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Discussion Starter · #1 ·
I'm in the process of converting a 2016 cargo Metris into a camper van. The floor plan will be similar to a VW Eurovan. My plan is to use it year round for camping so I have a Webasto gasoline fired heater and a fairly large AGM battery, a Trojan J185- 200 amp hours. The heater will be the main power user during colder and darker months, which is why I have a fairly large battery. I also have a 300 watt solar panel on the roof, which will be my primary charging source for the summer months.

Deciding on a charger for the battery was a major research project. The primary criteria were: A) it needed to do a 4 stage charge. B) be relatively small due to space constraints in the Metris. C) provide 30 amps of output. D) be reasonably easy to install.

I selected a Sterling Power BBW1212. (Sterling Power has some pretty confusing model designations, this might also be referred to as a BBW1220.) It met all of my criteria, except for the power out put. It provides 30 amps for 30 minutes then it drops to a 20 amp output. Its actually designed for charging batteries for trolling motors in boats- it has an IP68 rating which means its waterproof to 1 meter for 30 minutes. I'm hoping I'll never test out that aspect of the unit....

I mounted it under the passenger seat next to the small aux battery and behind the start battery. Its a pretty tight fit. Its not the most elegant install, but it works. You need to remove the start battery and the passenger seat to cut a hole into the seat base to route the BBW1212 cables to the connection points on the Pre-fuse box under that seat. The charger has a built in fuse block on the input positive wire and on both output wires so you do not have to deal with any additional fuses. However, the fuse blocks are rather bulky which can make routing the wires more challenging. I had the option of leaving the input fuse in place and drilling a larger hole in the seat base or cut the input wire, drill a smaller hole in the seat base, and then splice the wire. I drilled a larger hole in the seat base since that makes it possible to remove the seat base in the future if I need to.

Connecting it to the vehicle's electrical system was easy using the start battery ground for the chargers negative wire. The positive connection is the "A2 Catch" which is for the "Control Unit, preglow system" according to the description in the Fuse Allocation Supplement. Since I have a gasoline engine, there are no glow plugs. That circuit is fused for 100 amps which is more than enough for this charger. Since I do not get power directly from the alternator, there is no need for a battery isolator.

The unit is programmed for the correct charging profile using a small magnet since there are no button or switches on the unit. The instructions are adequate but it took me several tries to get the correct profile selected.

The tucked away location will make it a bit more difficult to monitor to see that its providing power, but I can see the 2 LEDs at the top of the unit, between the mounting screw holes, by going toward the rear of the van or by bending down. I'll also be able to monitor the power input by looking at my Magnum battery monitoring system.

Pictures

1- Front side of the Pre-fuse box showing the A2 connection point for the positive wire. The grounding point is on the left side of this image at the base of the fuse panel, but not visible in this pic.

2- The general layout below the passenger seat. The output cables go beneath the floor to my house or storage battery near the left rear wheel. My floor is elevated an inch to accommodate foam insulation so embedding the wires in the insulation was easy. The white cable is DC power to a 12 volt socket and dual USB port that I have mounted in the passenger seat.

3- The input wire fuse block and the hole in the seat base. The gray plastic gang box in the seat base is for the 12 volt socket and USB ports.

4. I mounted the unit onto a 1/2 inch sheet of plywood with 1/4 inch pieces of plywood under the mounting points to provide a bit of ventilation for cooling. Even though it was tight fit for the plywood, it was easy to secure the plywood using the aux battery screw and a 90 degree bracket.

5. I forgot to shoot a picture when I ran the out put wires to my storage battery, but his shows the basic layout. The battery will be mounted over the groove in the plywood that is painted white.

6. The wires from the Sterling charger are in front of the battery bracket. I have a 1000 watt Magnum inverter installed and you can see the basic layout of my electrical system on the mockup of my galley cabinet. There will be a small spaghetti bowl of wires between the various components of the electrical system.
 

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I'm in the process of converting a 2016 cargo Metris into a camper van. The floor plan will be similar to a VW Eurovan. My plan is to use it year round for camping so I have a Webasto gasoline fired heater and a fairly large AGM battery, a Trojan J185- 200 amp hours. The heater will be the main power user during colder and darker months, which is why I have a fairly large battery. I also have a 300 watt solar panel on the roof, which will be my primary charging source for the summer months.

Deciding on a charger for the battery was a major research project. The primary criteria were: A) it needed to do a 4 stage charge. B) be relatively small due to space constraints in the Metris. C) provide 30 amps of output. D) be reasonably easy to install.

I selected a Sterling Power BBW1212. (Sterling Power has some pretty confusing model designations, this might also be referred to as a BBW1220.) It met all of my criteria, except for the power out put. It provides 30 amps for 30 minutes then it drops to a 20 amp output. Its actually designed for charging batteries for trolling motors in boats- it has an IP68 rating which means its waterproof to 1 meter for 30 minutes. I'm hoping I'll never test out that aspect of the unit....
Great write-up! You said it was a major research project to find Sterling Power BBW1212. What were your other options (besides Sterling)? Just curious.
 

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Discussion Starter · #3 ·
Thanks for the kudos kllbosmetris.

My research was mainly on ways to avoid having to run heavy cables to get a lot of DC amps to the rear of the van. One idea was to put an inverter up front and run AC power to the back, meaning you might end up with 2 inverters in the van. AC power requires far smaller wires for the same amps compared to DC power. For larger vans with greater electrical needs (frig, water heater, electric furnace, etc), there is certainly merit to that idea. Dave Orton has some great ideas in the work he's done on his Sprinter and Dodge Transit vans. http://ortontransit.info/ Space considerations were also a big strike against two inverters.

The location of the start battery inside the passenger compartment, and the very tight space that it fits into, also made some options less feasible in my mind. Some (most?) large work vans have a bus bar near the main battery to for connecting auxiliary equipment. Not the case with the Metris, which in many regards seems more like a passenger van stripped out on the interior so it can haul cargo. (Strictly my opinion, other will certainly disagree.) The electrical system certainly has no where near the flexibility that you find in a Sprinter. The tight space around the Metris start battery makes it impossible to add a bus bar onto the positive terminal- something that is done on boats. Blue Seas sells a device for that purpose.

A battery to battery charger also eliminates the need for a battery isolator. One less thing to buy, mount and connect to the electrical system.

Once I found out about battery to battery chargers, Sterling was the best option for my needs. The other ones that I looked did not provide as much amperage, or they provide way too many amps. I actually ordered a different Sterling model (BB1230) which provided 30 amps continuously, but Bay Marine Supplies (thru Amazon) sent me an AC to DC charger by mistake. (Again, Sterling has similar and confusing model numbers so look carefully if you order their products.) However, what I got was similar in size to what I actually ordered. I had trouble fitting it into my layout so I went with the much smaller BBW1212. Its certainly much smaller but has lower continuous output.

CTEK has 2 models of DC to DC chargers- the 100 amp was way more than I needed. The 20 amp model, D250S, was pretty darn close but it cost more. The D250S can also accept solar input and function as a MPPT solar controller, but my solar panel produces too many amps for it so that feature was worthless to me. The BBW1212 also provides 30 amps for the first 30 minutes so that was another plus. Installation also looked easier with the BBW1212 (and it was easy to install). I have a smaller CTEK AC to DC charger and certainly like it so I have nothing against CTEK. Sterling's product simply meet my needs better at a lower cost.
 

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Great write up RR just wish I had come across your post earlier. Would have saved me a lot of research. Seems like I arrived at a similar conclusion by deciding on a battery to battery charging system by Sterling. Since my Metris has a 190amp 14v alternator and alternator efficiency management the Sterling products seem to be able to function and compensate for the various voltage values that I suspect the Metris alternator normally performs. Not 100% on how all this works but have a grasp on the basics. I had not come across the unit you installed but was looking a these none water proof Ultra units.
http://www.sterling-power-usa.com/library/NewB2BHandout.pdf

I hadn't decided on what size to get. Was thinking of the 60 amp model untilI I read your post. Perhaps the 30amp would be sufficient. However if there is no downside to getting the larger unit, other than cost, I may go the 60 amp route incase load needs increase over time. What do you think? I do like the physical size of your Sterling unit and how efficient your installation turned out.
 

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Another reason for selecting the BBW1212, other then the smaller size, is that it has built in selections for output to various battery types. For example, l decided to use a lithium (LiFePo4) battery for my house battery, and the 1212 had a built in setting for that type. The 30 amp output also means your wires can be smaller. As I mentioned, it fits nicely under the drivers seat, and the metal there already has holes, so I did not have to do modifications to the seat base at all. I placed my new battery right behind the drivers seat.
 

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Discussion Starter · #6 · (Edited)
Great write up RR just wish I had come across your post earlier. Would have saved me a lot of research. Seems like I arrived at a similar conclusion by deciding on a battery to battery charging system by Sterling. Since my Metris has a 190amp 14v alternator and alternator efficiency management the Sterling products seem to be able to function and compensate for the various voltage values that I suspect the Metris alternator normally performs. Not 100% on how all this works but have a grasp on the basics. I had not come across the unit you installed but was looking a these none water proof Ultra units.
http://www.sterling-power-usa.com/library/NewB2BHandout.pdf

I hadn't decided on what size to get. Was thinking of the 60 amp model untilI I read your post. Perhaps the 30amp would be sufficient. However if there is no downside to getting the larger unit, other than cost, I may go the 60 amp route incase load needs increase over time. What do you think? I do like the physical size of your Sterling unit and how efficient your installation turned out.
Glad you found my info useful Mikit. The first thing to consider is how big is your house battery/batteries? Obviously a larger battery or battery bank will need a larger charger to get restored to full capacity in a reasonable amount of time. But there is a down side to too large or a charger since too many amps is not good for a battery.

Here is one site that has some helpful info. http://solarhomestead.com/battery-amp-hour-ratings/

I installed a Trojan Solar AGM 12 volt 205 amp hour battery, ie the C20 rating is 205 amp hours. Trojan recommends a charging rate of 10 to 13% of the C20 rating, so 20.5 to 26.65 amp. Page 18 in their User Guide. http://www.trojanbattery.com/pdf/TrojanBattery_UsersGuide.pdf

The Sterling Pro Charge B (model BBW1212) produces 25 amps for the first 30 minutes then it drops to to 18 amps. http://www.sterling-power-usa.com/library/Sterling Power USA - IP68 Batt to Batt Product Sheet.pdf That's pretty darn close to what Trojan recommends for my battery. The Sterling also has a charge profile that closely fits what Trojan recommends for the Bulk, Absorption, Finish and Float voltages. I also have a 300 watt solar panel to augment the Sterling so I'm far less concerned about under charging the battery when I consider the two systems together.

For my 205 AH battery the Sterling BBW1212 was an excellent fit. The Sterling literature says its good for up to a 200 AH battery bank so my battery is just a tad bit over their recommendation.

Unless you have something approaching a 400 AH battery bank, a 60 amp charger would likely be way too much power going into your house battery/batteries. What recharge rate does the battery manufacturer recommend?
 

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The Metris equipment guide states that maximum charging current for additional batteries should be less than 40 amp. May have to be careful with 60 amp charger coupled with lithium batteries.
 

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These are wonderfully documented posts RR, thanks.

Does anyone have the factory auxiliary battery and EK1 - Body Builder Connector Under Driver Seat? Is the Sterling needed with the factory set up?
 
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Glad you found my info useful Mikit. The first thing to consider is how big is your house battery/batteries? Obviously a larger battery or battery bank will need a larger charger to get restored to full capacity in a reasonable amount of time. But there is a down side to too large or a charger since too many amps is not good for a battery.

Here is one site that has some helpful info. http://solarhomestead.com/battery-amp-hour-ratings/

I installed a Trojan Solar AGM 12 volt 205 amp hour battery, ie the C20 rating is 205 amp hours. Trojan recommends a charging rate of 10 to 13% of the C20 rating, so 20.5 to 26.65 amp. Page 18 in their User Guide. http://www.trojanbattery.com/pdf/TrojanBattery_UsersGuide.pdf

The Sterling Pro Charge B (model BBW1212) produces 25 amps for the first 30 minutes then it drops to to 18 amps. http://www.sterling-power-usa.com/library/Sterling Power USA - IP68 Batt to Batt Product Sheet.pdf That's pretty darn close to what Trojan recommends for my battery. The Sterling also has a charge profile that closely fits what Trojan recommends for the Bulk, Absorption, Finish and Float voltages. I also have a 300 watt solar panel to augment the Sterling so I'm far less concerned about under charging the battery when I consider the two systems together.

For my 205 AH battery the Sterling BBW1212 was an excellent fit. The Sterling literature says its good for up to a 200 AH battery bank so my battery is just a tad bit over their recommendation.

Unless you have something approaching a 400 AH battery bank, a 60 amp charger would likely be way too much power going into your house battery/batteries. What recharge rate does the battery manufacturer recommend?
Thanks for the information. Looks like the smaller unit is the way to go since my house system will probably be your size or less. I had been looking at this line: https://baymarinesupply.com/media/downloadable/Sterling/BB1260_30_Ultra_Instructions_Eng.pdf but will see what I can find on the BBW1212 before making a decision. The Ultra line has a fan that might be annoying.
 

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These are wonderfully documented posts RR, thanks.

Does anyone have the factory auxiliary battery and EK1 - Body Builder Connector Under Driver Seat? Is the Sterling needed with the factory set up?
My factory aux battery is under the driver's seat but the EK1 is in the passenger footwell.
I was planning to just connect solar panels directly (400W max = 33 amps at 12 V). The charge controller should take care of the charging current. The battery is otherwise charged when the car is running.

Anyone think there's a problem with this?
 

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Discussion Starter · #11 ·
The Metris equipment guide states that maximum charging current for additional batteries should be less than 40 amp. May have to be careful with 60 amp charger coupled with lithium batteries.
Thanks for adding that important info QNF. I had researched that last year when I was setting up my electrical system but forgot to mention it.
 

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These are wonderfully documented posts RR, thanks.

Does anyone have the factory auxiliary battery and EK1 - Body Builder Connector Under Driver Seat? Is the Sterling needed with the factory set up?
I have the factory aux battery. However I found out it was not enough for my camping needs to run fridge and propane heater. That is why I added the Sterling and an additionsl (third battery).
Sterling would not be needed ifyounthink solar would sufice.
 

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Discussion Starter · #13 ·
These are wonderfully documented posts RR, thanks.

Does anyone have the factory auxiliary battery and EK1 - Body Builder Connector Under Driver Seat? Is the Sterling needed with the factory set up?
Glad you found my posts helpful. I try to provide a reference for my info so people can read it for themselves and decide if its a credible source.

If you have a factory installed aux battery, it is charged just like with your regular start battery. There is a thread on the Body Builder Connector already- apparently it does NOT draw power from the aux battery. But I don't have either of those options on my van so I did not pay particularly close attention to that thread.
 

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Discussion Starter · #14 ·
Nice write up. I am planning on copying your hookups but with a older Ctek 250S DC-DC charger. Before I pull the seat can you tell me is the A2 connection always hot or only hot with the ignition. It is my understanding the the smart alternator will drop voltage below the ctek cutoff. I was either planning on using an ignition-on source or have to run a relay and connect to the Ctek solar input.
Thanks for any help
Durst- Thanks, glad you found my info helpful.

The A2 connection is apparently intended for the glow plugs on a diesel engine based on how its labeled. It is energized when the ignition switch is moved into any position other than OFF.

The CTEK 250S looks like a really good unit to incorporate solar into your charging system as long as your solar panel (s) meet the parameters of the CTEK. In hind sight, I would have been better off with a slightly smaller solar panel and the CTEK. It would have saved me the expense and space of a separate MPPT solar controller. Plus the CTEK can be set up to charge your start battery also using the solar- a useful benefit if your van sits idle for multiple days.

"It is my understanding the the smart alternator will drop voltage below the ctek cutoff." I don't know how the alternator works on the Metris. I tried to find out if it had a 4 stage charging profile to optimize the life of the AGM start battery but I couldn't find any info on the alternator. Its safe to assume that it produces enough power to meet the all of the electrical demands that it detects- ie the demands of the CTEK to charge your aux battery. (Within the limits of the alternator, of course, which won't be a problem with the CTEK 250S.) I also assume that the alternator produces a constant voltage at all times since all of the other electrical appliances (lights, computers, etc) need a steady voltage. It seems unlikely that that voltage would be below the CTEK cutoff voltage.
 

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Discussion Starter · #15 · (Edited)
My factory aux battery is under the driver's seat but the EK1 is in the passenger footwell.
I was planning to just connect solar panels directly (400W max = 33 amps at 12 V). The charge controller should take care of the charging current. The battery is otherwise charged when the car is running.

Anyone think there's a problem with this?
I didn't quite understand what you're connecting the solar panels to- the aux battery or the EK1. From a different thread, my understanding is that the EK1 is NOT connected to the factory installed aux battery. I do not have the factory aux battery or the EK1 feature on my van so I'm not 100% sure how the connections work.

Regardless of which you're connecting the solar panel to, you'll need to have a fuse on the positive wire between the panel and the recipient device (battery or EK1).

For a small van, I have a relatively complex electrical system. I ran both the positive and negative wires from my solar panel to bus bars for the respective polarity. The bus bars also have connections with my inverter, my aux battery and my 2 fuse panels. That way the solar energy can flow directly to user appliances without having to go through the battery. YMMV.

If you don't have a lot of electrical connections, you might be able to use this small fuse block on your battery. [ame]https://www.amazon.com/Blue-Sea-Systems-ST-Blade-Terminal/dp/B00SE6Z2WI/ref=sr_1_3?ie=UTF8&qid=1525879189&sr=8-3&keywords=blue+seas+battery+fuse+block&dpID=51wuP3zSTCL&preST=_SY300_QL70_&dpSrc=srch[/ame]
 

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Thanks RR,

Sorry, my post was confusing! The EK1 won't have anything to do with the solar. I was just responding to a previous post that mentioned it under the driver's seat. I do use the EK1 to power my dashcam; terminal 15 while driving and terminal 30 for parking mode (although I might switch parking mode to the auxiliary battery).

I have a 30A 10 circuit fuse block on the auxiliary battery that currently serves just the trailer (10G 20A) but I will be adding a circuit for the ceiling fan (to keep the dogs cool) and maybe one for a powered cold box and who knows what else. I'm thinking now of 300W max solar ([email protected]) and I don't see why I can't just run it in through the fuse block. Battery charger could go in that way as well.

Just got back from shows in New Jersey so just saw your post. About 26mpg overall, although for the last 100 miles or so on back roads at about 50mph, the car claimed it was getting over 30. People were impressed with the size and low floor. Makes it easy to get big dogs in and out without lifting or a ramp.
That is the way I have it set up: From Metris aux battery positive under the drivers seat to a 30amp switchable circuit breaker to a fuse block. The fuse block runs wires to fuses(mostly 10 amp) to lights, propex heater, water pump, solar cell, etc. My solar right now is only 40 watts, enough to stay even with the fridge. I used a 30 amp switchable cicuit breaker first, so I can easily turn off the parasitic battery drain when not camping.
 

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Discussion Starter · #18 ·
Imacd- The fuse block should work fine the way you have it set up. Its certainly simple and elegant. Going slower is always good for the mileage. I have a Prius also and 45 MPH is about optimum to maximize fuel economy. I have not driven the Metris for a sustained distance at moderate speeds (40 to 50 MPH) so I'm not sure where its sweet spot is at.

Imants- your set up is quite similar to Imacd's.

I have a 1000 watt inverter so that pretty much necessitates bus bars, plus wiring for the AC. The battery charger is connected to the battery. Power from the battery goes through a 150 amp switchable breaker, a master switch, the inverter and then to the positive bus bar. The bus bar are connected to the inverter, the solar, the main fuse panel with up to 12 circuits, and small 4 circuit fuse in the rear of the van. Of course all of the wires coming off the positive bus have switchable breakers.
 

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RR,
Looks like you're really enjoying yourself with that heavy-duty wiring. The inverter alone (1000VA) must be drawing up to 85 amps @12V or more depending on efficiency so 150amps sounds reasonable.
I like your color coded wiring - very neat. #2AWG? Gives me some ideas, but I don't think I'll need 1000 watts.
 

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Discussion Starter · #20 ·
RR,
Looks like you're really enjoying yourself with that heavy-duty wiring. The inverter alone (1000VA) must be drawing up to 85 amps @12V or more depending on efficiency so 150amps sounds reasonable.
I like your color coded wiring - very neat. #2AWG? Gives me some ideas, but I don't think I'll need 1000 watts.
Yes it is 2 gauge cable. I got a deal on the inverter, it had been a demo unit- the cable and breaker were included. The 150 amp breaker is the size recommended by Magnum. 1000 watts is probably overkill for my needs, but I've owned a Magnum inverter/battery charger in the past and they're a very good product. The charger feature of that unit is as important as the inverter to me. I also installed a shunt, which ties into the Magnum controller, so that I can more accurately see the state of charge on the Trojan battery.
 
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