Inverter woes

Submitted: Monday, Sep 26, 2005 at 23:23

ThreadID: 26788 Views:2420 Replies:5 FollowUps:5

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Jimbo (WA)

I've just recently rewired my hilux with a second battery (in the rear tray area) and a OL Chargemaster dual battery system. I've put all the add-on accessories such as fridge, radios, compressor etc to the second battery, but now my inverter won't fire up.

I did a bit of rough fault finding and found the following:

#2 battery - inverter won't turn on at all; no LED and no fan / motor running

#1 battery - inverter turns on momentarily; LED goes on briefly then goes off and fan / motor continues to run

Does this suggest any obvious problems or areas I ned to check?

BTW, it's a 600 watt inverter and both batteries are N70ZZ cranking batteries.

Any advice would be much appreciated, thanks.

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Reply By: AT4WD ADVENTURES - Monday, Sep 26, 2005 at 23:54

Monday, Sep 26, 2005 at 23:54

Hey Jim,

You may need a minimum load required to be plugged into the invertor before she fires up. Some inverters do this to be more energy efficent ie. if no load no power consummed in standby. Try that and report back.

Regards

Stuart

AnswerID: 131927

Follow Up By: Jimbo (WA) - Tuesday, Sep 27, 2005 at 00:21

Tuesday, Sep 27, 2005 at 00:21

Thanks Stuart, I'll try that tomorow and let you know.

FollowupID: 386257

Reply By: hl - Tuesday, Sep 27, 2005 at 06:40

Tuesday, Sep 27, 2005 at 06:40

Me thinks your inverter is cactus.
Try another.
Cheers

AnswerID: 131934

Reply By: Member - Jeff M (WA) - Tuesday, Sep 27, 2005 at 11:18

Tuesday, Sep 27, 2005 at 11:18

What size wiring are you using to the inverter and how far is it run? Voltage drop could be causing the unit to shutdown from an internal LV cutout circut.

I have a 450w Pure Sinewave in my rig and run 2g cable (starter type cable) to it as 450w @12vDC is 37.5amps. Then you add in all the inefficianies of inverters and you'd be drawing well over 40amps at full load with a 450w inverter. The voltage drop over say 3m of cheapo thin 12v cable would be staggering, that's if it didn't catch on fire...

AnswerID: 131977

Follow Up By: Jimbo (WA) - Tuesday, Sep 27, 2005 at 14:07

Tuesday, Sep 27, 2005 at 14:07

Jeff, that's what I'm thinking the problem is - bugger! I didn;t really want to do any more wiring.

I'm running 50 amp cable to the rear battery for power - about a 5 mtr run; and 50 amp cable to the front battery to earth.

When I put the heavy duty clamps (about 400 mm length cable) direct to the battery, the inverter fires up.

I think I'm going to investigate what cable size I need to run the inverter from the rear battery and if it's too big then I'll just run the inverter off the front battery the way i used to.

Thanks,

FollowupID: 386321

Follow Up By: V8troopie - Tuesday, Sep 27, 2005 at 14:55

Tuesday, Sep 27, 2005 at 14:55

Jimbo, do also check your cable connections/ cable to connector termination. It is easy to get enough voltage drop across a few of not 100% connectors to shut down your inverter. The connection to the battery post is a prime candidate here.

Klaus

FollowupID: 386327

Follow Up By: Member - Jeff M (WA) - Tuesday, Sep 27, 2005 at 15:39

Tuesday, Sep 27, 2005 at 15:39

Yeah when your working with 12vDC I find what the cable is actually rated to means squat. If it's "50amp" cable all that means is that it will take 50 amps before it catchs on fire. It doesn't mean anything about voltage drop. Voltage drop increases exponetially the more amps you run through it. With a 600watt inverter (if you are planning on using it up to its full capacity) you should either be running it direct off the battery or using some decent really heavy duty stuff. The cable I use is out of residential power transformers, it's really hefty stuff! LOL (a mate work sponsered it for me).

I can run the surf at a normal low idle and run the entire entertainment system in my lounge room from an extension cord (109cm rear projection, amp, setop box, etc etc et,a full sized pedistal fan and a 75watt globe without the batteries dropping from 13.8v. (I know this cos I've done it in power failures before). Having the right cable can be a PITA (especially trying to get thick kick ass cable through the firewall etc) but it's well worth it in the end.

FollowupID: 386330

Reply By: Jimbo (WA) - Tuesday, Sep 27, 2005 at 21:23

Tuesday, Sep 27, 2005 at 21:23

Thanks guys, I've rewired with 8B&S / 8mm sq / 85 amp cable and things are working. I re-run it by drilling a hole in the rear of the car (ouch!) and that way I only needed a 2 mtr run of cable. Thanks for everyone's help.

AnswerID: 132065

Reply By: Member - Scrubba (NSW) - Tuesday, Sep 27, 2005 at 22:22

Tuesday, Sep 27, 2005 at 22:22

Hi Jim,
I had a problem running a 300w Pure. Ran a 4mtr 60amp cable and had a 35amp circuit breaker at battery end. Although everything tested OK, the inverter behaved mostly as you described for battery#2 but occasionally as you described for battery#1.
I replaces the 35amp circuit breaker with a 35amp fuse and all works perfectly. Interestingly, there is nothing wrong with the circuit breaker. I guess it reduces the voltage flow a lot more than a normal fuse.

I know you fixed yours but this info may be useful to others with similar problems.

AnswerID: 132082