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I ran the + - cables directly to the 48V connections since the inverter has its own fuse.
Just in case you didn't see what I posted earlier - you can't connect it directly to the batteries without having a disconnect. It has a constant current draw even when output power switch is off and/or no load is connected. Not only that can drain your batteries if you don't stay on charger, but potentially can damage them completely if inverter doesn't implement undervoltage protection correctly.
 

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You shouldnt connect any of these units directly to the circuit that makes the Sevcon controller live. It should have its own connection directly from the battery. Turning on with the Sevcon can cause spikes to the Sevcon, and even cause the sevcon the not function (may cause main capacitors to charge too slowly causing a fault). Its just too costly to risk doing this. Use a separate connection/ contactor or even simply a set of Anderson connectors (175a min) .
 

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Unless I got ohms law wrong 25amps at 110v should be about 57 amps at 48v. I'm putting a separate contactor and 50 amp fuse on the plus side per suggestions. I only plan to use it when the ranger is off and turn inverter off before restarting the ranger. I'll post current measurements on it soon although I don't notice any significant leeching on the battery when the inverter is off.

Homey
 

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Unless I got ohms law wrong 25amps at 110v should be about 57 amps at 48v.
110 is really a colloquial term. Generating equipment is supposed to put out 120v, including this inverter. Then it properly rounds up to the claimed 3000W. The current using your formula is then 62.5 amps... except this inverter is probably only some 85% efficient, so 25 amps on output becomes 72 amps on input. Then there is the question of peak during load startup, such as for inductive loads. This inverter is advertised to peak to 6000W (never understood how these cheap vendors do it: all serious vendors state their peak at around 25% above continuous rating), so that's up to 144A on input...
 

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The peak load is an issue, and that can cause current to be drawn back from the sevcon. There have been issues with some EV builds in the past with DC to DC burning out as they act as a small reservoir of power to the main controller and they burn out. . Same with doing this with an Inverter. Never try and use it when the Sevcon is connected. Its just not worth the risk. If all else fails simply use a pair of Anderson connectors. One on the pack one on the inverter. Check the inverter is fused on the inlet many/ most are. If not consider a Midi fuse they are fairly compact, and the std inline fuse holder will do 150a. with 6mm connections you can use on crimped cables. Check the holders though some have small cable inlet mouldings. And Never, Never solder any of the connections, always crimp. If you cant properly crimp, get someone else to do it. Its really important.
 

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The frame is grounded when you ar plugged into the mains, via the charger and its screw connection to its mount with the crinkly washer. Not the best connection but probably OK for its purpose. As to grounding when using an inverter, all the circuits do get connected back to the main negative pole on the Sevcon. As above nothing is grounded through the chassis. So connecting the chassis to ground on the inverter is probably a reasonable thing to do. Never use the inverter when connected to the charger / mains. Again spikes / loads on the pack could damage the charger.
 

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Lesson here … don't run the inverter when the Polaris is on (sevcon). This one has a cool remote that turns it on and off without drill a hole in the dash for a switch. The manual says 20W draw when in "standby" mode. That's about 0.4 amps in the "off position". I think that was the original connect to battery spark.

I decided to use a waterproof 100A fuse breaker as a main disconnect and double check on the battery side current draw instead of a relay/fuse combo. I really don't want to drill a switch into the plastic dash. When I don't use the EV for a while I break the main battery connect this way. Cricket is right to account for peaks and DC/AC efficiency. Thanks for catching that!

https://www.amazon.com/gp/product/B07LD37DNL/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1

I also ran the AC side on the inverter to a ground fault outlet on the back, hence the question about earth grounding the inverter.

I do have to say that it is awesome to have a mobile power station on this ranch!


Homey
 

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FYI, I measured current draw and here are the results.

Generally, nothing was over 30 amps to the 48v battery here. I might replace the 100a breaker with the 50a one.

The leeching (when off and connected to power) was about 0.4 amps.
When ON, it was 1.5 amps.

Drill - 6 amps
Sawzall - 9 amps
Leaf Blower - 29 amps (high)


Homey
 
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