thomaskwscott
- Nov 6, 2013
- 16
- Joined
- Nov 6, 2013
- Messages
- 16
I've wired everything up as above but I'm experiencing some strange results. I would try to explain but figured the easiest thing was to draw the whole thing out so please see the attached image,
The relay is of the normally closed type and when running on battery power the battery charger and 5V power supply are disconnected. These are ganged together so that both will always be connected or disconected simultaneously (the dashed power brick). The idea is that when the power supply is connected the battery will be isolated and the power supply will take over responsibility for powering whatever is on the output of the regulator. This means the battery has in effect nothing connected to it and can be safely connected to the battery charger.
This all seems to be working correctly and i've been testing it without the battery charger. However i'm having trouble proving the battery is isolated. I thought i could measure voltage across the points marked in red on the picture and should read zero but in fact i'm seeing around 2.8V. I assume this is coming off the 5V power supply but I can't see how any voltage can get to this point.
The relay is of the normally closed type and when running on battery power the battery charger and 5V power supply are disconnected. These are ganged together so that both will always be connected or disconected simultaneously (the dashed power brick). The idea is that when the power supply is connected the battery will be isolated and the power supply will take over responsibility for powering whatever is on the output of the regulator. This means the battery has in effect nothing connected to it and can be safely connected to the battery charger.
This all seems to be working correctly and i've been testing it without the battery charger. However i'm having trouble proving the battery is isolated. I thought i could measure voltage across the points marked in red on the picture and should read zero but in fact i'm seeing around 2.8V. I assume this is coming off the 5V power supply but I can't see how any voltage can get to this point.