What is Meant by Tough Solar (and Eco-Drive) in Casio (and Citizen) Watches?

For those who are unfamiliar with the term, I explain what “Tough Solar” means as a feature in Casio watches. The same concept is used in Citizen watches, where they call it “Eco-Drive”. Basically, there is a solar cell built into the face of the watch and it charges the watch’s power supply automatically when the watch is exposed to normal lighting conditions.

I found a well-made video showing how someone changes a battery in a Casio G-Shock “Tough Solar” watch. This features the same model of watch I purchased in 2006 (and which is still running on its original battery!). So, while I haven’t personally opened up any of my Tough Solar watches for battery maintenance, this video shows you how it’s done on one of the older Tough Solar models.

I caution anyone who attempts to change the battery on a Tough Solar watch to be sure that the replacement is the proper item. Even if you have a professional change the battery, be sure they have the right replacement item.


  1. Equaliser on September 30, 2020 at 4:22 pm

    In a draw it will go into sleep mode. It’s not a problem. 12mths mine was in the dark and started up straight away… if you ever need to change the battery which you won’t. Send it to Casio.

  2. alex.mail123 on September 30, 2020 at 4:23 pm

    The Citizen Eco Drive battery lasts approximately 20 years …

  3. Super Sonic on September 30, 2020 at 4:23 pm

    My Tough Solar is gonna arrive this Friday or the weekend, I can’t wait! Apple and Samsung can learn a thing or two…

  4. Steve Salem on September 30, 2020 at 4:23 pm

    Thanks for your video. Just got my first Casio pro trek solar tough. Hope mine lady’s 14 years.

  5. Jim Hine on September 30, 2020 at 4:25 pm

    Greg video Greg.

  6. Darin Mich'l on September 30, 2020 at 4:27 pm

    Hi Greg My Name is Darin I live in Huntsville also. is there a way to contact you directly? not a sales call i promise. 🙂

  7. ryan johnson on September 30, 2020 at 4:27 pm

    Go on the watchuseek forum. People will post about leaving there solar Gs in the dark and then wonder why there dead lol. It even says in Casio manual to store in the light. Good video maybe more people will use this to keep there watches happy

  8. 12 Hebrew Tribes on September 30, 2020 at 4:30 pm

    I think that is the GW2310 on your wrist. I have the newer model of that watch but I did not like one feature so I sent it to Casio and they built me a model using that watch frame that they do not even sell in stores. I just wanted to ask you why do you wear two watches.

  9. Keis Choi on September 30, 2020 at 4:31 pm

    The most important point he didn’t tell in this video, in door artificial light won’t charge these solar watch, out door sun light is a must no matter how bright it is.

  10. cMonsalveAdm on September 30, 2020 at 4:32 pm

    in your opinion which solar power tecnology has better perfomanve ; ecodrive (citizen) or tough solar (Casio) ?

  11. labrat7357 on September 30, 2020 at 4:35 pm

    I have a number of solar watches and give them an outside charge each half year. A word of warning about birds I have had birds try to steal watches. I now slip the watches over the bar of an F-clamp and that seems to have worked. All the best.

  12. Down Tempo on September 30, 2020 at 4:36 pm

    could you please review the RED G-SHOCK Square on your right wrist?
    I’ve been thinking to get one but just not sure how will it look from couple of feet away. Thank you.

  13. Jake Rockwell on September 30, 2020 at 4:36 pm

    Greg what the heck is tough solar then? I need more than an explanation than its a rechargeable battery or a capacitor….why is it "tough?"

  14. 112deeps on September 30, 2020 at 4:39 pm

    Capacitors can go through vastly numerous recharge cycles than rechargeable batteries might outlast human lifespan!

  15. william jc on September 30, 2020 at 4:40 pm

    i have a citizen,seiko,and 2 casio solar watches. when i first got them, i put them on my window sill for a full(sunny) day. then i
    just keep them on my dresser. all are working great.

  16. matt thomas on September 30, 2020 at 4:43 pm

    it means you replace capacitors and not batteries.

  17. Imran Chowdhury on September 30, 2020 at 4:47 pm

    Once the battery is out of power, or let’s say the watch is kept in darkness for about 3-4 months, shall I keep the watch in direct sunlight? Is keeping the watch under direct sunlight on a regular basis can harm the battery due to overcharging? What is the best way to charge the solar powered batteries?

  18. Alan H. on September 30, 2020 at 4:50 pm

    Off topic – wondering if anyone can help me out on my Gravitymaster GPW1000-1A. It is the GPS model. I am unable to adjust the 24 hour hand to correct position. It is 12 hours off. My current and second time zones are correct, but can’t get that 24 to cooperate. I have set the watch via GPS and it is still wrong. Any ideas? Thank you

  19. vivek sarathe on September 30, 2020 at 4:52 pm

    I have Casio gravitymaster grb-100 for almost 8 months it was in box. I took it out today it is out of charge.so what should be my next move to charge it should leave this into sun for a day?
    Can anyone help?

  20. Serge Fog on September 30, 2020 at 4:52 pm

    I would not take a solar watch to your local jeweler. I posted my g-shock to Casio and asked them to swap the rechargeable battery which they did for 20 dollars! So check with manufacturer, they sure things will have the right tools and parts to do it. I’d say that a 300-dollar g-shock deserved a 20-dollar treatment at its birth cradle! Don’t be cheap!

  21. anthony marino on September 30, 2020 at 4:52 pm

    well said

  22. John Personage on September 30, 2020 at 4:53 pm

    I have a solar Seiko SNE. On a motorcycle tour around Europe last year the watch spent a large part of the day covered up so consequently, it ran out of power a lot of times. I never realised how much exposure to daylight they required.

  23. kenneth_7 on September 30, 2020 at 4:54 pm

    He really is wearing 2pcs of watch on both wrists! 🤣

  24. Owl29 on September 30, 2020 at 4:55 pm

    Dave, you look like the kind of guy like me, who built a heathkit stereo back in the day.

  25. Travis Walker on September 30, 2020 at 4:55 pm

    A really informative video. My father had a similar calculator (the credit card one) called the Casio film card.

  26. Alice Copper on September 30, 2020 at 4:55 pm

    my first tough solar lasted seven years before it had any issues .still have it but bought a new one

  27. Robert Alan on September 30, 2020 at 4:56 pm

    This dolt Greg Anderson blah, blah, blah 6 minutes into this boring crap and he still refuses to tell us what a "Tough Solar" watch is. Complete waste of time!

  28. Kevin Myers on September 30, 2020 at 4:57 pm

    I have owned a Solar G Shock for 15 years now…never had a problem and don’t even wear it that much. Just take out to charge once a month or so,..

  29. Tan Shin on September 30, 2020 at 5:00 pm

    The rechargeable battery in my Citizen Eco-Drive watch only lasted 4 years, and it’s expensive to replace.

    I’d never buy another Citizen Eco-Drive watch.

  30. Glenn Powell on September 30, 2020 at 5:00 pm

    Good video and enjoy someone so enthusiastic about a decent quartz.Off topic a bit but a retired jeweller friend of ours advises that Seiko solars are difficult to replace battery/capacitors on and reccomends straight quartz models? Cheers.Len,UK.

  31. Gary Petersen on September 30, 2020 at 5:00 pm

    You had me at 0.7734 😉 I once put my solar watches in full sun, but noticed there were very hot after 10 mins. Now, I only charge them in indirect light in a window sill.

  32. Drone Tuber on September 30, 2020 at 5:01 pm

    Great channel, specially in regard to Casio watches. There used to be a gentleman on here YouTube that did Casio watch reviews. I enjoyed watching them they were relaxing just like your videos. Unfortunately that gentleman became homeless I believe and sold almost all he’s Casio collection.
    From time to time he used to make videos from Internet he got in public libraries, yet it’s been a long time since he’s been on hope he’s ok and covid didn’t get him.
    Anyways thanks for the Casio reviews, I enjoy them I have about 7 protreks 7 eco drives 3 gshocks solar and a smart protrek. Wich price came down from $500 three years ago to $149 now on amazon. Subscribed with both my accounts.

  33. rubikfan1 on September 30, 2020 at 5:01 pm

    I wear all day. But outside i wear a coat. So my watch mostly charges on lamps or windows sun. Is that enough power to keep it going. Or do i need to put a lamp on it every few months?

  34. Seb W on September 30, 2020 at 5:01 pm

    Maybe the most Interesting and detailed Casio chanal.Keep going this great Work 👌🏻Would be awesome to see customizing/Moding content for G-Shock’s and casios

  35. radioactive.cat on September 30, 2020 at 5:02 pm

    How come this is the first tine I’ve ever seen your videos? Excellent presentation. Got a new sub. Seriously, all the years I’ve been looking at watches and watch reviews on YouTube and I’ve never come across your channel. SMH. I’m looking forward to seeing more of your videos

  36. Drone Tuber on September 30, 2020 at 5:02 pm

    I do have a question, do you think that for the solar batteries health it would be better to leave my watches on power save mode on or off? I store them in power save on and twice a month bring em out to the sun. However I’m not sure if I should leave on all day in the dark shelve to let batteries run down some seems it’s always on high . In other words maybe let batteries drain some? So it’s not always on full?

  37. Mark Diggers on September 30, 2020 at 5:02 pm

    Fantastic vlog extremely interesting I love Casio g shock and will one day treat myself to a tough solar and now I know what battery to purchase if and when I need a new one keep up the great work best regards Mark from Billericay Essex U.K. 🇬🇧

  38. SupaBuma on September 30, 2020 at 5:04 pm

    my oldest Tough Solar ProTrek PRG-50T-7V finally got a new rechargeable battery last year. if memory serves me correctly, the early version PRG-50 came with bad cells. however, the OEM battery held up for me for approximately 6 years. I got her working again last year after using the same YouTube video linked in this videos description. let’s just say that I only use the Auto El feature when needed. 👍

    Great video!

  39. Darkcore on September 30, 2020 at 5:05 pm

    My Casio Protrek is nearing 20 years with my G shock and no problems, both tough solar

  40. Chris Bannister on September 30, 2020 at 5:06 pm

    Thanks for the good info. By the way, if someone was for whatever reason to leave one of these watches in a drawer for six months, or even longer, put it on a well-lit window sill for a few hours before you buy a new battery. It will most likely come back to life.

  41. Noobs ROBLOX on September 30, 2020 at 5:10 pm

    Don’t ask your jeweler to replace your solar watch battery, ask your manufacturer of the watch

  42. Equaliser on September 30, 2020 at 5:10 pm

    Battery spec is on the case.

  43. PetLove NewYorker on September 30, 2020 at 5:10 pm

    enjoyed your show…really nice sir…love from India

  44. Mike Brown on September 30, 2020 at 5:11 pm

    Three ecodrives only one had to be replaced Capicitor and repair was 40 $. One I bought used and it hadn’t been in the light much. Its second hand skipped two sec. to conserve what was left.

  45. Bills Sawshop on September 30, 2020 at 5:12 pm

    As stated, the cells are capacitors, not batteries. Batteries store energy in a chemical form, and capacitors store energy in an electrical field. Thanks for the video, I enjoyed it.

  46. Alton Rowell on September 30, 2020 at 5:12 pm

    I’ve got one of the caseo watch like yours. I had to replace the capacitor last year. Ctl 1616 capasater. The watch is 20 years old.
    It’s not very difficult to replace the capacitor. There is a video on utube showing how to replace the capacitor. I replaced it just in time before corrosion damage the inner part.
    If u haven’t replaced the capasater yet , I would suggest u did. And relube the case seal if the seal looks ok. Cleen the seal area with a cleen qtip dipped in alcohol and let dry.

  47. Carlo D'Agnolo on September 30, 2020 at 5:15 pm

    I used this watch at my previous job out in the field. Sad to say I kind of lost touch with it, but just found it again. Has probably been close to a year in the drawer. The screen was black, the hands were on the 12. Just clicked a button, the thing reset itself and is ticking bang on time as I’m writing this. Incredible watch actually.
    Didn’t know it was solar powered, thanks for the video. Will be wearing it more!

  48. Anonimous on September 30, 2020 at 5:18 pm

    Review casio g-shock GW-2500b please

  49. Robert Carcolé on September 30, 2020 at 5:19 pm

    Good video! When I was a child (80’s) I bought a Solar Casio AL-180, but I lost it. In 2007 I bought another on Ebay from a New Old Stock and it’s still working with the original battery.

  50. Arman on September 30, 2020 at 5:20 pm

    Citizen’s manual states that the fully charged battery lasts for 8 months, so I just leave my watch on my desk for a few days. The watch will probably die from it’s 40m water resistance before I change the battery.

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