I did something dumb. Left headlights on in the middle of nowhere.

[TMG51]

I did probably the dumbest thing one can do in the desert. I left my headlights on and drained the starter battery. I've never done that before, and of all places I did it now in the middle of nowhere.

I'd driven out into nowheresville BLM land. Went out for a walk for several hours. When I got back, I realized what I'd done. The battery was so drained it wouldn't even operate the electric door locks. When I got out for my walk after parking, I'd used the passenger door, so the "headlights are on" reminder buzz never went off as it does when the driver's door opens.

I had previously theorized to myself that if I were ever stranded with a dead starter battery, I could rescue myself by swapping the house battery up front. Well, my house battery is now made of a 2x golf cart battery bank, so in practical application I couldn't fit them in the engine bay in any way that would reach the existing battery connections. I had no jumper cables either.

What I did have was a 50' extension cord. I stripped the outer jacket off the cord and pulled out two 12ga insulated wires. Then I cut them in half lengthwise, stripped several inches of insulation off each end, and twisted two of each together. So, I then had two 25' 6ga cables.* I ran my new cables from my house battery bank up to my engine battery. I didn't have ends for them, I just twisted the stranded wire tight around the terminals with a pair of pliers. I left this in place to charge without touching the ignition, also constantly feeling the wires to see if they were getting hot. They stayed cool to the touch. After 40 minutes I turned the key and it cranked over with no problem. I let it idle for a half hour before shutting off.

Really the solution to this issue is to have a battery disconnect so you can't strand yourself like a dumbass. But if you've been a dumbass as I was, and you have house batteries, then you may be able to get by with a bunch of copper wire.

*In the purest electrical sense, I'm not sure that two ends of a doubled up 12ga wire twisted together are strictly the same as one 6ga wire. But I'm pretty sure what I did offered less resistance than a single 12ga wire would have.

 

[BigT]

Nice job with the extension cord. You could also get one of these. http://www.amazon.com/Nekteck-Multi...1-2-spons&keywords=battery+jump+starter&psc=1
Not necessarily this particular model, but something like it.

They pack away very small and could really come in handy if/when your starter battery dies. Just knowing it's there is great for peace of mind.

 

[GotSmart]

It sure feels good when an emergency hack works!

 

[SternWake]

Do you charge the house batteries with alternator?

If so, then one can just move the charge cables wires to the same terminal on the solenoid/isolator device.

I ripped out my buzzer the first day I got my Van so I am certainly at risk of leaving the headlights on too, but have not yet done so.

Remember it takes at least 4 hours to get from 80% charged to 100% charged, and who knows how long to get to 80%, when a battery requires a jumpstart, so get that starter battery back to a true full if you want to get more life from it, otherwise you will be replacing it sooner than desirable and might have to be using your jury rigged cables again.

 

[TMG51]

Looked at another way, at least you were in the middle of nowhere so no one saw you.

Good work on the jury rig. I'm sure it was music to your ears when the motor cranked over.

Small point, Parallel #12 wires are close to an oddball #9 (between #8 and #10) rather than the larger #6.
http://www.engineeringtoolbox.com/awg-wire-gauge-d_731.html

Guy

Right, so, as the note in my post implies I knew enough to know my concept was correct, and I knew enough to know that I didn't know the specifics.

But that's interesting to know the specifics.

Nice job with the extension cord.  You could also get one of these.  http://www.amazon.com/Nekteck-Multi...1-2-spons&keywords=battery+jump+starter&psc=1
Not necessarily this particular model, but something like it.  

They pack away very small and could really come in handy if/when your starter battery dies.  Just knowing it's there is great for peace of mind.

I've thought about one of those, but I have this fear that as soon as I buy one it's going to live in the back of my mind as a persistent maintenance item. "Have I charged that thing enough recently? Do I need to get it out and check?"

Something like that is certainly good to have but if I ever had a dead battery AND a dead jumpstart pack thing, then I'd REALLY feel like a moron.

Do you charge the house batteries with alternator?  

If so, then one can just move the charge cables wires to the same terminal on the solenoid/isolator device.

I ripped out my buzzer the first day I got my Van so I am certainly at risk of leaving the headlights on too, but have not yet done so.

Yes there is factory wiring in place to charge off the alternator. I had the same thought, myself, and then decided that I could rig up my extension cord swap faster than I could figure out which of the factory wires were doing what. If the extension cord hadn't worked, I would have taken a second look.

When I bought my Jeep years ago, the very first thing I did was disassemble the dash and unsolder that buzzer thing from the instrument cluster. One of the reasons I like my van is that its interior dials and such are very similar to the Jeep, and I knew straight away I could disable that buzzer easily. But, I decided to leave it in place this time, just for the perceived security of the headlight warning... emphasis on perceived...

For now, it's good to have proof of concept that I can charge off my house batteries in an emergency.

Incidentally, the charge controller did not report the system as over-discharged during this time. I was about to break out the multimeter until I decided I didn't care enough.

 

[TMG51]

Do you charge the house batteries with alternator?

If so, then one can just move the charge cables wires to the same terminal on the solenoid/isolator device.

Yes there is factory wiring in place to charge off the alternator. I had the same thought, myself, and then decided that I could rig up my extension cord swap faster than I could figure out which of the factory wires were doing what. If the extension cord hadn't worked, I would have taken a second look.

After giving this another moment's thought, it now makes total sense to me to just put the house battery charging terminals on the same side of the isolator.

At the time I felt something independent would be less complicated than changing factory wiring. But I agree this would have been faster and better overall. If it ever happens again that's what I'll do - thanks for the tip!

 

[highdesertranger]

get some good jumper cables. I had to jump myself the other day. highdesertranger

 

[rvpopeye]

Skuh kuh kuh kuh
Somehow , I get a feeling you won't leave the headlights on again ......

 

[ACagedTraveller]

That must have put a delay on any plans he might have had for the day. This sort of thing happens towards me occasionally as well. This simply illustrates the point that even the best people occasionally forget things.

 

[B and C]

x2 on the jumper cables.  I have a 20 foot set so I wont have to disconnect/reconnect anything.  I just have to dig them out  as they are buried.

 

[eDJ_]

If you had the luxury of time and could spend the night without need of power,  then the battery may have rebounded enough by the next morning (or even evening) that you could restart the motor and allow it to run
in order to charge the battery again.  An alternator will charge a battery (some) with the engine idling.

 

[BigT]

If you had the luxury of time and could spend the night without need of power,  then the battery may have rebounded enough by the next morning (or even evening) that you could restart the motor and allow it to run

I was going to mention that.  I've done that a time or two when I accidentally left the fan and radio on in the Sprinter at work (now I start it once in a while). 
I'm fortunate that I have a 200W solar panel connected to my starter battery, so I don't have to worry about leaving my lights on as much.  
My starter battery, a Northstar AGM, is also my deep-cycle house battery, so it might not even kill it to leave the lights on for a day.  

I do have the jumper pack and a set of jumper cables, but I doubt they'll ever be used to start my car. 

 

[karl]

A Friend wired a momentary switch from his house battery to the solenoid so that he could activate the solenoid when the start was dead, and instantly having house power to the start battery.

 

[blars]

My motorhome has a switch to start from the house battery, but since it's momentary and starting is a two-hand job, it's pretty useless. I purchased a battery charger that I can use off of an inverter or my generator, so I don't need to call coachnet for jump starts anymore.

 

[MrNoodly]

The way I see it, the vehicle manufacturer did the dumb thing by making it possible to leave your lights on long enough to drain the battery. They're also dumb for making it possible to lock your keys inside. I suspect they have a deal with the tow truck cartel and the locksmith mafia.

 

[Goshawk]

You can get an alarm. If the car battery drops below a preset voltage it goes off. Think it's 12.2 volts as low as you want to go and still have enough power to turn over an engine.

 

[Theadyn]

I did that thanksgiving night, don't feel bad. My ignition sometimes doesn't turn off completely, even when the key is out, it will sometimes buzz with the door open. I had gotten to where I ignore it. Well no more, dead, dead battery the next morning due to headlights left on. It makes the same buzz sound, just assumed and all that. Now I make sure that sound doesn't go off, period.

I did have a small jumper pack save the day. Even a v8 motor, it worked. I like having that peace of mind.

 

[Optimistic Paranoid]

You can get an alarm. If the car battery drops below a preset voltage it goes off. Think it's 12.2 volts as low as you want to go and still have enough power to turn over an engine.

That wouldn't have helped.  He went off on a hike and the battery was dead when he got back.

Regards
John

 

[highdesertranger]

also those low battery alarms place another load on an already low battery. so if you are not there you just drain your battery even faster. highdesertranger

 

[Spaceman Spiff]

The way I see it, the vehicle manufacturer did the dumb thing by making it possible to leave your lights on long enough to drain the battery. 

Way back in '73 Porsche had a solenoid that would disconnect headlights when the ignition was turned off.  Don't know why that hasn't been a standard feature for a long time.

There are low voltage disconnects that will fix the problem:

https://www.bluesea.com/products/7635/m-LVD_Low_Voltage_Disconnect

-- Spiff