Meter fuse question

[calab]

I could put this in battery section but its for some cheap digital meters the fuses that were sold for them were ceramic but they no longer sell them and I found some glass ones at a different store.

If the meter wants 250ma is it ok to put 500ma instead the 250ma were 2.25$ each but the 500ma were 0.93$ each sold in packs of 5 the other difference is all the ones I bought were glass not ceramic that were sold in store beside the the meters on the shelf. I got the same fast blow rating but they were 250v rating not 300v as labeled on circuit board inside meter. The glass ones would be more fragile then the ceramic right

 

[E-HP]

If the meter wants 250ma is it ok to put 500ma instead the 250ma

I can think of a couple of analogies.

1. You ask your wife, "I was going to give you $25 to go buy something nice for yourself, but would it be OK if I gave you $50 instead?"
or
2. You ask your wife while she's at the sink, "I thought I'd only have 25 dishes to wash, but would it be OK if I gave you 50 instead?"

I think maybe it's more like the second, more is not better.

 

[calab]

500ma might damage the meter components and need to replace the entire meter with another $5 meter which is worth the risk I learned I have to pay close attention to what I expect to measure and what dial the selector is on as I blew both small and high rate fuses. My meter has a 10a selection which needs the red probe to be put in a different hole, the other amp selection dials are 200m 20m and 2000u, when I measured 10a I got between 1 and 2.50a so does that mean I need to use the 10a dial setting for 250ma-10a? and 200m 20m 2000u for 0-250ma when using a 250ma fuse?

If the meter wants 250ma is it ok to put 500ma instead the 250ma

I can think of a couple of analogies.

1. You ask your wife, "I was going to give you $25 to go buy something nice for yourself, but would it be OK if I gave you $50 instead?"
or
2. You ask your wife while she's at the sink, "I thought I'd only have 25 dishes to wash, but would it be OK if I gave you 50 instead?"

I think maybe it's more like the second, more is not better.

 

[E-HP]

500ma might damage the meter components and need to replace the entire meter with another $5 meter which is worth the risk I learned I have to pay close attention to what I expect to measure and what dial the selector is on as I blew both small and high rate fuses.

LOL, that's a throw away item. I wouldn't have even taken the time to open it up; but ya, if that's the case, why not?

 

[amberwolf]

I could put this in battery section but its for some cheap digital meters the fuses that were sold for them were ceramic but they no longer sell them and I found some glass ones at a different store.

https://forum.digikey.com/t/glass-vs-ceramic-fuses-whats-the-difference/8475

If the meter wants 250ma is it ok to put 500ma instead the 250ma

If the meter was designed to handle half an amp of current on that lead, it would have had a fuse for that rating.

At the price level, it's not much of a risk, but for future reference you should replace fuses with the identical fuse, both rating and type, that came in a device, if you want the fuse to continue protecting it as designed.

 

[amberwolf]

LOL, that's a throw away item. I wouldn't have even taken the time to open it up

For some of us, there are times when a $1 item isn't a throwaway item. Been there, done that, am there again.

 

[calab]

I knew there were intricacies between the two styles glass ceramic but thought it was rigidity over graph curves 100a ceramic breaking voltage is quite dramatic over 35a glass I did find some cheap ceramic fuses on the major online suppliers but need to make a complete list to justify the extra shipping costs powerpoles, solder, wick, connectors I realize now I should have purchased alligator clips with the sleeve.

What connectors do you use for throttle, phases, sense wires, pas as I want to try out a pitch of molex I used 4mm bullets in the past but abandoned them long ago as its to fine work to solder for me no need to mention anything on mechanical fastening I rarely solder.

LOL, that's a throw away item. I wouldn't have even taken the time to open it up

For some of us, there are times when a $1 item isn't a throwaway item. Been there, done that, am there again.

 

[amberwolf]

What connectors do you use for throttle, phases, sense wires, pas as I want to try out a pitch of molex I used 4mm bullets in the past but abandoned them long ago as its to fine work to solder for me no need to mention anything on mechanical fastening I rarely solder.

Whenever possible, I directly wire such things, with no connectors. (because I ahve had so many connector failures over the decades, of all types, for many reasons).

If I had to use connectors for small-signal stuff, I would get pre-made Higo / Julet waterproof connector sets with the wire length I needed already attached, and build them into the devices I am using them on. There are other similar connectors, but these are common and cheap enough and easy enough to use as long as you get them pre-wired the way you want. (there are panel-mount versions that you can solder up, but I wouldn't want to make cables out of those).

For large power connections I use the Anderson SB50 and/or PP75 with crimp contacts (not solder), or crimp-on ring terminals for things that have bolt-on terminals on them (like my battery's busbars.

 

[calab]

I noticed that the one unique meter I have will double the dc voltage reading when the meter is selected on ac voltage, over the years I hardly used that meter because I thought it was defective its a small unit the size of adult males palm with the lettering even smaller with very little contrasting colors so my eyes could not see the curve wave next to the letter v indicating ac which to me looked like a straight line indicating dc voltage comparing it to the bigger meters with clear markings that are brightly contrasted they both read the same when measuring dc on ac meter selector. The diagram is right on all the meters dc being dotted line with solid line so I just got out the white permenant fine tipped marker and corrected it.
I was all ready to buy the same meter at the store and swap it the meter was not in stock in the store in stock online for 6$ delivery. I originally bought the smaller meter to carry around with while I ride but never needed it.

A sine wave selection to measure voltage the meter either measures rms or true rms but why would a dc voltage of 7.9-8.1v read 15v on the ac v setting is it because its reading the top half of the voltage and doubling it or is it because the battery dc voltage never goes down to zero like ac does.
https://electronics.stackexchange.com/questions/234539/what-is-the-difference-between-a-multimeter-with-rms-and-one-with-true-rms

Most likely it is an inexpensive meter that has a half wave diode rectifier input followed by an averaging filter as its AC measuring circuit.

Applying 12VAC to such an input would result in an internal voltage of about 5 VDC, because the signal is off half the time (during the negative part of the cycle) and

 

[E-HP]

LOL, that's a throw away item. I wouldn't have even taken the time to open it up

For some of us, there are times when a $1 item isn't a throwaway item. Been there, done that, am there again.

Sorta mean from the economics standpoint. If your going to spending $5 on fuses to repair a $5 meter, it's probably better to throw away the meter and spend the $5 on a new one.

 

[amberwolf]

true :wink: