Hello All,
I posted a few months ago about building a discharger for a DeWalt 18v battery. Thanks to everyone who contributed suggestions and ideas. We have our first one built and working.
A bit of background - We have a DeWalt 18v recip saw on our rescue van. We have used it during extrications where we have a great deal of water (i.e. a stream). We use our corded recip saw in less hazardous environments. We have three DeWalt batteries. Each battery rotates from 1) charger to 2) saw to 3) spare every week. It's not unusual for this recip saw to go unused for almost a year at a time. We needed some way to check the batteries. So, we decided to build a discharge unit to determine the condition of the batteries.
We would like to add one additional feature to our discharger. Some sort of voltmeter that we could hold the last reading. This would allow us to double check that we stop the discharge process at 15v.
We have a DPDT relay that we use to control a timer. This allows us to monitor how much time it takes for each battery to drop to 15v. We hope that this will allow to determine when we need to replace a battery.
Does anyone know of a voltmeter that would allow us to hold a reading via some sort of external relay or contact?
TIA, Mark Firefighter Sky Valley / Scaly Mountain Volunteer Fire & Rescue