dc to ac converter fault

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Forum Name: Vehicle Wiring Information & File Requests
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URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=115512
Printed Date: May 01, 2025 at 12:12 PM

Topic: dc to ac converter fault

Posted By: ptero
Subject: dc to ac converter fault
Date Posted: August 06, 2009 at 9:52 PM

1998 Ford Windstar Cargo Van (stripped - no back seats)

Hello all

It began intermittently but, as of this morning and much to my consternation, the problem is now "solid".

When I plug a DC to AC converter into my cigarette lighter the converter throws a fault and doesn't operate.

I thought my converter had gone bad so I purchased a new one today (400W Black & Decker) and the results were the same.

Oddly, I can plug in my "strip" (for multiple cigarette lighter chargers) and it works (apparently) fine. It kept my GPS charged all day today.

I'm heavily reliant on having A/C current in the cabin as I must have my laptop w/ me and fired up @ all times for my work - the computer's battery power won't cut it.

I am a tech of many moons. Though I'm not an electrician, I've wielded my share of soldering irons, wire strippers, crimpers, DVM's and the like so, I'm not shy about tearing into this to get it fixed.

I need it to be a quick fix if possible, though. I don't have a day to spare tearing the console apart and tracing wiring if I can avoid it.

Obviously the issue isn't a fuse as has been posed to me - rather, I suspect (if it isn't just a bad cigarette lighter) the issue is chassis ground and that perhaps the "strip" (and my GPS) doesn't care but the converters will not operate w/ out it.

Could it be just a matter of swapping out the (original equipment) cigarette lighter - or do you think I'm going to have to hunt down an open ground?

I'm not adverse to pulling the cigarette lighter out all together and crimping on a couple of terminals to the wires in order to get power to my new converter (which includes a set of leads w/ clips (like those of a battery cable) that can clip on to the terminals). It would be a more reliable connection - not one given to wear. I could just forgo the clips all together and crimp the wires for the lighter directly to those of the converter - even better. The wires/leads are detachable at the converter so quick uninstalls wouldn't be an issue.

Y'all are welcome to weigh in on this. I'd be most grateful. I'm desperate as I need to get this fixed a.s.a.p. but can't afford to lay out a wad of $ to pay a mechanic or - worse - a dealership to fix it.

Thank you all in advance,
Lady Tech
Ptero

Replies:

Posted By: i am an idiot
Date Posted: August 06, 2009 at 10:02 PM

You really need to look into running a 10 Ga. wire to the battery. I know a laptop will not be that much of a strain on the wiring, but with a 400 watt supply, I think you really need to run a wire to the battery. Fuse it at 30 amps or less if all you are using it for is the laptop.

A cigarette lighter plug is not designed to handle loads of current for more than 20 seconds or so.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

Posted By: ptero
Date Posted: August 06, 2009 at 10:13 PM

Thank you for responding so quickly.

The direct wiring w/ in-line fuse is a good idea. I haven't run wiring in the van before.

So, do you think the cigarette lighter is shot for misuse?
w/ respect to direct wiring; This means drilling through the fire wall?
Or do you think I can slip it in along w/ an existing harness?
Am I looking at needing to have the van up on a lift to do this?

For now, I'm needing the quickest fix to hold me 'till I can take on a "project".

I've been using my original converter in the van for more than a year now w/ no problems. Only recently did I start to see issues developing w/ faults.

Ptero

Posted By: i am an idiot
Date Posted: August 06, 2009 at 10:31 PM

There should be a way to get through the firewall without drilling. You will not need a lift to do this. Open the hood and look for an existing rubber grommet around the main harness or the hood release cable. Do not run through with the trottle or clutch linkage or cabe. if you find the main harness has a large rubber grommet with room for the new wire, simply pierce the grommet with a phillips screwdriver or some other not really sharp object, while being very careful not to cut any wires in the harness. Run the wire through the new hole. Go inside the vehicle and look for the wire.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

Posted By: ptero
Date Posted: August 07, 2009 at 6:48 AM

Thank you again, iaai. I read thru the manual that came w/ the new converter. I will run two wires of appropriate guage - one off of ea. batt' terminal - into the cabin and, per mfgr recommendation, install an in-line fuse near the batt'.

I'll replace the cigarette lighter w/ a new "auxiliary equipment" plug as the former is likely shot. This will be an improvement as it will give me the use of the ae plug for the lower current devices (GPS, phone charger, etc) while still being able to keep my laptop fired up on a/c off of the converter.

I hope to be able to knock this out on Sunday. Will let you know how it goes.

Thanx again,
Lady Tech
Ptero

Posted By: i am an idiot
Date Posted: August 07, 2009 at 7:47 AM

Run only the positive wire to the battery. Ground the unit to the Chassis of the vehicle. The shorter your ground wire the better off you are. Additional length of the ground wire will yield more voltage drop when the unit is under a load. This will not be good for the unit. Remove all of the paint from a small area of metal very near the unit and ground it there.

I am slipping, I forgot to mention the fuse.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

Posted By: ptero
Date Posted: August 07, 2009 at 8:11 AM

You mentioned the fuse - so, no worry, you're not slipping.....

The mfgr's instructions called for running a wire to both batt' terminals. I see your pt., though, w/ the shorter run to chassis ground. Not to mention it'll be a hec' of a lot less trouble.

I have a laptop stand between the bucket seats. I secured it to the floor w/ self-tapping sheet metal screws. That might be a good spot for the converter's ground termination. Maybe not, I'll see once I'm in there. I'll make sure there's good continuity to the chassis from the converter ground-side.

Thanx again
Lady Tech
Ptero

Posted By: i am an idiot
Date Posted: August 07, 2009 at 8:12 PM

I am still slipping, I should have stressed the AT the battery part.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

Posted By: ptero
Date Posted: August 07, 2009 at 8:50 PM

You're fogiven - REALLY. :o)

I meant to ask; why is the fuse to be located near or at the battery and not in the cabin or on the cabin-side of the fire wall say...?

Lady Tech
Ptero

Posted By: i am an idiot
Date Posted: August 07, 2009 at 9:16 PM

The fuse is located at the battery incase there is a problem where you penetrate the firewall. If the firewall scrapes through the insulation and the wire grounds out, the fuse will blow. If the fuse were inside the cabin, there will be some very hot wire between the battery and the firewall. Very Hot wire. At the battery the fuse will protect the Inverter and the entire length of the wire. In the cabin it will protect the Inverter and only part of the wire.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

Posted By: ptero
Date Posted: August 08, 2009 at 7:11 AM

Ahhhhhhh. Wow. Hey, great info., iaai. Thank you. At the battery it is! I'm gonna see if I can find everything I need at Lowe's or Home Depot today. Shooting for taking care of the mod.' tomorrow. Fingers and toes crossed....

Lady Tech
Ptero

Posted By: ptero
Date Posted: August 08, 2009 at 9:47 AM

OK, now for makin' sure I have the right materials, etc. for the mod.' t'morrow. We're "country" 'round here - nothin' 'll be open on Sunday. So - gotta make sure I get everything to complete the job today. If you'd like to weigh in, again, I'd be most grateful.

SPECIFICATIONS WORKING W/:
The cabin firewall is >/= 5' from the battery. My intention is to mount the inverter on the console or on the floor or firewall near the console.
The inverter is a "Vehicle Power System Black & Decker 400W Power Inverter w/ USB Charging Port" Catalog No.: PI400AB
Even though for now I'll use the inverter primarily to power my laptop (uses a 90W power supply), I'd like to wire the inverter for its capacity.
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PROPER MATERIALS NEEDED (?):
Wire: Correct guage and type (stranded, solid, copper, etc) and insulation (jacket)
Fuse: Type (slow blow or not) and amperage
Termination @ Battery: Best way to terminate @ the battery; best type of terminals to use
Termination in cabin: Best way to terminate in the cabin; best type of terminal to use
Cabin Mount: Mount the inverter on something between the cabin (e.g. block of wood, etc.) and inverter case?
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MFGR RECOMENDATIONS:
According to the manual, this inverter is designed to support a load of up to 80W when using the DC accessory plug (to the cigarette lighter).
> 80W and </= 400W, it requires a direct connection to the battery
The mfgr manual calls for #6 AWG wire for </= 6' and #4 AWG wire for up to 10'
The fuse called for is a 35ANL (the trick is going to be finding ANL fuses around here - I don't think Lowe's or Home Depot is going to carry them...)
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BTW, I found a nice write up on basic car wiring and fuses HERE. (didn't know what ANL fuses were)
I tried to get to Black & Decker's site for more info. on the inverter but they're apparently down.

Thank you,
Lady Tech
Ptero

Posted By: i am an idiot
Date Posted: August 08, 2009 at 10:15 PM

You will not find an ANL fuse rated at 35 amps. They do make Mini ANL fuses but I have no idea if they come in 35 amp ratings. Most of those inverters are between 80 and 90 percent efficient. At 12 volts assuming 90 percent, it will pull less than 40 amps of current at 400 watts out. A 10 Ga. wire will be fine. You should be able to find a fuse holder with a 10 Ga. wire already attached to it. Maybe not on Sunday, but you should be able to find one. Using it to charge laptops will not stress a 30 amp fuse at all.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

Posted By: ptero
Date Posted: August 09, 2009 at 6:04 AM

Thank you, iaai. Apparently the mfgr is ill-informed - having called for a 35 ANL fuse.

NP. I found an inline mount that takes 30-80 amp Maxi's @ WalMart yesterday. The mount's in a water proof enclosure - made to be under the hood. Closest thing I could find for what I need so, I think 'm gonna go w/ that using the 30-40 amp Maxi. I can easily change that out later - the hard part will be running the wire.

Lady Tech
Ptero

Posted By: i am an idiot
Date Posted: August 09, 2009 at 7:02 AM

Just make sure you keep the wire off of the exhaust manifold and any belts or moving parts under the hood. Also keep it away from throttle, brake and steering linkage inside the cabin. Depress and turn the above 3 items while looking under the dash before you decide on a route for the wire.

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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

Posted By: ptero
Date Posted: August 09, 2009 at 8:34 AM

Thank you, iaai. I really appreciate all your helpful advice and instructions.

Well! I just looked under the hood and there ain't no way on God's green earth I'm gonna be able to get @ that firewall to pull that wire thru. The firewall's set way back from the windshield-end of the hood behind a whole mess of stuff - well outta reach.

"T' h**** w/ that!" I says to mahsailf. I'm gonna take it down the road to my mechanic 1st thing t'morrow mornin' and have him just get the wire through the firewall for me (following your instructions) then I'll do the rest - dress and terminate, etc on both ends. He's got a lift an' he knows how to take all that mess apart (if necessary) an' get it back t'gether right. I know my strengths as well as my limitations. Ain't no sense in killin' myself - or my van - tearin' stuff apart I know nothin' about to get at the wiring harness @ the firewall.

So, I'm off to Wally World (WalMart) and Lowe's to get the wire, fuse mount, fuse, etc.

Lady Tech (**definetely NOT a mechanic**)
Ptero