spinningmagnets
Member
- Joined
- Dec 8, 2017
- Messages
- 123
I am starting this thread as a place to park info I find about possible fuse wire I may use in the future. I am hopeful that it may prove useful to others. please post fuse wire you have used in the past, and the results you achieved.
CAT5 wire:
A friend recently suggested I should look at CAT5 wire as an option. CAT5 cable is used for Ethernet grids in a home and uses wire that has been used in the past for "land line" telephones. CAT5 cable typically contains four twisted pairs of 24AWG solid copper wire, 0.50mm diameter, 0.020-inch. This means one foot of CAT5 contains eight feet of 24AWG solid copper wire.
edit: some CAT5 cable uses the slightly smaller awg26, 2A continuous, 4A temp peak, blow at 20A...0.40mm dia-0.016 inch
A quick Google shows 3.5A continuous, and 5A temporary peak for a single 24AWG conductor. I am looking at using two wires per cell as a fuse, so dual-24AWG should handle 7A continuous and 10A peak (to reduce voltage sag and wire-heat). If I am drawing 1A per cell under normal loads, and my paralleled groups are at least 10P (or larger), I suspect a cell with a cascading internal short would flow 20A+ to blow the fuse(es), and that would be only 2A per cell in a 10P group...and a larger P-group would be even safer if using dual-24AWG.
edit: ajw22 below lists the "blow" current at 29A for a single solid copper awg24 (58A for double fuses)
By this I mean that an individual cell fuse-set would blow at a P-group per-cell amp-draw that would not damage the remaining cells. More cells in the P-group would result in a lower amp-draw per cell during an "incident" from an internally shorting cell.
I am trying to get away from spot-welding onto the NEGATIVE end as much as possible. Solder may require a two-second contact, but the temps are roughly only 360F. A spot-weld only takes 1/4 second (250-milliseconds?), but nickel requires roughly 2600F to melt into a solid contact. In the pic below, wire tips have been flattened by a hammer and pre-tinned before connection to cell...
(many spot-welding manuals specify to avoid welding onto the center of the negative end. Internal construction shows that the center is where the jelly roll is connected to the shell during construction. Added heat in that spot may loosen that internal connection)
CAT5 wire:
A friend recently suggested I should look at CAT5 wire as an option. CAT5 cable is used for Ethernet grids in a home and uses wire that has been used in the past for "land line" telephones. CAT5 cable typically contains four twisted pairs of 24AWG solid copper wire, 0.50mm diameter, 0.020-inch. This means one foot of CAT5 contains eight feet of 24AWG solid copper wire.
edit: some CAT5 cable uses the slightly smaller awg26, 2A continuous, 4A temp peak, blow at 20A...0.40mm dia-0.016 inch
A quick Google shows 3.5A continuous, and 5A temporary peak for a single 24AWG conductor. I am looking at using two wires per cell as a fuse, so dual-24AWG should handle 7A continuous and 10A peak (to reduce voltage sag and wire-heat). If I am drawing 1A per cell under normal loads, and my paralleled groups are at least 10P (or larger), I suspect a cell with a cascading internal short would flow 20A+ to blow the fuse(es), and that would be only 2A per cell in a 10P group...and a larger P-group would be even safer if using dual-24AWG.
edit: ajw22 below lists the "blow" current at 29A for a single solid copper awg24 (58A for double fuses)
By this I mean that an individual cell fuse-set would blow at a P-group per-cell amp-draw that would not damage the remaining cells. More cells in the P-group would result in a lower amp-draw per cell during an "incident" from an internally shorting cell.
I am trying to get away from spot-welding onto the NEGATIVE end as much as possible. Solder may require a two-second contact, but the temps are roughly only 360F. A spot-weld only takes 1/4 second (250-milliseconds?), but nickel requires roughly 2600F to melt into a solid contact. In the pic below, wire tips have been flattened by a hammer and pre-tinned before connection to cell...
(many spot-welding manuals specify to avoid welding onto the center of the negative end. Internal construction shows that the center is where the jelly roll is connected to the shell during construction. Added heat in that spot may loosen that internal connection)