Pellet scale

[YorkshireDave]

This might not be the problem you have, but it's worth mentioning. Make sure your cellphone (and anything else which transmits eg wifi, bluetooth) is well away from the scales. A few years ago I was weighing titanium fasteners for a project and I noticed that the scales often read wrong when there was a cellphone within 8-10' of them. Not far enough wrong to be an obvious rogue reading but far enough wrong to screw up the results. Tried 4 sets of scales, got exactly the same type of errors on everything from a £25 pocket scale to a £1500 pharmacist's lab balance, the only difference was that the pharmacist's balance needed the phone within about 2-3' before the problem started.

[Murphy]

This might not be the problem you have, but it's worth mentioning. Make sure your cellphone (and anything else which transmits eg wifi, bluetooth) is well away from the scales. A few years ago I was weighing titanium fasteners for a project and I noticed that the scales often read wrong when there was a cellphone within 8-10' of them. Not far enough wrong to be an obvious rogue reading but far enough wrong to screw up the results. Tried 4 sets of scales, got exactly the same type of errors on everything from a £25 pocket scale to a £1500 pharmacist's lab balance, the only difference was that the pharmacist's balance needed the phone within about 2-3' before the problem started.

Do you have a reason for this??

Because that explains when I was using my scales downstairs they was being funny when I used my phone for the calculator.

But upstairs I use a normal calculator and they are fine.

[MrChipShoulder]

Oddly in the winter, when I placed my hand over (not touching) the scale, it increased the weight
Doesn't do it now the weather is warmer !?

[YorkshireDave]

Do you have a reason for this??

Because that explains when I was using my scales downstairs they was being funny when I used my phone for the calculator.

But upstairs I use a normal calculator and they are fine.

Phones emit RF energy, some circuits are sensitive to interference. It makes sense that scales can be very sensitive to interference, they're a circuit measuring tiny little changes in a strain gauge, the finer the reading of the scales the more a bit of stray radio frequency energy can muck up their readings. If the scales were better shielded they might be able to overcome the interference, anything with metal casings connected to earth has a far better chance of rejecting RF interference, but that generally means having a 3 core mains cable plugged in, might be possible on expensive laboratory scales but not realistic on a plastic-cased lightweight pocket scale.