Dumb battery charger

Dellortoman

Dellortoman

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Location
Tasmania, Australia
I've been looking for a cheap, simple, non-intelligent battery charger, so far without luck. I want one that will resurrect a dead flat battery - or at least attempt to. But all the battery chargers I own, and all those I've looked at in shops are "smart" chargers. When connected to a battery, they look for a voltage above a certain threshold level before they'll consent to dispense the charging juice. If you hook one of those to a flat battery it'll just sit there and look stupid. What I want is one that actually is stupid. Too stupid to know that the battery I'm trying to charge is probably fucked.

I had an old "Arlec" charger that was exactly the kind of thing I'm looking for. All that was inside its tin case was a fuse, transformer, rectifier and ammeter. I'd had for about 40 years. It was all kicked about, dented and scratched, and the ammeter busted, but it still worked - right up to the day when it slipped out of my hand while I was climbing aboard a boat. I managed to grab hold of the cord near the plug, but there was too much length in it and the charger took a dip in the water before I could yank it back. It didn't like going for a swim.

Before I resort to buying the parts (transformer and rectifier) and making one from scratch, I thought I'd ask if anyone here knows of a "dumb as fuck" charger on the market. Preferably in Australia.
 
Same as you, I've been using an earlier version of this Arlec one for years. It's one of the dumbest!

www.mitre10.com.au

Arlec Compact Auto Battery Charger 2500 6 + 12V with Hi-Lo Switch

Output 6 or 12V Hi/Lo charge switch 2.5amp continuous Suitable for charging small automotive lead-acid batteries The perfect charger for drivers who wish to maintain their batteries in superior condition Great for use on vehicles such as classic cars, boats, ride-on mowers, jet skis etc
www.mitre10.com.au www.mitre10.com.au
 
You can have this spare one of mine if you want to pay the postage to Tassie. It's as dumb as a beetle, but it works.
 

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A trick I was taught to trick a smart charger into charging a dead battery is to hook it up to the battery it won't charge, and then momentarily hook up any size charged battery to it as well. The smart chargers algorithm then decides that the battery is worth the effort and starts charging and when you take off your second battery it will usually keep on charging. I have one of the KarMate chargers in the pic, from KMart about 40 years ago, still working as good as new, and am on my fourth smart charger for the modern batteries I have been warned not to use the good old one on.
 
Tippie said:
A trick I was taught to trick a smart charger into charging a dead battery is to hook it up to the battery it won't charge, and then momentarily hook up any size charged battery to it as well. The smart chargers algorithm then decides that the battery is worth the effort and starts charging and when you take off your second battery it will usually keep on charging. I have one of the KarMate chargers in the pic, from KMart about 40 years ago, still working as good as new, and am on my fourth smart charger for the modern batteries I have been warned not to use the good old one on.
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I used to do that, until the expensive smart charger died… I think part of the reason they don’t charge a too-flat battery is self-preservation!
Although generally if a battery has gone that flat then it’s not recoverable, except at a much lower output. When I killed my charger I was charging old batteries to run an electric fence.

Cam, Blackjota beat me to it, I have a spare you could’ve had for postage 👍
 
Yes, I've done the parallel battery trick before. You need to have another battery within jumper lead range to do it, but I don't have any spare batteries lying around at present. It's a pain in the arse to take a battery out of something or re-arrange parking in the garage so the jumper leads reach the dead bike.

Thanks for the offers of freebies. I wasn't expecting that.

Barry, your charger looks to be in way better nick than the one I dunked in the sea. And you're closer than Andy, so in true cheapskate style I'll go for yours as it'll be the lower cost option for postage. But only if you're 100% sure you don't need it. I'll send you a PM.
 
I recently bought one of these, its clever as fuXX and switches from swizzy batteries to old hat ones, does 24 volt (handy for me) and is pretty much fully auto, it has recovered two batterries worth 130GBP each (digger and 4x4) which were left for far too long
using the "pulse charge" mode, all on auto, it's Chinese, of course, but it has already paid its way.
cheap as chips which are doubling in UK
CLEM

ebay item 393903730413
 
Dellortoman said:
I love that retro charger Jo :)
I wonder how the current (strom) dial works. There's a few ways I could guess at.

BTW, I looked on eBay and Gumtree, but there was nothing local to me.
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Yes, I also love the design! However, unfortunately, I can't answer you how the current is regulated (besides, you're the better analyst)!
:)

My BMW mate is a physicist and uses an old laboratory power supply from his father, which he adapted for battery charging purpose. Sometimes it looks like Frankensteins laboratory on his bench ...
:cool:
 
Dellortoman said:
I love that retro charger Jo :)
I wonder how the current (strom) dial works. There's a few ways I could guess at.

BTW, I looked on eBay and Gumtree, but there was nothing local to me.
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I'm guessing it's a rheostat in series with the DC output. What's the bet it uses a selenium rectifier as well. No (modern) rocket science there.
cheers
bazzee
 
Cam. serious;ly mate, take a look on ebay at 393 903 730 413
very cheap and recvered two batteries that would not charge when jumped from another car and left idling for 20 minutes.
they are not at all heavy, worrying light in fact and if you can't buy locally from some source or other, I will happilly buy for you here in UK and ship it, cant be costly. I think the mug of tea I am holding is heavier.(nearly empty so must get another.)
CLEM
 
I have a number of "smart" battery chargers and I too have the problem that if the battery is close to dead, the smart chargers won't do anything.

So I use a variable DC power supply ( 0 to 30V and 0 to 10A ) I got off Amazon as it will charge anything at what ever voltage and current you want. And they are sometimes cheaper than a battery charger. When I bought it about 5 years ago is was only about $40.

My is similar to this one.
 

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Cam. serious;ly mate, take a look on ebay at 393 903 730 413
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I did actually look at that very ebay listing the other day. I was put off by the word "automatic" in the specs. I thought it might be too clever for what I want.

Barry (BlackJota) is sending me his old one. He told me it's in the mail. So is my cheque. ;)
 
This bad boy still works and incredibly brings dead battery’s back to life when other chargers don’t- works on gel batteries a treat. Switch him on and the needle flies round to “Danger” and buzzes loudly like in a Frankenstein movie, then the needle slowly returns to “ relative safety” of the green zone and the loud buzzing becomes a hum .
If you look at the bottom of the meter you can see it was made Feb 1950. Not so much an intelligent charger as a small arc welder.
 

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Cleaning out some shit from my old workplace today, I found my old charger.

More interesting though, a Brembo twin bleed calliper with no Brembo name on the body. I wonder where it’s mate is?
 
Hi,

I know you said about not wanting a smart charger, but what about a Optimate charger? I have a couple and leave the Zanes on , it will recover a flat, or dead battery if possible, and maintain and keep topped up, without overcharging? If there is a duff cell though there’s no coming back from that of course.

Just a thought.

Alistair
 
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