CTEK Multi XS 15000 destroyed by Desulphator?

On Sun, 25 Mar 2012 13:18:24 -0700 (PDT), joost put finger to keyboard and composed:

I'm not familiar with your charger, but I would look for a device, eg a MOSFET, in series with the output.

A photo of the innards might help.

- Franc Zabkar

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Please remove one 'i' from my address when replying by email.

There are lots of claims made by desulphator vendors. I've never read anything, outside the vendor sphere of information, that said they worked at all. My experiments agree that they don't work. I assume you wired the desulphator correctly?

The symptom of a sulphated battery is high internal resistance. One theory is that if you put a huge voltage spike into the battery, you can dislodge or reverse the sulphation.

One measure of the progress of desulphation is to watch the amplitude of the spikes go down as the process proceeds. In my experiments, I never saw any reduction in spike amplitude and never experienced any improvement in ability to take/deliver charge.

So, if your batteries are sulphated, you'll see high voltage spikes. Only a good battery could absorb the spikes...in which case you'd not need a desulphator.

Sounds like you shorted whatever controls the charge current in your charger. May be a FET or SCR. Is there any activity on the lights on power up that suggests the logic might still be working? I assume you checked for a fuse somewhere in the logic supply? If the pulser jacked the VCC up to the peak of the voltage spikes, you probably fried the whole thing.

Not clear what charger you have, so downloading the manual is ineffective. Without schematics, or an understanding of battery chargers that you don't appear to have, it's gonna be difficult to fix it.

You're probably going to want to probe around in it live with an oscilloscope. Looks like an offline converter that can be dangerous to service without proper equipment (AKA You get dead).

Just found the model number in the subject line. Manual says it has a built-in desulphator. Why did you add a second one?

I agree. I maintain several mountain top radio and weather station sites, all on various mutations of battery power. Various experts have arrived with desulphators and magic anti-sulphation potions (EDTA), none of which have done anything beyond a short term revival.

One problem is that none of the articles I've read that proclaim miraculous battery rejuvenation bother to run before and after tests. I have a West Mountain Radio CBA-II battery tester.

With a 10A discharge rate, the L16 batteries that I usually use (2V

465A-hr) take about 4 days to hit the knee in the curve. Your T105 (6V 225A-hr) should take about 2 days. However, that's with a new battery. What I've found is that a pre-treatment battery, may have about 1/4th of it's original capacity, while a post treatment battery will have even less. The post treatment battery will "take a charge" better than one that seems sulphated, but the discharge capacity isn't there.

Diversion: When you discharge a wet cell battery, you solve the lead plates into the electrolyte solution. When you charge the battery, you electroplate the lead back onto the plates. It never quite goes on the same way it came off. Do it often enough, or too fast, and the lead plates start looking like a coral reef with attendant loss of capacity.

What's happening is the result of doing a post mortem on only one battery, so this is admittedly rather anecdotal. What desulfation does is remove the coating of lead sulphate from the lead plates. That's fine, except that by the time the battery becomes sulphated, the normally porous (sintered) lead plates, now look rather like a coral reef. Exposing more of the lead plate surface should will improve the ability to take a charge, but the discharge is still at the mercy of the lack of sufficient surface area, and that's going to be as bad or worse than what you started. Worse, the shock treatment of de-sulfation can cause chunks of lead sulphate to fall off the surface of the lead plates and fall to the bottom (i.e. deep cycle), taking some of the coral reef looking lead to go with it. The reduction in the amount of lead in the battery plates will have a detrimental effect on future charge/discharge cycles.

Links to a typical crude desulphators:

Good battery advice:

As for connecting two charger in parallel, you're lucky that one of the chargers didn't blow a fuse, or an internal component. Don't do that again. If you RTFM at:

it says: "Do not place the charger on the battery while charging"

I couldn't find a schematic of the CTEK MULTI XS 15000 which might help with a repair. On paper, it looks like a really nice battery charger. My guess(tm) is that the desulfation contrivance is capable of producing some rather high voltage pulses. Those could easily have destroyed whatever output power FET's are inside.

Make and model of the desulfation device?

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

I am sceptical about the desulphator, but as a new set of batteries costs me

300 euro, I thought, let's give that 30 euro kit a try. Of course not knowing that it would kill my 200 euro charger... To get some more info on my spikes, I just connected a capacitor and a diode. It showed 62 volts. Oops. This must certainly have been the cause of my charger problem.

The logic of the charger seems to be fine and looking at the amount of gassing it also seems to be putting out plenty of current. I did saw at least one FET inside and will go and check out that one and others that I can find. I tried to find a schematic, but couldn't.

The funny thing indeed is that this charger has a built in desulphator. This also led me to think that desulphators could work. If a reliable manufacturer like CTek is building it into its chargers... The problem that is that the CTEK only stays in desulphation mode for about 5 seconds. I cannot imagine this to be effective at all. Therefore a tried the desulphator kit.

The desulphator comes from Courtiestown:

Thank you all for your comments. I hope I'm lucky and can get it running again. Will keep an eye on the peak voltage of the desulphator too, to see if mine is perhaps dropping.

Joost

Hi,

It is all not so very accessible inside the charger. I identified at least one IRF1405 FET. There is second one which might be the same type. Then there are two larger boxes also attached to the heatsink. Three heavy legs. One has the writing D4 on the PCB and the other one D4A. Could these be the SCRs that you mentioned? Are these sensitive to voltage spikes too?

Joost.

.

Output SCR's go with battery chargers having huge transformers.

Your smart charger probably is a straight forward converter with logic built around the current and voltage sense to control it. The good news is that it sounds like the charging path is working. Bad news is that you probably broke something hooked to the output to sense voltage and current. Follow the signal path from the + and - output terminals back to some IC. That's probably what you broke...maybe... There are lots of ways to do this function. Hard to know what to expect knowing nothing about it.

The things labeled D are probably diodes.

You need an oscilloscope and an Isolation Transformer, and someone who knows how to use both, to work on this thing.

Don't underestimate the potential of this thing to hurt you. You don't have to get electrocuted. All you need to do is go flying across the room and land on the corner of a desk.

Wear safety glasses. I scratched a cornea in a freak accident when I came flying out the back of a TV set I was working on. And I've still got scars where a slip of a probe caused a FET to explode in my face. There's a lot of energy in a tiny space. Be respectful.

I've avoided using desulfators with any of my intelligent chargers for the very reason that you've experienced.

BTW, something that seems kinda odd, is that the pdf instructions for the desulfator kit are dated as modified 25/03/2012, the same date as your post.

The desulfator instructions caution against using sophisticated/intelligent battery chargers with the desulfator unit.

The desulfators I have are made up of just common components used for creating the pulsing circuit.

I'm generally very doubtful of "miraculous recovery" products.. dead is dead (although I do like a good Zombie movie). Weak, old batteries need to be replaced. Neglect and abuse typically aren't reversible, IMO. That said, I do find it believable that a desulfation cycle can be useful as part of regular service, maintenance and charging routines. By desulfation cycle, I mean a separate action, not applied while the charger is connected/active (although marketers claim desulfators can be connected permanently.. car battery applications, for example).

I'm not familiar with the CTEK charger, but the 17V you're seeing could be the full upper voltage level of the charger power supply, before it's regulated down to 13.8V (or the appropriate output voltage), so the suggestions regarding the likely damaged output devices seem reasonable.

Lead acid batteries are basically the same as they have been for generations.. the capacity density has been improved and newer production methods and materials have improved reliability. Even though chargers now have uP control/monitoring, proper charging practices are the same. The most practical approach is routine monitoring and testing.

The most reliable option may be to have CTEK repair and recertify the charger.

-- Cheers, WB .............

Nice kit. Unless I'm reading the manual incorrectly, it suggests that it is possible to run a battery charger and this desulfater in parallel, at the same time. DO NOT CONNECT THE DESULPHATOR TO THE BATTERY CHARGER - CONNECT IT TO THE BATTERY & THEN CONNECT THE CHARGER. MAKE SURE THE BATTERY CHARGER IS UNPLUGGED FROM THE MAINS SUPPLY BEFORE CONNECTING/ DISCONNECTING.

In my never humble opinion, this is a bad idea, and asking for a failure. I don't want to think about what high voltage pulses can do to the attached electronics should the battery discharge and go to high internal resistance.

If repeated at regular intervals, that's allegedly the desireable mode of operation. Short bursts to break off the lead sulfate encrustations, and long periods in between bursts for normal operation.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

The instructions also state:

1. The desulphator should be used in conjunction with a simple trickle battery charger. We would caution against using the desulphator in conjunction with more modern intelligent chargers...

And.. recommendations to use a choke in series with (other) inverter type chargers.

So it seems, the only types of chargers which are considered immune to damage when used while desulfator pulsers are conected to a battery, are transformer-rectifier types.

I'd done a considerable amount of reading about desulfator pulsers a few years ago and found no mention that only the use of basic/dumb chargers as being the recommended equipment.. although it seemed risky to have high energy pulses applied to sophisticated chargers' output leads.

-- Cheers, WB .............

Test for shorted power semiconductors or anything attached to a heatsink.

It's probably a Murphy's law type thing, but most power supplies fail with no output, but battery charges like to magically fail at full voltage output, just to destroy your batteries at the same time.

On Tue, 27 Mar 2012 16:36:27 -0400, "Wild_Bill" wrote: (...)

I found this article on sulfation problems and pulse chargers:

from the Aug 2011 issue of Popular Communications magazine. Gordon West and PulseTech claim that pulse charging works to prevent sulfation. Nothing on how to deal with an already sulfated battery. Includes some interesting photos of what the plates look like with technologies.

More on the X-ray diffraction tests for battery sulfation: Summary:

Full report is 50 MBytes:

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558