ZYTCWaterproof QC3.0 Car Charger USB Outlet Socket 12V/24V Blue LED Digital Voltmeter with On/Off Switch for Car Boat Motorcycle Marine

I had severeal questions that werent completly answered by the description, so before I started cutting holes, I thought I would do some bench tests. Here are my results. This assumes you have wired in a fuze and went straight to the batterey (not a switched solution).1. The VoltMeter is accurate. It is not as fast as my good bench meters, but they agree when you factor in rounding. 14.48 on the good meter = 14.5 on the USBCharger, for example.2. I then wired it up in series for a current draw. When the switch is off, there is 0.00A current draw and the Voltage Display is off. When the switch is on (and no USB) there is a tiny draw. Conclusion = DO NOT LEAVE IT ON WHEN YOU PARK THE MACHINE. Over a period of time it could draw down your battery.3. The USB port ONLY CHARGES when the switch is "on". When the switch is off, it does not pass voltage. The switch must be on to charge.Opinion:For a hobbyiest or small agricultural application this thing is just fine. ATVs, SideXSides, etc. If youi want to mount it on a machine you RELY on, such as an on road motorcycle or autombile I STRONGLY suggest using a relay triggered from a switched source (something that energizes only when the key is on). They use that relay to energize a fused circuit that drives this adapter. And if its on a motorcycle, better think about contaminants!I reccomend these parts:RELAY - https://www.amazon.com/ONLINE-LED-STORE-Waterproof-Harness/dp/B01N66W2XFFUSE - https://www.amazon.com/MUYI-Inline-Holder-Waterproof-Pigtail/dp/B07G7YMJXWSealant - (after using the proper connectors) https://www.amazon.com/Proxicast-Pro-Grade-Weatherproof-Self-Fusing-Electrical/dp/B00K5GW67OHope this helps people.

After having my alternator die on me, I'm a little paranoid. This seemed like the perfect solution... a USB port to charge my phone, a voltmeter, AND a switch to turn it on and off. Quality seems good, voltmeter is accurate... what more could you need?

Works well. Installed on my boat so I could read the voltage of my auxiliary battery. Can only see the reading with the power switch on. Love the fact you can turn it off and on. Saves battery life.

It's only a single QC 3.0.2nd Port is standard 2.4AVoltmeter seemed accurate, before it stopped working.Getting a replacement, but have to wait 2 weeks : (

Installed on my boat to monitor my trolling motor battery. LED display could be brighter and the USB port could output a higher amperage but over all, works as it should.

I've been looking for a USB charger for my motorcycle that wouldn't require an external relay. This fits the bill perfectly. I can turn it off so it doesn't drain the battery when not in use and the digital voltage readout is a bonus.

Works great so far. Used it for a week long fishing vacation. It is mounted on my casting platform, where it was subjected to somewhat significant water.It stopped working for a bit, but I tried it later that day and everything was great. Probably from being flooded.

No where close to Wawaterproof.They die the moment they get wet.

Save your money, it's cheap Chinese garbage.It simply does not work. I tested the wires with a multimeter, installed the socket, and it doesn't work. I even tried it on a different cigarette lighter in my car, and it still doesn't work.

After some months it has stopped working. it was hardly ever used, does not make any sense

Replaced one of the standard cigarette lighter type plugs in my truck. Looks and works great.

三日間は性能を維持していましたが、突然、、、電源が入らなくなり電圧も表示されなくなりました。故障原因に興味があったので分解してみると　フェライトコイルが根元から折れていました。

この商品は電圧計とスイッチ、USBポートがついているためバイクに取り付けましたが、アクションカメラの電源としてバッテリーの状況を把握しながら使用でき大変便利な品物です。