Charging SLA batteries

[ppppenguin]

I've just bouhgt a coupple of new Yuasa Yucel SLA batteries (6V, 3.2Ah) for the Vintage Wireless Museum's RF spectrum analyser. They are behaving very strangely. When on charge they are virtally open circuit. Won't take more than a fraction of a milliamp whatever voltage (within reason) I apply to them.

I reckon they are faulty and need to go back to Toolstation where I bought them.

Any ideas?

[Nick]

These are normally fully charged when you buy them.

[AlanBeckett]

Never had a problem with them They're just Lead Acids after all.
As Nick says they usually come charged. However, jacking the supply up should force some Current into them.
I'd be inclined to flatten them some with a suitable Resistive Load and try again.
Of course they may be faulty.
What Current can you draw from them?

Alan

[ppppenguin]

They are flatter than pancakes that have been under a steamroller. One has a o/c terminal voltage of about 2V, the other 3V. I've given them 11V and get no more than 4mA. Don't really want to go higher than that.

I reckon they are either very old stock or ones that have been abused and returned without Toolstation knowing about it.

[AlanBeckett]

I suspect they have internal High Resistance Joints, or the Plates are so Sulphated that they'll never recover.
Take them back.

Alan

[ppppenguin]

Phoned Toolstation. They are sending out replacements today, shoudl arrive tomorrow. They don't want the old ones back.

I suggested they check stock rotation on this item as I suspect these have been around for years on the shelf. Just hope it isn't a very low demand item where their entire stock is ancient.

[AlanBeckett]

Is there anything resembling a Date Code on them Jeffrey?

Alan

[ppppenguin]

They each have this stamped on the top: 141211EM. Possibly December 2011? Some very old (1993?) similar Yuasa batteries have 2100102 on them.

[Murphyv310]

Hi.
I'd be inclined to ask for your money back Jeffrey, I'd suspect Toolstation wont turn these round very much.
CPC will supply a suitable SLA battery for your needs and they will have a much bigger turnaround.
Good Luck.

[ppppenguin]

Trevor, I'd already suspected this. If the replacements are no good I'll get my money back and order from RS or CPC.