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  Topic Review (Newest First)
03-02-2015 11:48 PM
fredellarby
Quote:
Originally Posted by Dash8 View Post
Hey all,

Searched, but wanted exact answers.
I don't want multiple stuff attached directly to battery, so am looking at a fuse block.
I know you can buy a pc-8 etc, centech, etc, but looking for something that's not 70$+...
The west marine 6 block for 30$ looks good, but wondering,from the more tech savy crew, what the difference between switchable and non switchable is?
Going to be running iphone power, heated grips, heated vest, etc...maybe aux lights...
Anyone with any insightful knowledge?
Sorry for the late reply. If you haven't already bought, Princess Auto on Dixie Rd sells a block for around $7.
01-21-2015 12:18 PM
TAC PRO Eastern Beaver, although any automotive relay with the correct amperage rating will work.
01-21-2015 03:00 AM
Wallygator
Quote:
Originally Posted by TAC PRO View Post
You can get a short 8 or 10 ga. wire with fuse holder at most shops that install automotive sound systems. They're usually under $10.

https://www.stromtrooper.com/maintena...tallation.html


Nice and clean setup Tac Pro! Do you have a part number for those relays?
01-21-2015 02:57 AM
Wallygator
Quote:
Originally Posted by SCraig View Post
This is for *ANY* circuit:

Step 1 - Determine the combined load (in amps) on the circuit. Doesn't matter if it's a branch circuit or several circuits combined, the rules are the same. If you know the wattage divide that by 12 to get amps (watts = amps x volts or amps = watts / volts). Using a 50 watt lamp as an example: 50 watts / 12 volts = 4.16 amps per lamp. Assuming (2) lamps = 8.32 amps on the circuit.

Step 2 - Multiply the combined load in amps times 1.25 for a surge / safety factor. 8.32 x 1.25 = 10.42 amps.

Step 3 - Pick a wire size that will handle the current. I use the "Free Air" column on This Ampacity Chart.

Step 4 - By that chart #20 wire will handle 10.42 amps however I don't like to use wire that small since it tends to break easily. I never go smaller than #18 and actually prefer #14, but do as you please.

Step 5 - Size the fuse NO LARGER than the ampacity of the wire and no smaller than the load. Rounding up to the next highest standard value is acceptable, however with very small wire I will increase the wire size if I have to round up more than about 20% of the ampacity of the wire. For #20 wire, which is rated at 11 amps, I would use a 10 amp fuse. Using a fuse with an ampacity less than the ampacity of the wire is fine as long as it will handle the load of the circuit without blowing.

There are four critical determinations:

1. NEVER GUESS. If you don't know the load of a device FIND OUT. It should be shown with the documentation of the device, printed on the device, or available somewhere. Electronic devices such as GPS devices, cell phones, etc. are very low-current devices and are no big deal. Lights are not low-current devices and can easily have a significant load. Anything with a motor is most assuredly something you do not want to guess about.

2. The ampacity of the wire chosen MUST exceed the circuit load. NEVER use wire rated for lower ampacity than the circuit.

3. The ampacity of the fuse chosen MUST be less than the maximum ampacity of the wire. NEVER use a fuse with an ampacity hier than the wire of the circuit.

4. The ampacity of the fuse chosen MUST be equal to or greater than the circuit load otherwise the fuse will blow.
Excellent info! So I'm happy with what I did. It's overbuilt but that is what I was going for. It should be able to handle anything I hook up to it.
01-18-2015 12:00 PM
chirosyd
Quote:
Originally Posted by TAC PRO View Post
You can get a short 8 or 10 ga. wire with fuse holder at most shops that install automotive sound systems. They're usually under $10.

https://www.stromtrooper.com/maintena...tallation.html


TAC PRO
Thanks, a picture is worth a thousand words.
01-18-2015 11:28 AM
TAC PRO You can get a short 8 or 10 ga. wire with fuse holder at most shops that install automotive sound systems. They're usually under $10.

https://www.stromtrooper.com/maintena...tallation.html


01-18-2015 11:24 AM
SCraig This is for *ANY* circuit:

Step 1 - Determine the combined load (in amps) on the circuit. Doesn't matter if it's a branch circuit or several circuits combined, the rules are the same. If you know the wattage divide that by 12 to get amps (watts = amps x volts or amps = watts / volts). Using a 50 watt lamp as an example: 50 watts / 12 volts = 4.16 amps per lamp. Assuming (2) lamps = 8.32 amps on the circuit.

Step 2 - Multiply the combined load in amps times 1.25 for a surge / safety factor. 8.32 x 1.25 = 10.42 amps.

Step 3 - Pick a wire size that will handle the current. I use the "Free Air" column on This Ampacity Chart.

Step 4 - By that chart #20 wire will handle 10.42 amps however I don't like to use wire that small since it tends to break easily. I never go smaller than #18 and actually prefer #14, but do as you please.

Step 5 - Size the fuse NO LARGER than the ampacity of the wire and no smaller than the load. Rounding up to the next highest standard value is acceptable, however with very small wire I will increase the wire size if I have to round up more than about 20% of the ampacity of the wire. For #20 wire, which is rated at 11 amps, I would use a 10 amp fuse. Using a fuse with an ampacity less than the ampacity of the wire is fine as long as it will handle the load of the circuit without blowing.

There are four critical determinations:

1. NEVER GUESS. If you don't know the load of a device FIND OUT. It should be shown with the documentation of the device, printed on the device, or available somewhere. Electronic devices such as GPS devices, cell phones, etc. are very low-current devices and are no big deal. Lights are not low-current devices and can easily have a significant load. Anything with a motor is most assuredly something you do not want to guess about.

2. The ampacity of the wire chosen MUST exceed the circuit load. NEVER use wire rated for lower ampacity than the circuit.

3. The ampacity of the fuse chosen MUST be less than the maximum ampacity of the wire. NEVER use a fuse with an ampacity hier than the wire of the circuit.

4. The ampacity of the fuse chosen MUST be equal to or greater than the circuit load otherwise the fuse will blow.


Quote:
Originally Posted by chirosyd View Post
Greywolf,
Thank you. Why is there no documentation in the installation instructions that says a 30 amp fuse needs to be installed in the red positive wire as you recommended? If this is the case, whst is the best way to accomplish this? The red wire is a large diameter wire that goes from the fuse block directly to the battery. Do I need a wire as large to splice in a fuse holder?

Also, how do I know what amperage the fuse in the fuse block should be used to protect this circuit? I believe the Adventuretech flood lights are 10 watts each.
Thanks again.
01-18-2015 11:13 AM
Riddletw I'd second Mr Greywolf's recommendation, any great length of unprotected wiring especially 12ga poses a risk of a thermal event. As previously mentioned there is a limit to the output of the alternator...the wee new to me but believe its 400 watts. I just installed a 3 circuit ... 2 switched one live from Cycle Terminal...sorry I wasn't able to post the actual link...too new to this site. I looked into purchasing all the items and assembling myself but couldn't justify based on their pricing.
01-18-2015 10:46 AM
greywolf The idea behind mounting the 30A fuse close to the battery is because the wire between the battery and fuse is unprotected. Having a tool or metal part make contact between the unprotected wire and the frame will cause a dead short circuit. The shorter the unprotected wire is, the less likely that is to happen. One good method of protection is a 12V 30A auto reset circuit breaker. http://www.amazon.com/s/ref=nb_sb_no...ircuit+breaker shows some but make sure any exposed metal gets insulated.

12ga is plenty to power the fuse block as it is not far from the fuse block to the battery.
01-18-2015 09:02 AM
chirosyd Wallygator,
Thanks for the info. Splicing in a fuse holder yo 18 gauge wire is easy. I don't know how easy it's going to be with 8 gauge wire. I am going to call twisted throttle and get their take. I temporarily put in a 5 amp fuse on the switched side of my fuseblock to test the lights, and they work fine. Of course, the 30 amp fuse is to protect the fuse block itself.
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