I need 1F/5V supercap as a replacement of battery and need a low leakage super cap.
Are supercaps known to have low leakage or do I need a particular type?
Datasheets are where this kind of information resides. There are many different manufacturers, each will have different specifications. Dual-layer capacitors have several uses, some may be optimized for energy density, some for high current, some for low-leakage.
Also "low leakage" can mean very different things to different people, so use numbers, not adjectives
to communicate in electronics.
wonderfuliot:
I need 1F/5V supercap as a replacement of battery and need a low leakage super cap.
Are supercaps known to have low leakage or do I need a particular type?
Some of the products we sell have 1F capacitors to maintain the time in their RTC. Although I've never properly tested it I think they are good for at least 30 days, so that's 30 days while powering a RTC module and any leakage. When they fail I just replace them with standard 1F capacitors from RS, nothing special.
PerryBebbington:
When they fail I just replace them with standard 1F capacitors from RS, nothing special.
Backup for a RTC is quite gentle application for a (super)cap. How often they fail?
Smajdalf:
Backup for a RTC is quite gentle application for a (super)cap. How often they fail?
Difficult to answer. We supply and maintain telephone systems. Some of the old Samsung kit has 1F capacitors and we occasionally get calls from people describing the symptoms we know mean the capacitor has failed. I guess the systems are well over 10 years old, maybe 15 years or more. Of course, what I don't know is how many old systems there are out there that have not failed, or ones that have failed but the didn't phone us for help.
A supercap does not hold charge like a battery. Forr 30 days backup it is a good option.