Help - Problem charging old UPS dead battery's

[SeaMonkey]

The only difference in behaviour i have noticed between a new battery and this is the capacity. Instead of having claimed 72Ah or even 50Ah it has... 2-3Ah ! Actually it shows no signs of sulfation to me, as it would take eagerly pulse or whatever charging.

...
regarding the electrolyte, i do not have a clue.
This is hermetically sealed type battery having a little clear indicator labeled (green-ok, black-need recharging, clear - needs replacing) Its clear, unless stired a bit that becomes OK, and when the electrolyte subsides becomes clear again.

The Calcium-Lead alloy batteries are frequently 'sealed'
and labeled 'maintenance free.' This is because the
Calcium tends to reduce gassing during battery charge
so the electrolyte rarely needs replenishment with water.

In order to see into the cells you'll have to devise a way
to open the tops of the cells where the vent is located.
It is in the middle of each cell, in the same place as a
normal battery has the removable cell cap. By very
carefully cutting into the plastic top you'll eventually
find it and be able to add water if needed.

Unless the battery has sustained physical internal damage
causing some of the plates to become detached, the
most likely cause of the very small capacity is a lack
of water.

Whatever the case, this battery will certainly become
a great 'learning experience' to advance your knowledge
and understanding!

Please keep us all informed of your results.

[bolt1]

Get hold of Chinese DC motor speed controller 250/350 watts 24 v. Connect TWO 12 volt batteries to the speed controller they are very cheap but you cant even make then for less then least 30 bucks as the fets alone cost quite a bit. They are found in many kids toys, electric bikes, scooters etc cost around 20 bucks. check ebay.

Now charge a single 12 volt battery from the DC speed controller and set the PWM "speed control" to around 50%.

Usually they come with lots of connects and wires for features on scooter but you only need power in and out and short the ignition switch wires together then add a 4k7 pot on the 3 throttle wires and set to 50%.

The battery being charged will be hit by 25Khz of spikes at around 15/20 amps and makes a good VERY fast car charger. The PWM makes a much better job then hooking up pure DC.

This is not for reviving old batteries but this will start a flat car battery usually within 5 mins so you can get going again.

As always put fuses in the right places!

[SeaMonkey]

Still amazed to see that I can push 330mA to the battery without making them hot .

The NiCd is rather odd - while charging it will
actually absorb heat and feel cool. It is only
when it reaches full charge that it begins to
'gas' internally and produce heat as the
hydrogen is oxidized.

Many NiCd chargers sense this heat to
reduce charge current to 'trickle' for the
final 'equalizing' charge rate which is
safe and produces little heat even for
long periods of time.

[jeanna]

I'm unclear regarding the pulse magnitudes you measured.
The pulses ranging from 147 Volts to 1111 Volts - where
and how did you measure them; with or without any load?

I measured these from the free ends of the secondary wires using a scope.
There was no load.

Are you taking the output pulses from the secondary
winding of a transformer in the collector circuit?

Sort of.
If you want to call the toroid of a joule thief the collector circuit.

These are the spikes produced by the wire that is wrapped around the ferrite toroid which freeloads off the action of the joule thief.
Most of my work has used this.
(I am using the joule thief withOUT al light as a pulse generator and studying what happens on this 'secondary'. Some people call it L3 instead of secondary)

The variable resistance in the base circuit will cause the
pulse width of the oscillations to vary as well as the
consequent pulse amplitude at the output.

Yes.
That is the reason I changed the charger circuit to this one.
This will allow me to vary the pw by hand.

The voltage that seemed to change polarity - was that
measured across the battery being pulsed? If so, the
apparent change of polarity would be difficult to explain.

Yes.
I connected the jt charger and it read 9.6v as usual across the battery terminals, but when I adjusted the pulse width to be wider letting higher voltage spikes with lower frequency therefore wider pulse it went negative.
After some time it became positive again.
When it became positive again it read about 9.4v

This morning the positive battery voltage was low again so I put it back on a regular charger and when that was charging the voltage of the 12v being charged went to 12.45v which is the highest it has reached since it originally died.

Can you make a drawing showing how everything was
connected?

Do you still need a drawing?

thanks for this help.

jeanna

[sucahyo]

This is not for reviving old batteries but this will start a flat car battery usually within 5 mins so you can get going again.

Wow, good tips .

The NiCd is rather odd - while charging it will
actually absorb heat and feel cool.

Using 555 driven 2N3055 radiant oscillator I would observe the heat right away, even at 10-15% ON time, sign of poor switching. I observe it on SLA and lead acid too.

[SeaMonkey]

I measured these from the free ends of the secondary wires using a scope.
There was no load.

...

Yes.
That is the reason I changed the charger circuit to this one.
This will allow me to vary the pw by hand.


Yes.
I connected the jt charger and it read 9.6v as usual across the battery terminals, but when I adjusted the pulse width to be wider letting higher voltage spikes with lower frequency therefore wider pulse it went negative.
After some time it became positive again.
When it became positive again it read about 9.4v

This morning the positive battery voltage was low again so I put it back on a regular charger and when that was charging the voltage of the 12v being charged went to 12.45v which is the highest it has reached since it originally died.

Your good explanation cleared things up!

Would it be possible to perform this 'experiment'
once again with the scope also across the battery
to monitor the pulsing waveform?

If you are able to duplicate the polarity reversal
while watching the pulse waveform on the scope
you may be able to see something which will
offer more clues. Something unusual apparently
happened which is difficult to 'diagnose' without
knowing more.

Could you tell us more about the JT inductors;
how many turns; type of core; etc...?

Since the pulsing voltage you've measured is very
high the impedance of the winding may be too great
for pulsing a battery. Ideally, the DC resistance
of the coil feeding the battery should be no
more than about 0.2 Ohms.

[SeaMonkey]

Using 555 driven 2N3055 radiant oscillator I would observe the heat right away, even at 10-15% ON time, sign of poor switching. I observe it on SLA and lead acid too.

Are you feeling the heat of the transistor or of
the batteries being charged?

The 2N3055 will produce a lot of heat while switching
heavy current flow. In order to assure that it goes
into deep saturation for minimum conduction loss
the base current pulse must be quite heavy. For
10 Ampere pulses the base pulse has to be about
700 mA of drive. Then, to switch it off quickly the
base current should go slightly negative with a polarity
reversal. Power Transistors are difficult to 'drive' for
efficient fast switching.

[totoalas]

Fast charger

Hi Bot1,
thanks for the tip as I am in
China they usually dont repair these things and just throw away
Now the hunt begins for the parts
Just a question for the pot 4k or 47k????will 2 7ah sla battery do the trick????


cheers

totoalas

[bolt1]

I think the throttles are 4k7 or some use a hall effect throttle. Yes 7aH gell batteries work fine and make a more portable booster charger unit. I have started a car many times off these batteries.

[totoalas]

Fast charger

Thanks again Bolt1
4k7 is 4.7 k Im learning
totoalas

[TanTric]

i missed this post... yeap, im working on a portable one inside a small wood box, to charge car batterys also.. will have connection to grid, and to 1.3Ah small battery!

i will try to charge my 9V non rechargeble batterys as dodosholdo!!

[IMG][IMG=http://img295.imageshack.us/img295/1585/jtcharger004.jpg][/IMG] Uploaded with ImageShack.us[/IMG]

Hi Tantric Sucahyo and all

Tantric Hope you can make a super fast charger desufator for most type of batteries rolled into o ne

cheers
totoalas

[sucahyo]

Are you feeling the heat of the transistor or of the batteries being charged?

Both. My coolest transistor operating temperature is around 10-15% ON duty cycle. On other duty cycle I usually can smell the heat too . Even at the coolest setting, it still heat the battery up considerably on 300mA.

Only after I use 2N3055 differently I observe cool charging on the battery.


Now I use different circuit that heat up the transistor real fast because of 50/50 duty cycle (self oscillating). I have to use heat sink. But any battery will be charged with very little heat even at 700mA charging current.


I think the running temperature of the transistor is not associated with batery charging temperature. You may still get hot batery with cool running transistor at high charging current. I hear some people able to do both cool, but I satisfied with just fast and cool battery charging .


I currently charge 2500 mAh nimh for 1.5 hours now at 250mA and the heat is barely noticeable on touch. I am more than sure that I will charge it much faster than specified 5 hours needed at that charging current, and do not have to worry about battery temperature too .

The 2N3055 will produce a lot of heat while switching heavy current flow. In order to assure that it goes into deep saturation for minimum conduction loss the base current pulse must be quite heavy. For 10 Ampere pulses the base pulse has to be about 700 mA of drive. Then, to switch it off quickly the base current should go slightly negative with a polarity reversal. Power Transistors are difficult to 'drive' for efficient fast switching.

Agree, I have 4 times better efficiency than 555 driven 2N3055 now.

[totoalas]

Super Charger

i missed this post... yeap, im working on a portable one inside a small wood box, to charge car batterys also.. will have connection to grid, and to 1.3Ah small battery!

i will try to charge my 9V non rechargeble batterys as dodosholdo!!

Tantric
excited to see your new toy
Thelron Stark seem to be a guru in capacitor charging
His advice
thicker wires bigger bifilar air coil using solid plastic insulated cores
6 inches out dia 4 inches inside dia and 8 inches tall air core
Fast charging effect
Unfortunately his video response to Dodoshlodos channel was deleted

Hope this help
totoalas

[baroutologos]

The Calcium-Lead alloy batteries are frequently 'sealed'
and labeled 'maintenance free.' This is because the
Calcium tends to reduce gassing during battery charge
so the electrolyte rarely needs replenishment with water.

In order to see into the cells you'll have to devise a way
to open the tops of the cells where the vent is located.
It is in the middle of each cell, in the same place as a
normal battery has the removable cell cap. By very
carefully cutting into the plastic top you'll eventually
find it and be able to add water if needed.

Unless the battery has sustained physical internal damage
causing some of the plates to become detached, the
most likely cause of the very small capacity is a lack
of water.

Whatever the case, this battery will certainly become
a great 'learning experience' to advance your knowledge
and understanding!

Please keep us all informed of your results.

I devised a coil pulser (that takes several coils that i have on hand e.g. ferrite e-cores, laminated I-cores etc) that consists of a master astable 555timer (adjustable) that commands 2 x 555 monostable timers (adjustable) each one edge triggered at high and low period respectively.

Those monostable 555 control IRFP4229 power MOSFETs. I can work with 12v, 20v and 40V input. Frequencies can range from 2Khz down to 200Hz and pulse width 5% to 90%.

....
Concerning the particular battery, i pulse charge it for days and days and showed not sign of betterment. I drilled the top (sealed type) and substituted the acid (that was still strong) with distilled water and pulse charge it for many days. Nothing again. Then i substituted the water with new battery acid with a part of destilled water and continued the pulse charging, super-charging at low Amps and letting cool overnight.

I did not cycle the battery, only charging without end and add water to keep a certain level.

Today i decide to cycle it with a 20w bulb (74 Ah battery). It lasted almost 2 hours totaling 3,5 ampH draw. Last measurments was about 2 Ah draw from the same bulb. (1 hour last)

Battery behaviour have changed. Initially had a standing voltage 13,2v and below 12,5 volts its charge was decreased "exponentially fast" under the same load whereas now it has a standing 12,6v and the "break point" is 11,8 volts.

....
IMO, the battery has developed something upon its plates that prohibits the acid to do its function. Perhaps a chemical treatment is by far a better solution (since i saw betterment with changing fluid and not pulse charging).

Bellow few photos of my setup.

[SeaMonkey]

....
Concerning the particular battery, i pulse charge it for days and days and showed not sign of betterment. I drilled the top (sealed type) and substituted the acid (that was still strong) with distilled water and pulse charge it for many days. Nothing again. Then i substituted the water with new battery acid with a part of distilled water and continued the pulse charging, super-charging at low Amps and letting cool overnight.

I did not cycle the battery, only charging without end and add water to keep a certain level.

Today i decide to cycle it with a 20w bulb (74 Ah battery). It lasted almost 2 hours totaling 3,5 ampH draw. Last measurments was about 2 Ah draw from the same bulb. (1 hour last)

Battery behaviour have changed. Initially had a standing voltage 13,2v and below 12,5 volts its charge was decreased "exponentially fast" under the same load whereas now it has a standing 12,6v and the "break point" is 11,8 volts.

....
IMO, the battery has developed something upon its plates that prohibits the acid to do its function. Perhaps a chemical treatment is by far a better solution (since i saw betterment with changing fluid and not pulse charging).

Below few photos of my setup.

Your description of your pulsing circuit sounds very
good. It should be effective.

What you've described so far with your battery sounds
like extensive sulfation, and it too is good.

Do you have a hydrometer to test the battery acid
strength with? It is the only way to find out for sure
whether the battery is fully charged, partially charged,
or discharged.

It is likely that even a sulfated battery would have
some percentage of acid still remaining in the electrolyte
solution and being able to 'read' its specific gravity will
tell instantly what the state of the battery's health is.

The higher than normal voltages are characteristic of
a sulfated battery. As are the declining voltages after
partial recovery. Typically, while desulfating a battery
by pulsing, the monitored voltage at first is quite high,
well above the normal 14 ~15 Volts.

Then, as the desulfation begins the voltage will drop to
an abnormally low level, well below 12 Volts. (Sometimes
as low as 6 or 7 Volts.)

Slowly, with continued pulsing, the voltage will begin to
climb until it eventually reaches 14 ~ 15 Volts and levels
off. At this point the sulfation has been largely reversed
and the battery is nearly rejuvenated.

Several discharge/charge cycles with continued pulsing
should bring it back to maximum capacity relatively
quickly.

It is not unusual to have to pulse a battery for many weeks
before it begins to show signs of response. Desulfation
takes time when it is done to a battery which has not been
used for months or years.

What you've described sounds quite normal and it seems
that the battery is responding. Don't give up on it! With
a little more work it should get even better.

You've done a good job of telling us all about your experience
and documenting your progress. You've provided much very
useful information to all who will be trying the same
procedure.

Tell us more as you continue.