Thomtek5

Has any one seen or done a mod to the electrical system to fix the voltage drop when the heaters are cycling? I was planning to add some electronics. but I am worried about undervoltage.

loch

I run dual batteries, I cant tell when grids are cycling.

wannadiesel

Jim Lane's Leece-Neville alternator install is the only thing I can think of that might help.

Ace

I don't ubderstand what there is to fix? I mean, that is normal behavior. The grids momentarily draw more than the system outputs, so you get a voltage drop. It's only a few seconds, so doesn't hurt anything. Why fix somethiing that isn't broke?

gomerpile

i know this is a stupid question, but do the heaters continue to cycle after its started

Geico266

Yes, they do, until you reach about 25 MPH.

Geico266

What electronics are you running? I'm pretty sure "low voltage" should not be an issue. If it is really a problem you could run a small "gellcell" 12 volt battery to the device and have a diode allow charging voltage into the battery, but it will keep discharging voltage from leaving the battery. A diode is like a "one way checkvalve" for electricity.

This battery would work, and you could get a diode from any electronics shop / Radio Shack.

http://www.batterymart.com/p-12v-1_3...d-battery.html

Thomtek5

Thanks for all the help. I undersatand that this is normal behavior for my truck and that these heaters cycle until the intake temp reaches around 50* which doesn't take long. But I plan on putting an inverter, video and computer for nav and mp3's. My background is in electronics, I appreciate all of the info you guys gave me. I was thinking about the dual battery setup. Or running the heaters on thier own system with a charging diode.

Ace

Don't turn on the audio/video/computer/whatever until after about 5 minutes down the road?

I don't think dual batteries is going to do what you want, and the charging diode thing seems to me to be making something that is relatively simple alot more complicated than it needs to be.

The real answer I believe is as Dave mentioned, increasing the alternator output to the level required for the grids. And that's alot. How much, dunno. I'd be interested to hear if Jim Lane's grid heaters pull a noticeable voltage drop.

edwinsmith

I've got a couple of those little inverters. One is a 150 watt which won't run much and the other is a 400 watt which will run my laptop and other goodies. In my car sometimes I have a problem with them cutting off when I start the engine from the voltage drop off. The extra battery with a diode to isolate them seems like the best solution to me. That way if your heaters come on or you need to hit the starter you won't cause the inverter to reset.

Edwin

Begle1

The rockin' way to do it would be to run the computer off of the wiring harness without a power supply or inverter; it's all 12 volts DC, right?

Never seen an electrician brave enough to try it, though.

bgilbert

Unplug the grid heater relays, no more voltage drop. Truck should still start to about 20*f. If not, a little ether.

BC847

Hope this helps.

Ace

Wow, that is alot. Almost double the OEM alternator output. Good luck with that.

Jim Lane

Here is So-Cal my Grid Heaters have never had a chance to cycle. However I can leave my headlights on for about 30 minuets and when I start the truck you will not see them dim but get brighter as the alternator hits 14.0 volts.

If I were to rely on the grid heaters I would replace the small gauge wires from the grids to the relays and then from the relay to the battery with a #2 gauge welding cable also replace the 2 ground wires to the block with the same #2 gauge wire.
This should make a significant difference.
Jim