Combined battery desulphator and charger idea.

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (tundrawolf) — Thu, 13 Nov 2008 14:07:15 GMT

I thought I was posting a new thread.. Sorry about that. I'm also sorry about the refrences to commercial products.

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (tundrawolf) — Wed, 12 Nov 2008 16:48:35 GMT

I realize that, however I use the inverter minimally, and the solar panel is really only for maintenance. If I HAVE to, I can jump the system with my truck, but I rarely if ever have to do that.

I'd like to build a desulfating charger myself, but the absence of a schematic and parts list (Including full tolerances, a "Shopping list" of components if you will. Like: R1 is a 1/4 watt 30 ohm, 5% tolerance resistor.) makes it hard.

I will keep an eye on this...

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (desulfator2) — Wed, 12 Nov 2008 09:01:51 GMT

Offhand it doesn't sound like a 6 amp charge source is enough to recharge 5 batteries regardless of the configuration of the charge controller.

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (tundrawolf) — Mon, 10 Nov 2008 14:17:04 GMT

I have about 5 110 AH batteries wired for 12V, and a 110 watt solar panel. The panel nominally puts out 6 amps.. Is there a pulse charger, or a charger with built in desulfator schematic and parts list available? I am pretty well versed in electronics, and I do have several oscilloscopes, however it is proving difficult to understand what you guys are discussing here. My batteries are going out slowly, and I thought "What if there was a do it yourself schematic on this forum for a built...

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (NavyTrained) — Mon, 31 Dec 2007 15:10:50 GMT

I too have considered a circuit such as the one you have linked to.

Bipolar transistors may be used as high speed switches but it is necessary to use a drive enhancement circuit to assure speedy on and off switching times. MOSFETS generally work better and with much less loss as heat provided they are driven with sufficient gate voltage to assure minimum drain to source resistance in the on state.

The circuitry needed to adequately drive a MOSFET is a little easier to deal with...

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (vgtz) — Thu, 08 Nov 2007 11:45:07 GMT

I was thinking about giving something like this a try:

www.isd.net/csoren/desulfator.jpg" width="877" height="316">

I don't think the 1 ohm resistor strictly necessary...

Thoughts, anyone?

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (als) — Sat, 21 Jan 2006 08:50:37 GMT

Already done. Long ago. One version:
people.consolidated.net/a...html#vers3

I have other versions; all work. Some better than others.

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (BOARDMAKER) — Thu, 12 Jan 2006 17:49:26 GMT

A good low on resistance fet that can hanle some current is the IXFH58N20.
This is a N channel fet,i have used several of these for a 200w transmitter with a TC4422 fet driver at 1.9mhz!

The gate capacitance is approx 4400pf + miller effect,also the voltage rating is 200v and has an resistance of 40milli ohm.

If you go to higher voltage devices the input capacitance and miller effect are far less,at the expense also of higher on resistance.

This fet i used on the 555...

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (fun4menow20012000) — Thu, 12 Jan 2006 16:14:06 GMT

Hi All.

I too have been working on a new pulse charger design. I had a very sucessful first prototype in april of 2005. I posted my results here, but most of those posts have disapeared now.

The new model is still only on paper. It takes in 5VDC from a standard/cheap computer PSU and makes whatever charge voltage it needs using a boost stage. I have chosen 24V because I know it works well at charging and desulfating. The output voltage is set via a feedback resistor in the...

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (desulfator2) — Thu, 12 Jan 2006 14:54:39 GMT

I suspect you are right in using a singular large FET at 10 times the pulse rate.

What FET did you plan to use?

I do not vary the pulse width for battery voltage regulation. It does sound like an effective method for float charging with a pulse charger though.

In the equipment I build, FET duty cycle is governed by FET heat gain. FETs are only allowed to rise 20 degF over ambient. This is why I have the Stamp or PICAXE closely monitor ambient air and FET...

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (BOARDMAKER) — Thu, 12 Jan 2006 13:03:11 GMT

Yes i live in the UK.
I am just wondering what the advantage to sequentially firing say 10 fets over using one bigger fet at 10 times the pulse frequency,i thought this would be the same.

Do you still use a very narrow pulse(similar to an inductor),or do you fire the fets at say 1% duty cycle each at 1khz?
Also do you vary the pulse width for battery voltage regulation?

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (desulfator2) — Thu, 12 Jan 2006 10:24:00 GMT

I was a little puzzled over your first sentence,

"I would imagine you would use sequential pulsing with separate inductors and then combine through diodes to the battery?"

In the pulse charger, no inductors were used. The NFETs simply interrupted the negative from the power supply to the battery negative.

I gather from your use of "whilst" that you reside on the other side of the pond.

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (BOARDMAKER) — Wed, 11 Jan 2006 20:08:55 GMT

I would imagine you would use sequential pusing with seperate inductors and then combine through diodes to the battery?

I was not thinking about varying the pulse width for charge control,i was merely thinking of getting a reasonably high voltage sharp waveform in to the battery.

Any sharp rise and fall wave forms will produce plenty of rf,sm psu's are a prime example.

As i have not got in to pic micro controllers i logically thought of using fet driver ic's,the reason...

Re: Combined battery desulphator and charger idea.

feeds@yuku.com (desulfator2) — Wed, 11 Jan 2006 18:24:49 GMT

I think Pulse Charging is a great idea. It combines desulfation capbility with a charger.

I suspect that the voltage used to pulse with will be dependant on battery size (resultant amps).

I think you may find that only the ON time is critical. The leading edge of a fast rising pulse is needed to desulfate.

I just shipped a prototype unit that...

Combined battery desulphator and charger idea.

feeds@yuku.com (BOARDMAKER) — Wed, 11 Jan 2006 16:24:46 GMT

I have been very interested in the desulphator circuitry on a technical level for recovering desulphated batteries.
I have 4 85ah leisure batteries that are not old but have been left discharged for a month or two.

I have put together the 555 circuit and monitored the battery posts with a scope.

What springed to mind was making a pulse width battery charger,beside charging the battery,it could desulphate too.

Would the battery desulphate faster if say you were to...