Gear Review: Nitecore EMR10 EMR20

In this review of the Nitecore EMR10 and EMR20 portable mosquito repellers / powerbanks, we take a detailed look at all aspects of their performance and function.

The EMR10 and EMR20 are two new devices from Nitecore combining portable insect repellers with a powerbank. The EMR10 has ultrasonic repellent, a repellent mat heater and a 10,000mAh powerbank, and the EMR20 is slightly smaller and simpler but without the ultrasonic function.

If, like me, you protect everyone else from mosquito bites, by being the one the mosquitoes make a beeline for, then you may be as pleased as I am to find the new Nitecore EMR10 and EMR20 portable insect repeller devices.

The thermal runtime graphs for these units are a first for Tactical reviews with the final graphs having 3500 manually entered data points!

Making his first appearance below is “Stoppo”, Tactical Reviews’ “don’t do that” guardian. Mosquitos beware, armed with the EMR units Stoppo says NO!

Review Videos

Starting with a short format sixty second review:

Onto a full video review covering many more details:

Looking closer at the EMR devices:

Both units boxed and unboxed, before we go into the finer detail.

What’s in the box – EMR10:
Along with the main unit are a charging cable, instructions and 10 of the double-size repellent mats.

A good look round the EMR10 – Things to look out for here are:
Of the two, it is a bigger and more feature packed unit, with the EMR10 there is a lot to see.
The OLED screen has a protector you need to take off. Notice the slider on the bottom, we’ll come back to that. Molded into the rubber section on the sides are some grip grooves. On each side are small ultrasonic speakers that emit a dual frequency repelling sound. On the back is a metal wire clip that is designed to work with MOLLE / PALS, pocket or belt use. The top has a USB-C port for charging and for use as a powerbank.
The repellent mat heater/holder has a retaining spring wire to keep the mat from falling out.
Then onto the EMR10’s biggest trick, the removable twin 21700 cells.

What’s in the box – EMR20:
Along with the main unit are a charging cable, instructions and 10 of the double-size repellent mats.

A good look round the EMR20 – Things to look out for here are:
The EMR20 is a smaller and simpler unit which has no grip texturing or screen. Instead it has a set of four indicator lights plus the power switch has dual coloured illumination. On the back is the same metal wire clip used by the EMR10 that is designed to work with MOLLE / PALS, pocket or belt use. The top has a USB-C port for charging and for use as a powerbank.
The repellent mat heater/holder has a retaining wire spring to keep the mat from falling out.

Batteries and output:

The following section is all the technical testing for both units. This includes temperature measurements for the repellent mat heater, plus power curves for charging each unit, and the powerbank output for each unit.

First up is the repellent mat heater output for both units. The test was carried out on the highest, ‘outdoor’ mode which takes the heater to the highest temperature.
The temperature measurement was taken by inserting a K-type thermocouple under a used mat to keep it pressed tightly against the heating plate and insulate it. Another ambient temperature thermometer was also recorded, making it three temperature measurements being monitored.
For this dual run I had to set a camera on time lapse photo to take a photo measurement every 30s. Unfortunately I had no computer logging so had to manually type each measurement – over 3500 of them!
The resulting graphs are very interesting. They show the temperature varying between an upper and lower limit. The EMR10 keeps the lower limit higher than the EMR20 and as a result uses more power and has a lower runtime. The graphs do speak for themselves, so take a bit of time to read these.
Also included are some thermal images of the EMRs during this test taken with a FLIR thermal camera.

The next gallery shows the USB input and output graphs for each unit. Charging graphs are from empty to full. The powerbank graphs show each unit charging a Oneplus phone on fast charging (9V output); they are not the full capacity of the powerbank, just to show the output characteristics which are excellent.

What it is like to use?

I want to start this section by introducing my very helpful assistant, Klaus. One of the things I was worried about with the EMR10’s ultrasonic repeller is if it would distress animals. Dog whistles are also ultrasonic (above human hearing range) so I needed to use the EMR10 around a dog to see what would happen. Not once did Klaus seem to react at all to the EMR10 negatively, or even pay any attention to it, so assuming he could hear it, it didn’t bother him. A good start.

Nitecore make and supply double size repellent mats. This is clearly the easiest way to load up the EMR10 and EMR20. It is possible to use two standard size mats instead giving you more flexibility.

You can see in one of the photos how the mats go almost white when the active ingredient has evaporated. The photo shows areas on the mat around the heat shielding that have gone white on this part used mat.

An observation relating to the EMR10’s display and capacity indication is that I’ve found the percentage show to not be accurate at all times. You can use the EMR10 while it is on charge. While doing this, the battery percentage always stays lower than it really is. You can see the input power as well on the screen and as this gets closer to being fully charged, the input watts gets lower and lower (the example here shows 10W input) but the percentage charge indicates it is much lower than it really is. Once you turn off the EMR10 it recovers and corrects itself. Just something to be aware of and I suspect relates to the charge percentage being based on the cell voltage which will of course be lower while the repeller is turned on.

I’ve been using both the EMR10 and EMR20 in a variety of indoor and outdoor locations carried separately or clipped onto a bag.

So how did they do?

Firstly, with me being apparently the finest of dining for mosquitos, if they are determined enough, you will still get bitten; I did. I’ve been bitten when covered in deet, so using repellent mats outdoors might deter some, but is not absolute protection.

It is not at all possible to properly measure the effectiveness of these repellers as the number of bites will also depend on the time, temperature, and hatching of the insects, so this can be impressions only.

Assuming the mats themselves are effective, I have been aware of the aroma coming from the mats. Considering this is outdoors, that is reassuring. Effectiveness is so subject to wind direction and strength, so you might not actually have any cover of the repellent and insects might reach you undeterred. Where the EMR10 has another string to its bow, is the ultrasonic repeller. The ultrasonic won’t be affected by wind, but having no active ingredient, it again relies on the mosquitos not being determined to bite.

NOTES on the repellent mats:

There are a few different active ingredients used in repellent mats, and these are also frequently in combination with Piperonyl butoxide. Prallethrin, Transfluthrin and D-Allethrin are the most common with Nitecore’s MRM10 Mosquito Repellent Mats using Prallethrin.

Piperonyl butoxide (PBO) is a man-made pesticide synergist. By itself, PBO is not designed to harm insects. Instead, it works with bug killers to increase their effectiveness. PBO is often combined with natural pyrethrins or man-made pyrethroids. It has been used in pesticide products since the 1950s, when it was first registered in the United States.

A repellent mat needs to be changed when it turns white. You can use Repellent Mats for a shorter period of time than the manufacture specifies and they will still be just as effective. However, if there is going to be several days between usages, you might want to keep the mats in their foil packaging or in a sealed plastic bag between uses.

Having used them a lot, the one feature I wish they had was an auto-off timer. Once you turn on either one of them, they will run until the battery is flat or you turn it off. I found that treating at critical times was more important than all night and I would have preferred to be able to fall sleep with the repeller turning itself off after an hour or two and leaving power to run on another night. On this subject, the EMR10 allows you to either only run on one of the 21700 cells, or carry spares.

The clip has a one-way design where it fits on much more easily than taking it off. Good for not losing it, but on occasion puts up a bit of a fight to take it off, especially from MOLLE more than from a pocket.

Initially I was dubious about how much I would want to use the powerbank function when I want the power for insect repelling. But, after travelling by air a few times with these devices, the use comes from having a powerbank to use on the plane, and once getting to where I really need the repeller, then recharge and only use it for the repellent. So like this, the two functions allow for infrequent use as a powerbank while travelling, but then change to only using them as repellers when not travelling.

While using the EMR10 and EMR20 I have been bitten. I am convinced I would have been bitten more without them. The most difficult aspect of their use is the protection zone they can provide. If you are walking, then the repellent vapour is trailing after you and not surrounding you. If there is wind, the repellent is blown away. In instances where you are not moving and there is wind, you need to put the device a few meters away from you and up-wind.

Some of the better results are for smaller or enclosed areas. Treating a tent, or a hammock net are idea uses. While on holiday, using it in a hotel or guest room works well.

Review Summary

The views expressed in this summary table are from the point of view of the reviewer’s personal use. I am not a member of the armed forces and cannot comment on its use beyond that covered in the review.

Something that might be a ‘pro’ for one user can be a ‘con’ for another, so the comments are categorised based on my requirements. You should consider all points and if they could be beneficial to you.

I’m trying something slightly different and starting with what doesn’t work so well, so I can finish on a more positive note.

What doesn’t work so well for me

No auto-off timer.
Clip can be awkward to remove.
USB-C port cover needs a firm hand to get it out of the way.

Things I like

Portable outdoor insect repellent device!!!
Double size repellent mats (and able to take two standard mats).
Powerbank function with rapid charge 9V output supported.
Up to 18W input power when charging.
Indoor and Outdoor modes.
Secure one-way clip.
EMR10 has replaceable cells.
EMR10 can run on one 21700 cell.
EMR10 OLED display is informative.
EMR10 also has an ultrasonic repellent.
Removable secondary heat shield.

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