Accessories draining battery?

[Paraphoe]

Guys,

Wanted to ask a question regarding wiring accessories and my battery. I’ve gone through 3 batteries in the past 3 years – high end, Die hard Platinum $200+ batteries. Thankfully, they’ve all been replaced under warranty each time, but it’s become very tedious. I can see the one I have in there now already losing power.

A lot of my lights are tapped into power from the positive terminal on the battery and run all the way back and tap in to the negative on the battery to complete the circuit rather than grounding to the body of the truck or frame. I always thought this was the “proper” and “clean” way to complete my wiring. Perhaps I’m mistaken, because the last time a battery was replaced, the shop advised me to remove all of the accessories I have running back to the negative end of the battery and instead ground them to the frame. They said something along the lines (without much confidence) that with the accessories running back to the negative on the battery, that there can maybe be a slight, consistent draw on the battery at all times which could be killing the unit prematurely. This doesn’t really make sense to me because none of the lights/accessories are on when the truck is off and I’m not too good with conceptual electronic stuff beyond your basic completing a circuit and wiring lights/switches.

Could anymore A) Verify if this makes sense? Should I ground all my accessories to the frame instead of back to the battery? And B) If yes, explain why this is causing a drain?

Thanks in advance!

 

[Maniak]

Running the wire to Ground on the battery is the same as running to a grounded surface. Normally, you are relying on a single point for your Ground BUT by running individual ground wires you are trading a single point of failure to a possibility of many points of failure (ground wire connections) but each single point should only effect 1 thing.

My guess is they don't like how many "wires" are on the battery as you have more places for corrosion to grow. You could always take a Ground bus/bar and run a nice bit wire from the negative terminal to the Ground bus/bar. Now run all your negative wires to that bus bar.

However, you don't "need" to run the wires back like that.. Only things like CB's and other things that you don't want to pick up EMI benefit from the separate ground wire.

As for killing the battery.. Parasitic drain isn't going to kill the battery like your describing. It would be killing the battery overnight or a few nights. What your describing is more like overcharging the battery (running it low on water) etc. Also, if you run you battery low often that is hard on it too (run the Radio/Amps/Lights long enough to make the vehicle almost not start).

Also, If you have the AGM version of the Diehard Platinum battery, that is the same battery I have in our X. Its about 2 or 3 years old now and replaced the exide orbital we used to use. The Diehard battery is much better and so far.. Its taking the abuse of the dirt road/off-road runs and there is still no corrosion on the terminals.

For full disclosure.. I'm running the 140 amp alternator from a 2nd gen limited AND currently I'm using a 1.9" pulley on the alternator (only been there a few months)..

Back to the orig issue. I'd take the truck into a place that can check the alternator for you "on vehicle". You want to know what its charging at while at idle and higher rpms. You are also interested in the Ripple.. A lot of ripple isn't going to be helping the battery. I'm pretty sure Oreilly Auto (some) still have the old tester that can show ripple voltage.

~Mark

 

[DjDom]

Someone correct me if I'm wrong,

But I read somewhere the the alternator detects how much power to regenerate based on the ground. So if you ground directly to the battery terminal, the car won't recognize the loss of power until the voltage drops quite a bit. Grounding to the frame/body however, the car recognizes that there is a constant power loss.

I'm not sure if Fords use the same system, but I believe read this somewhere on a Toyota forum?
Anyway, I know everything I hook up is grounded to the frame and it works.

 

[Paraphoe]

Running the wire to Ground on the battery is the same as running to a grounded surface. Normally, you are relying on a single point for your Ground BUT by running individual ground wires you are trading a single point of failure to a possibility of many points of failure (ground wire connections) but each single point should only effect 1 thing.

My guess is they don't like how many "wires" are on the battery as you have more places for corrosion to grow. You could always take a Ground bus/bar and run a nice bit wire from the negative terminal to the Ground bus/bar. Now run all your negative wires to that bus bar.

However, you don't "need" to run the wires back like that.. Only things like CB's and other things that you don't want to pick up EMI benefit from the separate ground wire.

OK, so it’s looking like I was given faulty information on the “draining”.

As for killing the battery.. Parasitic drain isn't going to kill the battery like your describing. It would be killing the battery overnight or a few nights. What your describing is more like overcharging the battery (running it low on water) etc. Also, if you run you battery low often that is hard on it too (run the Radio/Amps/Lights long enough to make the vehicle almost not start).

Yea, I never do that. The only extra accessories I run with normally are my 3 KC 26 series lights (small, below the headlights) which are on 90% of the time. Everything else is off unless I use it.

For full disclosure.. I'm running the 140 amp alternator from a 2nd gen limited AND currently I'm using a 1.9" pulley on the alternator (only been there a few months)..

Back to the orig issue. I'd take the truck into a place that can check the alternator for you "on vehicle". You want to know what its charging at while at idle and higher rpms. You are also interested in the Ripple.. A lot of ripple isn't going to be helping the battery. I'm pretty sure Oreilly Auto (some) still have the old tester that can show ripple voltage.

I don’t know anything about ripple voltage, it’s actually the first time I’ve heard that term, but maybe I can find a place to test for me. Regarding the alternator – is yours an upgrade? What are the amps on the stock one - 95? is it worth it to upgrade? This could be the issue, perhaps. I’d be willing to put in a 220 AMP one or so if it’ll fix the issue.

Thanks Mark.

Someone correct me if I'm wrong,

But I read somewhere the the alternator detects how much power to regenerate based on the ground. So if you ground directly to the battery terminal, the car won't recognize the loss of power until the voltage drops quite a bit. Grounding to the frame/body however, the car recognizes that there is a constant power loss.

I'm not sure if Fords use the same system, but I believe read this somewhere on a Toyota forum?
Anyway, I know everything I hook up is grounded to the frame and it works.

This would make sense, but I've never heard of it before on a Ford or at all, really.

 

[Maniak]

I don’t know anything about ripple voltage, it’s actually the first time I’ve heard that term, but maybe I can find a place to test for me. Regarding the alternator – is yours an upgrade? What are the amps on the stock one - 95? is it worth it to upgrade? This could be the issue, perhaps. I’d be willing to put in a 220 AMP one or so if it’ll fix the issue.

The Ripple check is just to make sure the power that is being put out by the alternator is a nice flat signal. Its been a long time since I had to look it up BUT I "think" anything over .5V of ripple is considered excessive.

I've never done it this way, but I've "heard of" people using a volt meter, set on AC and set for the lowest setting (assuming its over 14V). Now they measure between the alternator and the negative terminal on the battery. I don't now how accurate this will be as some (many) volt meters only look at around 50hz-60hz when measuring AC.

As for the alternator.. My factory (I think All 1st gens) come with a 95 amp alternator. In 1996+ (might be 1995) there is a 130 amp optional alternator (I goofed on my first post.. I thought it was 140, its 130). It normally came on the Limited models.

I just upgraded my stock 95 with a stock 130 from a 1996. The 95 amp seems to also be common on the 1997's so you might have the smaller one.

Since I wheel our Explorer which means extra lights, and the aux electric fan while sitting at idle often I changed the alternator pulley size. The factory size was 2 5/8". I now have a 1.9" pulley. That increased the pulley speed by quite a bit. The issue with doing this mod is that if you spend a lot of time in higher RPMs you can wear out your alternator bearings faster. Back when our X was a DD I had a 2" pulley on it and would have to change the alternator every 35k miles or so.. At that time it spend most of it's life at 2400 rpms or so.

~Mark

 

[2000StreetRod]

alternator capacity vs load

If your alternator is good and your connections are good I suspect your real problem is its capacity is insufficient to recharge your battery adequately while supplying power to a large load. I suggest that you check your electrical connections for corrosion and tightness. Then determine the rating of your alternator and have it tested. Also, determine the load of your accessories and compare that to alternator capacity. You may need to upgrade to a higher rated alternator.

I can remember when vehicle generators had a rating of 30 amps. Alternators have a much higher current capability but their output is alternating which must be rectified. Filtering to smooth out the ripple is usually minimal (but adequate) because capacitors require space to store energy. You probably don't need to worry about ripple in your vehicle. If you purchase a higher rating alternator make sure it outputs more at the engine speed you normally run. Some have high outputs at high engine speeds but little or no increase at idle or normal engine speeds.

 

[Maniak]

Then determine the rating of your alternator and have it tested.

While I was looking for a 3g alternator chart (showing the amperage out vrs alternator shaft speed) I found the dimension difference between the 95 amp and 130 amp so Paraphoe can easily tell how big of an alternator he has.

The 95 amp alternator case is 5.3" across. The 130 amp alternator is 5.8" across. By across I mean if you measured the height of the alternator case as it is installed in the vehicle..

I did find the chart I was looking for.. the 130 Amp ford 3g alternator can put out 100 amps @ 1500 rpm (shaft speed). To get shaft speed you take Engine RPM x Crank Pulley Diameter ÷ Alt Pulley Diameter.

~Mark

 

[Paraphoe]

Thanks guys. I'll give it a look when I have a chance. Unfortunately, money is really tight right now as I just blew a brake line Friday night and had for fork over hundreds of dollars to replace all the lines and get the rig back on the road and inspected. Picking her up tonight. This right after dropping $2k for the Superlift. Murphy's Law....

 

[2000StreetRod]

2.75 ratio

Mark, I estimate my crankshaft to alternator ratio to be about 2.75. So if my engine idles at 700 rpm the alternator would be rotating at 1925 rpm. I don't know if the ratio is similar for the 1st generation.

Jason, sorry to hear about your brake lines. You guys that live in winter salted roads have it tough!

 

[Paraphoe]

Just to follow up here, my battery died completely again. I took it back, got the battery replaced for free, and had the alternator inspected. It turns out it was barely putting out 9 volts and was on it's last leg. As it didn't crap out in one single moment on me, I suspect that it started its downturn 2-3 years ago and has slowly been losing function and killing batteries on me.

New Alternator is in, hopefully this solves my woes. Especially because I have some new lights to install that I think Santa may be bringing.