No cell battery

[Tom in SW VA]

Question:
The battery in my 37 Ford is a show battery with Ford logo.
It doesn’t have cells, but an electronic apparatus.

It is constantly running down. I recharge it with a 6 volt charger, but it reads
8 plus volts.

Question: Has anyone seen a battery like this? Do you have to have a special charger for it?

Your help will be greatly appreciated.

Thanks.