mudroller

I want to put some lights on my cherokee but not sure if i'll manage enough power to support it. I've got a 1,000 watt sound system being delivered, plus I want to put 4 Hella 500 series lights on top of the rack and 2 Hella 550 fog lights at the front bumper. Will I have enough power if I upgrade my alternator, should I convert to a double alternator setup or should I get a seperate battery for my sound system alone and leave the alternator specifically for the lights/car?

Thanks for any input

humboldt2door

Upgrading to a high performance battery and alternator would be a good idea and should probably cover it I would think. But some other member would probably know more than me. just my .02

TheGreatGazoo

LOL iv'e been here when i was a kid 20 years ago. what i did back then was i added a second alt it was a single wire hook-up alt so and ran that wire a # 6 awg directly to the positive on a second battery a 1000cca marine. and ofcourse a ground from the batt to chassies somewhere, and used that set up just for my sound system i was running 5 Sherwood 200watt amps and it worked great. no power robbing from the engine or light flickering form my bass. thats what i recomend, my 2 cents.

humboldt2door

humboldt2door's .02 < TheGreatGazoo's .02
In case you didn't know who to listen to.

TheGreatGazoo

LOL yea info here is kinda cheep

humboldt2door

exactly, everything should be taken with a grain of salt, and with the seniority of the member taken into account.

humboldt2door

hey i just noticed i moved up to junior member. woohoo my .02 is worth slightly more!!!

mudroller

i think your .02 just turned into .03 =) lol

thanks for the info

should i upgrade to higher quality alternators or keep same quality alts?

5-90

It would help if you gave with your year (there were some changes over time - primarily going from the Delco CS-130 to the Nippondenso,) but it's possible to do parts-house upgrades - or junkyard, but I don't trust JY electrics "off the lot" unless I'm going to overhaul them,) and get an increase that way. Tell me what you've got, and I can look up more and see about telling you some donors.

If you're planning on running a lot of this stuff at idle, a second battery is the better way to go. Alternators can't generate full output at idle (spindle speed isn't fast enough,) they usually can't until around 3500rpm or so at the alternator spindle, or ~1200rpm or so at the crankshaft. The second battery should be a deep cycle, should be isolated from the starting battery (solid-state isolator or a solenoid isolator, in case you run it with the engine OFF,) and connect whatever you want to run at idle directly to the secondary battery.

Upgrading the alternator usually also requires upgrading the OEM wiring to take full advantage of it - automakers are notoriously cheap (because beancounters are cheap bastids, and insinuate themselves into engineerin decisions on a depressingly regular basis.) If you decide to add a second alternator, you'll also want to fuse the output circuit - an alternator "surge" means swinging to something well past full output - think something like 90VAC @ 500-600A for a second or two, vice the more typical 12VDC @ 40-100A (depending on regular note of demand and alternator rating.)

Hit me backchannel if you want to discuss this further - I can help you design a setup for your needs (and even help you get it wired up!)

01LimitedXJ

might be a good idea to run a capacitor with that audio system.

and x2 on upgrading the wires

mudroller

99 cherokee

mudroller

i was reading on a forum (the12volt.com) that running a capacitor to a system is pointless.

5-90

OK - 99? That means you have the Nippondenso, and I've given lists of possible donors. The 136A is known to fit with minimal mods, and the 160A fitment is currently unconfirmed (I'm waiting for someone to get back to me on that...) However, the list is certainly here, and probably on several other boards as well - you can check by searching for Alternator posts with my moniker (5-90) and that should turn it up for you.

A cap is useful for a system, but it can quickly become a question of "how much?" The voltage regulator has a small but definite "lag" behind demand - typically a quarter-second or so while it makes its decision. The caps are good for a "quick hit" (damned near instantaneous, in fact) and can be mounted very close to the amps - vice having to pull that surge from the battery and take it from other systems. But it takes a fair bit to decide "how much" to start with, and it often needs fine-tuning afterwards.

Anyhow, you may want to start by searching up that list of donors (it takes me a while to recreate each time, so I prefer to not do so if I'm sure I've done it on a board before...) and go forward from there. I'm still waiting for someone to confirm whether the 160A unit will fit and with what modification (or I may end up having to go and compare it myself.) FWIW, your 99XJ probably has a 90A Nippondenso, so you get some idea of what sort of improvement you can get (if you have "power everything," it may be a 117A unit instead.)

00XJ

you defiantly want to upgrade the alternator depending on the year, your alternator is not pushing enough to run both lights and a kick a@# sound system but because you are upgrading might as well do both alternator and battery. jmo.

4.3L XJ

Well, we discussed he sound system well, but we left out how much power the lights pull. I am assuming that he will run both simultaneously. If so, you will need to factor in the lights with the sound system and power for the engine electronics, plus a heater motor, unless you are into no climate control. I think once you factor all this together you might find a 136 amp alternator is not enough and will have to put out the big bucks for a 200 amp alternator.