Operation Rejuvinate!

[Joster]

Hi All,

I have recently acquired 24, 69.1 Amp/hr deep cycle lead acid CD Technologies Telecom batteries and hardware. They have been in service for about 4.5 years as back-up power for some small telecom equipment deployed in apartment buildings. They came from six different apartment buildings. 4 batteries per installation. They would have been used in series to provide -48V DC to the gear during a mains outage.

Physically, the batteries are in great shape. Some have some minor bulging however. They all test above 12.6V after being removed from the sites about a week ago. I load tested one of them with my CBA at 8 Amps. This resulted in a 40 amp/hr tested capacity for this particular battery.

I would like to restore as many as possible to full capacity.

I have an SG running as well as a high-efficiency vortex coil radiant pulse charger. It can do 3 Amp pulses per 1.5 sec consuming 10 Watts.

If I where able to run my SG on some a power supply, how long would it take to do 20 cycles with these batteries? Are these cycles from 10.5 to 16.2?

Or perhaps I could use a pulse charging method? If so, I assume these batteries would need at least 10 Amp pulses per sec to show any charging? I have charged a 7.2 Amp/hr battery in 24 hrs with 1 Amp/sec pulses using my vortex coil radiant pulser consuming 5 Watts.

It's obvious I will need to build some kind of heavy duty charger either radiant or pulse and the consumption element is a whole other topic that for this application I am not overly concerned about. Perhaps a heavy duty solid state sg? Or beef up my vortex could setup?

Any tips would be great!

Thanks!

Joster

[wrtner]

This unit is well respected. It is a DIY circuit which is easy to make up and not expensive:

http://www.alton-moore.net/graphics/desulfator.pdf

Note the error report on page 1.

[Joster]

This is an excellent article. Thanks for the link!

I think I'll give it a try especially since it's so cheap and easy to build plus he explains the basic circuit function.

I have two questions:

1. He says he operates the circuit with a 12V solar panel paralleled across the battery to compensate for the 40mA draw from the circuit. Does this not put the battery in a charge/discharge state? To my current knowledge is not a good idea to do this but perhaps it' so little of a draw the effect is negligible?

2. I would rather use an independant supply for the circuit however I am unsure of the connections for this as outlined here. He says to remove R3 and place 12V across C1. Would this not short the supply directly to the battery? Also, I'm not sure how the dual-rail supply is generated since the supply is single rail. I'm sure Im missing something simple there.

Cheers!

Joster

[wrtner]

Would this not short the supply directly to the battery?

It isn't shorting across the battery but connecting the two in parallel. I would have thought this might drop the voltage quite a lot.

It is the 555 that needs the voltage, isn't it? That is 8 and 1. So, I suppose there is some sense here.

[wayne.ct]

Regarding your two questions

1. He says he operates the circuit with a 12V solar panel paralleled across the battery to compensate for the 40mA draw from the circuit. Does this not put the battery in a charge/discharge state? To my current knowledge is not a good idea to do this but perhaps it' so little of a draw the effect is negligible?

I think he is saying to alternate back and forth between his desulfating circuit and charging using the solar panel. Depending on your specifics it may be possible to have both attached at the same time but you would want to have an oscilloscope and make sure it functions correctly according to the theory of its operation. There are quite a few factors to consider but 40 mA is not much current for the battery to supply even if it has quite bit of sulfate. If the sulfated battery cannot supply 40 mA, then you would have a very different situation.

2. I would rather use an independant supply for the circuit however I am unsure of the connections for this as outlined here. He says to remove R3 and place 12V across C1. Would this not short the supply directly to the battery? Also, I'm not sure how the dual-rail supply is generated since the supply is single rail. I'm sure Im missing something simple there.

I don't think the article described how to power the circuit independently. It doesn't make sense to me why you would want to do that. If all you want to do is desulfate the battery, just do it the way it was suggested. If you are thinking you want to apply pulses to the sulfated battery because the battery itself won't supply 40 mA, then an independent supply would make sense. Supply current to the circuit from a separate power supply and the take the pulse from the collapse of the field around L2 and direct it into the sulfated battery through a high-voltage diode. There are quite a few parallels between what you would be doing then and other circuits on this forum. To me, it would then resemble a Joule Thief circuit. There are many examples of that floating around.

I hope these comments are helpful!