Reality: SMPS vs Linear supplies

[tvtech]

Hi Folks

Those that have followed my love of Linear and hate of SMPS should consider a few things...

First thing is I deal with rubbish SMPS every day of my life....the Chinese designed? basic CRT SMPS...2sc3807, Chopper Transistor (could be anything),
around 3 1N4148 Diodes, a Zener, a few Caps and a few other resistors here and there...basic crappy SMPS is what I deal with daily. Designed to be fixed but not to last...if they did it properly...I would be free and flying. Not fixing the same stuff day after day.

So, I hate SMPS?. Yes I do. Except well designed SMPS that I truly envy...

SMPS supplies that in a sealed little plastic box can be so damn reliable. Even after 8 Years in my Lappie. Common, @90W for my Acer 5680 this little box that feeds it is still good to go.

Caps are not popping. Sealed and has been through multiple power surges and brownouts in 8 Years....just keeps doing it's job.

So reliable but also well designed. I don't work for Delta Electronics that make these...but I will acknowledge them every time. They know their stuff..

Onto me. Linear man.

My thoughts have changed. If you work with rubbish SMPS all day long..you tend to hate them....the proper ones last. Linear PSU's are wonderful and reliable and don't radiate EMI. I believe Toroidals and Linear will be around for the hi fi fundis..

Battery charging is another matter. Different horses, different courses.
I wanted to re start my 2004 project with crap going on here now..

In 2004 a 160Va Toroidal rated @ 220Vac in and 15V out @ around 6A cost me R300.
The same thing Today will cost me around R700 to R800...

I can buy a three stage charger now...SMPS....gives 20.85 A, continious rating 12.5 Amps...three Year Warranty included. It can think and do stuff to keep a SLA happy..

Three Year Warranty...but they also talk about 115 K Hours MTBF....115 K hours = maybe 13 Years running 24/7/365.

I cannot build a Linear charger for anywhere near that kind of price or reliability...and the SMPS puts out minimum 3X more Current than the best Linear I could do with the same money

Link here:

Serious re think about SMPS for me.

 

[tvtech]

Ordered it and it arrived today. I am very impressed. Build quality is excellent. Made in Taiwan and not China.

First thing I did when I opened the box was to shake it and see if anything rattled around. Nope. Smooth edges too on a product that consists of an extruded Aluminum casing with excellently assembled other bits. Looks and feels like it will last a lifetime.

Plug it in, switch it on (no load)...output Voltage spot on. Let it sit there for a while on Mains. Kind of a simple run in test. Leave it like that for a while.

Check with my Fluke if anything has changed after an Hour or so...nope, still the same.

Take my 65Ah SLA and connect it to charger and let it fly. It is pulling the battery up to 14.4V now and the battery is loving it. Sitting @ 14.15 V now and it will take a while still. No drama or anything.

Funny thing...I have never messed up a tiny little rechargeable PP3....but I have had some bad experiences with Lead Acid batteries dying. So far, looking good.

Yup...my new investment has reached 14.4V for the battery and has now settled on Float @ 13.65V. Green light is on and I am one very happy camper

I bought a well made battery charger....for me it feels like I was just handed the keys to a Ferrari. Feels so good to deal with quality again with all the rubbish I deal with daily. Thank you Manny and your Staff. I will try my very best to promote you and your business on the the WWW.

Regards,
tv

 

[tvtech]

Anyway FWIW from a guy that has stuffed up SLA and Lead Acid Batteries in general over the last 10 Years or so...I thought I should share this so people can learn and not make my expensive mistakes. My little PP3 project has never slayed a battery yet with all it's ongoing testing for the last two years..all are still well.

Lead Acid is another animal though. I never got that right even though I thought I understood them. I have slayed a Lead Acid Battery within 20 Minutes by using it for an application it was never intended for.....deep discharge a normal car battery.....and it's capacity is reduced permanently...no proper charging will even fix it.

Remember leaving your car lights on or playing music loudly while the alternator is not charging the battery....because the cars motor is off?
Car won't start thereafter and pushing it or jump starting is a temporary solution. The battery has already been damaged.

That horrible click, click,click sound you hear when you try and start and you ain't going nowhere

Anyway here is a nice link as to why car batteries are a bad choice of things to use until they are totally flat: https://www.otherpower.com/off-grid-battery-guide

Aaanyway, hope that I am not boring people.

So, making an all night post quick, I have learned a bit.

Purchased a 65aH 12V SLA Battery, a PROPER charger for it (SMPS good quality and able to throw all the Amps that the battery can handle when charging). Used in a UPS system and not cars...

Probably everyone is confused now. Wondering what I am on about

What I really want to say is to buy the charger that get's your flattened batteries up to speed as fast as possible. If your flattened SLA or whatever need say 60Amps....and they can handle it...feed it to them. You cannot do this with a Modified setup like in the Video below....they will take forever to charge.

And that's that. One thing to flatten batteries.......charging is another matter altogether.
That is how I stuffed them up. Witness below video...

Enjoy

tv

 

[MikeMl]

Good write up why automotive starting batteries are no good for deep discharge applications.

After you do the D.S. thing, leave your headlights on in a car to where the battery goes completely dead, even though it appears to take a recharge, in my experience, you might just as well recycle it and buy a new one, 'cause the damn thing is going to leave you stranded right when it is most inconvenient...

I get a chuckle out of all the newbies that come on here making a small solar home system that think they are going to use car batteries for storage...

 

[tvtech]

Good write up why automotive starting batteries are no good for deep discharge applications.

After you do the D.S. thing, leave your headlights on in a car to where the battery goes completely dead, even though it appears to take a recharge, in my experience, you might just as well recycle it and buy a new one, 'cause the damn thing is going to leave you stranded right when it is most inconvenient...

I get a chuckle out of all the newbies that come on here making a small solar home system that think they are going to use car batteries for storage...

Thanks Mike

I never stop wanting to learn. And help those that are prepared to listen to my never ending adventures where I sometimes shoot myself in the foot...but then they learn too.

That post took me ages. Was worth it though

Regards,
tv

 

[JimB]

It is probably only in the last 10 years or so that I have learned that a "Car Battery" is not good for powering things long term and going in to deep discharge.
How this little snippet of info evaded me for so may years I do not know. Maybe because I was introduced to car batteries at an early age and never had a job which called for any in-depth knowledge of lead acid batteries, other than that they can go BANG and seriously ruin your day!

Traditionally, battery chargers for lead acid types were just a transformer and rectifier, a crude ammeter if you are lucky.
I still have such a device which I use for topping up batteries on a car which has sat unused for a week or two. Just dont forget about it for several days.

I once left my car at the airport for two days, with the lights on. Battery was as flat as they come.
My wife was not impressed to get a phone call at 20:00hrs or so, asking to get the jump leads and drive 30 miles to come and get me started.
Got the car started and the battery kept going for a couple of years after that. Lucky.

JimB

 

[tcmtech]

When it comes to SMPS and battery charging I have mixed views. For low charge/maintaining work I love them but to be honest when it comes to getting a stone dead vehicle or piece of heavy equipment started quick I have yet to ever find any SMPS that was affordable or that could be affordably built that could put out 200 - 400+ cranking amps until either the engine started or the main power line breaker tripped.

Heck to be honest have not found any SMPS based chargers that would even try to revive a flat dead starting battery whereas most any old school transformer type could care less about what the battery condition was.

 

[Overclocked]

Theres also the simplicity of a linear power supply that makes it very attractive. They are so dirt cheap and simple. They can be small when Vin is close to Vout. They can also give great performance without breaking the bank, and can be tailor made to spec (A opamp and a transistor/fet). I like linear power supplies for powering off line stuff. I LOVE smps tech when Im powering stuff from batteries (LEDs, micro's, etc). For battery charging, its linear all the way.

 

[Mosaic]

I have learned a lot about lead acid batts in the last 3 years. Having processed about 100 totally dead auto sized batts I have seen all types of failure modes. There can be some surprising recoveries though. I have documented 12V batteries sitting @ 3 to 5 V with near water for electrolyte coming back with 75% plus AH capacity and going back to running vehicles on the road.
If a battery suffers a slow drain like a roof light or just ECU drain until it's not serviceable, it has a good chance of being restored with proper charging procedures. It's the high current, deep drain activities like using auto batts for UPS purposes that will warp the plates, shed the grid material and basically wear out the battery in no time.

 

[b.james]

When you discharge them below 11 volts or so a new battery is buggered . Seems as thouugh the inside reserve energy in the plates comes out and never goes back in again. Then it just slowly sulphates up , that falls off with the movement and there is no room for it to go down there on the floor so it soon shorts the plates.

Interesting aside is to take a tired lead acid battery ,empty the electrolite out ,fill with strongish bicarbonate of soda solution ,allow it to fiz and empty and do again . That neutralises the sulphuric acid , then fill up with Alum ,pickling salt or aluminium sulphate , whatever you know it as . Charge it and get a few more years out of it.

All fun but we realy need a bloody good battery for cars. These LiPo are the best I have seen yet.

 

[Mosaic]

When you discharge them below 11 volts or so a new battery is buggered . Seems as thouugh the inside reserve energy in the plates comes out and never goes back in again. Then it just slowly sulphates up , that falls off with the movement and there is no room for it to go down there on the floor so it soon shorts the plates..

Partially right and partially wrong. I have recovered batteries under 5V @ no load.

Amorphous sulphate becomes crystalline over some time, months really. Only extreme crystalline sulphation can cause swelling and destroy the battery. There is a window of perhaps a year or more during which the battery has not physically warped and proper recharging can recover the battery. Ordinary voltage limited chargers cannot charge the battery. It boils down to the amount of intact plate material.

 

[b.james]

Apologies tvtech . I fully agree on well made Swiching power Supplies and ham radio is much the lighter and more reliable with them.
Some posts need to be answered however

Partially right and partially wrong. I have recovered batteries under 5V @ no load.

Amorphous sulphate becomes crystalline over some time, months really. Only extreme crystalline sulphation can cause swelling and destroy the battery. There is a window of perhaps a year or more during which the battery has not physically warped and proper recharging can recover the battery. Ordinary voltage limited chargers cannot charge the battery. It boils down to the amount of intact plate material.

Whaen you have 60 years of playing with them talk to me again. If you are talking about a 12 Volt battery discharged to 5 volts and made new again its pie in the sky friend.

Your use of the term " Amorphous" is wrong I think. Have a google on it . What gives the problems with lead acid batteries is "Lead Sulphate ". Having pulled many hundreds apart it is a white powder when dry. These days the problem is exacerbated by the brown spongy lead that is packed in plastic sheaths between the plates. It breaks up with vibration

 

[Mosaic]

Clearly you think you know it all....
Very good.

BTW, 60 years of lead exposure does things to the brain and body....FYI.

 

[b.james]

Well mate you are saying I'm wrong and I know I am right . That said I could go on learning about lead acid batteries for another hundred years and still have some to learn . Hope not though

 

[Mosaic]

When I publish my data, we shall see who is mistaken.

 

[tcmtech]

BTW, 60 years of lead exposure does things to the brain and body....FYI.

Only if it was handled wrongly or foolishly for extended periods. Otherwise it surprisingly harmless despite what the media would have you believe.

 

[schmitt trigger]

tvtech:
It is surprising how much Taiwan-made products have improved. ln the late 70s and early 80s they were synonimous with junk.. Not anymore.

 

[b.james]

tvtech:
It is surprising how much Taiwan-made products have improved. ln the late 70s and early 80s they were synonimous with junk.. Not anymore.

Mate in regard to lead acid batteries you have got to be kidding !
We used to have battery cases that you could replace a defective cell and reseal ,now one defect and you throw it away.
The Taiwanese keep reducing the size of connections to save money . Pull one apart and have a look . The intercell connectors are about a tenth the size needed if the battery is to last . They are built to last 3 years max now and getting less.

 

[Mosaic]

Gotta agree with that. My recovered units eventually fail due to grid or interconnect positive corrosion. Not because the battery capacity is gone.

 

[schmitt trigger]

Mate in regard to lead acid batteries you have got to be kidding !
We used to have battery cases that you could replace a defective cell and reseal ,now one defect and you throw it away.
The Taiwanese keep reducing the size of connections to save money . Pull one apart and have a look . The intercell connectors are about a tenth the size needed if the battery is to last . They are built to last 3 years max now and getting less.

Correct!
But I was talking about electronic assemblies