UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > Components and Circuits

Notices

Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

Closed Thread
 
Thread Tools
Old 22nd Mar 2017, 10:26 pm   #1
poppydog
Banned
 
Join Date: Oct 2015
Location: Cornwall, UK.
Posts: 849
Default Battery reverse polarity?

Listening to my small Grundig Solo Boy yesterday afternoon, after about an hour or so of listening it started to go very quiet and distorted. I had only put new batteries in just after Christmas and it was only used for a couple of hours since, so I was a little disappointed that they had run out already, or so I thought. I removed them, they were all installed correctly, and put them across the meter to find 3 of them were still very good and one was reverse polarity. They are the Kodak Xtralife alkaline C size 1.5v almost certainly from Poundland. Has anybody ever had this happen to them? Also could it cause any damage? The battery on the left is the culprit and if you look you can see the pressed part at the top is ever so slightly rounded/bulged compared to the battery on the right.

Regards
Poppydog
Attached Thumbnails
Click image for larger version

Name:	20170322_140417.jpg
Views:	139
Size:	66.0 KB
ID:	139656   Click image for larger version

Name:	20170322_135858.jpg
Views:	114
Size:	51.6 KB
ID:	139657  
poppydog is offline  
Old 22nd Mar 2017, 10:37 pm   #2
Biggles
Rest in Peace
 
Join Date: Feb 2004
Location: Hexham, Northumberland, UK.
Posts: 2,234
Default Re: Battery reverse polarity?

I have experienced cells being reverse charged when connected in series before. I think it happens when one of the cells runs flat before the others do. This is why they always say to replace all the cells at the same time and don't mix cells of different type or old and new ones. Saying that I once had a new motorbike battery which was incorrectly marked polarity wise. It was only by luck that I connected it to a charger before putting it on the bike and found the charger meter reversed and the cut out tripped. So it has been known.
Alan.
Biggles is offline  
Old 22nd Mar 2017, 10:51 pm   #3
The Philpott
Dekatron
 
The Philpott's Avatar
 
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,081
Default Re: Battery reverse polarity?

Yes i have had it happen. Occasionally with dry/primary cells (but also with Ni-Cads that have been flat for too long.) I don't imagine it would ruin the other cells in the stack, but i have nothing other than instinct to back this up.
The Philpott is offline  
Old 22nd Mar 2017, 10:57 pm   #4
emeritus
Dekatron
 
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,316
Default Re: Battery reverse polarity?

I have very rarely had this happen too, even with sets of fresh batteries from well-respected makers that were installed from the same pack. I think the only type of battery where serious damage would arise from reverse charging is Lithium rechargeables, where reverse charging would cause the production of metallic Lithium. Lithium metal is extremely reactive and will readily ignite or even explode. That is why individual cells are not normally available to the public, only made-up sealed battery packs where the individual cells, being permanently connected, cannot accidentally become reversed and incorporate suitable protection. I do wonder if the exploding laptops that featured in the news a year or so ago, were caused by unscrupulous battery manufacturers omitting safety components to save money, just as some cheap switch-mode power supplies omit the components that would deal with the RFI once they have got their CE approval.

Some years ago I acquired a couple of ex-equipment 12V battery pack made up of 10 SAFT 4Ah NiCads. Across each cell was a inverse-connected diode, evidently to prevent reverse charging if the pack were to be discharged to exhaustion.

Last edited by emeritus; 22nd Mar 2017 at 11:06 pm.
emeritus is offline  
Old 22nd Mar 2017, 11:15 pm   #5
Tim
Dekatron
 
Tim's Avatar
 
Join Date: Jan 2003
Location: Bradford on Avon, Wiltshire, UK.
Posts: 3,301
Default Re: Battery reverse polarity?

Yes I had this happen with an "Energiser" alkaline AA battery. Perfectly good but in reverse!
__________________
"Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."
Tim is offline  
Old 22nd Mar 2017, 11:56 pm   #6
Nuvistor
Dekatron
 
Nuvistor's Avatar
 
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 9,427
Default Re: Battery reverse polarity?

Yes , quite recently, not seen it before though, alkaline Tesco one if I remember correctly. The others of same age were ok but the lot were replaced.

Frank
Nuvistor is offline  
Old 23rd Mar 2017, 7:03 am   #7
FrankB
Heptode
 
Join Date: Oct 2005
Location: Olympia, Washington, USA.
Posts: 663
Default Re: Battery reverse polarity?

Kodak batteries are rubbish. I had mass problems with them when I was servicing.
The folks bought them because they were cheap.
Philpott has it correct on the cause. Never saw any other brand do that, excepting reverse charged NiCad's.
FrankB is offline  
Old 23rd Mar 2017, 9:20 am   #8
trsomian
Hexode
 
Join Date: Oct 2010
Location: Box End, Beds. UK.
Posts: 271
Default Re: Battery reverse polarity?

Standard problem with series strings of NiCad and NiMh rechargeables. The one that gets reversed is very quickly ruined. With primary cells it doesn't matter so much, because the one that has charged backwards is rubbish anyway

This is the reason I am very cautious about more than two rechargeable cells in series unless the load has low battery switch off/warning, which they seldom do
trsomian is offline  
Old 23rd Mar 2017, 10:42 am   #9
Philips210
Nonode
 
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,562
Default Re: Battery reverse polarity?

Hi.

I also experienced this a couple of months ago with some AA alkaline cells made by GP. I had 3 in series supplying those timed LED Christmas lights. GP cells are generally very good and I've so far not had any leakage problems with them so would continue to use this make.

Regards
Symon.
Philips210 is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 2:28 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.