I am installing a 2000 watt rectifier in my truck

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straps

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I am installing a Harbor Freight 2000 watt transformer/rectifier in my work van for chargeing batterys,cell phones and a very small frig ( Love my energy drinks cold) What size would you folks recommend. The service instructions say #2 wire it is a 9 foot run to the battery. I am also contemplateing adding a second battery just in case. Like the kids do for their boom boom boxes they mount in the trunks of their cars. Any ideas?

All help is appreciated I thought number 6THHN in 1+1/2 inch pvc for roadway protection. No snow or ice in Florida figured go down under the chassis then back up into the engine compt.
 
Re: I am installing a 2000 watt rectifier in my truck

Originally posted by straps:
I am installing a Harbor Freight 2000 watt transformer/rectifier in my work van...
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I seriously doubt it. You might be installing an inverter, but you're certainly not installing a rectifier.
 
Re: I am installing a 2000 watt rectifier in my truck

The math is 12 volts needs ten times the current that would be required at 120 volts. Big wires, yep.

Edit: That is, for the same wattage.

Another edit: 2000 watts is 167 amps.

It's the transformer that wont work on dc.

[ May 28, 2005, 10:04 PM: Message edited by: physis ]
 
Re: I am installing a 2000 watt rectifier in my truck

I have a feeling you mean an inverter, which converts 12v DC to 120v AC. If so, the wire between the battery and inverter must be able to carry the load with very little voltage drop.

Remember, when you step 12v to 120v (and assuming 100% efficiency), the current converts proportionately. In other words, each amp at 120v requires 10 amps at 12v. The wattage is the same.

For the input circuit: 2000 /12 = 166 amps; That's a hefty current, especially for continuous loads. Methinks you need a 3/0 or 4/0 cu. wire; welding cable is a good choice.

2000 /12 = 16.6 amps;. I'd suggest using #12 AC/MC for all 12v wiring. If the inverter doesn't provide GFCI protection (some do), I'd add it; a truck body is a good sized ground plane.

As with long-distance electrical transmission lines, longer high-voltage and shorter low-voltage runs are more efficient (and usually less expensive). Two batteries should use isolators*.


* Boating supply stores and RV dealers are great sources for 12v electrical supplies.
 
Re: I am installing a 2000 watt rectifier in my truck

12v Dc to 120v Ac Invertor:

Input: 2,000Watts / 12Volts = 166.66 Amps
Output: 2,000Watts / 120Volts = 16.6 Amps

It will depend on what type of wire...temperature rating on the wire, as well as the Temp. ratings on all the terminals.
#6 will not be near large enough to handle the full 2,000 watts at 12 volts.
If you use a #2 rated for 150 degrees it is rated for 160 Amps.
If you put the #6 on a 60 Amp fuse it should be safe.

I say that because thats what I did for my 1,500 Watt inverter in My truck! Works Great! I used liquid tight from the battery, down, underneath, then came up through the floor under the passenger side seat, where the inverter is mounted.
I also bought the dewalt radio/battery charger! :D
It's a very cool set-up, no more radio batteries to buy, and no more dead cordless drill batteries...charges my cell phone...
A pain to hook up, but time and money well spent.

60*12= 720Watts
720Watts / 120volts?= 6 Amps

Do your chargers pull more than 6 amps?


Dave
 
Re: I am installing a 2000 watt rectifier in my truck

What would happen to the alternator in the truck over time if you actually loaded the inverter to 2000 watts? I think that the typical Chevy work truck or van only has a 105 amp alternator. I don't know if my concern is valid, but I'm just wondering.
 
Re: I am installing a 2000 watt rectifier in my truck

mdshunk,
Your concern is Valid! The auto alternators are not supposed to charge constantly, I think most of todays alternators have a voltage regulator built in. This monitors the battery's voltage and controls when the alternator actually charges or not. The more load on the battery, the more the alternator charges it, like most things, the more you use it, the shorter it's life span is.
:)
Dave
 
Re: I am installing a 2000 watt rectifier in my truck

I believe that automotive alternators are basically self-current-limiting. They'll simply put out their rated current. The diodes are rated high enough to withstand this current.

As with any other 12v load, the battery will supply whatever the alternator can't, and then will get recharged with whatever current isn't used when the load reduces.

If the load exceeds the alternator for an extended time, the battery could be depleted. A second battery allows starting the engine if you run the inverter with the engine off.

I just got a 2500-watt (20a @ 120v!) inverter and a deep-cycle marine battery for my truck. I plan to wire in a power inlet for those times I'm near power for a charger.

Oh, I already use a 200-watt inverter for the 2-tube 8' fluorescent fixture in the back of the truck. The new setup will allow me to run power as if I had a generator on-site.
 
Re: I am installing a 2000 watt rectifier in my truck

Especially if the new current demand exceeds the capability of the of the existing alternator. The overcurrent device wont last long.

A couple years ago I lost the alternator in my van. I was basically driving around on the battery a couple times before I figured it out. It was kind a funny when I realized what was going on. :D
 
Re: I am installing a 2000 watt rectifier in my truck

You snuck in on me Larry. Maybe you're right. I don't remember how it's done.
 
Re: I am installing a 2000 watt rectifier in my truck

Ok, since we're talking about over charging batteries...here's a good story!

I was about 16 or 17 cruising around in my 1970 Plymouth Satelite! (Alternator charged ALL the time, and I mean 24-7!) (If the car was running)The head lights would get brighter when I excellerated, wipers would go faster! I was on my way to my buddy's...had the radio blasting...heard a loud BOOM!...turned the radio down, everything was fine or so I thought. When I went to leave my buddy's house the car wouldn't start, nothing, not even a single crank, I knew I needed a jump-start so I went back to him and asked if he could help a brother out! He pulled his car next to mine, we opened my hood first, and all that was left of the battery was the 2 lead posts that were attached to the wire terminals! It was GONE! Just little pieces of plastic and battery acid all over. Of course my buddy said, I think you need more then a jump-start!

That was the day I realized a car can run without a battery, once it is started. :)

Dave

[ May 29, 2005, 12:57 AM: Message edited by: davedottcom ]
 
Re: I am installing a 2000 watt rectifier in my truck

I used to test the alternator by pulling a battery cable off.
 
Re: I am installing a 2000 watt rectifier in my truck

After acconting for inverter efficiency and a safety ( ignorance ) factor you need more like 4/0 copper wire. Once you get to individual batteries you can drop down to #2 or even #4 depending on how many batteries you have.

An automotive alternator puts out 15 to 16 volts under normal conditions. 15 volts equalizes the battery constantly and 16 volts ( luxury cars ) fast charges the battery constantly. That is why automotive batteries need more water than forklift truck batteries.

At a certain level or current the transformer steel in th alternator stator will saturate causing the output voltage to collapse. In the early days of car alternators the diodes were not sized to carry the stauration current and as a result people burned out their diodes when giving a jump start if their engine was running.

I one time had an alternator that did not really produce enough juice to charge the battery particularly when the headlights were running. A ripple voltage test showed that a diode was parly open. Sure enough, cleaning the copper oxide out of the connection straps in the diode bridge fixed the problem!
 
Re: I am installing a 2000 watt rectifier in my truck

An automotive alternator puts out 15 to 16 volts under normal conditions. 15 volts equalizes the battery constantly and 16 volts
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I don't think I've ever seen those kind of voltages. 13.8 is sort of standard. You're talking about a battery heater.

The cells are two volts nominal. 2.67 is too high. You'll be making a lot of flammable gas unnecessarily, burning off the electrolite solution and, it probably wont get that hot, but you could warp the plates.

That would just be battery abuse.

It sounds like a voltage for seven cells maybe.

Edit: If you're talking about an electronic charger that stops doing that (charging at 16 volts) after it's fully charged that would be ok with me (like it matters what I think :D ) but to keep 16 volts on a charged battery is no good.

[ May 29, 2005, 02:27 AM: Message edited by: physis ]
 
Re: I am installing a 2000 watt rectifier in my truck

Originally posted by davedottcom:
That was the day I realized a car can run without a battery, once it is started. :)
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I think that's hell on the alternator, though. :D

I seem to recall my Blazer maxing out at 14.7 VDC, but I haven't had electical problems in a while.

Dave, one time I was "four-wheeling" my old 2WD 1/2 ton '72 Chevy Standard-Bed around in the hills, and thought it would be cool to jump it. Found out pretty quick I didn't have the battery tied down. It swung around on one of the cables and landed in the fan, killed the engine instantly. Managed to roll with gravity's help down to the road, thumb a ride down to NAPA to get a new battery. :D
 
Re: I am installing a 2000 watt rectifier in my truck

If your planing on running a frig why not simply buy a 12 volt frig at a truck stop ?They do not use a motor,they use some method of changing heat.No power inverter will carry a frig very long with a normal battery.You could buy 4 truck batteries and maybe keep it going 8 hours.My method is dryice in my cooler,keeps drinks and food nice and cold even in our Florida heat.Simply put the dryice back in freezer every night.I have used small inverters to keep my batteries up before.Then simply bought extra batteries and dont even need the inverter anymore
 
Re: I am installing a 2000 watt rectifier in my truck

Jim's suggestion to buy a 12 volt frig. is probably the way to go.
But unlike Jim, I use my invertor Every Single Day!
</font>
  • <font size="2" face="Verdana, Helvetica, sans-serif">I like to have my radio on (The money I save on the 6-C batteries every 2 weeks paid for the invertor in about 1 year) I tried rechargable ones...they only last 1 - 2 days and take about 8 hours to charge :(</font>
  • <font size="2" face="Verdana, Helvetica, sans-serif">I like having an outlet for working on stuff right at my truck</font>
  • <font size="2" face="Verdana, Helvetica, sans-serif">It's great for most of my small power tools & drop lights.</font>
  • <font size="2" face="Verdana, Helvetica, sans-serif">Saves on Generator Gas costs too</font>
  • <font size="2" face="Verdana, Helvetica, sans-serif">Has saved me tons of trips out to the truck to start or shut down the generator. (That alone makes it worth having one! :D )</font>
  • <font size="2" face="Verdana, Helvetica, sans-serif">less noise pollution too! (If you heard my generator you would agree!)</font>
  • <font size="2" face="Verdana, Helvetica, sans-serif">and it looks really cool! :cool:</font>
  • <font size="2" face="Verdana, Helvetica, sans-serif">Oh yea, and not having to remember to charge my batteries at night is priceless too!</font>
<font size="2" face="Verdana, Helvetica, sans-serif">
Dave

[ May 29, 2005, 11:55 AM: Message edited by: davedottcom ]
 
Re: I am installing a 2000 watt rectifier in my truck

Originally posted by davedottcom:
...not having to remember to charge my batteries at night is priceless too!
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(Mildly OT) I've developed a habit of charging a battery immediately when taking it off the tool. If there's no power, or no time, I'll put the dead battery back onto the tool when I'm done.

Next time I need the tool, I'd rather be reminded that I have one dead battery (and a charged spare) than discover that I have a dead spare when the one I'm using dies.

[ May 29, 2005, 10:41 PM: Message edited by: LarryFine ]
 
Re: I am installing a 2000 watt rectifier in my truck

(Hiccup!)

[ May 29, 2005, 10:40 PM: Message edited by: LarryFine ]
 
Re: I am installing a 2000 watt rectifier in my truck

Looked at 12 volt refrigerator they cost over $200 plus dollars. A small 110 volt office frig costs $89 local. Many thanks for all the input all of your inputs have been taken into consideration so it looks like dave has had the best personal experiences. But I wish to thank 1 and all of the replyiers to my post. Have a great and glorious future to all.
Happy Memorial day to all but especially to our troops in harms way. :cool:
 
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