Auxiliary Battery question

Just bought a '16 Crew Van 4x4. Trying to figure out a quick Dry Camping weekend to break-in the new van! My van came with 'Additional Battery Package (X27) which includes Cutoff Relay (E36) and Aux Battery (E28) under the hood.

If I'm parked in a campground (engine off) and I plug some DC comforts (fridge and light) into the rear door and driver's seat cigarette lighter plugs...will I be drawing electricity from the starter battery or the Aux Battery?

I asked the salesman and he said Aux Battery. But reading around this forum, I see there is a 'retro-fit' electrical connection in the driver's seat podium to tap into the Aux Battery.

Sorry for the complete newbie question. Thank you in advance...

Jeff

The driver’s seat plug and the rear door plug are the only connections to the auxiliary battery (from the factory). Otherwise, you tie in under the driver’s seat (as shown on other posts).

Hi Jeff,

Welcome to the forum.

If you would like to talk Sprinters some time, feel free to drop by.

Harry

Hi Harry. I live close by and am waiting on a 2016 4x4 High roof maybe in Jan. It's a cargo and I plan to do most of the build. What have you done to your rig?

Thanks
Chino

RE: Aux Battery (E28) under the hood.

Attached is the battery under the hood , what came with 2016, V6, 4X4.

Made in USA

wilf0rd said:

Hi Harry. I live close by and am waiting on a 2016 4x4 High roof maybe in Jan. It's a cargo and I plan to do most of the build. What have you done to your rig?

Thanks
Chino

Click to expand...

Hi Chino, thanks for posting. So far I am primarily "preparing" for buying one.

The electrical system upgrades appear to be the big thing that slows people down, so I am building up a parallel auxiliary power system using my dodge caravan as a test mule.

Once this is complete, it should be a relatively easy process to transfer this setup into the much larger Sprinter van.

My big goal is to have enough power to run air conditioning, etc. with the engine off / no generator, even on those hot local days, and I am very close to having this.

Hi, sorry for taking the thread off topic from auxiliary battery discussions.

Here is a link related to auxiliary battery charging.

https://sprinter-source.com/forums/showthread.php?t=51313

Hi, I was told the aux. battery is not connected to any consumers the only connection to the truck is thru the isolator under the drivers seat so the alternator charges it. You can make connections to it at the battery or under the seat on the battery side of the isolator. I put my amp for the sound system and the max/air ventilator unit on it. Remember to add a fuse to protect the equipment. Fact!

Since this is labeled "Auxillary Battery" I figure maybe I could ask this here. I know there are a bazillion threads and responses out there on solar - but I am trying to simplify. I too have the Aux battery factory option on my 2016 4x4. And currently I am running fairly modest electrical [fridge and max air vents + few led lights]. I would like to top off the battery with solar. I ran into someone who said they just ran the MPPT into the connection under the driver's seat. Is it really that simple????

Can I just take the output of the MPPT and connect pos to pos and neg to neg on that connection point??

Also, I have heard of people mounting larger capacity batteries in that position. Some have modified the tray. Is this cool to do? With a little more Amp hours I think I might almost be able to live with one battery under the hood.

Thanks-

David

monday said:

Since this is labeled "Auxillary Battery" I figure maybe I could ask this here. I know there are a bazillion threads and responses out there on solar - but I am trying to simplify. I too have the Aux battery factory option on my 2016 4x4. And currently I am running fairly modest electrical [fridge and max air vents + few led lights]. I would like to top off the battery with solar. I ran into someone who said they just ran the MPPT into the connection under the driver's seat. Is it really that simple????

Can I just take the output of the MPPT and connect pos to pos and neg to neg on that connection point??

Click to expand...

yes, add fuse in positive line.

monday said:

Also, I have heard of people mounting larger capacity batteries in that position. Some have modified the tray. Is this cool to do? With a little more Amp hours I think I might almost be able to live with one battery under the hood.

Thanks-

David

Click to expand...

Maybe consider swapping the tray for the RB components tray that holds 2 batteries~200Ahrs....the Aux package 2GA wiring and Mercedes ACR should be sufficient

Ddunaway-

Just found that RB tray - pretty cool!! It'd be sooo nice to capitalize on the factory setup. And [according to the battery sizing spreadsheets] I should be good for 1.5 to 2 days [with no solar] on about 200 amp hours. That would work for my needs. Now if the snorkel will still fit ;-)

Regarding the fuse...I assume you mean between the MMPT and the tie in point?? Also, any idea what size? [200 watt system]

Thanks again - so much!!!

David

monday said:

Ddunaway-

Just found that RB tray - pretty cool!! It'd be sooo nice to capitalize on the factory setup. And [according to the battery sizing spreadsheets] I should be good for 1.5 to 2 days [with no solar] on about 200 amp hours. That would work for my needs. Now if the snorkel will still fit ;-)

Regarding the fuse...I assume you mean between the MMPT and the tie in point?? Also, any idea what size? [200 watt system]

Thanks again - so much!!!

David

Click to expand...

For 200 Watts a 20 Amp fuse would be fine.

I really want a snorkel too but am too embarrassed to get one

HarryN said:

My big goal is to have enough power to run air conditioning, etc. with the engine off / no generator, even on those hot local days, and I am very close to having this.

Click to expand...

Any details you can share on how you plan on achieving this goal? I'd be interested, Thx!

Craig

TinMan.KC said:

Any details you can share on how you plan on achieving this goal? I'd be interested, Thx!

Craig

Click to expand...

Actually yes. In fact I opened a shop in Livermore CA and sell APU systems for this application.

More or less:
- It takes about 1 kW average to run an air conditioner, so 8 hrs = 8 kW-hrs minimum of usable storage. Our system has 25% extra built in.
- 48 volt battery pack to keep the wiring easy and the inverter efficient and moderate size
- LiFe pack that we build using net worked LiFe batteries, BMS, etc from a very reputable, commercial supplier
- Combination of solar (small but important) and a really healthy alternator.

There is no free lunch, batteries store energy, so it has to come from somewhere.

Sometimes that "somewhere" is running a generator during "generator allowed" hours and using the battery pack at night during quiet hours if sitting stationary.

If your van has fast idle, then it can be the power generator to recharge.

It isn't cheap though and our margins aren't that large. Prices run $12 - 30K depending on how many hours of air conditioning you need, etc.

If you think that price is crazy - I agree. Every month I add it up and am annoyed at what I have to pay for components that will actually work in this application.

For someone doing a pure DIY for their own use, there are some cheaper options. For a company that has to stand behind their product and be certain that it is actually designed for mobile use, this is price reality.

We are going to go with the RB dual battery under the hood in place of the factory aux... would really like to find some examples of what others are running with that set up; ours will be simple ish too... fridge / LEDs / chargers... may eventually go inverter just for the occasional microwave use (warm up coffee on the road or soup for quick eats). We will almost always travel every couple of days; but, likely get a mobile solar set up for use when needed. Anyone running this set up?

For just a fridge, LED's, and misc charging you will last more than a few days on 200Ahr.

My Syncro has a whopping 72Ahr house battery, no solar, and we've camped for 3 - 3.5 days without moving (recharging).


I plan on a 2x factory batt system, with the RB tray, and add some solar. I expect that that will cover me for many days. No AC or microwaves.... a more basic camper setup than some I see detailed.

I will have a esparD2 for heat, but I expect the additional 130+Ahr to cover me over the fridge/lights-only that I run now. The solar will be icing on the cake!

Thanks Farfrumwork, I forgot to mention that I plan for a Espar D2 and fan too; appreciate the reassurance, I find the 12v system / charging complicated for some reason. Going with the RB dual battery kit with the existing charging system!

Ive been looking around at various battery systems, including LifePO4, and comparing cost vs practical use. The one solution that has me going is Victron's "Super Cycle" AGM. They have a far superior discharge/charge characteristics than most gel or AGMs. Their 170ah will fit in the stock aux bat tray in my 2016 4x4. I run pretty low loads; some LED's, an ASU fridge that draws 1.3 amp and a MaxxFan. The current 90ah factory battery lasts me almost 72 hours in prime conditions (70 degree weather, parked in the shade, etc.), a 170 should give me plenty of wiggle room, not to mention the savings in time and money installing new stuff to work with bigger or different batteries.
Anyway, check them out here:
https://www.victronenergy.com/batteries/gel-and-agm-batteries
Scroll down to the pdf on the Supercycle AGM for the skinny.

Vanzer Pagen said:

Their 170ah will fit in the stock aux bat tray in my 2016 4x4

Anyway, check them out here:
https://www.victronenergy.com/batteries/gel-and-agm-batteries
Scroll down to the pdf on the Supercycle AGM for the skinny.

Click to expand...

Nice! Would two of the Supercycle 170Ah fit in the RB double tray under the hood? I don't have my van quite yet so I cant go out and measure the stock battery for comparison.

340Ah in a 'stock' configuration would be killer! (albeit expensive at ~$400 a piece)

From some research I found that the two batteries are close in size

Stock 95Ah
L - 353mm
W - 175mm
H - 190mm

Victron Super AGM 170Ah (M8) BAT412117081
L - 339 mm +/- 2
W - 172mm +/- 2
H - 281mm +/- 2


Slightly smaller in length and width, but 91mm taller (considerable at 3.6" more)... not sure how much headroom there is over the stock Aux Bat(?)

Looks promising to fit 340Ah under the hood in the RB tray with minimal effort.
Maybe Pagen will try one out (?)