Alternator

Im looking to fit a Battery Isolator to allow me to charge my AGM's from the alternator for when the sun doesnt shine. The guy in the shop told me some Sprinters had a 'clever' alternator and if mine did i would need an additional part (expensive). Anyone know if this is true? Mines a 2013 313CDI LWB, if that helps.

Cheers

I wouldnt be fitting a simple Battery isolator. The alternators on a lot of new vehicles are high tech with temp sensing etc.
When I get round to doing mine I will be fitting something like a redarc bc / dc system.
Lots of smarts built in to monitor charge etc as well as solar input etc.

There are quite a few other brands as well that work the same

Cliff.
The correct way to charge your secondary battery is to use a relay driven by "D+" any so called smart relays do not work. You will find "D+" under the drivers seat. Many write ups on this. Eric.

the OM646 4 cyl has an alternator which varies voltage to improve fuel economy. There is a crude shunt on the battery which measures when the battery is full, so the voltage is dropped to around 13V or so. You can pick up a cheap cigarette lighter voltage meter and watch your charging votlage. If its pretty constant around 13.6-14.1V, you don't have the "smart alternator".

Even if you have the smart alternator you can still charge from the alternator. It will be slower though. Just tie your isolation relay to the power distribution block, and fuse appropriately. There is a good writeup in the NCV3 section on the factory aux battery setup, which you can roughly copy.

If you give your VIN to http://carinfo.kiev.ua/cars/vin/mercedes/vin_check
it will cough up your MB "datacard" listing the options built into **your** Sprinter.
(you can screen-scrape the results to keep a local copy)

Look for: EK1 Terminal Strip.

If you have it, it provides a fused "D+" signal that can drive your isolation relay.
That also means that the Sprinter *is* intelligently providing the signal, so your alternator should be happy.

The EK1 strip is located (probably) under the left-side seat (the same seat that has the fuse panel on the side of the pedestal)
It has a plastic flip-cover, so the terminals won't be instantly visible when you remove the seat cushion.





--dick

autostaretx said:

If you give your VIN to http://carinfo.kiev.ua/cars/vin/mercedes/vin_check
it will cough up your MB "datacard" listing the options built into **your** Sprinter.
(you can screen-scrape the results to keep a local copy)

Look for: EK1 Terminal Strip.

If you have it, it provides a fused "D+" signal that can drive your isolation relay.
That also means that the Sprinter *is* intelligently providing the signal, so your alternator should be happy.

The EK1 strip is located (probably) under the left-side seat (the same seat that has the fuse panel on the side of the pedestal)
It has a plastic flip-cover, so the terminals won't be instantly visible when you remove the seat cushion.

--dick

Click to expand...

So do I just connect the isolator to this terminal? (sorry, this is all new to me).

The isolators small wire (trigger) will connect here. The large wire, which carries charging current, needs to be connected to the PDC block or the battery, Or to the alternators output stud.

Here's what's supposed to be going on: (very basic, no fuses shown)



--dick

I'm not sure if a simple relay will give you ideal results.

If your Sprinter has an 'intelligent' alternator (I use the term loosely) then you might want a DC/DC charger to bring the voltage back up.

I have not seen anyone actually test this. But if you connect directly to the battery (both positive and negative), the software will see the battery pulling current, and refrain from dropping the voltage early, thus enabling regular charging voltages?

A DC-DC is a good option. Not everyone needs one though, and they can be pricey. So evaluate based on your needs.

cliff1654 said:

Im looking to fit a Battery Isolator to allow me to charge my AGM's from the alternator for when the sun doesnt shine. The guy in the shop told me some Sprinters had a 'clever' alternator and if mine did i would need an additional part (expensive). Anyone know if this is true? Mines a 2013 313CDI LWB, if that helps.
Cheers

Click to expand...

Hi Cliff
There are a lot of suggestions good and bad but no hard information yet ! I do not know if your model has a "smart" alternator but here is my suggestion. Get a volt meter and see what happens to the voltage when you drive. You can buy a cheap unit which plugs into the lighter socket and is accurate enough for your use. Or you could buy a mulimeter and make a couple of long leads so you can read the battery voltage and see the meter while you are driving. A multimeter is agood investment as a tool for lots of useful things in the future.

Now that you have a meter, look at the battery voltage while you drive, it should come up to 14.2-4.4 V in a short time after the motor starts and then stay around there. If it stays there all the time while the engine is running you do not have a smart alternator. BUT if after 10-15 minutes or so the voltage drops to a lower figure, say 13v or even lower then you have a modern BS "smart" alternator. On some cars this function can easily be turned off in the computer. Not sure about Mercs, but unlikely to be simple or cheap.

If you have the smart function you will need a DC-DC charger to support a second house battery. Just more money and more to go wrong IMHO ! If you do not use a proper charger the second battery will never get properly charged and will fail early.

If you are fortunate and have an old fashioned normal 'dumb' alternator then you can get a VSR(voltage sensitive relay) and run the second battery with that. I do that and have been very happy with the results. I have very heavy wires from the battery at the front to the rear second house battery and the VSR. It switches the second battery on charge when the voltages rises a bit after starting the motor and switches it off when the motor stops. A VSR is "cheap as chips" to buy and easy to setup. And they now have a switch function that can be used to jumpstart the main battery also.

I also run solar panels with a regulator into the system to charge both batteries as well.
Jaahn

Have you checked your VIN?
Do you have the EK1 option??

If so, a simple isolation relay will work. It's what MB does.
The Sprinter programming (and hardware) needed will have been "baked in" to your Sprinter to provide the "D+" signal.

--dick
p.s. what engine do you have? (i fear the 313 indicates "small").
In the US, the 6 cylinder had the more "conventional" alternator,
whereas the 4 cylinder had the "too smart" flavor. (both were LINbus, but the 4-cyl backed off from continous charging)
Both operate properly for isolation with the EK1 option.
(your alternator is also shown on the VIN-based option list)

If anyone is interested in Redarc bcdc1240. Send me a PM. I can get at a very competitive price.

autostaretx said:

Have you checked your VIN?
Do you have the EK1 option??

If so, a simple isolation relay will work. It's what MB does.
The Sprinter programming (and hardware) needed will have been "baked in" to your Sprinter to provide the "D+" signal.

--dick
p.s. what engine do you have? (i fear the 313 indicates "small").
In the US, the 6 cylinder had the more "conventional" alternator,
whereas the 4 cylinder had the "too smart" flavor. (both were LINbus, but the 4-cyl backed off from continous charging)
Both operate properly for isolation with the EK1 option.
(your alternator is also shown on the VIN-based option list)

Click to expand...

Yep. 313 is the 2.1l 95kw i believe
It does have the EK1. See cut and paste below.


EK1 TERMINAL STRIP FOR ELECTRICAL CONNECTION
MG9 ALTERNATOR MANAGEMENT
M49 ALTERNATOR 14 V / 180 A

Cheers

My 2008 318 doesn't have the MG9 ALTERNATOR MANAGEMENT option.

Is the MG9 ALTERNATOR MANAGEMENT code, mean you have the "smart alternator"?

In the 2016 option book, "M47 Alternator Management" only appears with the 4 cylinder engine... that that was the combo that did things like using the alternator as a brake (thus recovering "free power") and probably off-loaded (i.e. stopped asking for) alternator charging at times to improve fuel mileage.

The 6 cylinder didn't have "management", just a beefier alternator.

So i'd suspect that not having MG9 means you have a more-or-less "conventional" alternator.

Digging through a 2010 options guide (for the US) does not reveal any "alternator management" option code.

But your alternator is still a LINbus device.

--dick

autostaretx said:

Have you checked your VIN?
Do you have the EK1 option??

If so, a simple isolation relay will work. It's what MB does.
The Sprinter programming (and hardware) needed will have been "baked in" to your Sprinter to provide the "D+" signal.

--dick
p.s. what engine do you have? (i fear the 313 indicates "small").
In the US, the 6 cylinder had the more "conventional" alternator,
whereas the 4 cylinder had the "too smart" flavor. (both were LINbus, but the 4-cyl backed off from continous charging)
Both operate properly for isolation with the EK1 option.
(your alternator is also shown on the VIN-based option list)

Click to expand...

Hi Dick,
I know the above post was a couple of years ago, but are you able to please explain a bit more, exactly how to wire up this "D+" to a new house battery so the alternator will charge it....cheers

First, you need an "isolation relay" (such as a Cole Hersee unit).
The isolation relay will have 3 or 4 terminals.
Two really BIG studs, and one or two much smaller ones.

Each one of the BIG studs goes to the positive posts of the two batteries (one to one, the second to the other) with thick wires.

The D+ signal goes to one of the smaller studs. If there's a 2nd smaller stud, it goes to frame ground (or starter battery negative).
If there is not a 2nd smaller stud, the metal of the relay case itself is the "ground" and needs to be screwed to metal with decent connectivity (that will not be carrying much current).

When the alternator is running, D+ is turned "on" by the Sprinter (via a relay) and presents 12v to its wire.
That 12v (and the ground connection) cause the isolation relay to "pull in" and join the two batteries.
Charging current flows through the BIG studs (and thick wires).
The D+ is just a dinky signal to tell the isolation relay to act.

--dick

Dick.
Congratulations on your description of the Factory recommended D+ charging system, you are spot on, There are so many "experts" on this forum pushing crazy charging ideas so its good to read someone actually understands the Bosch design system. Eric,

autostaretx said:

First, you need an "isolation relay" (such as a Cole Hersee unit).
The isolation relay will have 3 or 4 terminals.
Two really BIG studs, and one or two much smaller ones.

Each one of the BIG studs goes to the positive posts of the two batteries (one to one, the second to the other) with thick wires.

The D+ signal goes to one of the smaller studs. If there's a 2nd smaller stud, it goes to frame ground (or starter battery negative).
If there is not a 2nd smaller stud, the metal of the relay case itself is the "ground" and needs to be screwed to metal with decent connectivity (that will not be carrying much current).

When the alternator is running, D+ is turned "on" by the Sprinter (via a relay) and presents 12v to its wire.
That 12v (and the ground connection) cause the isolation relay to "pull in" and join the two batteries.
Charging current flows through the BIG studs (and thick wires).
The D+ is just a dinky signal to tell the isolation relay to act.

--dick

Click to expand...

Awesome dick....cheers. So can i just confirm the picture i have attached. The smaller Terminal is the D+ terminal?
thanks again