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windlight
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Joined: 03/03/2007
Location: Australia
Posts: 331

Posted: 04:53pm 14 Jul 2017

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My neighbor purchased a new Woods D2430 charger, paid a kings ransom I may add, it ran fine for a few months then died. Question is are these suitable for charging gel batteries?

The supplied repair report shows a very burnt secondary, but states that it is functioning as per spec. I do have a copy of the report but as always I can't attach it, computers hate me.

Allan

"I like this place and willingly could waste my time in it" - (Act II, Scene IV).

brucedownunder2
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Joined: 14/09/2005
Location: Australia
Posts: 1548

Posted: 01:11am 15 Jul 2017

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Hello Allan,

John, of Oztules , would be a Good start.
He,s very cluey,has constructed many parts . I suppose that comes with living on an island,.sort of ,have to fix it, type of situation.

When you coming down to the big smoke,mate.??
There,s a bed and workshop available.

Bruce,Ilda, .

Bushboy

windlight
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Joined: 03/03/2007
Location: Australia
Posts: 331

Posted: 01:10pm 15 Jul 2017

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Hi Bruce, good to hear from you ol mate, yea it seems the dial o matic are not suitable in so much as they are not voltage limited, and as such can over voltage a gel battery.

They do make a more sophisticated charger that is suitable, but at a cost, it seems to me that my neighbor needs to upgrade to a Selectronics inverter/charger.

Further it seems to me that Woods expect the charger to be matched to battery amp hour for safe operation of the charger, all in their brochure. Their expectation seems to be that the charger will bring up the battery voltage and charge current will be backed off before the charger overheats. As always a 30 amp charger is only a 30 amp charger for about an hour.

Am finding that some "modern" switch mode charger are not all that compatible with inverter generators in so much as the generator does not see it as the load it potentially is.

I just keep having fun up here in the jungle.

Allan

"I like this place and willingly could waste my time in it" - (Act II, Scene IV).

yahoo2

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Joined: 05/04/2011
Location: Australia
Posts: 1166

Posted: 02:34pm 15 Jul 2017

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I run across quite a few woods chargers when I do system upgrades.

the way I get around this is to fit a voltage switch that disconnects the charger at a set point at around 85% charged voltage. I also have fitted mechanical timers out of clothes driers for some of the wet lead acid guys.

There is no real point in trying to charge to 100% with a manual charger, bulk charge only, it is the job of a solar controller to do the topping up we just have to make it easy for it to get there on those sh

ty days.

I'm confused, no wait... maybe I'm not...

oztules

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Joined: 26/07/2007
Location: Australia
Posts: 1686

Posted: 10:49pm 15 Jul 2017

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Alan

EDIT.... I misread this, and the below may not be what you required, but as it is typed, I'll leave it, you may glean something out of it.

My recollection of the woods chargers a decade or more ago, was when I saw them used in some instances as floor scrubber chargers.. I recall they were not to good at that, but were cheaper than the stanbury scarf. which were the best in their day... most agricultural transformers ever placed in a device, gee they worked perfectly.

They worked so well as traction battery chargers, when most of their competition died along the way ( taking many battery banks with them ).

They were very long, and the primary was miles from the secondary ( about 3-4 inches from memory)..... and that gave mountains of flux leakage.... which is exactly what you want when your tranny has to operate over a very wide range of say 45v to 60v. Thats a big ask from a normal E I transformer design, which are cheap and easy to wind.

To get around that pesky problem.... I seems to me that the woods type and others like them used basically light dimmers to try to control the output from being so terribly gruff with the loads.

Others used to push the primary up one end, and the secondary up the other, leaving enough space to place iron plates in between (flux shunts), and this wold create lots of controllable leakage, at far less expense than the stanbury type.

If it is working to spec at the moment, and the windings are looking shabby ( secondary?) then one can only suppose they are running on too high a primary voltage perhaps, or the battery bank is very low impedance.

As it is a non- flooded type, then yes, they will present as a lower impedance load than the wet ones.... the electrolyte is a longer path in the flooded units, which would lead to more heat in the not so low impedance parts of the circuit. ( windings )

The only thing that may save the situation is a decent inductor in the primary..... and Bruce has one of these in his old GTI inverter ( the inspire or aero sharp... can't remember which he had).

I found I could use two of them in series to tame a tightly wound EI transformer, that went from trying to push out 60 amps at start up to 30 amps, but kept the regulation better.... partly constant current... ish. That would have been 8mH.

Your problem has some current softening in the light dimmer, so one may be enough, and they would have had the windings separated a bit at least we hope so.... mine were secondary around the primary... worst case for charging, best case for well regulated raw output for some other application.

The alternative is a bank of capacitors on the primary..... if you can get em cheap, that will solve the excessive current at start up...probably 300uf will make a difference.

Funnily enough, the other thread I am on at the moment uses a nano and a little board, and it would control that thing and make it a programmed charger from start to finish... that would be the cheapest and probably the best in the end.... even the lousy software I put up will do that out of the box now I think of it.

Best of luck up there in the hot country..... had -2C the other day... I had a 350 acre ice skating rink.

........oztulesEdited by oztules 2017-07-17

Village idiot...or... just another hack out of his depth

Warpspeed
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Joined: 09/08/2007
Location: Australia
Posts: 4406

Posted: 03:56pm 16 Jul 2017

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I have never even heard of a Woods Charger, so did not responded earlier.

The above post explains the whole situation very clearly.

Back before the golden age of electronics, many clever (if rather crude) systems were used to help reduce transformer and battery destroying overcurrent.

Deliberate or externally enhanced transformer leakage inductance is one way, and transformer shunt gaps were another solution to current limiting.

Another ancient method was to connect a filament lamp in series in either the primary or secondary.

It glowed dimly, and the ohmic resistance of the filament varied with the current and the temperature of the tungsten filament. This works over about a 10:1 to 15:1 filament resistance range.
If you tried to draw huge current, the filament would heat up and the resistance would rise, reducing the current.

It sounds pretty crude, but in fact it works surprisingly well. You just need to experiment with various wattage lamps or combinations of lamps to get the current limiting effect you are after.

I use a system like this to keep a very rarely used engine starting battery in an old car fully charged. It uses a 15 volt dc plug pack in series with an 18 watt turn indicator globe. It will easily withstand a dead short, and under normal charging about 900 mA into the battery with the filament barely red hot with only a volt or two across the lamp. No way to overload the 15v plug pack this way, and the lamp gives a wonderful visual display of charging current.

A programmable digital voltmeter and a relay charges the battery up to 14.2 volts where the relay totally disconnects the charger. The battery voltage then self discharges back down to 12.6v the charger then re connects. It cycles the charger on and off, and keeps the battery in excellent health, and has now done so reliably for over two years. No added water needed and no sulfating.

The cycling on and off gradually changes to longer off periods and shorter on periods as the battery gets nearer full charge. And the cycling at reasonable current followed by complete rest is much healthier for the battery than a constant float voltage.

Very simple, low cost, and very easy to make.
I am sure something like this could be done effectively on a larger scale.

Edited by Warpspeed 2017-07-18

Cheers, �Tony.

windlight
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Joined: 03/03/2007
Location: Australia
Posts: 331

Posted: 11:14pm 16 Jul 2017

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Thanks everyone, the unit is in transit Brisbane to Mossman, my first move will be to merger the burnt secondary.

I have several dead inverters so will try inductors but clearly it is the wrong charger for those batteries.

thanks for the input
Allan

"I like this place and willingly could waste my time in it" - (Act II, Scene IV).

oztules

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Joined: 26/07/2007
Location: Australia
Posts: 1686

Posted: 11:53pm 16 Jul 2017

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If you have the right inductors it is not soo wrong if the secondary is intact.

If you have enough inductor there, it will be soft enough.... providing you can control the absorb upper voltage and control the float voltage.

I don't really have an affinity to gell type cells... I mess up too much to be left alone with them.... fla take a lot of flack, but they are tough too.

........oztules

Village idiot...or... just another hack out of his depth

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