Battery Self-Discharge Protection Switch


Staff member
477 Owner
This switch can be of immense value for those who use their bikes only occasionally or with longer periods of inactivity.

The self-discharge of the OEM lead acit battery is between 2 and 5% per month at 25°C as I have found after reviewing many data sheets. At higher temperatures a bit more at lower temperatures less. GEL batteries tend to be at the lower end of this range, AGMs in the middle and liquid acid batteries at the upper end. Without taking ambient temperature into account, a fully charged battery will lose between 12 and 30% of its capacity over 6 months. It tends to be even less, as it is likely to be significantly cooler than 25°C over the winter half-year to which this figure refers.

So why the problem with the Hima - some of which lose enough charge within a few weeks to become useless for starting purposes. The reasons are many and some can be fixed but not all and to fix them is not always easy.

What IS easy however is installing this switch. Place the switch in the space next to the battery under the seat. Its also a quite ingenious theft protection - unless someone carries the bike away on a truck.

The toothpick is not part of the set - its just for size comparison.

This switch is widely available on ebay and amazon. Just google for SFC-300a


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