Tuesday, November 21, 2017

Fixing a Hoover Quest ( 700  / 800 ) That will not charge 

Did your Hoover Quest just stop taking a charge altogether, or won't charge it's batteries ? 


I have two robot vacuums.  Both that I fixed, and bought inexpensively because they were 'problem' machines -- that common problem they both shared was power related.

I think this is probably due to the cheap chinese cells that manufactures are fitting their devices with.  Could be wrong, but probably not.  I fixed a Roomba about a year ago with a battery rebuild (usually the first two cells or the last two cells will be bad in the battery) so you can just replace those and the unit will usually function again as new.  I opted finally after testing extensively to just replace the entire battery with a new unit.

Next I purchased the HOOVER QUEST 700 on ebay for a mere $50 ; and it was like new in the package with all of its accessories.  When I got the unit, I quickly discovered that this thing simply refused to take a charge.  I tested the docking / charging dock with my meter.  It was fine.

So  next I opened the unit ** BE CAREFUL when you open the unit, as there are two wire connectors you have to remove before taking the top off the bottom part completely. 

Then I put the battery on my meter.  It was under 1v ; so I quickly figured the unit must not "see" the battery because of the low voltage .  If the charging circuitry cannot see the battery, it won't charge it.

 I took out the battery and hooked it up to a simple 5v 500ma charger for a couple of hours ; then reconnected it to the Quest.  Your average cell phone charger puts out about that same voltage, so just sacrifice one of those adapters to charge the battery up.  When you strip the charger wires, the wire with the white line will be positive, and the solid black wire is negative.    

When putting the unit back together, place the battery in first and then jiggle the top plastic frame onto the bottom.  If it doesn't want to work the first time, don't worry -- just check wires from the battery and make sure nothing is obstructing reassembly.  A couple screws in the unit will work for testing / final charging, if you don't want to completely reassemble the unit.

After unit is assembled, place it back onto it's original base station / charger as the battery should only have a 5V charge now, but enough for the base station to "see" the unit, and charge it fully.

Unit immediately began to charge and still works fine today.  If those batteries get too low, the unit will not charge them.  Its a really bad design flaw, but other than that these are pretty good units and work alright for what they are.  Eventually I will rebuild both battery packs with higher quality cells ; which is the way to go. I do not see anyone selling an aftermarket battery for the quest / or even a replacement battery yet on ebay.   Of course, you could test and or replace cells in these packs individually.  Usually when rebuilding a battery pack -- the first and second cells in from the positive wire will be the bad apples.

Hope this helps others to fix non charging Hoover Quest 700 and 800 models!


UPDATE:  The device goes into this mode (will not charge) frequently, and as I result I cannot recommend the purchase of this model or make. Hoover has also made NO attempt to rectify the situation and I will  no longer recommend the Hoover brand to anyone. 

Kyle