Can you use aux batt electric for Sterling B2B (60amp)

I am finishing up my electric system and am planning on installing a Sterling BB1260 (60amp) b2b charger to charge my battery bank. I'm an electrical newbe so was wondering if I could hook the wiring for the Sterling to the aux battery connection under the driver seat instead of running wiring to the starter battery? I have a 2016 2500 4x4 170wb

Thanks for the help!

Sure.... in fact, that's where MB suggests you connect to the Aux battery (and add a fuse box):



Although that is a connection to the Aux battery ... it would only "see" the starter battery when MB isolation relay was active (i.e. engine running)

What is the Sterling getting its power *from* in your design? (and going to?)

--dick
p.s. those two terminals just to the left of item (1) in the first photo IS the isolation relay

The photo you show is exactly where we want to connect.

I have attached the installation diagram from Sterling.

So we have a 260amp hour AGM battery bank. We are not planning on running solar at this time. The only thing connected to the battery bank at this time is our Espar D2 heater. Just bought the van and doing a minimal conversion just in time for ski season!

So do you also have an MB Auxiliary battery in place?
(not that it matters much, the B-to-B won't kick in until the "source" is 13.2 volts, which means the isolation relay is active )

--dick

Yes our sprinter came with the aux battery under the hood.

There is a 40 amp load limit when using the auxiliary battery circuit.

autostaretx said:

Sure.... in fact, that's where MB suggests you connect to the Aux battery (and add a fuse box):

Although that is a connection to the Aux battery ... it would only "see" the starter battery when MB isolation relay was active (i.e. engine running)

What is the Sterling getting its power *from* in your design? (and going to?)

--dick
p.s. those two terminals just to the left of item (1) in the first photo IS the isolation relay

Click to expand...

I'm planning on doing pretty much the exact type of system for my 2011' 144 2500. I want to add a simple battery bank, DC/DC charger (CTEK/Kisae), and fuse panel mainly to power a couple lights and my Espar for ski days this winter (for now). I was just under my drivers seat to access the up fitters block (stereo upgrade) and didn't notice - if my van does not have the aux battery package - does it still have the MB relay and terminal for adding the charger/second battery?

OrioN said:

There is a 40 amp load limit when using the auxiliary battery circuit.

Click to expand...

So, if we hooked directly to the starter battery we could use the Sterling 60 amp? We are thinking of returning our 60 Amp and getting a 30 Amp due to the amount of info we are reading on capacity limits.

Thanks

2VanCrew said:

So, if we hooked directly to the starter battery we could use the Sterling 60 amp? We are thinking of returning our 60 Amp and getting a 30 Amp due to the amount of info we are reading on capacity limits.

Thanks

Click to expand...

Keep the 60A, then tie it in on the alt/starter battery line.

mtncrawler said:

I'm planning on doing pretty much the exact type of system for my 2011' 144 2500. I want to add a simple battery bank, DC/DC charger (CTEK/Kisae), and fuse panel mainly to power a couple lights and my Espar for ski days this winter (for now). I was just under my drivers seat to access the up fitters block (stereo upgrade) and didn't notice - if my van does not have the aux battery package - does it still have the MB relay and terminal for adding the charger/second battery?

Click to expand...

Enter your VIN to http://carinfo.kiev.ua/cars/vin/mercedes/vin_check to get a copy of your datacard: what MB built into it
(you can screen-scrape the results to save a local text copy)

Without the MB Aux battery, you probably do not have the isolation relay.

But you probably DO have the "EK1" option, which provides the "D+" signal for *driving* an isolation relay's coil.
That, plus a $40 Stinger or Cole Hersee relay, (plus heavy wires) and you're there...

What the EK1 looks like (under its flip-cover):



Where to find it (item (4)):

https://sprinter-source.com/forum/album.php?albumid=769&pictureid=4848

(front of sprinter is at bottom of that photo)

--dick

2VanCrew said:

So, if we hooked directly to the starter battery we could use the Sterling 60 amp? We are thinking of returning our 60 Amp and getting a 30 Amp due to the amount of info we are reading on capacity limits.

Click to expand...

If you're going into the battery box, then why not add a fuse to the PDC (power distribution center) that's in there? You can fuse to whatever you'd like (60 amps is fine).



(this is bolted on to the starter battery's positive post, and tucked down beside the battery)

Remember to disconnect the Negative disconnect before playing in there....

Locator photo (ignore the "You can add a wire" comment, that's from another thread.):
((the PDC is freed by removing the nut near that comment's left arrowhead))



--dick

There is no relay but you can still add an aux battery. I have a 2017 3500 4X4 and installed an 100amp AGM battery under the passenger seat which is charged via the alternator or shore power. I installed this Blue Sea ACR under the drivers seat, I like the fact that I can manually disconnect the batteries. https://www.amazon.com/gp/product/B...TFDKG&linkId=01038c257f4882c6d6f277f91cf8c464
I also added a 100amp Mega fuse next to the ARC. Under the passenger seat I installed the battery, a small Blue Sea distribution panel and a marine grade smart AC to DC battery charger along with fuses and cutoff switch. I mainly need the power for my Espar D4 heater, LED lights and to charge camera, computer and phone batteries. I installed a refrigerator/freezer in October which I use intermittently. So far the system has worked great, I use as handheld voltage meter to monitor the battery. This spring I'll add solar to the mix, but for now the system has been great for biking and skiing.

autostaretx said:

Enter your VIN to http://carinfo.kiev.ua/cars/vin/mercedes/vin_check to get a copy of your datacard: what MB built into it
(you can screen-scrape the results to save a local text copy)

Without the MB Aux battery, you probably do not have the isolation relay.

But you probably DO have the "EK1" option, which provides the "D+" signal for *driving* an isolation relay's coil.
That, plus a $40 Stinger or Cole Hersee relay, (plus heavy wires) and you're there...

What the EK1 looks like (under its flip-cover):

Where to find it (item (4)):

https://sprinter-source.com/forum/album.php?albumid=769&pictureid=4848

(front of sprinter is at bottom of that photo)

--dick

Click to expand...

Thanks! Yep definitely have the EK1 upfitters terminal block. Used it to power a stereo amp, new USB charger plugs in the dash and backup camera.

That’s a good pic on the underseat works - didn’t recall seeing the aux battery terminal or relay but we’ll see.

A more complete NCV3 under-seat photo:



(if you have the options....)
If you don't have the MB Aux Battery option, you won't have items (1) and (2).

--dick

I've got the Sterling BB12120, 120 amp charger. It's been hooked up to the PDC on the vehicle battery (as Dick suggests) for 4 years without an issue. I ran 4-0 cable under the seat and in the floor channel to the passenger seat, where the B to B resides. From there, similar cables to my battery bank (390 amp hours LiFePO4) on the drivers wall behind the drivers seat.

John