Cordless battery charger
US4857820A · kind A · utility
Inventors
Key dates
| Filing date | Sep 8, 1987 |
| Grant date | Aug 15, 1989 |
| Priority date | — |
| Expiry date | Sep 8, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02J2207/20
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A rechargeable emergency portable battery charger for starter motor storage batteries. The device includes a sealed lead acid battery as a source of energy. An oscillator circuit connected to a transformer generates 3 V in its secondary. This voltage is rectified and added in series to the 12 V of the self-contained battery to provide charging current to a starter motor storage battery. Connection is made via a cigarette lighter socket in the disabled vehicle. Current is limited to approximately 4 amps so as to limit heat dissipation to a safe level. Furthermore, a voltage-sensing circuit determines if the voltage of the starter storage battery is below approximately 6 V or is shorted to ground. In either case, output current is further limited to the point of cut-off. Recharging the self-contained battery is made possible by a switch that connects the cigarette lighter of a running car directly to the self-contained battery of the charger. This switch also permits connection of any 12 VDC device directly to the self-contained battery. An ammeter monitors current flow in this power pack mode, as well as the charging and recharging modes. A light-emitting diode circuit indicates whe…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.