dewalt 20v or 18v battery diy

[simojoker]

my XR 20v tool has 4x terminals, 2 are negative & positive, the other 2 appear to be sensor wires (yellow/brown) (second from left & second right on battery top row) they go into the board (resin moulded) and back to the switch that powers the tool, what is sent from the battery via these two wires and how? Can you mesure with tester for me?

I ' ve the drill but not the battery and i want to male it with lipo. so need to supply the correct votlage/current to these wires so the tool will operate

any help here greatly appreciated!!

[big-all]

my XR 20v tool has 4x terminals, 2 are negative & positive, the other 2 appear to be sensor wires (yellow/brown) (second from left & second right on battery top row) they go into the board (resin moulded) and back to the switch that powers the tool, what is sent from the battery via these two wires and how? Can you mesure with tester for me?

I ' ve the drill but not the battery and i want to male it with lipo. so need to supply the correct votlage/current to these wires so the tool will operate

any help here greatly appreciated!!

they are the same cells as in 3.6v nominal rating
they will overcharge by 20% in a 1hr charge so a 5 times 3.6v will be rated at 18v but when fully charged will read 21.5v
the capacity the high volt and low volt will be the same just the point they choose to take as the average will be different so the 18v are 20v and 20v are 18v

[simojoker]

yes, but the tool don't start, mybe it needs some kind of consensus from the pole called th and c3

[big-all]

i would phone up dewalt uk
http://service.dewalt.co.uk/
or your local service center or tool supplier with a repair shop
the fact its called 20v means its a us import so may cause problems with back up

[kellys_eye]

'th' is probably a temperature signal from a thermistor (variable resistor) fitted close to the cells themselves. These are often monitored to prevent over-charging.

'c3' is likely to be an actual measurement for the charging process itself. Depending on the cell type you can monitor when the cells are charged by the rate at which they draw current OR by the cell end-point voltage.

If you are changing to a different cell technology you will need to change the charger too - the skills necessary to adapt one type of charger to another set of charging 'rules' is often way beyond those any normal person possesses.

There are specific charging devices (integrated circuits) that can be set to charge 'any' type of battery (user selectable, and some can even detect the type of cells in use and change their operating parameters accordingly) but they are only one part of the whole charging mechanism. Whilst designs (circuit diagrams etc) exist for these devices it means building it entirely yourself.

You 'may' find such a universal charger on eBay or the likes, in which case all you need do is fit it to the old charger casing but there's no guarantee the 'th' or 'c3' connections will be correctly used - they may not even be NEEDED.... but that's something I can't comment on without further information.

[ericjohnson]

My dewalt also sometimes needs second starting. Don't understand why.