2032 battery only last about three weeks
1322252
Battery still running after over a year, but one of the 3 units shorted out on me in that same period of time.
1322253
My battery's have lasted well over a year and are still ok. Possibly the battery contacts inside has been bent. You can fix it if you open it up.
868416
The battery is low. Mine does that every time it's close to running out of power, which is every 2-3 weeks.
1418027
The battery it came with lasted about three weeks. I suggest buying name brand batteries. They last longer.
1814355
*mine lasted three months, I suggest to buy good batteries, and it also depends on how much you're using your toothbrush...
127110
charge has been holding 3 days..I only recharge when the battery is completely dead.
2203144
You need to send it in periodically to have them replace the battery. Last I knew it was $15 and they turn it around in 3 days. They told me batteries wear out about every two years.
1329199
even on lowest setting(1) the battery lasted about 20minutes for me. I am just using it to trim.
1766497
Purchased this device 3 weeks ago and the rechargeable battery on my unit doesn't last a week with no use at all.
2275741
I purchased two cameras just over a month ago and have already replaced the batteries three times. I would imagine they should last a lot longer than 2-3 weeks. I'm going to use rechargeable batteries from here on. If I hadn't missed the 30 day return window, I would be returning my two cameras.
288618
If it uses 2-2016's then use those because the voltage of two cells is required. The 2016 is half as thick(1.6mm vs 3.2mm) as the 2032. The 2032 is over twice the capacity (lasts 2X longer) than the 2016 (~200mAhr versus 90mAhr), BUT two 2016's is 6.4V, whereas a single 2032 will be just 3.2V. Blue and White LED's will most likely require 2x2016's, while red for example might be just fine (and work longer) on 1x2032. Sorry it isn't simpler. Unless you are having problems with batteries not lasting long enough I would go with 2x2016's as one person states and just get a bunch of them (they can be found pretty cheap nowadays).
2116478
I found battery life to be comparably short but my unit stopped charging the battery and then stopped powering on after three days of use. I'm not the best judge most likely.
1780452
I need to change the battery every three weeks or so. It will last longer if you turn the trackball OFF manually on the bottom - but who bothers to do that? Really eats battreries. (Duracells)
2039699
At first the battery is ok, but like I said in my review, the battery time has gone down to only MINUTES! It goes from fully charged to 3% charged within a few minutes.
25815
to date I've had it sit for 3 weeks before having to use it. I'd guess that after 3 weeks it still had about 90% of its charge.
1112128
Has lasted two to three weeks for me without recharging. Probably longer but I have not gone there.
30863
I haven't used it that much, so I really don't know. However, I suspect it somewhat. Hmm ... I noticed the build date was 3 years before I received the battery.
741170
I think 3 months is reasonable. Maybe 4 - 5 months. It really all depends on how often the sensor is triggered by something detected. Every time something is detected, it triggers a "send" signal, and this uses a tiny bit of battery power. In my case, I have replaced all the 9V batteries with the long lasting 9V Lithium batteries. These should allow me to go 6 - 9 months instead of the approx. 3 months. 12 months may actually be the norm. I will soon find out. ( I don't remember anything about a zero delay. I have the set to what ever was the default setting (except no visible red LED settings). I think 3 months is reasonable. Maybe 4 - 5 months. It really all depends on how often the sensor is triggered by something detected. Every time something is detected, it triggers a "send" signal, and this uses a tiny bit of battery power. In my case, I have replaced all the 9V batteries with the long lasting 9V Lithium batteries. These should allow me to go 6 - 9 months instead of the approx. 3 months. 12 months may actually be the norm. I will soon find out. ( I don't remember anything about a zero delay. I have the set to what ever was the default setting (except no visible red... » Read More I think 3 months is reasonable. Maybe 4 - 5 months. It really all depends on how often the sensor is triggered by something detected. Every time something is detected, it triggers a "send" signal, and this uses a tiny bit of battery power. In my case, I have replaced all the 9V batteries with the long lasting 9V Lithium batteries. These should allow me to go 6 - 9 months instead of the approx. 3 months. 12 months may actually be the norm. I will soon find out. ( I don't remember anything about a zero delay. I have the set to what ever was the default setting (except no visible red LED settings). « Show Less