In addition to some solar panels (wired but not yet mounted) I want the vehicle alternator to provide some charge current to the coach batteries while driving. -But only when vehicle system voltages are within a specified (safe?) range. (I've been trying to get an idea of what that is by watching the Scangauge.)
Under these conditions the combiner will allow up to 25 amps to flow from the alternator to the coach batteries. Why the limit?
I want to use a fairly narrow range (high connect setting) to protect (maintain good voltage) in the Sprinter electrical system. Why?
I only want the combiner to connect the two banks while the engine is running. A 40 amp relay triggered by the ignition (with an override switch) controls the connection between the combiner and the main (chassis) battery.
The other side (N.C.) of the SPDT relay is connected to a trickle charger for the chassis battery. When the ignition is off the trickle charger is connected to the battery and the combiner is not. This prevents the voltages generated by the trickle charger from triggering the combiner to connect.
I don't want the trickle charger trying to charge the house batteries. Why?
It's only there to maintain the starting battery. The relay disconnects it when the engine is running.
The combiner is wired with #8 wire and 30 amp fuses are located at each battery. A common connects the chassis ground to the coach negative bus so the BMK shunt can record the current supplied by the vehicle alternator.
Make sense?
My plan is similar to yours using Magnum SBC and a narrow voltage window to get connection to minimize impact on MB system. I am thinking to have an override switch allowing connection to the engine battery from house batteries charging circuits and to disconnect the system.In addition to some solar panels (wired but not yet mounted) I want the vehicle alternator to provide some charge current to the coach batteries while driving. -But only when vehicle system voltages are within a specified (safe?) range. (I've been trying to get an idea of what that is by watching the Scangauge.)
I connected a Magnum ME-SBC with the chassis (starting) batteries as main and the coach batteries as auxiliary. The idea is to use the adjustable connect and disconnect settings to allow the banks to be combined when the vehicle system is above 13.1 volts and below 14.4. Under these conditions the combiner will allow up to 25 amps to flow from the alternator to the coach batteries. I want to use a fairly narrow range (high connect setting) to protect (maintain good voltage) in the Sprinter electrical system.
(look Ma! no mounting screws; VHB tape)
I only want the combiner to connect the two banks while the engine is running. A 40 amp relay triggered by the ignition (with an override switch) controls the connection between the combiner and the main (chassis) battery.
The other side (N.C.) of the SPDT relay is connected to a trickle charger for the chassis battery. When the ignition is off the trickle charger is connected to the battery and the combiner is not. This prevents the voltages generated by the trickle charger from triggering the combiner to connect. I don't want the trickle charger trying to charge the house batteries. It's only there to maintain the starting battery. The relay disconnects it when the engine is running.
The combiner is wired with #8 wire and 30 amp fuses are located at each battery. A common connects the chassis ground to the coach negative bus so the BMK shunt can record the current supplied by the vehicle alternator.
Make sense?
Can you expand on: "to minimize impact on MB system"My plan is similar to yours using Magnum SBC and a narrow voltage window to get connection to minimize impact on MB system. I am thinking to have an override switch allowing connection to the engine battery from house batteries charging circuits and to disconnect the system.
Great progress on your conversion.
George.
In case of drained house and engine battery banks I don’t want to connect both banks at the engine start time which would happen using a simple battery combiner. I don’t know what this inrush current would do (impact) to the MB alternator system. Using the narrow voltage window connection will allow the engine battery to be charged and once a higher voltage is reached the alternator will start charging the house batteries. Perhaps it is not a big issue because the Magnum ME-SBC limits the amperage to 25A or even one half of 25A if there is a high current demand. I will copy the Magnum ME-SBC connection from Hein using the existing MB auxiliary relay with override in case I want a house battery charger (solar or Magnum) charge engine battery.Can you expand on: "to minimize impact on MB system"
I've used a few 'smart' combiners/isolators, and most recently a Surepower 1315-200 & a BlueSea ML-ACR Automatic Charging Relay with Manual Control - 12V DC 500A, both 'bi-directional' sensing to control the open/close.In case of drained house and engine battery banks I don’t want to connect both banks at the engine start time which would happen using a simple battery combiner. I don’t know what this inrush current would do (impact) to the MB alternator system. Using the narrow voltage window connection will allow the engine battery to be charged and once a higher voltage is reached the alternator will start charging the house batteries. Perhaps it is not a big issue because the Magnum ME-SBC limits the amperage to 25A or even one half of 25A if there is a high current demand. I will copy the Magnum ME-SBC connection from Hein using the existing MB auxiliary relay with override in case I want a house battery charger (solar or Magnum) charge engine battery.
George.
Under these conditions the combiner will allow up to 25 amps to flow from the alternator to the coach batteries.
It is set by the combiner although it can drive a solenoid if more ampacity is desired.Why the limit?
I want to use a fairly narrow range (high connect setting) to protect (maintain good voltage) in the Sprinter electrical system.
I keep reading it is finicky about voltage. I'd like to do a big 3 upgrade before drawing anymore current from the alternator. Thanks for your insights above.Why?
I don't want the trickle charger trying to charge the house batteries.
It's only 4.3 Amps and I have a fancy Magnum inverter/charger that takes care of the house batteries. If I used the combiner the other way around (coach on main; chassis on auxiliary) then I could maintain the chassis battery with the Inverter/charger. But then the house battery voltage would be driving the connect status and I'd rather the chassis battery/alternator drive that.Why?
Congratulations on your purchase. I may decide to install the secondary alternator if there is a need to run the roof top AC while driving. I hope the Thinsulate insulation and choice of destinations will help alleviate that need. If I get the auxiliary alternator then there will be no need for the combiner. The coach batteries would be charged by the inverter/charger when on shore power and by the dedicated 2nd alternator while driving. The cat's meow!i just purchased a 2014 Roadtrek SS Agile with solar, I want to add Mercedes 2nd alternator 280 amp used to run air conditioner but want to use to charge new battery bank though sw3000 freedom inverter , I want to maintain sprinter warranty so will have Mercedes dealers install $$$, just alternator not wiring - any suggestions?
It is set by the combiner although it can drive a solenoid if more ampacity is desired.
I read that on the site... nice or required feature.
I keep reading it is finicky about voltage. I'd like to do a big 3 upgrade before drawing anymore current from the alternator. Thanks for your insights above.
MB system runs on 'caps', momentary drops in v's has no effect on the ecu's (this has been in play in vehicles for a long time). Constant low v's will cause the system to go offline, I imagine... but again, not gonna happen with a healthy alternator or large draw.
It's only 4.3 Amps and I have a fancy Magnum inverter/charger that takes care of the house batteries. If I used the combiner the other way around (coach on main; chassis on auxiliary) then I could maintain the chassis battery with the Inverter/charger. But then the house battery voltage would be driving the connect status and I'd rather the chassis battery/alternator drive that.
Consider bi-directional, as you have solar or shore, that will eliminate the chassis 'trickler'.
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Thank you for good summary, which of the combiner are you using currently?I've used a few 'smart' combiners/isolators, and most recently a Surepower 1315-200 & a BlueSea ASR, both 'bi-directional' sensing to control the open/close.
They combine banks when the v's on either side are 13.2v, and open circuit at 12.8v (with some time/duration parameters, so that fluctuating current/v's do not prematurely cause cycling).
I cannot see a situation where setting the upper limit higher than 13.2v (ie 14.1v), as that will negate having any alternator current most of the time.
I see the 25A current limit... limiting. Our alternators can and will provide substantially more current, and with my large bank I've drawn up to 90A, but most of the time 75A on engine run/start or 'bulk'. These draws have no negative effect on the chassis systems voltage, as the alternator/system volts never go below 13.4-ish.
Both of those switches had/were installed with manual & override remotes switches which were place on my dashboard. When desired, I could force open or closed.
Right now, the sun has poked out, and solar charger is outputting 13.5v's, and the ASR has 'closed' so that now my chassis battery is charging/floating.
BlueSea -- ML-ACR Automatic Charging Relay with Manual Control - 12V DC 500AThank you for good summary, which of the combiner are you using currently?
George.
It is set by the combiner although it can drive a solenoid if more ampacity is desired.
I keep reading it is finicky about voltage. I'd like to do a big 3 upgrade before drawing anymore current from the alternator. Thanks for your insights above.
It's only 4.3 Amps and I have a fancy Magnum inverter/charger that takes care of the house batteries. If I used the combiner the other way around (coach on main; chassis on auxiliary) then I could maintain the chassis battery with the Inverter/charger. But then the house battery voltage would be driving the connect status and I'd rather the chassis battery/alternator drive that.
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Congratulations on your purchase. I may decide to install the secondary alternator if there is a need to run the roof top AC while driving. I hope the Thinsulate insulation and choice of destinations will help alleviate that need. If I get the auxiliary alternator then there will be no need for the combiner. The coach batteries would be charged by the inverter/charger when on shore power and by the dedicated 2nd alternator while driving. The cat's meow!
What is the equipment you plan on using on the 12V system? What would be you total or largest amp draw?Thanks for all the information here, I have my eye on that magnum device, just have to figure it out.
I talked to the guy I want to install batteries underneath, I think Roadtrek mounts the extra 2 total 4 in the back under on passenger side. He said my roadtrek has a 200 amp alternator and he has one customer with 6 batteries off it, i want to end up with etrek copy with as many as 8 batteries.
I and determined as others are here to have that 2nd alternator. I called a Mercedes dealer and found out they can't order any part number that hasn't been installed on that unit. maybe get an etrek vin and order alternator installed ? I was told by Roadtrek its made by Mercedes
other option - much less with all the stuff, I have a person will install high idle option $600
http://www.nationsstarteralternator...nator-Kit-with-200-Amp-p/sprinter-dak-200.htm
I have a xtranex inverter\charger freedom 3000, have all the gauges worth lots, that works great, used it in the house for backup on computers with 2 batteries, it charges batteries excellent!
http://www.xantrex.com/power-products/inverter-chargers/freedom-sw-3000.aspx
I need to spend more time reading info here and testing
I purchased a 320 Amp alternator from Nations and highly recommend the company. I also ordered the second alternator prep feature and variable high-idle feature when I ordered the Van. The 320 Amp alternator was installed on the MB factory second alternator bracket. I'm using it with a Magnum MS2812 invertor, two 8D Lifeline batteries, and two 220W solar panels on top. The system works great. The people at Nations seem to be very aware of what all the Class B up-fitters are using, and are a good source of info about second alternators on Sprinters.I and determined as others are here to have that 2nd alternator. I called a Mercedes dealer and found out they can't order any part number that hasn't been installed on that unit. maybe get an etrek vin and order alternator installed ? I was told by Roadtrek its made by Mercedes
other option - much less with all the stuff, I have a person will install high idle option $600
http://www.nationsstarteralternator...nator-Kit-with-200-Amp-p/sprinter-dak-200.htm
What do you use that draws or requires 320 amps?I purchased a 320 Amp alternator from Nations and highly recommend the company. I also ordered the second alternator prep feature and variable high-idle feature when I ordered the Van. The 320 Amp alternator was installed on the MB factory second alternator bracket. I'm using it with a Magnum MS2812 invertor, two 8D Lifeline batteries, and two 220W solar panels on top. The system works great. The people at Nations seem to be very aware of what all the Class B up-fitters are using, and are a good source of info about second alternators on Sprinters.
I am behind in my posting about building my conversion, but am making slow, but sure progress.
Nothing. But the price of the 320 was right, and I am able to power the rear AC unit while driving, and operate the second alternator well-below its rated maximum. And, there is enough head-room that the alternator can supply both the rear Air Conditioner and charge the house batteries at the same time if they happen to be down when leaving camp before the solar had a chance to top-off the batteries. The Tri-Star solar controller and the Balmar three stage alternator controller appear to play well together.What do you use that draws or requires 320 amps?
So your planning on using the sprinter engine as a generator motor?Nothing. But the price of the 320 was right, and I am able to power the rear AC unit while driving, and operate the second alternator well-below its rated maximum. And, there is enough head-room that the alternator can supply both the rear Air Conditioner and charge the house batteries at the same time if they happen to be down when leaving camp before the solar had a chance to top-off the batteries. The Tri-Star solar controller and the Balmar three stage alternator controller appear to play well together.