What’s the fuel sensor accuracy? Below factors affect the fuel monitoring accuracy: The fuel sensor itself accuracy under correct installation, it is stable, 98-99% Calibration, the incorrect calibration process will reduce the fuel sensor accuracy The GPS tracker analog input signal error rate is <±2%. This error rate is constant, so it can be eliminated by fuel sensor formula adjustment. The quality of GPS tracker firmware algorithm. During the vehicle moving, the fuel level fluctuates, need the firmware of GPS tracker to deal with this situation, filter the fluctuations. All fifotrack models have built-in fuel filtration algorithm, that’s why we suggest use our own GPS tracker and fuel sensor solution together. Data uploading time interval to platform. The principle is configuring short time interval like at 10 seconds under ACC on condition, setting long time interval or stop uploading data under ACC off condition. The platform has more meaningful data to deal with, the accuracy is higher. The quality of platform algorithm to deal with the fuel data, especially the fuel filling/theft/consumption data, the platform need do lots of calculations. This part is out of the tracker and fuel sensor’s control. The stability of external power. If the external power is not stable, on/off too frequently, the fuel sensor accuracy will be affected. The fuel tank shape. Irregular size fuel tank need do height-capacity calibration, since the fuel tank height and the fuel capacity is not linear relationship. Incorrect key information such as the fuel tank full capacity, the fuel tank shape size is regular or irregular. What’s the fuel sensor accuracy if everything do correctly? Our answer is 97-98% Below is the example about the comparison between fuel filling report and the actual filled fuel.

AS10 capacitive fuel sensor is the priority option among above options. It is an economic, mature, adaptable and safe solution. However, the AS10 fuel sensor can’t cover all applications. If the customers have below problems: - Customers refuse to drill a hole on the fuel tank, at the same time need high accuracy fuel monitoring, ultrasonic fuel sensor is recommended. However, the ultrasonic need higher installation skills and the price is around usd30 higher than the AS10 fuel sensor. - Customers want to monitor the small car fuel. Both the AS10 fuel sensor and ultrasonic fuel sensor are not suitable for most small cars, so the original fuel sensor solution (using vehicle existing built-in fuel sensor) becomes a solution accepted by part of customers. However, this solution accuracy is only around 90%, but cost is 0, only need buy GPS tracker itself. - Customers have stationary big container like 5 meters height need to monitor level. The liquid sensor is the most suitable solution both on cost and installation convenience considerations. However the liquid sensor is not suitable for moving objects.

Below are the possible main reasons of device offline, we also provide checking way accordingly. 1.Power supply Some drivers like to turn off the battery of vehicle during parking, or the power wire connection between tracker and vehicle's power is disconnected (including be cut off by someone) Checking the latest online data like external power and internal battery value before offline will get clear answer to this question. 2. SIM card without available credit It is very common and is the main reason of device offline. However, the common mistake is that users think the SIM card has enough credit but actually the credit has run out. - The device can reply SMS command doesn't mean the credit is enough: Device online needs the GPRS data plan. Part operators provide different packages to their customers. For example, calling and SMS are one package, the GPRS data is another package. It is logical that the device can reply SMS or the calling is normal but the GPRS data has run out. - If the users use the M2M SIM card management platform, the situation is more complicated. The user can limit the data consumption of the SIM card. There are active/inactive SIM card, prepaid or postpaid options. Even everything looks normal, the M2M SIM card itself may have issues, especially under roaming network. The challenge is that the GPS tracker supplier doesn't have a reliable way to judge the SIM card credit. So the users need to keep a good record of SIM card recharging. Two further steps are suggested below: - Try to recharging SIM card if can't find other reasons of device offline - Replacing with another proved SIM card for comparison testing 3. Parameters are wrong IP, port, APN, and the time interval are core parameters affecting the online. We developed SMS command below to retrieve current parameters. 000000,C06 (000000 is default SMS command password) Below is an example of 000000,C06 reply C06,862273048221154,194.135.92.198:10502,TCP;APN:Etisalat,,, EXT:12.72V,BAT:3.94V;B03:10,0,0,ACC OFF,Stop According to the SMS reply you can know if the parameters are wrong About the APN, if you know the SIM card operator, you can Google out their APN. Normally each operator has own APN. Most operators only have APN, but part operators have APN, APN name, and APN password.