Ram Promaster Forum banner
1 - 20 of 61 Posts

·
Registered
Joined
·
93 Posts
Discussion Starter · #1 ·
I am still trying to figure out which DC-DC charger to get but my biggest question/concern is where to put it. I am thinking of putting it close to the car battery and running only one cable from the charger to the back to House batteries. Also should I run it through the van all through the nooks and crannies or should I just drill 2 holes and run the cable on the underside of the van and back up where the batteries are?
 

·
Registered
2018 Silver 159 HT
Joined
·
315 Posts
Depends on which unit you get. Sterling says to place closer to the Van battery. Renogy DCC50S you locate closer to the House batteries. Download the manual and see what it says. We ran our cables in thru the cavity behind the triangles.
 

·
Registered
Joined
·
93 Posts
Discussion Starter · #3 ·
Depends on which unit you get. Sterling says to place closer to the Van battery. Renogy DCC50S you locate closer to the House batteries. Download the manual and see what it says. We ran our cables in thru the cavity behind the triangles.
I am looking at getting the Victron Orion-Tr Smart DC-DC Charger Isolated seeing that I already have the Victron solar charger and battery monitor. I looked at the manual for the DC-DC charger here and one page 7 it says to mount the charger next to the battery and shows a picture of the input/starter battery but on page 10 there is a picture of the charger next to the house battery. So it is all confusing. I plan on installing it near the van battery because I plan to have it hooked up to the ignition. What do you mean by "Behind the triangles?"
 

·
Premium Member
Joined
·
738 Posts
You're most likely going to output LESS current on the output vs the input, but it's such a small amount, it doesn't really matter where you place it as long as you've got the appropriate sized cables/fuses/breakers. I'd install it where ever it fits best.

Just my two cents about the Victron DC-DC. I'm a huge fan of victron, in fact my entire system is victron, but I went with the Kisae DMT-1250 DC-DC. The max size that Victron makes is 30 amps and if you have a large bank, that's probably too small. Second is they don't have a fan on the unit so it COULD de-rate the current to keep the unit cool (I live in NV so that was a concern for me). Third, as of now, it doesn't integrate with any of the other victron gear (like how the MPPT can talk to the battery monitor, inverter, ect.). There is no VE.direct port or bluetooth smart networking on the Orion (it has bluetooth, but only for monitoring and programing). So from the victron point of view, it can't see the device other than positive current going to your battery. I opted for more charge current rather than less.
 
  • Like
Reactions: Wyoming07

·
Registered
Joined
·
93 Posts
Discussion Starter · #5 ·
You're most likely going to output LESS current on the output vs the input, but it's such a small amount, it doesn't really matter where you place it as long as you've got the appropriate sized cables/fuses/breakers. I'd install it where ever it fits best.

Just my two cents about the Victron DC-DC. I'm a huge fan of victron, in fact my entire system is victron, but I went with the Kisae DMT-1250 DC-DC. The max size that Victron makes is 30 amps and if you have a large bank, that's probably too small. Second is they don't have a fan on the unit so it COULD de-rate the current to keep the unit cool (I live in NV so that was a concern for me). Third, as of now, it doesn't integrate with any of the other victron gear (like how the MPPT can talk to the battery monitor, inverter, ect.). There is no VE.direct port or bluetooth smart networking on the Orion (it has bluetooth, but only for monitoring and programing). So from the victron point of view, it can't see the device other than positive current going to your battery. I opted for more charge current rather than less.
The DC-DC charger will be a back up to solar charging. My Battery bank is only 300A and I have a 30A MPPT. So theoretically I could charge most of my battery bank in one day if it is near depletion thus 18A to 30A is all I really need to top off my batteries while I am driving. If the Victron DC-DC charger does not talk to to the MPPT, I might go for the Renogy 20A charger. I hear decent things about it and it is only $130 or I can spend $200 and get the 40A charger.
 

·
Registered
2018 3500 EXT Camper Conversion in CT (TX for now due to Covid)
Joined
·
1,154 Posts
You're most likely going to output LESS current on the output vs the input, but it's such a small amount, it doesn't really matter where you place it as long as you've got the appropriate sized cables/fuses/breakers. I'd install it where ever it fits best.

Just my two cents about the Victron DC-DC. I'm a huge fan of victron, in fact my entire system is victron, but I went with the Kisae DMT-1250 DC-DC. The max size that Victron makes is 30 amps and if you have a large bank, that's probably too small. Second is they don't have a fan on the unit so it COULD de-rate the current to keep the unit cool (I live in NV so that was a concern for me). Third, as of now, it doesn't integrate with any of the other victron gear (like how the MPPT can talk to the battery monitor, inverter, ect.). There is no VE.direct port or bluetooth smart networking on the Orion (it has bluetooth, but only for monitoring and programing). So from the victron point of view, it can't see the device other than positive current going to your battery. I opted for more charge current rather than less.
I had a Sterling 1260 60 Amp and switched to a Victron DC-DC smart 30amp. The sterling terminals are only sized for maximum 4 gauge wire, which I though was a little too small for my likes at 60 amps.

This proved correct as it melted down the input terminals and desoldered themselves from the mainboard on a long drive with very low batteries. The sterling terminals are very isolated from the actual ventilation and have no cooling. Since the rest of my system is Victron I switched to the Victron, which has a seriously beefy heat sink (but no fan) compared to the Sterling.

If I end up needing to go back to 60 amps, I will add a second victron as they are able to operate in parallel and two 30 amp victrons are about the same cost as the sterling was. I am still waiting on a warranty replacement on the Sterling, at which time I will probably try to sell it.

I am thinking that 30 amps will be enough, since I now have 400 watts of solar. I am also running a 600 amp hour lithium battery bank so I don't feel compelled to have it at 100% all the time anyway. Except the summer when I want to run the Air conditioner, I can go quite a while without any need to run the engine or have sun.

FWIW, I don't think any Victron chargers other than MPPT or inverters talk on the network.
 

·
Registered
Joined
·
37 Posts
My thoughts are to place it as close to the house battery as possible. My reason is based upon voltage drop through your cables. I believe these chargers are essentially buck-boost transformers, with the ability to lower and raise the voltage as necessary for the particular charging profile selected. In some ways, it doesn't matter if you have voltage drop, as long as it isn't too large, from your alternator to your dc-dc charger as the charger will compensate. But you don't want voltage drop between your dc-dc charger and the house battery as the charger is maintaining its voltage at its output connections with no way to know the exact voltage being applied to the battery. Many of the charge profiles I have seen only vary by fractions of a volt between the various charging profile steps, so you want the charger to have as accurate of a reading as possible to the battery under charge. Even with large cables, 40 or 60 A can still easily give you a 2% voltage drop over these long runs, which is ~0.25V drop...which doesn't sound like much, but for battery charging profiles it could throw you out of the optimum range. For my 40A charger, I'm using 2 ga wire and only have a couple of feet of wire between the charger output and the battery whereas the starter battery is 12 ft away.
 

·
Registered
2018 Silver 159 HT
Joined
·
315 Posts
I am looking at getting the Victron Orion-Tr Smart DC-DC Charger Isolated seeing that I already have the Victron solar charger and battery monitor. I looked at the manual for the DC-DC charger here and one page 7 it says to mount the charger next to the battery and shows a picture of the input/starter battery but on page 10 there is a picture of the charger next to the house battery. So it is all confusing. I plan on installing it near the van battery because I plan to have it hooked up to the ignition. What do you mean by "Behind the triangles?"
You're right to install your charger in your electrical rack/space near the house batteries. The triangles are at the black plastic rounded triangle covers at the bottom of the wall where it meets the floor. If not covered with panelling, you can easily remove them and run the cables thru it. I ran the cables beside the driver seat, around the bottom of the B-Pillar (cover removed), into the triangle hole. To the battery space, in our van it's over the driver side wheels. Good luck.
 

·
Registered
Joined
·
93 Posts
Discussion Starter · #9 ·
You're right to install your charger in your electrical rack/space near the house batteries. The triangles are at the black plastic rounded triangle covers at the bottom of the wall where it meets the floor. If not covered with panelling, you can easily remove them and run the cables thru it. I ran the cables beside the driver seat, around the bottom of the B-Pillar (cover removed), into the triangle hole. To the battery space, in our van it's over the driver side wheels. Good luck.
I think I know what you are talking about but because I will have my electrical rack on the passenger side near the back wheel well, I am going to have to run the cable(s) up the passenger side b-pillar, above the sliding door along that upper cavity than have them come down at some point to reach my DC-DC charger. I am going to work on my van a little today and will try to get a good estimate of long that run is going to be. I am already thinking I will be using 6AWG for it.
 

·
Registered
Joined
·
93 Posts
Discussion Starter · #10 · (Edited)
So I bought the Renogy 20A charger with temp probe. The probe is only 9 ft long so I will have to place the charger near the house batteries. From the van battery to the path I want to take to the charger/house battery bank is about 25 feet. The manual here on page 14/15 says to use a 30A on the van battery side and a 25A on the house batter side. I am thinking 6 AWG cable should be adequate but should I run both a positive and negative line from the van battery to the charger or just run a positive line to the charger and connect the negative terminal to the chassis like they did with the van battery?


Also, I am guessing the floor can come out or what do you guys recommend to tunnel a hole from compartment to the passenger side b-pillar? Looks like they use expanding foam and so it wouldn't be too much of a problem if I need to tunnel through it.

62688
 

·
Registered
Joined
·
25 Posts
I had a Sterling 1260 60 Amp and switched to a Victron DC-DC smart 30amp. The sterling terminals are only sized for maximum 4 gauge wire, which I though was a little too small for my likes at 60 amps.

This proved correct as it melted down the input terminals and desoldered themselves from the mainboard on a long drive with very low batteries. The sterling terminals are very isolated from the actual ventilation and have no cooling. Since the rest of my system is Victron I switched to the Victron, which has a seriously beefy heat sink (but no fan) compared to the Sterling.

If I end up needing to go back to 60 amps, I will add a second victron as they are able to operate in parallel and two 30 amp victrons are about the same cost as the sterling was. I am still waiting on a warranty replacement on the Sterling, at which time I will probably try to sell it.

I am thinking that 30 amps will be enough, since I now have 400 watts of solar. I am also running a 600 amp hour lithium battery bank so I don't feel compelled to have it at 100% all the time anyway. Except the summer when I want to run the Air conditioner, I can go quite a while without any need to run the engine or have sun.

FWIW, I don't think any Victron chargers other than MPPT or inverters talk on the network.
With 600amp/hr of lithium onboard. I would just run it straight from the alternator. Why limit yourself to only 30 or 60 amps charging? I have a 540amp/hr lithium bank that charges directly from the alternator. The Victron BMV 712 stops charging via a relay at 13.8v. This system has been in place for over 2 years without a hiccup. The factory alternator self regulates output based on temperature. I have seen anywhere from 150amp/hr when the house batts are low in cold temps to 50/60amp/hr in warmer temps.
 

·
Registered
Van #2 2021 EXT
Joined
·
4,033 Posts
So I bought the Renogy 20A charger with temp probe. The probe is only 9 ft long so I will have to place the charger near the house batteries. From the van battery to the path I want to take to the charger/house battery bank is about 25 feet. The manual here on page 14/15 says to use a 30A on the van battery side and a 25A on the house batter side. I am thinking 6 AWG cable should be adequate but should I run both a positive and negative line from the van battery to the charger or just run a positive line to the charger and connect the negative terminal to the chassis like they did with the van battery?


Also, I am guessing the floor can come out or what do you guys recommend to tunnel a hole from compartment to the passenger side b-pillar? Looks like they use expanding foam and so it wouldn't be too much of a problem if I need to tunnel through it.

View attachment 62688
I know very little about B2B chargers, but what you may not know;

I think there are factory channels under the floor that are used to fed the “upfitter” positive from the van battery to the “B” Pillar behind the passenger.

If you look on my thread build I have photos of the “upfitter” wire I disconnected & connected my direct positive to my house bank.

Look at the drivers side photo below & you can see my abandoned upfitter red wire that goes to the B Pillar Passenger side

62709
 

·
Registered
2018 3500 EXT Camper Conversion in CT (TX for now due to Covid)
Joined
·
1,154 Posts
With 600amp/hr of lithium onboard. I would just run it straight from the alternator. Why limit yourself to only 30 or 60 amps charging? I have a 540amp/hr lithium bank that charges directly from the alternator. The Victron BMV 712 stops charging via a relay at 13.8v. This system has been in place for over 2 years without a hiccup. The factory alternator self regulates output based on temperature. I have seen anywhere from 150amp/hr when the house batts are low in cold temps to 50/60amp/hr in warmer temps.
I am not sure I want to run cables capable of handling 150 amps from the house to the primary battery!

I am not aware of the self regulating system of the factory alternator, but if I did I would be willing to consider this. Do you have a place I can find that information?

I have a relay I can use in that application and I have a 712 so I could easily set that up. Do you have a way to make sure the starter battery is not drained?

**** this forum, making me think about changing things again :)
 

·
Registered
Van #2 2021 EXT
Joined
·
4,033 Posts
I am not sure I want to run cables capable of handling 150 amps from the house to the primary battery!

I am not aware of the self regulating system of the factory alternator, but if I did I would be willing to consider this. Do you have a place I can find that information?

I have a relay I can use in that application and I have a 712 so I could easily set that up. Do you have a way to make sure the starter battery is not drained?

**** this forum, making me think about changing things again :)
I have 2 ways to ensure the starter battery will not get drained;

1) a manual switch
2) a smart switch (Victron); it will disconnect the positive like a solenoid does if the voltage drops below a set parameter. I can’t remember what that voltage parameter is, but that is how it works.

The PM alternator is “regulated” by the PM computer. If you find out how that works, please let us know. That was the big unknown when I did my alternator charging system to my house bank.
 

·
Registered
Joined
·
93 Posts
Discussion Starter · #15 ·
I know very little about B2B chargers, but what you may not know;

I think there are factory channels under the floor that are used to fed the “upfitter” positive from the van battery to the “B” Pillar behind the passenger.

If you look on my thread build I have photos of the “upfitter” wire I disconnected & connected my direct positive to my house bank.

Look at the drivers side photo below & you can see my abandoned upfitter red wire that goes to the B Pillar Passenger side

View attachment 62709
Thanks for this info, it will come in handy. Doing some searching and I found this thread on this forum that linked to some pdfs that show the route of the upfitter wire. My only problem is that it loops around the driver seat before looping back to the passenger side B-pillar. That adds a few feet to length which might knock me down to a 4AWG. Speaking of wire sizes, which gauge did you use to run to your house battery?
 

·
Premium Member
Joined
·
8,903 Posts
BTW 4AGW can be purchased off the roll at HomeDepot in black and red, stranded copper and relatively inexpensively. THHN
 

·
Registered
Van #2 2021 EXT
Joined
·
4,033 Posts
Thanks for this info, it will come in handy. Doing some searching and I found this thread on this forum that linked to some pdfs that show the route of the upfitter wire. My only problem is that it loops around the driver seat before looping back to the passenger side B-pillar. That adds a few feet to length which might knock me down to a 4AWG. Speaking of wire sizes, which gauge did you use to run to your house battery?
IIRC I used 2 Gauge (it has been awhile); I used the calculator @ wirebarn.com see photo below;

Parameters (voltage drop);

13.8 V
70 amps
18 feet
(total red positive “starter battery to house battery“ & black negative house battery post to chassis ground)
2% Voltage Drop. (My Victron BM712 measures the voltage across the house battery to ground). Why is this important? Depending upon the batteries you pick they will have charging profiles you are supposed to follow (including charge voltage). Many on here report the PM alternator voltage at this or that & to me it seems “off” what I get (in other words low). Makes me wonder if they have a higher voltage drop or if they used a 5% voltage drop in sizing their system. I can see 14.1 14.2 14.3 volts @ my BM 712 so basically @ my house batteries. Hope that explanation makes sense.


So my run was 16’ red + 2’ black. Some on here have criticized my understanding of “chassis ground” and Stated I should have included the length of the PM chassis frame back to the PM starter battery post.

For what it is worth ( correct or not ), that is what I did & how I calculated it.

Im not sure why you are concerned about wire size increasing to 4 gauge (the cost or the space to run?). I believe it is well worth going a bit bigger here than needed for the following reasons;

1) We do not know how much amps our custom systems will draw from the PM alternator via starter battery

2) We do not know how the PM computer regulates the alternator

3) If we “upgrade” change our systems, and run calculations for the new requirements, then we may be in the position to rip out a lighter gauge wire and replace it with a heavier one.

Hope that helps; GaryBIS IIRC had a “better” wire sizing chart he posted somewhere (may have been Bluesea, I can’t recall but you could message him);

Hope that helps !

62710
 

·
Registered
Van #2 2021 EXT
Joined
·
4,033 Posts
@librab103

So you got me thinking after I posted that, & went to my driveway just now to verify the wire size

It is 2 gauge “Marine“ boat wire (I used all boat wire & mostly boat electrical equipment as although I do not like the cost, I believe it is mostly better stuff than automotive).

The photo here also shows where my wire comes out gehind the left side of the driver’s seat “park brake” into the back of my van.


62711
 

·
Registered
MMXVI - L2H2 in Indiana
Joined
·
5,601 Posts
You can buy a drop in high amp alternator for the Promaster, that tells me the computer doesn't connect to the alternator.

I suppose the computer could be controlling the the alternator inputs, but that can't be true if they sell drop in high amp alternators.

IIRC someone already posted the alternator fail the "you do have a smart alternator test."

Don't all old school alternators self regulate based on the heat of the alternator? the higher the temp the lower the amperage.

Just a thought.
 
1 - 20 of 61 Posts
Top