I've seen lots of threads debating the merits of sending your HRM back to Polar for battery replacement, having a watchmaker do it or doing it yourself. Didn't come across any how-tos so I reckoned I'd post a quickie on this particular model.

First let me say that with an S150 you'd be a total sucker to have Polar do it for $40 or whatever. Super simple - the guy at the watch shop in the mall could do it in his sleep. You'd have to be pretty mechanically untalented to not be able to do it yourself.

You'll need a micro-screwdriver set (like they sell in the checkout line at Ace for fixing eye glasses, etc.) or some other very small phillips screwdriver. You'll also need a CR2032 watch battery. Radio Shack has them or easy to get online.

Lay the unit face down on something soft so you don't scratch it. Take the four screws in the corners on the back out. I recommend doing this progressively (do each one half way, then go around doing a few turns on each). There are a couple of springs in there that are held down by the back - see picture. In mine they seemed to be captured but I could see them popping out if you weren't careful. Once you have the screws out carefully remove the cover.

The battery is obvious and held down by a clip. You just need to flex the clip to remove it. I found that the "fat" end slid out first - again, see picture. After removing the clip, use a toothpick or something to pop the battery out. Put the new one in ("+" up) and flex the clip back into place.

Take a quick look at the gasket - the ridge that runs around the outside of the electronics - for cracks, nicks, etc. I wouldn't remove it if you can help it. If it looks bad you might want to send it to Polar for replacement.

Put the cover back on and put the screws back in. Again the best way to to this is progressively, working diagonally (e.g. left top, right bottom, left bottom, right top, repeat) to insure a nice even seat against the gasket.

Done - redo all your settings and such.

See picture below. Sorry about the quality - I was doing this at work and all I had was my crappy phone camera. Once you have the watch open in front of you it will be very clear, I think.....

Regards,

Chris

I have the local watch shop at the mall do it. The only thing you can't replace yourself is
the chest strap band battery and those things last eight years.

Frankly, the S150 is "okay" but it's a little too susceptible to interference from ultrasonic
dog fences, power lines and radio sources. The dog fences (going by the brand name
"invisible fence - your dog safe at home") are particularly offensive - it will cause the
S150 to give a 220 bpm rating if you get near enough. Totally skews my average hr.

Anyway, they're nice for what they are. They also are susceptible to readings from
other S150s or S120s if you take group spin classes like I sometimes do.

Yeah, my wife bought it for me. I really don't use many of it's functions - occasionally I'll look back at my profiles after a ride, etc. I haven't even bothered to hook up the computer sensor - most of my rides are short and slow according to the computer since without an altimeter it can't understand that I climbed, then descended at an average 12% grade! I don't think I'd necessarily recommend it. I'd probably like it a lot better if you could download the data off of it.

Haven't had interference problems but I usually ride solo and I guess people in my neighborhood don't have those dog fences.....

I guess for $75 it's a reasonable value - I don't think I'd buy it for myself, though and I sure wasn't going to blow another $40 on it!

Hi there

Just wanted to say thanks for posting this article. I cracked open a new S150 that had a dud battery from the shop and managed to get pretty much all the "layers" of the watch separate semi by accident. Anyway, had no idea where the springs came from and your post gave me the answer. Shame they don't trust owners to do the swap and publish their own guide - not trivial but not so hard after all.

Thanks again
Michael

Thanks for taking the time to submit the pic of where the springs go. I took my wife's watch apart and when I was done ended up with 2 extra springs. Thanks to your pic, I was able to get it put back together correctly.

Joe

The battery in my F11 only lasts about 3 months and then I need to change it. I bought it from someone, knowing that it had this problem so it is not an issue. CR2032 batteries are under $1.00 online and I buy them in bulk since I use them for other electronics I have. Sending it back to Polar was not an option since I was not the original owner and it is cheaper for me to just do it myself.

Thank you very much for taking the time doing this post.

Replaced my battery, ($4.99) at RadioShack.

Your picture helped alot... I initially had the clip in wrong

Hey,

Chris from Polar here.

I realize this is an old thread and just resurrected with the last post, but have a few points that may help someone in the future if they stumble on this post through search.

I agree completely, you would be a "total sucker" to pay $40 for someone to change the battery. Luckily Polar, and all authorized Polar service centers charge nowhere near this. The charge for a battery replacement is approximately $12.00. The standard procedure for basic service/battery replacement includes new gaskets, everything adjusted, a complete cleaning and everything fully tested. All with a new battery and a warranty on the service. I would definitely recommend on a high dollar Polar to use the authorized service, it is worth it.

All new Polar products have user changeable batteries, in both the watch and transmitter.

Hope this helps Drop me a PM if anyone has any questions.

Chris

GV27,
Appreciate the write-up. I had replaced the battery on my Polar S150 before, but it has been so long since I did it last that I needed the reference. Always nice to do self-help projects.
Thanks again,
Phil

Such a handy article. I found it again on my latest battery change. This time, my son found the watch in a draw and asked if he could use it on his kids road bike. And hey presto, back to life!