wiring an inverter

Hi there

I'm currently trying to wire an inverter into the back of a truck but seem to be having a few problems.

The inverter is used to power a light and a linisher. The linisher struggles to start. It's ok if i start the belt rolling by hand first. But if I just click the start button, it fires up then the inverter cuts out. If I then click start again while the belt is moving it will start ok.

If I situate the battery in the bakc of the truck and wire both the car battery and secondary battery to the inverter, the linisher starts fine everytime. If I experiment with the secondary battery at the front of the car and use jump leads to connect it in parallel to the car battery, the linisher won't start first time.

The inverter has something built into it which doesn't let the car battery drain to less than 10V. It converts 10Vdc to 230Vac.

Advice on the correct wiring sequence, fuses etc would be greatly appreciated.

Thanks

What is the brand and model of inverter? Also the linisher. I as because it does NOT sound like a wiring issue UNLESS you are using a very small gauge wire to the inverter. It sounds like the inverter is too weak to power the linisher.

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Gary Sather

To me it sounds like wiring because the inverter starts the linisher with 2 close batteries...

A ROT for motors is to allow 2 to 3 times inrush. IE - a 1kW motor needs a 2kW or 3kW peak (inverter).

Down here all inverter ratings are long-term RMS - not peak.
But peak is 2x the nominal (RMS) rating.

Thanks to the posts so far guys.

Ok so...

The linisher itself bares no markings. That was one thing I looked for straight away. Strangely enough, the same inverter and linisher models are used in a friends truck and they work fine.

The trucks are brand new Hilux's. My friends came with 2 batteries under the bonnet, however, mine just had one. The setup in my friends is that the batteries are connected in parallel with a live going from one battery to the inverter which is situated at the very start of the cabin at the back of the truck (say about...7 or 8ft of cable maybe as an estimate). The inverter is then grounded to the chassis. The linisher works every time.

I then put a second battery under my bonnet, connected the batteries in parallel and ran the cables the same - except my cables ran probably an extra 3 or 4ft to the very rear of the cabin. This worked fine up until last week.

I've now experimented with the secondary battery in the cabin at the back, so that I have one live coming from the car battery and a live and earth coming from the secondary battery all to the inverter. Then an earth from the inverter to the chassis. This seems to work, however, I would much prefer the battery to be in the bonnet than in the cabin.

After the first arrangement (both batteries under the bonnet) stopped working, I changed/charged/bought a new battery and tried it again but it still won't start the linisher that way.

The inverter has an output of 3100W and all it needs to power is a fluorescent light and the linisher.

One thing I did notice was that with just one battery, the inverter reads something like 11.9V (the DC input it is receiving). With a second battery attached the inverter reads something like 12.75V. When the linisher is switched on the voltage drops to just over 10V.

I'm trying to think of anymore info I can give to help get a solution. I'll keep thinking.

Cheers

Your 11.9V battery is flat or faulty. (Assuming that voltage is with zero or a small load.)   
A fully charged battery should be 12.6-12.7V (12.67V) after resting.
A cranking battery should not be discharged more than 20% - ie, to ~12.5V.
11.9V open-circuit (and after dissipating "surface charge" which can take several hours) suggests it is at least 70% discharged (0.1V per 10%; ie, assuming a conservative 1V from full to flat). Even deep cycle batteries should only be discharged 50%!   


The inverter will probably start (better) on only the 12.75V battery. Connecting a flat battery will only lessen the power to the inverter - and will eventually wreck other batteries if left connected - hence the desire (IMO - need) for a battery isolator else ensuring batteries are isolated when not being used.


PS - legally and safety-wise, only sealed batteries shall/should be in the vehicle including boot/trunk (eg, AGM, gel-cels). Vented batteries must be in a sealed enclosure (which is vented to the outside) or in the engine bay. (NB - the engine bay elevates the battery temperature probably 30°C which shortens battery life between 4- & 9-fold.)

Chuck a deep cycle gel type battery in the cargo area and use a split charger. Another locksmith per chance?

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.