Lead-acid cells, the perfect power supply?

[microx]

Not much has been said on this forum about the use of lead -acid batteries for powering preamps etc. Seems to me there is a lot in their favor. Very low impedance, no hum, very low noise. no heat etc. I use them where practicable, does anyone else?
Oh yeah, and they are cheap!
Steve

 

[Guest]

[quote author="microx"]Not much has been said on this forum about the use of lead -acid batteries for powering preamps etc. Seems to me there is a lot in their favor. Very low impedance, no hum, very low noise. no heat etc. I use them where practicable, does anyone else?
Oh yeah, and they are cheap!
Steve[/quote]
I use them too, especially from japaneese motorbike.
They are 12 V and veryvery light.
I use them only for measurements, For continued power mains is
more practical.
xvlk

 

[microx]

I am using the type you find in alarm systems. I have -18-0+18v plus 48v phantom with a switching arrangement for charging the whole lot in series, works real good.
Steve

 

[PRR]

Spilled acid, explosive gases, potentially extreme current (molten metal) if shorted.

FWIW: in the 1930s the BBC ran ALL studio gear from battery. Big ventilated concrete room on each floor, busbars bigger than your arm, and a motor-generator in the basement.

 

[Kev]

I use the four 9 V batts in the Kev BATT-BOX

these small 9v batts don't have as much grunt as the lead acid ones above

works for me

 

[Guest]

[quote author="PRR"]
Big ventilated concrete room on each floor, busbars bigger than your arm, and a motor-generator in the basement.[/quote]

Yes, we have that concrete room full of bateries at the faculty,
but mainly used by power engineers. But in the night power engrs are
sleeping. Yes, someone would make some BBC gear for recording.
... In the dead chamber. There is no good recording room :-(

xvlk

 

[CJ]

The gel cells are alright, but you have to fuse them.

Went to a power sub station in Greensboro Id. last year.
UPS system was un real. Hundreads of huge clear white battery cases full of lead and acid. Wired into a big buss bar network.
Some guy has to walk around with a hydrometer all day. Buss bars are out in the open. Drop a wrench across them and instant vaporization.

Batteries good for heaters and phantom and DI boxes but tubes need hv.

 

[soundguy]

the problem I always eventually had with lead acid batteries was memory issues after a while. if you dont recharge them on the same schedule, they get all ****** up.

dave

 

[BYacey]

Batteries good for heaters and phantom and DI boxes but tubes need hv.[/quote]

All the old tube radios used batteries for HV until AC mains became readily available. 2 0r 3 90V batteries in series was not uncommon, although not many local hardware stores stock 90V batteries anymore.

 

[Samuel Groner]

I have -18-0+18v plus 48v phantom with a switching arrangement for charging the whole lot in series

Where do I find such a beast?

Samuel

 

[microx]

I got the idea of using the sealed gel types when I noted that the ones in the alarm system in the office were six years old and still work perfectly. They are in a state of constant charge from a very simple charging circuit and the alarm circuit runs straight from the battery. I f the mains supply fails the system runs from the battery with a audible warning tone.
You can get 6v and 12v so one of each in series gives 18v, two pairs gives 18-0-18v and 4x12v gives separate 48v phantom. Fuses at 2-5 amp
and when switched from "run" to "charge" the whole lot goes in series at 84v to a 95v trickle charger (small filament lamp in series).
A full charge powers preamps and mics for 3-4 days.
Steve

 

[NewYorkDave]

[quote author="BYacey"]All the old tube radios used batteries for HV until AC mains became readily available. [/quote]

That's right, as borne out by my old Philco 38-38 sitting only a few feet away from me...

Some folks here might not be aware that the term "B+" comes from the days of battery-powered sets. A set would typically have two or three batteries: "A" for filament", "B" for plate", and "C" for bias. Even now, you still hear some people refer to a negative bias supply as "C-".

45V was a common value for a "B" battery, and two were often used in series to deliver a B+ of 90V.

 

[Gus]

With the vintage whatever the name is now CAR market there is a demand for more intelligent lead acid chargers. To keep the batterys in good shape for the weekend drives.

Depending on the temp and internal chemisty a lead acid battery want the charging or float voltage to vary IIRC from about 2.26V float to 2.4 higher rate charging per cell and then a correction for temp. most USA car battery 13.6V to 14.4V IIRC. Uintrode or some name like that had a IC that could use a temp sense current senser and voltahe to control the chargeing and flooting of lead acid cells back in the mid late 80's I have not looked in some time at lead acid stuff. The basic stuff should be in a good chemistry book.

Lead Acids like to always be charged and every deep discharge takes life away.

NiCads like to be charged and then deep discharged this help prevent plaque from forming on the plates. The reaction not completing causes a reduction the porisostiy of the plates(active area) thus less area for the reaction to happen. Thats the badly named memory effect the chemisty is not in balence with the plate area causing a higher voltage start then a more curved drop off a nicad in good shape is more flat and has a less high starting voltage.

 

[CJ]

Dang Gus, is your **** together, or is you **** together!

You can still buy the old Simpson/Triplett 30 volt batteries for the vacuum tube voltmeters. Don't think you can recharge them, so why did I mention this?

Might be just the ticket for field recording with phantom.