Topic: SLAs and soldering... heat issues.

[aberg]

I was wondering if it's a bad idea to solder leads directly to the tabs. I have an SLA that worked fine when I first got it but since I've done some work with it... soldered RC clips to it, and ran it totally empty once by mistake, it doesn't seem to want to charge anymore. What can I do? Thanks.

[jk labs]

I was wondering if it's a bad idea to solder leads directly to the tabs. I have an SLA that worked fine when I first got it but since I've done some work with it... soldered RC clips to it, and ran it totally empty once by mistake, it doesn't seem to want to charge anymore. What can I do? Thanks.

It could so be that you have managed to damage the internals of the battery with heat.  I imagine that you had to apply huge amounts of heat to the terminals to make the solder melt. Did this melt any internal connections, destroy plastic separators or damage other components?
Don't give up before you are positive the battery is dead.

When it comes to "deep discharge survival" this depends strongly on how the battery was made and the materials used.

To recover a deeply discharged SLA let it sit on 3 Volts or so per cell for a few days. If you are lucky
it will start to accept charge.

Jon

[aberg]

I don't know how to let it sit on 3 volts per cell....

[jk labs]

I don't know how to let it sit on 3 volts per cell....

Well, let the SLA sit on the charger for a few days but make sure the charger puts a voltage across the terminals of the dead SLA.

See, some LA chargers will not output a voltage (or current) if the battery is dead. If you have this type of charger it will be of no use in bringing the dead SLA back to life.

The net is full of constant current & constant voltage circuits.

Personally I'd use the charger, the second SLA and a 12 V/6W light bulb to make a charger circuit for the dead SLA:
Charger on second SLA. Wire from ok SLA to dead SLA. Put a 12V 6W lightbulb in the charge-feed to prevent exessive
currents from flowing should the "dead" battery come back to life or present a short to the charger contraption.     

Best of luck

Jon

[aberg]

Whoa.... this might be a little out of my league... Where can I read up on this more?

[aberg]

Ok, I think I get what you're saying... unfortunately, I don't have a multimeter right now to see if my charger is even supplying a voltage to the dead SLA.. I will pick that up and then chances are it's the type of charger in question, which doesn't supply voltage to a dead battery. What you're saying to do then is to use the new SLA as a charger itself and then put a light bulb in series to act as a sort of current regulator/fuse type of thing... why would the charger need to be connected to the good SLA though?

[BCostigan]

If I remember right most chargers have indicators for faults and automatically won't send a charge if there's a short.  A dead battery may seem like a short to the charger so....it won't charge.  The extra load kinda tricks the charger into continuing outputting voltage in hope that your battery will eventually accept the voltage/charge.


As for soldering/heat....I think a few of us have soldered wire to sla's with no trouble.  The trouble seems to be too deep of a discharge.


My advice.....your battery is junk.  Even if you can revive it it won't have the capicity or reliabilty you want.  Find your local electrical supply house and buy a new one....usually less than $20.

[keepongoin]

i have soldered onto SLAs without a problem, but I prefer to use solderless connections and then put epoxy over them to hold them in place (if you are sure you don't want to remove the cables).  it would take a good amount of heat to mess up the cells in an SLA (or more sustained heat for a period of time). 

[F.O.Bean]

i have a 'dead' sla 12v 7amp that i got in great shape, and when i ran it down doing jb3 tests, it just wont charge up anymore, and its a damn ecocharge

i got a powersonic 12v 12 amp that i have now atht has worked beautifully so far, i think the key w/ some batts is dontlet them deep discharge

ive done that MANY times w/ my eco 6v's, but its not good practice, and because of the deep discharge thing, i beliefve i have a dead battery that i MAY get going w/ a bulk, ie~not smart charger

so if ya dont need to run your batts all the way down, dont

YMMV tho

[Lil Kim Jong-Il]

Find your local electrical supply house and buy a new one....usually less than $20.

And buy some connectors...usually less than $1.50 for a pack of 10.

[aberg]

Yeah, it's hard to avoid doing a deep discharge though when you're trying to test how long the battery will last.

[Lil Kim Jong-Il]

Yeah, it's hard to avoid doing a deep discharge though when you're trying to test how long the battery will last.

It's easy.

The manufacturer web site has a spec sheet that will recommend the lowest discharge voltage for the battery.  Put a DVM across the terminals of a fully charged battery and then run your rig until it hits .1V below the recommended lowest voltage.  Thats how long you can run within the battery's intended discharge curve.

If you want to run to deep discharge just to see how far you can push it, be prepared to replace the battery.  Some gear (a properly calibrated  V3 for example) will not allow you to run past the recommended discharge point so if you run until it shuts down, you won't damage the battery.

(Edited for spelling)

[F.O.Bean]

hence why my 6v's are ok, ive only used em w/ a v3 lately

[aberg]

Thanks, that's a great piece of information! Now I'm off to grab a multimeter.... cheers!

[aberg]

Ok, my SLA is made by a company called Exaltor. I can't find anything on the net but on the battery it has a chart which lists a few 'rules':

- Do not short circuit
- Avoid total discharging (deep discharge)
- Do not charge in sealed container
- Replace every 3-5 years

And there is info about voltage regulation for standby use and cyclic use

Standby: 13.5-13.8V
Cyclic: 14.0-15.0V

What can I make of those voltage quantities?