rally lights on remote battery

hey guys gonna run a solo battery off the grid to run rally lights
(hella rally 4000, 2pencil and 2flood) anyone have issues with battery life as it won't be running off alt. just install batt and lights at service. will be running switch,boush relay and inline fuse.
again looking for things i'm over seeing

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All bridges burnt, island life is beauty

This could help if you know the draw of the lights.

https://www.batterystuff.com/kb/tools/calculator-sizing-a-battery-to-a-load.html

Or if not there are a bunch of other battery life calculators online.



Edited 3 time(s). Last edit at 04/02/2016 09:28PM by Paul Buck.

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Snidewhips
hey guys gonna run a solo battery off the grid to run rally lights
(hella rally 4000, 2pencil and 2flood) anyone have issues with battery life as it won't be running off alt. just install batt and lights at service. will be running switch,boush relay and inline fuse.
again looking for things i'm over seeing

You won't get very far maybe 3-4 miles. unless you plan on running a 200# cat battery. Halogen brightness dies rapidly as voltage drops, I see no advantage to doing this. What is your reasoning?
Easy to test, fully charge the battery, turn the lights on, check the intensity and go inside for 5 minutes, come back out and view your 4 candles.

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Power means nothing if you cannot control it!

did the intensity test with just the pencils last night on a battery and they were great for 10 minutes. that was in series and voltage maintained at 12.2v (iknowiknowamps) didn't have an amp clamp doe

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All bridges burnt, island life is beauty



Edited 1 time(s). Last edit at 04/02/2016 10:29PM by Snidewhips.

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Snidewhips
did the intensity test with just the pencils last night on a battery and they were great for 10 minutes

Try all 4, time it.
Why do this?

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Power means nothing if you cannot control it!

why run a second battery? dont wanna stress an old ass alternator out. easy to rig, diag and maintain. not as much risk overloading circuits

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All bridges burnt, island life is beauty

100w bulbs in all 4? What size/type/capacity battery?

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Power means nothing if you cannot control it!

Easy, batteries have the reserve capacity as one of their specs. RC is how long it takes to run the battery down at 25 amps. Just figure the current draw of the lights (measure or calculate) divide 25 by that number, multiply the result by the RC, and that is how many minutes of time you get before the battery is completely dead.

Me, I think it'd be easier to get a decent alternator, which is important for other reasons too since a good charging system means good ignition and happy computers. They don't tolerate noise too much, old weak-ass alternators are electrically noisy.

I mean, if you really wanted to get fancy, you could run the lights full loss like that, and wire in a disconnect relay so you could charge the lighting battery when you have the lights switched off, kinda like how Mercedes cars have two batteries now, the BIG MONSTER in the trunk, and the little normal sized one under the hood whose only job is to turn the starter and gets disconnected electrically with the engine off, since Mercedes knows that they have so much electrical draw that they overload the alternator easily (only puts out 150-200a, film heated windows can draw 80a by themselves) and then you park the car with the parking lights on for 16 hours and that big battery goes too low to crank, maybe.

Or one could just get a beefy alternator.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.



Edited 1 time(s). Last edit at 04/03/2016 02:51AM by Pete.

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Snidewhips
why run a second battery? dont wanna stress an old ass alternator out. easy to rig, diag and maintain. not as much risk overloading circuits

If those are 100W bulbs, each lamp would draw ~8A (at 12V, in actuality, you'd actually be closer to 7A @13.8V). If you ran four, roughly 32A MAX (or, again, closer to 28A @ 13.8V). I'm sure the factory alternator is rated well above that. That's not "stressing" it in the least.

Diag- what's to diagnose? With the normal, single battery way, you have uh- a battery and an alternator (with regulator). Not much to look at there.

If you went with the dual-battery, then what? Did you charge the second battery? Are you sure it is charging/charged? How do you know until you get to stage and flip the switch and no lights? Does that mean you'll put in more complexity to monitor the second battery? Sounds like way more trouble than it's worth.

Overloading- Just run a direct run to the battery with appropriate fusing and relay for your switch. DONE. Nothing to overload if you do it right. Don't leech off of the factory high-beam circuit, of course. Now that would be overloading, and a bad thing.

Sounds like a no-brainer to me... If the factory alternator is somehow not up to the task (doubtful) just get a beefier one like Pete said.

Sell Hellas and extra battery, buy LED bar.

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Runamuck Rally

budget guys, i have hellas already, a good led bar is expensive

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All bridges burnt, island life is beauty

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Snidewhips
budget guys, i have hellas already, a good led bar is expensive

from one budget guy to another. .. fix your alternator.

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Mad Matt F

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Snidewhips
budget guys, i have hellas already, a good led bar is expensive

from one budget guy to another. .. fix your alternator.

Budget.....there's nothing wrong with his alternator, it costs about $30 to put a new diode pack and a set of brushes in it if it's that much of a worry. The lights won't effect other circuits. Toss your crazy idea and concentrate on other actual issues.

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Power means nothing if you cannot control it!

And how much is it to swap in a generic 100-130 amp modern alternator from some GM product that you can get from a junkyard for $20 because they never really fail?

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

Generally the problem is getting the pulley aligned right.

You can get a Bosch 90A reman for about $130US. That's probably cheaper than a second battery and it'll definitely run those lights.

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Self-righteous douche canoe