Quick fix for a basic car battery charger - replace the bridge rectifier

[@grandadsfishingboat7455]

Nice one Rob.. my new hobby repairing old battery chargers..Regards Stuart Bell from UK

[@sambodi5283]

I have 3 of these type chargers. I've just kept buying a new one each time they have failed. Now I can sort them all out. Thanks

[@Xynudu]

Glad I could help. Cheers Rob

[@thehobbymachinistnz]

Another useful video Rob. I'm sure there are many people out there with broken chargers who can now troubleshoot and fix them.

[@Xynudu]

It's pretty straight forward if you trace the output through from the transformer. I fixed up another identical Arlec 8 amp charger today with exactly the same issues. All good again for $2.65. A similar looking new one from Repco is over $139 AU. Interestingly the basic old style chargers are still available and cost a lot more than the modern inverter type for the same output. Cheers Rob

[@Xynudu]

Note: Bridge rectifier voltage upper limit is usually 400 - 600 volts and not an issue, as it can easily handle any voltage able to be put out by the transformer. The MAIN FACTOR is to make sure the amperage upper limit is sufficient. Going higher than standard (the maximum stated output of the charger) is a good thing. Cheers Rob

[@lomgshorts3]

I agree Rob! Always over amp the rectifier so the heat that the charger generates will not cook the rectifier. 8amps is either replaced by either 15 or 20 amp regulator. This makes the regulator more stout for long durability.

[@shawnmrfixitlee6478]

I use those old chargers to get a deep cycle battery going again after sitting . Great repair Rob !

[@Xynudu]

Hi Shawn. I have not had to do that, but I can see where one would be good for that. They are pretty tough units when treated right. The Bro Inlaw picked up this one and dropped off another identical unit to do the same repair. So that's the next thing on the agenda. Cheers Rob

[@glennfelpel9785]

Rob, I am very pleased that you did this video. Thank you. I have a charger which doesn't work and I was just going to get a new one. Not now Thanks again.

[@Xynudu]

Hi Glenn. Sometimes it's just bad connections from age, but this video will guide you through the other possabilities. I hope it works out for you. Cheers Rob

[@AmateurRedneckWorkshop]

G'day Rob. That one got me all charged up. Keep on keeping on.

[@SeanBZA]

The big killer of these is reversing the leads, which blows the bridge rectifier almost immediately. I solved that on the one with a relay powered by a diode from the output, so that you need at least 8V on the battery, and the leads connected right, before it will charge. Also added a switch just in case the battery is stone dead, or under 6V, but with a LED to show it is actually correct, so the relay can close with mains applied. Also put in a 35A bridge rectifier, barely more than the 10A one price wise, but with a 15A blade fuse there in the leads, inside the case, the fuse will blow first when you put the leads on backwards. Charger is a little old GE unit, made circa 1956 from the patent dates on it, and has survived many years. Did add in a charge contrtoller so it will not overcharge the battery, but tapers off to maintain it. Got another smaller GE unit, with similar 8VAV and 16VAC transformer, and with a selector plug for voltage for 3 cell or 6 cell batteries, and a meter. Had to replace the old rotted out leads, and also the bridge rectifier, as it was kind of rusted apart, and after a phosphoric acid bath and paint coat the case came back to looking acceptable. Not new, and I wanted to keep the labels, so just not looking like a collection of rust, but steel is now protected and no holes in it. Did have to drill all the original rivets, used to hold the case together, to get it apart, but it now works well. Made circa 1960, but transformers are pretty much going to last with only a small amount of care.

[@Xynudu]

I have a green 5 amp GEC charger from the 70's. It has two bridge type plugs on the front panel to select voltage. These corroded internally and needed attention way back, but is still going perfectly. Been used for all sorts of power supply work as well (electrolysis etc) which many modern IC units can't handle very well. Cheers Rob

[@SeanBZA]

@@Xynudu Glad to know GE has been using the same shitty jumpers for decades then. I had to make new ones for mine, they did the same thing. They do have a fusible link in them, which is made from soft tin alloy, which corrodes away inside the casing.

[@Xynudu]

Interesting info. I drilled a centre hole right though all four jumper pins and fed a bridging wire through from pin to pin at the plastic end (which I recessed for the wire) and soldered at each pin end. Simple fix and solved the problem. Great old charger. Cheers Rob

[@pgs8597]

G'day Rob. Good video brought back some of my very limited knowledge of electronics. These old chargers are great but have a problem of lack of regulation for those who are lazy, forgetful or simply trained by today's standards of just leave it plugged in and forget, you've gotta remember to turn em off. Thanks for sharing. Cheers Peter

[@Xynudu]

Hi Peter. Yes, they are pretty low tech, but they can handle shitty jobs like power supply for electrolysis etc. My old 5 amp GEC unit from the 70's has earned it's keep. Cheers Rob

[@CAROLDDISCOVER-1983]

Where will explain sir. I like the fact how you put the print on screen to give us more information. I have a charger that something like 2 amp 10 amps and two hundred amps. I have saved many batteries with his charger and I've been without it now for over a year. So now I'm going to take it apart and see what I can find. Here in United States they run on 110 so not near the danger I believe anyway as the 220 v you are used to. It shows the green lights and it will show which amperage I have it set at. But it won't show the red for charging. It doesn't matter which setting I have it on. I believe it also has six volt capabilities although I've never used it for 6 volt. Thank you I feel more comfortable after watching your explanation. I watched two others and yours has been the best

[@Xynudu]

110 volts can kill you just as dead as 240 volts. This is because the lower voltage usually has higher amps to give the same energy factor. So be careful when handling either voltage. Cheers Rob

[@theSam91]

I fixed my dads old 6v/12v battery charger this way, it was from England in the 1960's and had a selenium rectifier stack in it, changed over to a modern silicone type with no issue.

[@Xynudu]

I wondered how a selenium change over would work regarding the output voltage. One viewer said it is wrong. Did you check it ? Cheers Rob

[@markgardiner1767]

GREAT TUITION, WHERE DO I PURCHASE THE BRIDGE RECIFIER PLEASE ROB?

[@Xynudu]

Hi Mark. In Australia get it from Jaycar. Rest of the world try your local electronics parts store. A very cheap part. Also available on Ebay etc. It pays to get one that is a higher wattage than the rated amps on the charger. Larger is better and not much price difference. Cheers Rob

[@allthegearnoidea6752]

Great little fix thanks regards chris

[@Xynudu]

Useful to know. Even a non electric savvy person can do this one. Cheers rob

[@MartsGarage]

Hi Rob. I'm not too much of a sparky but I think even I could have a go at that. I have a couple of older battery chargers and they both work, my problem is the el-cheapo ammeters are all knackered. I've got a couple of late model so called more sophisticated jobs that I tend to use. I see the pos dc corner on the bridge rectifier has a bevel so it can be identified from the other side. that's handy. Cheers! Mart.

[@Xynudu]

Hi Mart. Yes, I noticed the notch. Handy if the pin markings are not visible. One of mine is so old it has a light bulb instead of an analogue meter. The bulb (red) gets dimmer as the amps get less - simple idea. Cheers Rob

[@johno7149]

Great Video, Thanks!

[@virtualmarc2383]

The problem with these old-style chargers is they're unregulated and the no-load voltage is quite a bit higher than the battery voltage. If you leave them on too long you'll cook your battery. By the time you're below about two amps you start to rise above a healthy charge voltage. This is partially due to the unfiltered peak-to-peak voltage being much higher than battery voltage.

[@Xynudu]

Yes, good points. Cheers Rob

[@Raj-nh3fc]

Yes very true. They are not as safe as the new smart chargers and I am surprised that people are still using these non smart charger. My Ctek charger has worked well for more than 20 years now. The cable got eroded and shorted on the low voltage side but no harm done to the charger due to short protection. Imagine if that happened to an old non smart charger! I plan to change that cable and keep on using it.

[@CAROLDDISCOVER-1983]

​@@Raj-nh3fcthe newest style of charger I just bought here in the United States probably about 3 years ago but they sell now Schumacher's the brand. If it don't have at least 9 you ever taken the battery won't charge it. Same thing with the batteries chargers at the parts store and Walmart and other places that charges batteries for free. I go through a lot of vehicles. So I have a number batteries on hand and I will tell you that 95 times out of a hundred batteries when they tell me they can't charge it I can bring it home and charge it. Why don't I charged it home well sometimes I'm using a battery on my trailer Hauling the car I ran the battery little low. I do not like the new style charges. But maybe that's not what you're talkin about. The reason why I'm looking at this video today is my fifteen-year-old charger will not charge. Is also a Schumacher. The oldest Schumacher I have is probably around 60 years of age. The newest one I have is three years old and I'll never buy another one I'll just continue to buy old secondhand charges.

[@apistosig4173]

I have one - had it for decades 🙂

[@Xynudu]

It should last you out if treated correctly ;) Cheers Rob

[@apistosig4173]

@@Xynudu Undoubtedly - last time I used it was messin' around with electroplating - far from ideal. I must have had it 40 years now. I reckon Arlec has always been underrated

[@jusb1066]

Some of the old metal case ones don't use a bridge rectifier but a selenium diode, it looks like a thing with heatsink plates. If you replace that with the modern diodes or bridge rectifier they overcharge..

[@Xynudu]

Interesting. I wondered about that. I take it the transformer output voltage is too high ? Cheers Rob

[@glennalldis5319]

Remember that the old selenium rectifiers are very toxic. Use gloves when handling - and if it has blown up and left any smoke residue clean up carefully!

[@wayneo7307]

Hi Rob . Thanks . I Never Complain about A Refresher Course.

[@seavee2000]

The older, cheaper classic battery chargers are far more reliable than the so called "smart" chargers-had several of those pack up but the old ones soldier on forever. Obviously unplug the unit before doing any soldering or replacement of components.

[@MiniLuv-1984]

Exactly right - battery chargers have gone from simple to complex for no good reason at all.

[@Raj-nh3fc]

Not true at all. My Ctek XS 3.6 amp smart battery charger has lasted more than 20 years and now one of the cable on low voltage side has shorted and I plan to replace the cable and keep on using it. Besides these modern smart chargers charge your battery correctly (by checking the battery state and charge it optimally, varying the current as required) and can keep the trickle charge on for months. They can even exercise and desulfate the battery. They are much safer than the old charger shown here.

[@RetroSteamTech]

Hi Rob. A nice cheap fix 👍👍 Sadly you don't seem to see those sort of chargers any more. Which is a shame because if looked after they would last for years. Cheers, Alan.

[@Xynudu]

Hi Alan. I have a couple and the Bro-Inlaw must have half a dozen. Old tech can be good. Cheers Rob

[@SeanBZA]

You still buy them new, but like everything else they have now been cost cut down to nothing. Way under rated in the transformer and rectifier, and the ammeter is often not present, so you just have a single LED to tell you if it is actually connected to the battery and hopefully the hum tells you it is charging. They are now almost empty, with no weight to them, because the tiny transformer is so small, and runs smoking hot.

[@Xynudu]

I'm not surprised ;) One of my old ones has a red light instead of an amp meter, which progressively dims as the amp draw drops. Simple idea. Cheers Rob

[@kentuckytrapper780]

Great info rob,thanks..

[@Xynudu]

Handy to know. It might even be useful one day ;) Cheers Rob

[@adamsorell4851]

where you get cheap rectifier?

[@Xynudu]

Jaycar or a similar electronics component stockist.

[@rcnelson]

Who sells these rectifiers?

[@Xynudu]

Most electrical component suppliers like Jaycar will have them.

[@james10739]

Mine seems to have 2 input windings for the 6v vs 12v and the outputs are 3 wires which appears to be center tapped and each of them went to a diode and from the diodes out so in my understanding not a full bridge rectifier and one of the diods broke off so i was trying a full bridge rectifier but i also had to have 2 extra diode to hook up both lines and it seemed to preform worse less current with them and the full bridge rectifier i know i have more diods in line now so the voltage drop wasn't a surprise but i assume without the full bridge rectifier i was getting 60 pluses a second vs 120 with the full bridge rectifier but that seemed worse not better i don't know what i expected but it didn't work for me so i went back with just 2 10 amp Schottky Diode and it seems to work fine but i expected a full bridge rectifier to be better

[@Xynudu]

Hi James. Did this unit originally have a Silenium rectifier ? Cheers Rob

[@james10739]

@Xynudu I don't know both the diodes were in a plate that became their commen output with a tab for the output on a corner but one if them broke off and the plate was riveted to the case with what appeared to be cardboard between as an insulator kinda looked like it could be soldered down but I don't know I just went back with Schottky Diodes I was thinking about using 1 full bridge rectifiers but I guess it's not that important

[@Xynudu]

Sounds like a pretty old unit. I have one similar but haven't fully investigated it. There are a number of circuits that were used over the decades. The more recent modular bridge rectifiers simplified things a lot. At least you got it working again. Cheers Rob

[@abelabner]

good explanation, ty very much!

[@Xynudu]

You're welcome!

[@dalemawby8717]

Great video. Will a charger still work if the amp metre is dodgy? I have one similar to this that's only 3 months old. It worked y'day but not today? Just found ur video

[@Xynudu]

The positive output all goes through the amp meter, so it needs to be fully conductive. If it is burnt out the current can't pass that point.

[@dalemawby8717]

@@Xynudu thanks Rob,,, fixed it this morning with an Amp metre from another broken charger

[@mohinderkaur6671]

Heatsink and heavier rectifier like 35 amps

[@ianbertenshaw4350]

And you can use it as a power supply for anodising if you’re into that sort of thing .

[@Xynudu]

Yes and also for electrolysis.

[@CraigLYoung]

Thanks for sharing 👍

[@Xynudu]

Thanks for watching

[@FrankLowe1949]

Very nice thank you.

[@MiniLuv-1984]

When you solder the legs, make sure you are holding the legs with a pair of plyers below the end to pull the heat away from the rectifier itself.

[@Xynudu]

Yes, good point Benny. I meant to add that but forgot. Cheers Rob

[@gorak9000]

You just need to be fast - if you solder it fast, there isn't enough heat to cause an issue. Ironically the hotter your iron (within reason) the faster you can go. The way you kill parts with too much heat is using an iron that's just barely hot enough to melt the solder and then sitting there with the iron on the part for a long time waiting for it to just barely get hot enough to melt the solder. I run my irons at 650F (~350 C). You should be on and back off the joint in 4 seconds or less with an iron that's sufficiently hot.

[@Xynudu]

Yes, good point. Also pays to tin the pins (and the leads) before soldering them together. Cheers Rob

[@MiniLuv-1984]

@@gorak9000 Correct, like you point out this is not a job for a once-in-a-while soldering, hence the suggestion to use pliers - invariably a newbie will have problems and could well apply too much heat and destroy the bridge rectifier....and when the bridge rectifier fails, they'll just decide to never touch anything like that again, which would be a shame.

[@NavinBetamax]

The output of the stepdown transformer is dependant on the input voltage. If the input is lower than rated voltage ----The output also will be lower than the raring specified. Also, if the input voltage fluctuates ---- will effect output voltage . This happens when this type of basic charger is used in remote village, where the grid is not stable !!!

[@Xynudu]

Correct. Mains voltage where I live is actually higher than standard. Some of this could be due to the use of solar panels to feed back into the grid. Cheers Rob

[@NavinBetamax]

@@Xynudu Yes Sir......Higher or Lower......Fluctuating when on same line as an Arc Welder....All have effect on this charger.

[@NavinBetamax]

I had to use Servo Stabilizer when working in remote villages with power from Single Cylinder Diesel GenSet ( ancient WW2 vintage ! )

[@oturanboga6225]

[@dumpy4289]

heatsink paste between rectifier to case can help keep the thing cool - note that paste is not nice to humans

[@Xynudu]

Good point. Cheers Rob

[@djpaulk]

Well the bridge rectifier sounds cool.. Don't wear out the word. It's 4x diodes.. Now. You own a tata, forget the charger. Mount a solar panel on the roof wired to battery via charge controller.. Then hang and paint shiney and bright colours on it... Don't electro anyone. Mind how yow go. Nice vid though. Paul

[@Xynudu]

I run a small solar panel on one of my cars to keep the battery topped up. Buy the correct type (number of cells) and you don't even need a regulator. Cheers Rob

[@djpaulk]

@@Xynudu But its only about 6 or 7 bucks from Banggood... Sorry, did that not turn out as a link 😉 And you need your panel to have a diode to stop battery drain.

[@Xynudu]

Yes, a diode is necessary for night time. Mine is an early panel made/sold by BP - about 0.75 amp and has a diode. Cheers Rob