Felt battery washers

[Donald]

I was looking at a new battery I installed and noticed there is a lip at the bottom of the terminal post that can provide additional surface area for current to flow beyond the vertical surface of the terminal post. By putting a washer there you eliminate that additional surface area. Maybe the vertical surface provides enough surface area so not an issue.

I did not use felt washers but coated all areas with a brush-on NOCO chemical to prevent corrosion.

 

[Kira]

Battery post felts have been uniformly discredited here.

 

[atikovi]

That's just how they are made and not for such a function. There is no provision to tighten the battery cable terminal to that lip you mention and few if any terminals go that far down to touch that area anyway.

 

[RitcheyRch]

Battery post felts have been uniformly discredited here.

I still use them on regular lead acid filled batteries.

 

[Hall]

there is a lip at the bottom of the terminal post that can provide additional surface area

Unless the battery terminals have a "flared" bottom adding add'l contact surface, what you might gain by pushing the terminal down onto this surface will be negligible. Can you even push the terminal down to contact it ? There could be parts of the terminal/cabling that prevent this. Have to remember that this add'l contact is what, 1/32" thick and 5/8-3/4" diameter. Someone could calculate the surface area but it's not worth it....

 

[Hall]

Battery post felts have been uniformly discredited here.

East Penn - probably the most respected battery producer on this board - sells felt washers. Do they do it 'cause it's a high-profit item for them ? Probably but at the same time, if they hurt battery performance, EP isn't going to sell them. At best they may provide a small benefit or do nothing (no gain, no harm).