote from: NiHaoMike on August 11, 2019, 03:05:59 amHow will faulty cells be replaced?

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 11, 2019, 03:24:54 am
content: Quote from: Mr. Scram on August 11, 2019, 03:13:56 amIn a shop equipped to handle destructively removing the bad cells.

author: coppercone2
author_rank: Super Contributor
timestamp: August 11, 2019, 04:13:37 am
content: Quote from: Mr. Scram on August 11, 2019, 02:49:54 amiirc copper prices were amazing in 2013, they suck now

author: coppercone2
author_rank: Super Contributor
timestamp: August 11, 2019, 04:15:53 am
content: treez designs don't need to be made more evil and less serviceable, he accomplishes that with his budget alone

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 11, 2019, 05:44:05 am
content: Quote from: NiHaoMike on August 11, 2019, 03:24:54 amWhat about the rest of the good ones? Making terrible products doesn't sound like a great answer.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 11, 2019, 05:45:13 am
content: Quote from: coppercone2 on August 11, 2019, 04:13:37 amNot enough to prevent copper theft from still being on the rise.https://www.pewtrusts.org/en/research-and-analysis/blogs/stateline/2018/12/10/copper-thieves-strike-americas-roadways

author: Zero999
author_rank: Super Contributor
timestamp: August 11, 2019, 08:47:13 am
content: It's not possible to prevent theft. I don't see why a solar powered light is any more vulnerable to theft, than a conventional one?All that needs to be done is to make it difficult enough to steal, that most criminals won't bother. Built it robust enough so it can't be easily cut down and special tools/keys are required to open the covers.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 11, 2019, 12:37:29 pm
content: Quote from: Mr. Scram on August 11, 2019, 05:44:05 amIt would be unusual for just one cell to fail, usually the whole set would be replaced to ensure matching capacity. Even then, it's not hard to design it so that individual cells can be cut out without affecting the others.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 11, 2019, 02:38:14 pm
content: Quote from: Zero999 on August 11, 2019, 08:47:13 amBecause the batteries and solar panels add a fair bit of value. Not to mention regular lights do get stolen or more specifically the valuable part, which is copper.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 11, 2019, 03:17:03 pm
content: The solar panel can also be designed so that attempting to remove it causes it to shatter. It would normally last at least as long as the rest of the unit so very rarely would it need replacement.There used to be street lights that run from a high voltage supply with many in series. Those would be a great choice where theft is a significant problem - less copper to begin with and the thieves completing a path for the high voltage would make some nice looking fireworks.

author: Zero999
author_rank: Super Contributor
timestamp: August 11, 2019, 07:12:40 pm
content: Quote from: Mr. Scram on August 11, 2019, 02:38:14 pmI can see how batteries and solar panels will cost a fair bit in a new unit, but question their resale value. I doubt they'll get much for them on ebay.