Battery Watt Help!?
Thread Starter
Newbie
Joined: May 2013
Posts: 20
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From: NW Ohio
Year: 2000
Model: Cherokee
Engine: 4.0
Battery Watt Help!?
i currently have 4 100W lights wired to my battery, i also want to put in a 500W amp, is this too much? would it be ok if i only had one of them on at a time? would i need a new battery/alternator? anything you have that will help please say! thank you!
::CF Administrator::
Joined: Feb 2011
Posts: 14,479
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From: Blunt, South Dakota
Year: 97
Model: Cherokee (XJ)
Engine: 4.6 stroker
http://www.kelleyswip.com/
Start here. There is some good reading here and I believe he sells some stuff, too.
Start here. There is some good reading here and I believe he sells some stuff, too.
CF Veteran
Joined: May 2008
Posts: 3,018
Likes: 23
Year: 1988
Model: Cherokee
Engine: AMC242
Batteries are rated in Volts & Amperes, not Watts (cf: Ohm's Law, Watt's Law. Learn it, know it, live it.)
However, if your engine is running when you have these accessories on, your battery should not be involved. However, if your alternator's maximum output is exceeded as a draw, your battery will make up the shortfall. You will notice this when your voltmeter drops, and your lights dim slightly.
Volts = Watts/Amps, so:
4 x 100W = 400W; 400W / 12VDC = 33.333... (33-1/3) Amperes
1 x 500W = 500W; 500W/12VDC = 41.666... (41-2/3) Amperes. (This is probably low, since 500W is the output rating of the amplifier. It doesn't take into account operating overhead or amplification/conversion losses. What's it fused for? Use that number to figure.)
Your 2000 XJ should have a 117A alternator in it (if OEM,) and you're going to be right on the edge of that. Recommendations:
- Wire the lights either in pairs (2x100W/switch & relay) or individually (1x100W/switch & relay,) if they're not already that way. Only have all four on when necessary. (And you'd better have them on relays, or have some heavy-duty switches! Even a single 100W lamp will draw 8-1/3A, most toggle switches aren't rated for that much current.)
- 500W is the maximum output of that amplifier. How often are you going to push it that hard? I have a 450Wx1ch amp feeding into a 600W-rated RF 10" driver, but I'm rarely up more than 1/3-volume. 450W/12VDC = ~38A, fused (I think) for 40. Actual draw? I haven't checked, but it's probably 10A or so.
And, since I've got an alternator tested for 198A full output, it's plenty livable. (I probably don't push my alternator past 1/3 of actual output very often - that's with 450Wx1, 50Wx4, 2x35W fog lamps, 2x100W driving lamps, and 90/130W headlamps. And a 500W inverter.)
However, if your engine is running when you have these accessories on, your battery should not be involved. However, if your alternator's maximum output is exceeded as a draw, your battery will make up the shortfall. You will notice this when your voltmeter drops, and your lights dim slightly.
Volts = Watts/Amps, so:
4 x 100W = 400W; 400W / 12VDC = 33.333... (33-1/3) Amperes
1 x 500W = 500W; 500W/12VDC = 41.666... (41-2/3) Amperes. (This is probably low, since 500W is the output rating of the amplifier. It doesn't take into account operating overhead or amplification/conversion losses. What's it fused for? Use that number to figure.)
Your 2000 XJ should have a 117A alternator in it (if OEM,) and you're going to be right on the edge of that. Recommendations:
- Wire the lights either in pairs (2x100W/switch & relay) or individually (1x100W/switch & relay,) if they're not already that way. Only have all four on when necessary. (And you'd better have them on relays, or have some heavy-duty switches! Even a single 100W lamp will draw 8-1/3A, most toggle switches aren't rated for that much current.)
- 500W is the maximum output of that amplifier. How often are you going to push it that hard? I have a 450Wx1ch amp feeding into a 600W-rated RF 10" driver, but I'm rarely up more than 1/3-volume. 450W/12VDC = ~38A, fused (I think) for 40. Actual draw? I haven't checked, but it's probably 10A or so.
And, since I've got an alternator tested for 198A full output, it's plenty livable. (I probably don't push my alternator past 1/3 of actual output very often - that's with 450Wx1, 50Wx4, 2x35W fog lamps, 2x100W driving lamps, and 90/130W headlamps. And a 500W inverter.)
CF Veteran
Joined: Jul 2013
Posts: 7,554
Likes: 17
From: Monett, MO.
Year: 1999
Model: Cherokee
Engine: 4.0
Batteries are rated in Volts & Amperes, not Watts (cf: Ohm's Law, Watt's Law. Learn it, know it, live it.)
However, if your engine is running when you have these accessories on, your battery should not be involved. However, if your alternator's maximum output is exceeded as a draw, your battery will make up the shortfall. You will notice this when your voltmeter drops, and your lights dim slightly.
Volts = Watts/Amps, so:
4 x 100W = 400W; 400W / 12VDC = 33.333... (33-1/3) Amperes
1 x 500W = 500W; 500W/12VDC = 41.666... (41-2/3) Amperes. (This is probably low, since 500W is the output rating of the amplifier. It doesn't take into account operating overhead or amplification/conversion losses. What's it fused for? Use that number to figure.)
Your 2000 XJ should have a 117A alternator in it (if OEM,) and you're going to be right on the edge of that. Recommendations:
- Wire the lights either in pairs (2x100W/switch & relay) or individually (1x100W/switch & relay,) if they're not already that way. Only have all four on when necessary. (And you'd better have them on relays, or have some heavy-duty switches! Even a single 100W lamp will draw 8-1/3A, most toggle switches aren't rated for that much current.)
- 500W is the maximum output of that amplifier. How often are you going to push it that hard? I have a 450Wx1ch amp feeding into a 600W-rated RF 10" driver, but I'm rarely up more than 1/3-volume. 450W/12VDC = ~38A, fused (I think) for 40. Actual draw? I haven't checked, but it's probably 10A or so.
And, since I've got an alternator tested for 198A full output, it's plenty livable. (I probably don't push my alternator past 1/3 of actual output very often - that's with 450Wx1, 50Wx4, 2x35W fog lamps, 2x100W driving lamps, and 90/130W headlamps. And a 500W inverter.)
However, if your engine is running when you have these accessories on, your battery should not be involved. However, if your alternator's maximum output is exceeded as a draw, your battery will make up the shortfall. You will notice this when your voltmeter drops, and your lights dim slightly.
Volts = Watts/Amps, so:
4 x 100W = 400W; 400W / 12VDC = 33.333... (33-1/3) Amperes
1 x 500W = 500W; 500W/12VDC = 41.666... (41-2/3) Amperes. (This is probably low, since 500W is the output rating of the amplifier. It doesn't take into account operating overhead or amplification/conversion losses. What's it fused for? Use that number to figure.)
Your 2000 XJ should have a 117A alternator in it (if OEM,) and you're going to be right on the edge of that. Recommendations:
- Wire the lights either in pairs (2x100W/switch & relay) or individually (1x100W/switch & relay,) if they're not already that way. Only have all four on when necessary. (And you'd better have them on relays, or have some heavy-duty switches! Even a single 100W lamp will draw 8-1/3A, most toggle switches aren't rated for that much current.)
- 500W is the maximum output of that amplifier. How often are you going to push it that hard? I have a 450Wx1ch amp feeding into a 600W-rated RF 10" driver, but I'm rarely up more than 1/3-volume. 450W/12VDC = ~38A, fused (I think) for 40. Actual draw? I haven't checked, but it's probably 10A or so.
And, since I've got an alternator tested for 198A full output, it's plenty livable. (I probably don't push my alternator past 1/3 of actual output very often - that's with 450Wx1, 50Wx4, 2x35W fog lamps, 2x100W driving lamps, and 90/130W headlamps. And a 500W inverter.)
Ohms Law the very first formula you are required to know to pass your Tech Class exam for your Amateur Radio License.
Fred/N0AZZ
Extra Class
ARRL
FCC License Examiner SW,MO. area
Thread Starter
Newbie
Joined: May 2013
Posts: 20
Likes: 0
From: NW Ohio
Year: 2000
Model: Cherokee
Engine: 4.0
Batteries are rated in Volts & Amperes, not Watts (cf: Ohm's Law, Watt's Law. Learn it, know it, live it.)
However, if your engine is running when you have these accessories on, your battery should not be involved. However, if your alternator's maximum output is exceeded as a draw, your battery will make up the shortfall. You will notice this when your voltmeter drops, and your lights dim slightly.
Volts = Watts/Amps, so:
4 x 100W = 400W; 400W / 12VDC = 33.333... (33-1/3) Amperes
1 x 500W = 500W; 500W/12VDC = 41.666... (41-2/3) Amperes. (This is probably low, since 500W is the output rating of the amplifier. It doesn't take into account operating overhead or amplification/conversion losses. What's it fused for? Use that number to figure.)
Your 2000 XJ should have a 117A alternator in it (if OEM,) and you're going to be right on the edge of that. Recommendations:
- Wire the lights either in pairs (2x100W/switch & relay) or individually (1x100W/switch & relay,) if they're not already that way. Only have all four on when necessary. (And you'd better have them on relays, or have some heavy-duty switches! Even a single 100W lamp will draw 8-1/3A, most toggle switches aren't rated for that much current.)
- 500W is the maximum output of that amplifier. How often are you going to push it that hard? I have a 450Wx1ch amp feeding into a 600W-rated RF 10" driver, but I'm rarely up more than 1/3-volume. 450W/12VDC = ~38A, fused (I think) for 40. Actual draw? I haven't checked, but it's probably 10A or so.
And, since I've got an alternator tested for 198A full output, it's plenty livable. (I probably don't push my alternator past 1/3 of actual output very often - that's with 450Wx1, 50Wx4, 2x35W fog lamps, 2x100W driving lamps, and 90/130W headlamps. And a 500W inverter.)
However, if your engine is running when you have these accessories on, your battery should not be involved. However, if your alternator's maximum output is exceeded as a draw, your battery will make up the shortfall. You will notice this when your voltmeter drops, and your lights dim slightly.
Volts = Watts/Amps, so:
4 x 100W = 400W; 400W / 12VDC = 33.333... (33-1/3) Amperes
1 x 500W = 500W; 500W/12VDC = 41.666... (41-2/3) Amperes. (This is probably low, since 500W is the output rating of the amplifier. It doesn't take into account operating overhead or amplification/conversion losses. What's it fused for? Use that number to figure.)
Your 2000 XJ should have a 117A alternator in it (if OEM,) and you're going to be right on the edge of that. Recommendations:
- Wire the lights either in pairs (2x100W/switch & relay) or individually (1x100W/switch & relay,) if they're not already that way. Only have all four on when necessary. (And you'd better have them on relays, or have some heavy-duty switches! Even a single 100W lamp will draw 8-1/3A, most toggle switches aren't rated for that much current.)
- 500W is the maximum output of that amplifier. How often are you going to push it that hard? I have a 450Wx1ch amp feeding into a 600W-rated RF 10" driver, but I'm rarely up more than 1/3-volume. 450W/12VDC = ~38A, fused (I think) for 40. Actual draw? I haven't checked, but it's probably 10A or so.
And, since I've got an alternator tested for 198A full output, it's plenty livable. (I probably don't push my alternator past 1/3 of actual output very often - that's with 450Wx1, 50Wx4, 2x35W fog lamps, 2x100W driving lamps, and 90/130W headlamps. And a 500W inverter.)
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