I want some 2v sealed lead acid batteries for a project, to drive the heaters of some vacuum tubes which need 1.5v at 2 amps. At present I'm using 6v batteries with big dropper resistors. I haven't investgated a voltage regulator yet, though this would be a good idea. I have a charger which can be set for 2.44v, and regular intervals up to 6.88v (and beyond). If and when I get 2v batteries, can they be charged at 2.44v? andy
Wouldn't you be better off using single C or D cells? It's probably what the valve heaters were originally designed for.
You might even get away with NiMh cells.
Depending on the age of the valves they are much more likely to be designed to run off a single lead acid cell of 2v nominal.
For the OP visit
Very old B4 and similar valves, yes, but the more modern DF series of B7G and B9A based valves were surely 1.4 volts weren't they? The OP did say 1.5 volts rather than 2.0 volts.
Yes, by definition, if it used the European numbering system and began with D, it was 1.4v for the filament/heater. Designed to run off dry cells (I had a radio with those for years...a portable too!).
Yes, by definition, if it used the European numbering system and began with D, it was 1.4v for the filament/heater. Designed to run off dry cells (I had a radio with those for years...a portable too!). >>
The valves are 26 - american type, and yes each is 1.5v at 1 amp. Not the usual radio valves, which were more like 0.1 Amp. You could use D cells for those. And yes, the European valves were often 1.4v like 3A5,
1LE3, DC90, DC93, DC96. DC96 had only 30mA of filament current. The CPC link was absolutely right - probably the lowest prices. Looked them up in my catalogue, then phoned the supplier. Cyclons (2v) should be charged at 2.35v, and can be done so in a single stage - just needs a very smooth supply of about 1% ripple and capable of 2 amps according to them. Sounds like a DIY power supply would do this.You might even get away with NiMh cells. >
Hello - Depends how many you mean - remember we're talking 2 amps at
1.5v. NiMH are 2.8Ah. I tried them - they ran down almost immediately. I think Cyclon 2v are the way to go.
Not if you go for D size NiMh or NiCd cells, NiMh can be up to 11Ah for a single D cell. I did explicitly say C or D size cells.
I dont have a direct answer, but a few thoughts...
1A heater current is huge for filament valves: are these indirect heated valves by any chance? If so, you can put muck through them quite happily. A chopper to deliver the 6v at 1/16th duty cycle would work. No way could you do that with direct heated filaments of course.Any lead acid can be converted to gel cell by mixing the right stuff into the electrolyte and pouring it back in. Trying to think, sodium silicate?
Finally your local lead acid battery manufacturer could always provide a cell to order.
NT
Hello Chris: Not if you go for D size NiMh or NiCd cells, NiMh can be up to 11Ah for a single D cell. I did explicitly say C or D size cells. >>
Cripes - 11Ah in a D cell! I had no idea - do you have a reference I could look at? The Cyclon D cells are 2.5Ah. - seems about typical in my cursory experience of NiMHs. 11Ah would be another story.
or 12Ah
Well, this re-writes the text book. I have a Maplins NiMH charger which takes 4 D cells. I wonder if it would charge 4 of the 12Ah ones?
Try it! Report back in a year or so....
Just do a Google search for "NiMh D" and you'll find lots of them. I found the 11Ah ones at
Or search for 2v cylindrical cells
thanks for all the references - The 9Ah NiMH seem to be about =A315 in RS. That's about double the price of 8Ah Cyclons, though the cyclons are bigger. Economically seems like Cyclons are the way to go.
In addition to the online sources, model shops - as in proper model shops that sell radio control planes etc - sell them as the power source for engine glow plugs.
MJ
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