Inverter/charger connection

I have a 2015 6 cylinder 4x4 Sprinter with a 220 amp alternator and the factory auxiliary battery and relay. I want to add an Outback 2000+ watt inverter/charger/shore power/solar system, shore power protection, and maybe more batteries.

My question is can I connect the new inverter/system to the relay under the seat, and ground it to the chassis? Outback says to use 00 electrical connection cables directly to the battery terminals. I worry that the factory battery cable to the existing auxiliary battery might be too small. I also worry that the electrical connection from the alternator to the batteries could be too small, heat up, and blow fuses.

Other threads on this forum seem to say it's OK to connect a 2000 watt inverter to the relay though. Please advise. thanks

I have mine hooked through a oem relay I installed with 0 cable but my inverter is only 600 watts. I would use the cable size and fuses recommended by the manufacturer of your inverter. You planning on running the inverter off the starter battery and what size loads are you going to pull? I don't think the starter or OEM auxiliary will handle much of a 2000 watt load no matter what size cable but I am no expert by no means.

Thanks for the reply. Your van is the same one I have, mostly, so I really appreciate your design pictures; lots of great ideas I can use!

Shadrax said:

I have a 2015 6 cylinder 4x4 Sprinter with a 220 amp alternator and the factory auxiliary battery and relay. I want to add an Outback 2000+ watt inverter/charger/shore power/solar system, shore power protection, and maybe more batteries.

My question is can I connect the new inverter/system to the relay under the seat, and ground it to the chassis? Outback says to use 00 electrical connection cables directly to the battery terminals. I worry that the factory battery cable to the existing auxiliary battery might be too small. I also worry that the electrical connection from the alternator to the batteries could be too small, heat up, and blow fuses.

Other threads on this forum seem to say it's OK to connect a 2000 watt inverter to the relay though. Please advise. thanks

Click to expand...

1) The factory battery is too small for a 2000W inverter load.
2) Therefore, the question of whether the factory wire size is adequate or not is moot.




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pfflyer said:

I have mine hooked through a oem relay I installed with 0 cable but my inverter is only 600 watts. I would use the cable size and fuses recommended by the manufacturer of your inverter. You planning on running the inverter off the starter battery and what size loads are you going to pull? I don't think the starter or OEM auxiliary will handle much of a 2000 watt load no matter what size cable but I am no expert by no means.

Click to expand...

Can you explain how the starter comes into play here?




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Believe Orion is correct. A 2000 watt inverter is too large for the Sprinter electrical system.

The 220 amp alternator at 14 volts is 3080 watts. The Sprinter will draw more than 1080 watts at times. The electric air heater uses about 1000 watts by itself and can not be turned off.

Your 2000 watt inverter probably has a surge capacity of an additional 2000 watts.

Connecting directly to the battery would allow you to use the inverter with the engine off without the alternator providing power.

I did have a 600 watt inverter connected to the added relay under the driver's seat in my sold Sprinter. It worked very well and I will use the same system in my new conversion. I will increase the inverter size to 1000 watts but think that is pushing the vehicle electrical system. Maximum load on the inverter will be 750 watts. I would not even consider a 2000 watt inverter.

OrioN said:

Can you explain how the starter comes into play here?




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Click to expand...

Sorry I meant to say starter battery like in the sentence before that one.

It should be stated that just because a 2000w inverter is installed, doesn't mean 2000w+ will be used.

One can install a 2000w inv now and later add batts to the system. Not sure what the OP plans to plug in, but he can safely pull 600-800w out of his setup for 2-5 mins at a time. My 600w microwave runs at a measured max of ~740w.

Everyone's stated concerns are correct, and the 2000w has a surge capability of 3-6000w for 20ms or longer. That's 400+ amps surge.

2000w is a lot in the sprinter, and 0 or larger wire is likely best and a min of 400AH batt bank is needed.

Rensho said:

It should be stated that just because a 2000w inverter is installed, doesn't mean 2000w+ will be used.

Click to expand...

Agree. Moreover, there are a number of applications in which driving a large inverter with a smallish battery makes sense. A single battery will get you several cups from you Keurig, for example. Or several happy spousal minutes with a hair dryer.

Definitely want adequate wiring throughout the system, though. Follow the recommendations in the Inverter installation book.

Rensho said:

It should be stated that just because a 2000w inverter is installed, doesn't mean 2000w+ will be used.

One can install a 2000w inv now and later add batts to the system. Not sure what the OP plans to plug in, but he can safely pull 600-800w out of his setup for 2-5 mins at a time. My 600w microwave runs at a measured max of ~740w.

Everyone's stated concerns are correct, and the 2000w has a surge capability of 3-6000w for 20ms or longer. That's 400+ amps surge.

2000w is a lot in the sprinter, and 0 or larger wire is likely best and a min of 400AH batt bank is needed.

Click to expand...

Draw or Surge on wiring is not the current issue here.... 166A draw or +300A surge on any single/100aH battery is a kiss of death, and it only takes once to significantly weaken it.

Secondly... wire size is equally dependent on its length between terminals as it is on load (or other factors). Do not guess, unless you are assuming the 'worst case scenario', which always means a waste of $$ for expensive copper.

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avanti said:

Agree. Moreover, there are a number of applications in which driving a large inverter with a smallish battery makes sense. A single battery will get you several cups from you Keurig, for example. Or several happy spousal minutes with a hair dryer.

Definitely want adequate wiring throughout the system, though. Follow the recommendations in the Inverter installation book.

Click to expand...

What AH size single battery will get you several cups of coffee from a Keurig? Any real world experience? I would love to be able to do that but reading posts here determined it was not feasible at least with a battery that would fit under the passenger seat.

Rest assured, that draw or surge won't be the kiss of death. There's enough internal battery resistance and cable resistance to protect the battery. The inverter's low voltage alarm will trigger and save the battery.

OrioN said:

Draw or Surge on wiring is not the current issue here.... 166A draw or +300A surge on any single/100aH battery is a kiss of death, and it only takes once to significantly weaken it.

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Click to expand...

pfflyer said:

What AH size single battery will get you several cups of coffee from a Keurig? Any real world experience? I would love to be able to do that but reading posts here determined it was not feasible at least with a battery that would fit under the passenger seat.

Click to expand...

A Keurig takes about 40 watt/hours to make a cup of coffee. That is well under 4 amp hours. A random 100A/H battery gives you ca. 50A/H usable. Should be fine, even if you have to go with a smaller battery. Where did you read it wasn't feasible? I have two batteries, not one, but my observed usage is consistent with the above. My Trimetric will show only a few percent drop/cup.

calbiker said:

Rest assured, that draw or surge won't be the kiss of death. There's enough internal battery resistance and cable resistance to protect the battery. The inverter's low voltage alarm will trigger and save the battery.

Click to expand...

I'm guessing...you don't understand the concept/meaning of surge...



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Since you want to make it personal, you'll have to keep guessing.....
Doesn't sound like you're good at it.

pfflyer said:

What AH size single battery will get you several cups of coffee from a Keurig? Any real world experience? I would love to be able to do that but reading posts here determined it was not feasible at least with a battery that would fit under the passenger seat.

Click to expand...

Seems like a Keurig type machine will require a large ish inverter.

1500w required for turn on, even for the small Keurig.

http://theboatgalley.com/keurig/

There is a model that is only ~700w
http://www.amazon.com/Keurig-B130-K130-Brewing-System/dp/B004978NKY

The article measured it at only 1AH per cup, so not too bad of a drain.