Too much connected to battery?

[Adam A]

Hi All,

Just want to see how much I can connect to the battery at once. Right now, I've got a secondary oogah horn, a 4w CB radio, and am hoping to hook up a pair of 100w flood lights and a 20w PA speaker. Too much to put on the battery? Anything special I need to do to connect all that or just battery connectors and washers between?

Adam

 

[RonD]

Not really a battery issue, car batteries have at least 400amps available for starting the engine.
What you need to consider is the alternator, it runs the electrical system when engine is running, and if you exceed its amp rating then battery will drain while you drive, instead of charge, leading to a no start from dead battery.

Find out what alternator you have for your year, engine, and model, get its AMP rating

Generally if your alternator is rated as 80amps then stock truck electrics with everything ON, will draw 1/2 those amps, so 40amps
An alternator can only put out 60% of rated amps at idle RPMs(650-750rpm), it only has full rated amps above 1,800RPMs.

Then go here: http://rapidtables.com/calc/electric/watt-volt-amp-calculator.htm
Enter watts and volts(12) then Calculate, and you will get the AMPs for each device you want to add

So what you may want to do is get a higher rated alternator, they go up to 200AMP rating, so 100AMPs would be available at idle.

AMPs are a "draw" so 200amp or 500amp(lol) alternator won't hurt battery or electrical system, it only outputs the AMPs required at any given time, so as you turn things on voltage regulator in alternator increases amp output, IF IT IS AVAILABLE.
So maintains the engine running 13.5-14.5volts, if you exceed the available amps then voltage drops, i.e. dimming headlights at idle is an example of exceeding alternators available amps

ANYTHING connected to vehicles power system needs to have a FUSE, and fuse size is determined by the device being powered AND(big and) the WIRE SIZE used.
If you use a 20amp fuse on a small wire to the device then the WIRE becomes the fuse, if there is a short or ??, then wire heats up and melts or starts a fire, instead of the fuse blowing.
So check 12volt wire size, length of wire and rated amps, there are charts for that, it is important
All a fuse is, is a smaller wire that melts when heated, lol.

 

[Adam A]

So correct me if I'm wrong. It looks like in total, at idle, I can draw 48 amps safely without draining my battery (80x60%). And if my truck already draw 40amps, I really should be using my lights (which would draw 8.5amps) for very long at all at idle. However, if I'm driving they will be fine. That sound about right?

 

[jeremysdad]

So correct me if I'm wrong. It looks like in total, at idle, I can draw 48 amps safely without draining my battery (80x60%). And if my truck already draw 40amps, I really should be using my lights (which would draw 8.5amps) for very long at all at idle. However, if I'm driving they will be fine. That sound about right?

2005 should have 95 amp stock, could be 130. Have to check to be sure.

 

[85_Ranger4x4]

A CB Radio and two lights shouldn't hurt anything.

The horn and speaker won't draw much and won't draw it often (unless you have questionable manners)

Do you have a primary oogah horn?

 

[Adam A]

A CB Radio and two lights shouldn't hurt anything.

The horn and speaker won't draw much and won't draw it often (unless you have questionable manners)

Do you have a primary oogah horn?

Unfortunately, I don't. That would be awesome.

 

[RonD]

Yes your math is correct.

But...............an alternators common failure as it gets older is one of the three Fields fail.
So if you notice the head lights dimming at idle that is what has happened.
With stock electrics you can usually go on driving for awhile since above idle the amps are still OK, but you should still shop for an alternator sale

If you have added 10-15amps to load at idle then engine could start misfiring or stall if voltage drops too much, it is also not good for the electronics in the vehicle, they don't like "Brown outs" almost as much as they don't like voltage Spikes.

And find out what YOUR alternator AMPs are, you know the year and engine size, we don't

 

[Curious Hound]

RonD's advice is exactly on target. 85_Ranger also alluded to something to keep in mind. Not all loads are using power continuously. Continuous loads and loads that are used for long periods are your primary concern - ignition system, stereo (especially if you have a high power amplifier), headlights, fog/flood/offroad lights, windshield wipers, etc. I would also consider a winch in that category.

Momentary loads, such as the horn, are not a big concern. even if momentary loads take you over the limit of your alternator, the battery covers the difference and in a few seconds the load is gone and the alternator recharges the battery. CB radio is one of those things. It only really uses that full 4 watts (which is negligible anyway) when you are transmitting.

So, consider all the loads in the vehicle and decide which ones really count in analyzing your total load. Then size your alternator for that load plus a safety factor of at least 10%.

If you install a larger alternator, don't forget to upgrade its wiring and fusible link accordingly. You don't want to have the big alternator and then burn up the wiring due to high current.

 

[Adam A]

All outstanding advise guys. So, if you were in my shoes, would you go for the 100w lights? That should be within my range.

 

[85_Ranger4x4]

All outstanding advise guys. So, if you were in my shoes, would you go for the 100w lights? That should be within my range.

LED's put out much more light for the current they use.

I have a 4.5" round flood light here at work on display, nothing fancy that pulls an amp and a half. That is less than an 1156 turn signal bulb pulls. Lights up my showroom in the day time... and they come much brighter.

Larson Lighting has good prices on LED lights.

 

[RonD]

If you want bright then look on ebay for "aircraft landing lights"
LED versions draw about 70% less(conservatively) than incandescent lights

100watts = 1600 lumens in light level

So a 1600 lumen LED light would draw about 30watts instead of 100watts for the same light level, 14volt version is what you want

These landing lights are BRRRR..IGHT
but also not meant to be run 24/7 they do get hot although the LED versions are much cooler than older style.

Years ago I put a set of Landing lights on my "Jimmy's" roll bar, jeeze, it was like daytime when I turned them on, lol, but they did get very hot
Like a spotlight on steroids

Jimmy = GMC version of full size Chevy Blazer

 

[fastpakr]

I have a set of 16 watt LED flood lights on my son's jogging stroller. Looks like an 18 wheeler going down the road and a small motorcycle battery is enough to run them for a couple of hours without damaging the battery. Lighting technology really has improved immensely. Still need to get focus issues worked out for LED headlights, but the efficiency is incredible compared to filament bulbs.

 

[4x4junkie]

I've never cared much for LED lights that have a color temperature over 4500°K or so (this includes every single aftermarket LED vehicle lighting product I've seen so far), too much blue-light glare, especially in the foreground. So I stick with halogen lighting on mine (I'd use HID if it didn't affect the radio equipment I have).

A GOOD quality halogen light (the Hella 4000 for example, not some cheap POS from Autozone, Harbor Freight, etc.) will put nearly every cheap (sub-$200) LED item on the market to shame for distance anyway. If your eyes are anything like mine, it'll likely rival much of the higher-end LED stuff too.

100W = ~8.3 amps (or 16.6A for two 100W lamps), this should not be a burden for any electrical system having at least a 60A alternator.

Of course a bigger argument can be made in favor of LED for something powered strictly by a battery (the stroller thing for example, or a flashlight).