Sealed 2 volt battery

[bcroe]

Just wondering if there are some small sealed 2V batteries out there? I have equipment
that originally used a flooded 2V (floating colored balls), long since gone. Though common
surplus half a century ago, I don't find any now. I'm thinking, probably better to find a
sealed battery anyway. It was about 5" high, 3 3/4" X 2 3/4" base. The capacity isn't
critical; suppose I'd need to replace the copper oxide rectifiers with something smarter.
Bruce Roe

[Sunking]

Bruce you will not likely find any small capacity 2 volt cells because it defeats the sole purpose of using 2 volt cells. 2 volt cells are for large capacity battery systems. For example a 1000 AH 12 volt battery would weigh in around 1000 pounds maxing it very difficult to handle. On the other hand a 2 volt 1000 AH cell weighs in around 170 pounds which is manageable, you would just need 6 of them to make 12 volts.

Smallest 2 volt AGM cells I know of are around 240 AH up to 3000 AH.

[bcroe]

Bruce you will not likely find any small capacity 2 volt cells because it defeats the sole purpose of using 2 volt cells. 2 volt cells are for large capacity battery systems. For example a 1000 AH 12 volt battery would weigh in around 1000 pounds maxing it very difficult to handle. On the other hand a 2 volt 1000 AH cell weighs in around 170 pounds which is manageable, you would just need 6 of them to make 12 volts.

Smallest 2 volt AGM cells I know of are around 240 AH up to 3000 AH.

Yes, looking for like 20 AH here. The 6V batteries have the cell jumpers inside
where I can't easily cut them. Trying to restore this 30s portable which used a
vibra pack, to avoid buying A and B batteries all the time. This may take a saw.

Would need a new charger. I like the one in this portable PA system, a red LED
starts flashing so fast as to appear continuous. It gradually slows down, then goes
out to indicate full charge. Bruce

[PNjunction]

Actually you'll love the small-capacity Enersys / Hawker Cyclon spiral agm's. Plenty of voltages with 2v cells available, although I currently see 2v/12ah as being the largest single cell available.

These are pure-lead tppl agm batteries. At one time, they were the only competitor to the Optima brand of agm's, but are in a different league because of their small capacity relatively. Since they are pure-lead agm's, you can recharge them very fast if you like, as long as you have CV regulation.

There are 2, 4, 6, 8 volt cells, and pre-built 12v packs. They come in either stand-alone cells or "monoblocks".

Outstanding batteries for small projects when you require agm along with the ability to hammer them with current if you please. (see manual for real-world limits of course).

[bcroe]

Actually you'll love the small-capacity Enersys / Hawker Cyclon
spiral agm's. Plenty of voltages with 2v cells available, although I currently see 2v/12ah
as being the largest single cell available.

These are pure-lead tppl agm batteries. At one time, they were the only competitor to
the Optima brand of agm's, but are in a different league because of their small capacity
relatively. Since they are pure-lead agm's, you can recharge them very fast if you like,
as long as you have CV regulation.

There are 2, 4, 6, 8 volt cells, and pre-built 12v packs. They come in either stand-alone
cells or "monoblocks".
Outstanding batteries for small projects when you require agm along with the ability to
hammer them with current if you please. (see manual for real-world limits of course).

Thanks, I had forgotten about them. No big surges for this project. I found a round cell
25AH that I expect can be fitted. Prices are all over the map on AMAZ++, but bigger is
better. Now I need to devise a good charger algorithm to preserve it, suggestions? Bruce

[PNjunction]

What is the battery voltage you are looking for?

If this is a 12v application, then assembling those 2v/ 25ah Cyclon cells might be more costly than using the 12v powersports-versions of the Enersys / Odyssey agm's, like the Odyssey PC625 (18ah) or PC925 (27ah). The Enersys application manual is practically the same, only the Odyssey's are flat-plate rather than spiral. This could also be overkill for a 12v application if you just want to use a ups-style agm, like a Powersonic or Universal battery and just replace them more frequently.

At the bottom of this page (I'm vendor-agnostic - it's just convenient) is a pdf link to the application manual. Close your eyes, and it can easily turn into an Odyssey manual:

http://www.atbatt.com/hawker-cyclon-single-cell-2v-25ah-bc-cell.asp

For a cyclic application, you'd want at least a CV charger that can hit 2.45v per cell (14.7v for 12v app), and at least 2.26v/cell float (13.6v for 12v app). Current smaller than 0.4C means extending float time to compensate. My interpretation of "cyclic" for the Cyclons and Odysseys means ultra fast turnaround such as would be seen in an EV application, and thus the 0.4C minimum might be eased for less critical applicatons. However, they demand the proper voltages. (either Cyclons or Odysseys)

For less critical applications where I'm not exceeding 50% DOD, I have been doing good so far with a minimum of 0.2C current with pure-lead agm's. Time will tell if I'm being too stingy here.

[bcroe]

What is the battery voltage you are looking for?

Thanks for the info. Its a 1930s something portable radio, which would normally
require a hefty 1.5V A battery to light the directly heated filaments, and a very
expensive 90V B battery for plate voltage. But this particular model used a single
2V wet cell, powering the filaments probably though a resistor, and a vibra pack
to generate B voltage. No buying dry cells.

The charger appears to be copper oxide rectifiers, and you turned it off when all
3 balls were floating. I will take the liberty of designing an automatic charger,
appropriate for the sealed battery. Since it'll charge from the line, I'll have more
than 2V to work with during charging.

There are a few pieces of equipment here from just before or just after the
war, because that is what I had to experiment with in school. Bruce Roe.

[Sunking]

Bruce wished you would have said this earlier. One of my hobbies is restoring antique radios. I have quite a collection of tubs, parts etc. There is an excellent forum you may be interested in with a lot of knowledgeable folks who can help over at Antique Radio Forum.

Anyway I have some experience with radios like yours. What series of tubes is it using and how many? I am guessing something like 19, 25 or 26 and 5 tubes total?

Thanks for the info. Its a 1930s something portable radio, which would normally
require a hefty 1.5V A battery to light the directly heated filaments, and a very
expensive 90V B battery for plate voltage. But this particular model used a single
2V wet cell, powering the filaments probably though a resistor, and a vibra pack
to generate B voltage. No buying dry cells.

The charger appears to be copper oxide rectifiers, and you turned it off when all
3 balls were floating. I will take the liberty of designing an automatic charger,
appropriate for the sealed battery. Since it'll charge from the line, I'll have more
than 2V to work with during charging.

There are a few pieces of equipment here from just before or just after the
war, because that is what I had to experiment with in school. Bruce Roe.

[bcroe]

Bruce wished you would have said this earlier. One of my hobbies is restoring antique radios. I have quite a collection of tubs, parts etc. There is an excellent forum you may be interested in with a lot of knowledgeable folks who can help over at Antique Radio Forum.

Anyway I have some experience with radios like yours. What series of tubes is it using
and how many? I am guessing something like 19, 25 or 26 and 5 tubes total?

I'm not big time into old electronics, but have a limited number of rather unusual
designs. Only superhets. Have a 1948 ANDREA 12" with continuous type tuner from
channel ONE to 13, hitting every FM, HAM, aircraft, & police band in between.

This radio is a GE LB530, the only prewar rechargeable portable I have found. Figured
I'd first rework the power supply, the actual radio should be straightforward. Tubes
are octal with grid caps, 1A7, 1N5, 1N5, 1H5, 1Q5. For $10, seems complete, kind of
a mess. Not sure how to get the cabinet rejuvenated.

I love the quarterly ANTIQUE WIRELESS ASSOCIATION. Will have to check that forum. Bruce

[bcroe]

For a cyclic application, you'd want at least a CV charger that can hit 2.45v per
cell (14.7v for 12v app), and at least 2.26v/cell float (13.6v for 12v app). Current smaller than 0.4C
means extending float time to compensate. My interpretation of "cyclic" for the Cyclons and Odysseys
means ultra fast turnaround such as would be seen in an EV application, and thus the 0.4C minimum
might be eased for less critical applicatons. However, they demand the proper voltages.
(either Cyclons or Odysseys)

For less critical applications where I'm not exceeding 50% DOD, I have been doing good so far with a
minimum of 0.2C current with pure-lead agm's. Time will tell if I'm being too stingy here.

Thanks, for my 2V 25AH a good charger would first do 10A charging till 2.45V, then drop back to 2.26V float.

For such low voltage remote sensing might seem necessary. But I built a circuit in school that sampled
voltage between charging pulses through the primary connections, when no current is flowing. Bruce Roe

[inetdog]

Thanks, for my 2V 25AH a good charger would first do 10A charging till 2.45V, then drop back to 2.26V float.

For such low voltage remote sensing might seem necessary. But I built a circuit in school that sampled
voltage between charging pulses through the primary connections, when no current is flowing. Bruce Roe

Remote sensing may not be necessary if the wires are short enough, but temperature compensation may still be important if the battery will be outside or subject to temperature swings.

If you do implement the gated voltage sensing, let us know more. Unfortunately that will not distinguish between the wiring resistance and the internal resistance of the battery, so it might not do what you really want.

[bcroe]

If you do implement the gated voltage sensing, let us know more. Unfortunately that will not distinguish between the wiring resistance and the internal resistance of the battery, so it might not do what you really want.

Not sure here either, if that is really what I want. The battery voltage will be higher
while the rectifier pulse is flowing than between pulses, due to battery resistance.
The numbers spec'd might be intended to include the battery resistance. With the
voltage between pulses lower, my target might be lower (but more accurate). Bruce