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Hints, Tips and Solutions (Do NOT post requests for help here) If you have any useful general hints and tips for vintage technology repair and restoration, please share them here. PLEASE DO NOT POST REQUESTS FOR HELP HERE!

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Old 15th Oct 2023, 2:20 pm   #161
ppalped
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Default Re: Leaking batteries. A reminder, a warning.

Quote:
Originally Posted by stuarth View Post
For tracking brands, it’s the ratio of leaky cells to not leaky cells which is important.

It’s all a numbers game. Any cell could leak, so it’s very good advice to remove cells from equipment which is not in use, but that’s not always convenient, batteries in clocks, remote controls and torches, or test meters and occasionally used radios for example. For those applications, you want to avoid brands with a leakage problem.

I’ve been collecting data on significant numbers of four different brands of cells from many sources for several years now. Three brands had leaks on less than 1 to just over 2 cells per hundred. Duracell’s had 18 leaks in 110 cells. Guess which brand I no longer leave in equipment?

Anecdotally on here we get reports of leaky cells from many brands, for example, Varta have been mentioned a couple of times lately, but without knowing how many of each brand are in use, it’s hard to know if they’re a problem to be avoided.

If folk on here who get to replace significant numbers of cells of any particular brand could collect data on cell numbers, leaky and not leaky, it could help identify problem brands we should avoid, or give early warning on brand changes, for example a previously good brand could have gone bad.

Stuart
Yes, the ratio is what matters, but according to some information in this thread, a ratios based on brands might not be the best way to reflect any kind of truth in the battery/cell world - I believe the year and factory where the cells were manufactured that would matter the most, and that's a lot more difficult to track.

For example, you claim that Duracell is what fails the most for you - for me, I had 2 failed Duracell cells in at least 20 years (and I know why they failed), accounting for at least 100 cells used (and this total number of used Duracell cells is extremely low for sure, I'm just playing safe). Of course this doesn't mean Duracell is great - I might just got lucky. But as I stated before in this thread, I still buy Duracell because they are always with some red price somewhere around here - and I have very little to complain about it so far.

As stevehertz pointed out a few times, it seems that brands switch their production location, or source cells from different locations/manufacturers every year, based on where they get the best price - so this will make any brand-centric data a lot less useful than it would be some years ago where stuff were mainly manufactured by the brands themselves.

On the other hand - yes, any cell will fail. The only hope is that it holds until its expiration date, but that's not a guarantee anyway, for any brand.

Alex
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Old 15th Oct 2023, 5:03 pm   #162
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Default Re: Leaking batteries. A reminder, a warning.

Silly names are an easy indicator of something that may not be up to the job. Something arrived at work recently with 'Mustang' AAA cells in it.

Thankyou for the PP3 vape cell idea Phil, if the 500mA/550mA ones are too large i'll use some of my 350ma for this. They seem to be the same diameter at least.

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Old 15th Oct 2023, 7:18 pm   #163
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Default Re: Leaking batteries. A reminder, a warning.

I had a Maplin own brand PP3 blow a hole in its end a few years ago. It was an unused one in the box where I used to keep my supply of fresh batteries.

These days I normally get my batteries from CPC. I recently got a box of ten PP3s (Pro-Elec Ultra) for just over £14. As well as my various multimeters, our "Slater" digital kitchen scales uses a PP3.

I use a long life Lithium PP3 in our smoke alarm, which due to its age must now count as "vintage" for Forum purposes. It certainly hasn't lost its sensitivity. It's in the hall, goes off when the toast burns, and can also be triggered by the steam from a boiling saucepan if you forget to turn on the cooker hood extractor.

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Old 15th Oct 2023, 7:23 pm   #164
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Default Re: Leaking batteries. A reminder, a warning.

Quote:
Originally Posted by The Philpott View Post
Silly names are an easy indicator of something that may not be up to the job. Something arrived at work recently with 'Mustang' AAA cells in it.
Dave
If they turn out to be leakers perhaps they could be renamed Must Stain.

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Old 16th Oct 2023, 12:24 pm   #165
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Default Re: Leaking batteries. A reminder, a warning.

Update on PP3 substitutes built up from vape cells- 500mAh 13350 cells are a suitable size, 550mAh 13400 may just conform if the terminal block isn't too deep. So that's a good capacity with a slight voltage drop. May trigger low voltage warnings in some devices, and any rechargeables probably shouldn't be used in smoke or CO alarms designed for primaries.

Based on what i've seen so far....they probably won't leak unless abused, and there's not much electrolyte in there anyway. Bespoke Li-Ion charging protocol required needless to say.

Dave
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Old 16th Oct 2023, 3:59 pm   #166
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Default Re: Leaking batteries. A reminder, a warning.

Just as an aside to leaky batteries. I just had a look inside an old Pye Radio tester a TM1A. Although not used for many years I decided to have a look internally and pulled out a Ever Ready Blue R14B 1.5 Volt cell which still read 1.4 Volts with the DVM and showed no external leaks, I think that could be from the 1970's.
I suspect the cardboard layer separating the cell from outer metal case may have soaked up any leakage without it showing externally and that as battery manufacturers try to squeeze every last mAH from a battery that this idea was scrapped in favour of a plastic label around the cell, so any leakage has nothing to soak into.

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Old 16th Oct 2023, 4:15 pm   #167
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Default Re: Leaking batteries. A reminder, a warning.

I think that's 1980's Adrian, i can't remember which name was used first- BLUE, or BLUE SEAL. Same sort of period though, and it's Zinc Carbon.
The Zinc Chloride were badged SILVER SEAL (but coloured mainly red) and the new alkalines were badged GOLD SEAL (but coloured mainly black!)
Quite feeble even by the standards of the day, apart from Gold Seal which would eventually leak.

The previous generation were, i think, SP11 or HP11 depending on chemistry. white/blue, and orange/blue respectively. Leak wise, not too bad; as you say, they weren't trying to squeeze loads of unwise capacity in.

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Old 17th Oct 2023, 2:19 pm   #168
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Default Re: Leaking batteries. A reminder, a warning.

I've bought some boxes of RS brand AA and AAA alkalines as I thought they were reasonably priced compared to the Duracells etc. So far I have had no leaks, and have used them to replace some that have leaked. I'll keep an eye...
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Old 10th Feb 2024, 12:17 am   #169
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Default Re: Leaking batteries. A reminder, a warning.

I thought that I had the leaking battery problem tamed after being caught out several times over the years. I've been religiously checking equipment for problems and removing any batteries where the instrument is infrequently used.

The one item that slipped through the net was an old Intracept N7118 TV pattern generator. Back in 2014, I modified the original 7.2V NiCad battery arrangement and fitted a GP PP3 NiHM battery with a separate voltage regulator.

It worked well for a few years but the pattern generator was put away and forgotten about. Today, I opened the unit and was shocked to find the battery had leaked quite badly. There's considerable corrosion to the PCB foil which happens to be tinned copper. This may have prevented excessive corrosion. The components don't seem too badly affected but I've only just had a quick look.

I put on some latex gloves and mopped up the majority of the greenish gunge and will try to properly clean it over the weekend. Quite annoyed really as I thought these GP rechargeables were good. Being in a plastic case you'd think there's less chance of this PP3 leaking but you live and learn!

In contrast, I've got a 30 plus year torch with NiCads. They've never leaked and still hold a charge!

What would be best to use to neutralise the NiMH battery residue when cleaning the tinned copper foil?

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Old 10th Feb 2024, 12:37 am   #170
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Default Re: Leaking batteries. A reminder, a warning.

The electrolyte is alkaline (Potassium hydroxide) so white vinegar or lemon juice should work.

I had a Freeplay radio where the NiMH cells had leaked, and the corrosion had travelled about 6 inches along the negative lead to the PCB and damaged the foil.
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Old 10th Feb 2024, 12:54 am   #171
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Default Re: Leaking batteries. A reminder, a warning.

Thanks for that Phil, so the electrolyte is the same as that in alkaline batteries. I'll give the PCB a clean with some dilute citric acid.

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Old 10th Feb 2024, 4:53 pm   #172
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Default Re: Leaking batteries. A reminder, a warning.

Hello again.

I've just been tackling the battery leakage on the N7118 TV pattern generator.
I thought I had some citric acid powder but can't find it at the moment so picked up a lemon when in Tesco.
Firstly, I used paper kitchen towels and cotton buds to soak up as much gunge as possible. I removed all ICs as they're in sockets. I then used some hot soapy water and worked it in with a tooth brush on both sides of the PCB taking care not to damage any components. The board was then flooded with clean tap water. Next, the undiluted lemon juice was then thoroughly worked in with the tooth brush. Finally a good flushing with clean water. It was then given a good shake to fling most of the water away and then put out to dry.

I have noticed some track discolouration under the foil which can be seen through the fibre glass substrate. It would seem that the leakage has crept under the foil in places due to capillary action. There's not much that can be done about that unfortunately and hope it won't be a problem. Some of the tin plating is also discoloured.

I'll leave the board for several days and then give it test, and hope for the best!

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Old 10th Feb 2024, 5:04 pm   #173
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Default Re: Leaking batteries. A reminder, a warning.

What a pain! Alkaline corrosion does seem to have an exceptional ability to creep by capillary action.

My only other suggestion would be to force-dry the board in front of a fan heater or similar, to try and encourage the removal of all traces of moisture from those hidden places. Avoiding overheating is important but, say, a fan heater on 1kW should provide a sufficiently warm air stream without making the board too hot.
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Old 10th Feb 2024, 5:14 pm   #174
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Default Re: Leaking batteries. A reminder, a warning.

Good point about the fan heater Phil, thanks.
Luckily so far, most components look to have been largely unaffected. Perhaps the leakage only recently occured.

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Old 10th Feb 2024, 5:46 pm   #175
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Default Re: Leaking batteries. A reminder, a warning.

An old cylinder vacuum cleaner that can blow is very effective in drying circuit boards, as it has sufficient pressure to blast air from beneath components but is not strong enough to damage them .
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Old 10th Feb 2024, 6:20 pm   #176
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Default Re: Leaking batteries. A reminder, a warning.

Yes, that's good too. I recall my parents had a Hoover Constellation whereby you could plug the suction hose into the base which blew the air. Quite a handy feature that's not seen these days.

Regarding the capillary action of the battery leakage, I've just found the screen printed legend on the aluminium back plate is falling away as on some radio glass tuning scale plates. The alkaline solution has crept under the protective laquer. Most annoying!

If I get the pattern generator working then I'm not installing any more rechargeable batteries inside the unit but devise an external mounted battery box instead. That way it's easier to inspect and hopefully avoid any problems.

I have a Seaward PAT500 portable appliance tester bought new in 1993 which cost £520 and it's been stored in the loft for a few years. It has a NiCad memory back up battery inside and I dread to think what it will be like once the unit is opened. I've yet to work out how it comes apart and pluck up enough courage to open it.

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Old 11th Feb 2024, 11:59 pm   #177
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Default Re: Leaking batteries. A reminder, a warning.

Hello again.

Well, the Intracept N7118 PCB has cleaned up reasonably well. After the washing treatment, I used a fibre glass cleaning pencil to remove some residual corrosion on the tin plated PCB foil.
Attached is a couple of pics of the PCB
In the first pic, you can see the corrosion through the PCB substrate, it's mainly around the UHF modulator section.

I'll test the board in the coming days and I'm hoping it will be OK as the N7118 kit was given to me as a Christmas present in 1982 by my late parents so there's a sentimental value to it.

Regards,
Symon
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Old 4th Mar 2024, 1:26 am   #178
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Default Re: Leaking batteries. A reminder, a warning.

Pleased to say that after thoroughly cleaning the board and reassembling it, I now have it all working. There seems to be a slight problem at the top of the display as if there's a blanking fault. Other than that, all patterns work with good stable colour. When I get a chance I'll look into the slight problem. I've also to decide about a suitable battery and where/how to mount it. I will return to it in due course.

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Old 23rd Mar 2024, 12:02 pm   #179
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Default Re: Leaking batteries. A reminder, a warning.

A nice surprise today. I thought I’d check the batteries in two torches I keep for emergencies, one in the loft and one in the garage. Both take two C cells and both were still working. The cells were alkaline and dated 2011 and 2014, they all test okay and show not a trace of leakage. I’ve replaced them anyway.

Oh, the make? Maplin. Sad they’ve gone. No idea who made batteries for them, but they were good. I’ve found several other Maplin-branded cells in perfect condition despite being years out of date.
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Old 23rd Mar 2024, 5:46 pm   #180
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Default Re: Leaking batteries. A reminder, a warning.

I've had a blitz on all appliances over the last two weeks, very easy to miss something as no written records kept..
Remote controls
Torches
Smoke/CO alarms
Meters & voltage references
Quartz clocks
Clock radio memory (This is the one that's easy to forget!)

Numerous sets of Panasonic Alkaline (Bronze) STILL haven't let me down, but I haven't allowed them to go much over their dates. I have a few Panasonic Alkaline Pro-Power (Gold) which also have been reliable, but are slightly higher capacity/weight/price so only a few get used where more power/endurance required.

I've noted that LED headlamps using AAA cells pull excessive current, rechargeable Li-Ion ones are preferable (but always remembering not to headbutt anything with a bomb attached to your forehead.)

Dave
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