Repair lithium ion Vacuum - Page 1
Forum section: electronics / repair

author: connectTek
author_rank: Regular Contributor
timestamp: May 07, 2020, 01:42:10 pm
content: Trying to repair my parents Hoover Stick vacuum.It has 6 x 18650 li ion cells, yet the charger only outputs 21.6v, wtf!.The unit never charges fully from day one.I have charge on test bench to 25.2 v, (4.2v x 6).Why would they supply a chargerThat would only charge each cell to 3.6v ( 21.6 ).Can some one help me with this problem.Cheers.

author: Miti
author_rank: Super Contributor
timestamp: May 08, 2020, 08:12:22 am
content: Are you sure it is Li-Ion? Li-Fe only changes to 3.65V max. Pictures of the battery pack?

author: Kilrah
author_rank: Unknown
timestamp: May 08, 2020, 10:40:13 am
content: Yup, sounds like LiFe. 3.6 for Li-ion would be almost empty.

author: connectTek
author_rank: Regular Contributor
timestamp: May 08, 2020, 12:04:01 pm
content: Definitely Li ion.Hoover 5221.I have bench charged each cell to 4.2v.At 3.6v they are flat,

author: connectTek
author_rank: Regular Contributor
timestamp: May 08, 2020, 12:16:12 pm
content: A Pic

author: xavier60
author_rank: Super Contributor
timestamp: May 08, 2020, 12:27:43 pm
content: That's really odd. I just had a look at my Dyson DC59. It's charger is specified as 26.1V for 6 cells. It measures 26.12V unloaded.

author: Miti
author_rank: Super Contributor
timestamp: May 08, 2020, 12:32:44 pm
content: Yeap, that’s weird. I wouldn’t expect to change to 4.2V for safety and extending the life time, but 3.6?How did you measure the charger voltage? Measure the battery when the charger shows full.

author: xavier60
author_rank: Super Contributor
timestamp: May 08, 2020, 12:40:47 pm
content: I see on ebay they describe the Hover battery as "22.2V-21.6V".I don't know about the 22.2V but 21.6V is the nominal voltage for 6x Li-ion cells witch is 3.6V per cell.Maybe the charger just happens to be set to 21.6V and the charge circuitry in the battery pack is supposed to boost it to a higher voltage.https://www.ebay.com.au/itm/Battery-Pack-For-Hoover-22-2V-21-6V-Ultra-Light-5221-Vacuum-Cleaner-5221BP-AU-/264409929485

author: xavier60
author_rank: Super Contributor
timestamp: May 08, 2020, 01:38:20 pm
content: This replacement charger is specified as 26V,https://www.amazon.co.uk/POWER-Adapter-SiriusXM-Portable-144D2427/dp/B071ZR5YZL

author: connectTek
author_rank: Regular Contributor
timestamp: May 08, 2020, 01:54:06 pm
content: Charger says 21.6v, I measured 21.9v.As I said before, at 3.6v per cell the battery is almost flat.I have input 25.2v from bench power supply and it chargesfine.Weird.Looks like a major design failure as I have read that many peoplehave replaced batteries, mmmmm I wonder why?

author: xavier60
author_rank: Super Contributor
timestamp: May 08, 2020, 02:05:08 pm
content: Maybe the charger's manufacturer made a mistake, setting the voltage to the marked nominal voltage instead of to the proper charge voltage.

author: Miti
author_rank: Super Contributor
timestamp: May 09, 2020, 03:11:02 am
content: Yes, nominal is one, fully charged is something else.Can the charger be adjusted?

author: connectTek
author_rank: Regular Contributor
timestamp: May 09, 2020, 05:10:23 pm
content: No, it's just a plug pack 21.6v