Installation Connection Problem: 0-Gauge to 8-Gauge, or Alternate?

Hello everyone,

I have an installation issue, but not one related directly to car audio, but one that is very similar in nature to amp installation, and for all intents and purposes, can be considered as such.

The situation is, I just purchased a Cobra CPI 2575 2500 Wat Power Inverter along with lengths of 1/0 gauge wire to power it. I selected the Stinger 0 Gauge to 4 Gauge Power Wire Reducer because Cobra stated that the power terminals are 4-gauge, I thought this was a great match and would provide a clean installation with minimal resistance. The problem is, the holes on the Cobra inverter do fit 4 gauge wire, but NOT the semi-rounded 4 gauge port of the Stinger reducer.

Hence the dilemma.

Ideally, I'd like to then use a 1/0 to 8 gauge reducer, but cannot find one anywhere online, and don't even know if anyone makes such a product. If so, please point me in that direction. They are not available from any of the most popular retailers or manufacturers. Nor ebay, for that matter.

So, unless I can find a pair of 1/0 gauge to 8 gauge screw-set reducers, my options seem limited to the following:

• (1) Trim the excess wire from the 1/0 gauge wire to fit the 4 gauge hole.

• (2) Use an 0 gauge butt-end coupler, 1/0 gauge on one side, folded and spliced 4 gauge on the other and use dual input on the inverter.

• (3) Use a distribution block with 1/0 in and 4 gauge out.

• (4) Other?

Save obtaining a pair of 1/0 gauge to 8 gauge reducers, one of the above will be necessary. I just don't know which setup will provide maximum flow. I'm thinking that option 2 above (the butt-end method) would be the least effective method, unless I fill one side with solder after the other side is set and hope for a good enough connection.

So, my questions are:

Does anyone know where I can find a 1/0 gauge to 8 gauge reducer?
If not, which method above would be best in this case?
If none of the above, please share your solution!

Thanks,
Jeff

For the benefit of others who may face a similar issue, I am posting my solution. I decided to grind down the posts of the 4 gauge connectors using a Dremmel and grinding tip. Took just enough off the sides, as well as 1/32 inch around the center so it fits prefectly snug with no gaps.

Carefully, and checking size along the way, it took about an hour to do both.

The images below show the installation process during test-phase only, so you may see a gap and a set screw extended. This won't be there when actual installation begins.

To add, I also plan to cover the entire post length from plastic base to an inch into the wire cover in thick heat shrink tubing, then top off with plastic wire loom in the engine compartment from the ANL fuse block to the firewall entry.

[PaulD]

why ate you using a 1/0 gauge cable if the input to the device is designed to accept 4 Ga ?

Originally Posted by PaulD

why ate you using a 1/0 gauge cable if the input to the device is designed to accept 4 Ga ?

The reason is simple. Number 4 gauge is the recommended gauge to use if the power inverter (or power run length, actually) is four feet or less from the battery. Unless I remove my passenger's air bag, I have no place to install the unit within that four-foot recommendation. From the Cobra manual:

We recommend #4 AWG copper cable (90°C insulation rating) as the minimum size for connections between the battery and inverter. Keep the cable length as short as possible, no more than four feet (one and a half meters). This will keep the voltage drop to a minimum. If the cable has too much voltage drop, the inverter may shut down when drawing higher currents because voltage at the inverter may drop below 10 volts. If you must use longer cables, choose thicker cables, such as #2 AWG, and trim the ends of the cable to fit the terminals.

My installation run, including terminal block and fuse block cut-ins is roughly 7.5 feet. Using eight feet as a guide with respect to voltage drop, the requirement jumps to 2 gauge wire. To minimize voltage drop and minimize resistance, as well as purchase wire and components that are readily available, I selected 1/0 gauge with the proper fittings thereto.

Plus, you can never go wrong using bigger wire. It doesn't "force" any more voltage or amperage, it merely allows greater current flow than a smaller wire with minimal restrictions, such as voltage drop and/or resistance; factors that can excessively deteriorate the effectiveness of the unit. And in some cases, render a unit such as this useless (or worse, dangerous).

[PaulD]

most of the resistance in a wire run is NOT the wire itself, 90% is the connections. Just how much power are you wanting out of this inverter ? Remember that it doesn't pull the whole 2500 watts all the time, only what the items connected to it demand.

As soon as I finish this job, swap out the alternator for a higher amperage version and get everything running (there are a few other things I'm working on), the inverter will primarily be used to run a microwave oven (okay on a modified sine wave) and a coffee maker. But it's not my primary inverter. It will only be used to run those items that draw over 250 watts or so.

And of course, all connector connections and terminal leads will be flooded with solder.

[PaulD]

If you crimp them correctly, it actually IS a soldered joint. Unfotunatyely, most cheap crimpers don't do a very good job. Sounds like you are making a van type vehicle into a small RV, tha can be a fun project.

I use a heavy duty hammer crimper for large crimping jobs (8 gauge to 2/0). At times, I'll set it into my 60 pound vice to obtain an optimum connection, if needed.

[PaulD]

ywea, those are pretty awesome ... a good way to insure a good crimp

Originally Posted by PaulD

ywea, those are pretty awesome ... a good way to insure a good crimp

Exactly. What I love about the hammer crimper is it's ability to both/either be struck by a very heavy hammer or be used in a decent vice. For times when you need a third hand, the vice is extremely "handy".

Here's an example with a smaller vice (for those who might benefit, I know Paul knows all about this stuff):

Hey all,

Wanted to post a follow-up to this thread and let you know the job is almost done. All wiring has been completed and everything works just fine. The last step is to secure the inverter under the seat.

Here are a few pictures of the project in process: