Here is another potential pitfall - whether doing the full mod with the new R/R or simply doing the 'charging mod' with an OEM R/R
(Charging mod is bypassing the OEM Wiring and connecting output of R/R directly to the battery - the + via 30A fuse.
The question has arisen as to "Why is my fuse holder melting - yet the fuse is still intact?" :confused
This is regarding the use of the popular ATM mini-fuse holders for this application.
I have now seen quite a few problems associated with this.
Even though the component is rated for 30A, the physical connection is simply inadequate for this high-current circuit.
The resistance of the connection between fuse and holder is significant enough to create a voltage drop across the connection.
This in turn disspates power in the form of heat and you get resultant melting, exacerbation of the problem & even arcing as a result.
The math goes as follows:
V = I * R - we already know the current is high (30A circuit) and as long as 'R' (resistance of the connection) is low, the volt-drop will also be low.
However if R is significant, then a voltage is dropped across it.
Then we have P (power) = V * I
Substituting for V, P = (I * R) * I = I^2* R
So the power is proportional to the square of the current times the resistance.
So as resistance increases the power rises dramatically and the power correspondingly!
Net result - HEAT! = further increase in resistance which exacerbated the problem - viscious circle!
Here is perfect illustration of the consequence:
So my general recommendation is NOT to use one of these mini fuse holders in this high current circuit.
The MetriPack 280 also uses the same mini ATM, however the physical contact of the fuse in the holder is much better that that of the Cooper Bussman style.
(note that I use the term CooperBussman style
- I suspect the issue may be with low cost/quality copies of the real McCoy and not necessarily
that of the original - however I would avoid this size completely, regardless of manufacturer, to be safe)
I have no empirical data to support long term robustness of the Metri-Pack but just personal opinion on the aspects of the physical design
To the contrary, I have seen quite a few failures as shown above, in the CooperBussman ATMs!
If you only have access to the CopperBussman style, I would suggest to use the physically larger ATO size as a more robust element, with more surface contact of the fuse in the terminals.