Sears Battery Jump Box whistling

[340wedge]

I have a Sears battery jump box I bought in 2011, it still takes a full charge and works but whistles loudly while off. It sounds like when a fuse box has that high pitch whistle. The whistling is constant if it is low or fully charged. Is this dangerous? Junk it? Thanks

 

[CJCar]

I have a Sears battery jump box I bought in 2011, it still takes a full charge and works but whistles loudly while off. It sounds like when a fuse box has that high pitch whistle. The whistling is constant if it is low or fully charged. Is this dangerous? Junk it? Thanks

I would say a capacitor is going bad - they start to leak or dry out and the top metal seal/lid of the cap will vibrate at high frequency.

You can find the bad cap by opening up the unit and putting pressure on the top of each cap, when the whistle is gone, you found the bad one.

Not dangerous in my opinion - eventually the cap will die completely though.

 

[texvn]

I would say a capacitor is going bad - they start to leak or dry out and the top metal seal/lid of the cap will vibrate at high frequency.

You can find the bad cap by opening up the unit and putting pressure on the top of each cap, when the whistle is gone, you found the bad one.

Not dangerous in my opinion - eventually the cap will die completely though.

If it is a bad capacitor you should be able to identify it by a swollen, bulging lid on the bad component. But don't think that replacing the capacitor is the sole fix. Capacitors can fail due to age but they can also fail because of incorrect voltage being applied to them which could be caused by a number of components upstream in the circuit from the Cap. If you find a faulty cap use your multimeter to test the input voltage to it to determine if it is an aging cap or more.

I personally would fully discharge the box before working on any power electronics and as always be sure to wear eye protection as capacitors can explode.

 

[Rookie2]

only if it has an internal 120v charger, but it may be over charging the maintenance free sealed lead acid battery inside ! that's my guess !