"The tool only at Home Depot is $150, from Amazon $100."
I don't know what brand you are considering, but Ryobi only honors warranties when purchased from an authorized retailer (Home Depot). They will deny warranty claims for product purchased on Amazon or eBay. Home Depot claims to have a price match guarantee, but it may not extend to online purchases.
"they are not always backwards compatible"
The lithium batteries won't physically fit into the old nicad chargers, but the lithium chargers (they call them "dual chemistry") can charge the old nicad batteries. Either charger will charge a NiMH (knockoff) battery.
We have a Ryobi stick vacuum (18v). It has it's own charger that is slow as hell. I'm not sure it scans the batteries because it will charge batteries the other chargers reject.
I've also read that Ryobi chargers won't charge a battery that is completely dead, which can happen if it sits in storage too long after a tool has drained it, but a work around is to trickle a charge into it by wiring it to a charged battery, but I've never tried it.
I don't know what brand you are considering, but Ryobi only honors warranties when purchased from an authorized retailer (Home Depot). They will deny warranty claims for product purchased on Amazon or eBay. Home Depot claims to have a price match guarantee, but it may not extend to online purchases.
"they are not always backwards compatible"
The lithium batteries won't physically fit into the old nicad chargers, but the lithium chargers (they call them "dual chemistry") can charge the old nicad batteries. Either charger will charge a NiMH (knockoff) battery.
We have a Ryobi stick vacuum (18v). It has it's own charger that is slow as hell. I'm not sure it scans the batteries because it will charge batteries the other chargers reject.
I've also read that Ryobi chargers won't charge a battery that is completely dead, which can happen if it sits in storage too long after a tool has drained it, but a work around is to trickle a charge into it by wiring it to a charged battery, but I've never tried it.