Battery Desulphators/ Desulfators - What are they?

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We are now trialling a potted basic desulphator/ pulser in response to some customer enquiries as per the adjacent photo. Production models won't have the capacitor poking out like this!!! Furthermore, unlike one of our competitors, we won't be charging you £125 for 'the only waterproof desulfator on the market'!!

A Google (or other internet search engine) search will bring up a whole host of references if you type in desulphator/ desulfator or pulser (although in truth these devices should be called battery desulfators to segregate them from pulsing type battery chargers which are a different animal).

Which route to go then you may well ask, we would recommend looking at http://www.homepower.com/files/desulfator.pdf or http://home.comcast.net/~ddenhardt201263/desulfator/desulf.htm as a start as this is what we did?

So you're probably wondering do these devices really work because we wondered exactly the same thing? The presence of the former ezboard BB now found at http://leadacidbatterydesulfation.yuku.com/ and people who clearly believed it did led us to 'give it a try'.

Reading through the whole of the BB's above took some time and is something that not everybody will have the time or inclination to do (unfortunately quite a bit of the historical stuff on the former ezboard desulfator forum has been lost). We certainly don't profess to understand all the technical parts of what they contain but it does allow you to see how some 'improvements' to the original AC design have been arrived at.

We make no claims to having 'designed' outright the Basic and High Power devices we offer for sale but have done some 'matching' with regards to the replacment parts we've used.

The 'High Power' desulphator/ desulfator version is a development of the original and is an amalgamation of several threads on the BB.

For those less confident in their electronic skills we offer the kits built up in two stages. One is simply the device built on its PCB and tested ready to be fitted with leads and boxed by the customer.

The fully built version is just that, it is supplied in a box c/w output leads and a pair of battery terminals ready to go (as noted elsewhere crocodile clips and the plain 8mm soldered ring terminal are other options).

Basic Pulser Kit

This kit is the circuit in its simplest form with some substitute components that have been tested to ensure they work. The cheapest way to start.

The only modifications are the addition of a Zener diode to protect the 555 from voltage spikes, an LED to show it is 'working' and both electrolytic capacitors are larger values.

All the necessary components and a PCB are supplied along with some brass nuts/ bolts and washers to make mounting posts to connect the leads to the battery. It consumes about 50mA.

High Power Pulser Kit

This version is a development of the basic version for which we take no credit that belongs to the contributors at the Desulfator BB.

In addition to the above basic modifications this kit has a superior MOSFET, a larger still output capacitor, larger capacity inductors and R2 (the 22k resistor) is replaced with a pair of 47k NTC thermistors in parallel. These will be supplied 'glued' directly to the components themselves.

All the necessary components and a PCB are supplied along with some brass nuts/ bolts and washers to make mounting posts to connect the leads to the battery.

This version is a more powerful pulser than the Basic device and consumes more current - circa 110mA.

PIC Pulser Kit

This device is based around a PIC (Programmable Interface Controller) and was designed by my Canadian colleague Rick who should take all credit for the design and development. Basically Rick had looked at the Alastair Couper original designs and concluded they had certain shortcomings being based around a simple 555 timer and set about developing his own device.

The current version is our most 'powerful' desulphator/ desulfator and consumes some 300+mA of current and is ideally suited to larger batteries. Additionally, as of 10/04/09, it has been revised to incorporate a TC4428 MOSFET driver chip in place of the previouse 2N3904/ 3906 driver (totem pole) set-up. As a kit the PCB is now double sided eliminating the two wire links previously required making it a more 'user friendly' kit.

Ready Built Units

Self-explanatory. If you are at all unsure as to your electronic abilities I would strongly suggest you let me build them and then you know that the supplied unit will have been tested and proved to be fully working. Peace of mind starting from only £10.

Output Leads

Our previous choice of two has now been rationalised to this one in view of its superior performance. It is 5mm diameter 10AWG 83 stranded copper wire, terminated in soldered ring connectors.

Battery Terminals

Self-explanatory really. Two off, one for each terminal, with a 8mm post for attaching the output leads.

Complete Pulsers

These units come complete in that they are in an ABS box with output leads connected to battery terminals and 'ready to roll'; as soon as they are unpacked. The LED is inserted in the lid.

IMPORTANT NEW POINT (as of 16/01/06)

We have now developed a working reverse polarity system and all devices will be provided with them with immediate effect. This will incorporate a user replaceable externally mounted fuse in the case of ready built units. Previously our kits were supplied with the necessary parts (Add-on Pictorial) to effect this add-on but with our recently revised PCB (01/02/08) all the parts are included on the PCB.

How do I know its working?

All battery charging operations should be carried out in a well-ventilated environment, this is doubly so when connecting or disconnecting a pulser.

Basically you can consider it is working if:-

1. The LED is lit
2. None of the components get hot or go pop. The recommended way of doing things is to connect the negative lead first and then touch the positive lead to the battery terminal briefly. This should be accompanied by some low level sparking (the need for the ventilation now clear perhaps?).

   If it sparks then leave it connected for a couple of seconds and then disconnect and check component temperatures.

   Re-connect for a slightly longer period and then disconnect again and check temperatures.

   It will be self-evident if all is well.

3. The unit emits a 'buzzing' near 1kHz tone, if you're hard of hearing then grab an AM radio and turn the volume up and stick it close by.

MOST RECENT DEVELOPMENTS

Various devices/ options continue to be investigated. As noted on the Home page we are now selling a 24V version of both our Basic & 'High Power' device in response to customer requests. We are currently working on a low voltage disconnect option.

FUTURE DEVELOPMENTS

We are currently looking to a SMD (Surface Mount Device)/ PTH (Push Through Hole) hybrid version of our PIC based device. This will allow us to market a much more compact device which we are also hoping will be an even more successful device than its conventionally built 'cousin'. We are looking to replace the discrete MOSFET driver set-up with a dedicated MOSFET driver chip which is showing a much improved, faster switching characteristic.

Once the hybrid is introduced we will continue to market the existing PIC device in kit form, although it will be upgraded in line with the hybrid version should it prove succesful.