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2014 Ram Promaster 2500, 136WB, 3.6L gas, High Roof
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Discussion Starter #1
Hey Forum Members,

I’m working on a simple house battery electrical system. The system will be charged via B2B and shore power.

If folks see anything that could be improved or needs changed, I welcome any feedback or comments and appreciate your time.

Thanks in advance.
 

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2017 159, w/dual sliders. SF Bay area
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Please post in the Introductory forum, per the rules.
 

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2014 Ram Promaster 2500, 136WB, 3.6L gas, High Roof
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Discussion Starter #3
Sure thing ThomD.
 

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2017 159, w/dual sliders. SF Bay area
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I love electrical reviews. You are showing duplex wires from your DC panel to you loads, so you do not need the chassis ground. Electricity only needs one path to make the round trip.

Did you use the Blue Sea wiring guide to set your gauges? Remember to use the round trip distance. Looks like you did.

You have some 20A fuses on the fuse block. If you use those, you might need bigger than 14 AWG if your runs are long.

No battery monitor? Not saying you need it, but most people put one in.

You do not have a fridge. If you add one, your daily load might be a bit much for 100Ah. Or not. Rule of thumb is 50% draw down on AGMs for max battery life, but I'm not sure how much occasional 70% draw downs would shorten the life. Probably not much, so you are probably OK with 100Ah. Somebody else here will know.

No solar. Nothing wrong with that. Depending on your use case, you could be just fine without it. But, it is not expensive and easy to do and gives you some wiggle room.

You have a few wiring sizes on the bus bars. If you can limit the number of sizes, your life will be easier. Not saying run 4 AWG everywhere, but you have 6, 8 and 10.

not sure if you expect to expand your system, but as shown, you total load would be under 25A DC (estimated). OTOH, you sized the breaker at 50A, so with that 6AWG would be right. And it would leave you lots of room for growth.

4AWG on the bus bars seems big. That would support 80A and I don't see any way your systems could move 80A (load or charge).

You are right to step up that long run from the starting bat. fuse to the Charger compared to the side going to the bus bar.

what's the output on that Samlex charger? 15A 110AC is 150A DC(ish). that 30A fuse connected to that long run at 10 AWG might be an issue. OTOH, if it only pushes <25A then it would be fine.
 

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2014, 138WB, High Roof, Gas, SW MT
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Hi,
Good advice from ThomD.

I would think about whether you will want to add a fridge -- most people find the 12 volt compressor fridges to be a really good solution. As Thom says, the 100 AH battery would be marginal with a fridge -- the fridges use 40 to 50 amp-hrs on a warm day. Otherwise your loads are low and 100 amp-hrs should be OK.

I guess you are not planning to run any 120VAC loads in the van as you have no shore power connection? No problem with this as long as its what you want. If you do want to be able to run 120VAC loads, you could change the shore power battery charger for an inverter/charger which has the advantage of changing over from shore power to inverter power.

The Samlux charger is shown shown charging both your house battery and van battery - I've not seen that before but might be fine.

The BlueSea Circuit Wizard can be used to check all your wire gauges for both max current and voltage drop plus a few other things -- easy to use.

Gary
 

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2014 Ram Promaster 2500, 136WB, 3.6L gas, High Roof
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Discussion Starter #6
I love electrical reviews. You are showing duplex wires from your DC panel to you loads, so you do not need the chassis ground. Electricity only needs one path to make the round trip.

Did you use the Blue Sea wiring guide to set your gauges? Remember to use the round trip distance. Looks like you did.

You have some 20A fuses on the fuse block. If you use those, you might need bigger than 14 AWG if your runs are long.

No battery monitor? Not saying you need it, but most people put one in.

You do not have a fridge. If you add one, your daily load might be a bit much for 100Ah. Or not. Rule of thumb is 50% draw down on AGMs for max battery life, but I'm not sure how much occasional 70% draw downs would shorten the life. Probably not much, so you are probably OK with 100Ah. Somebody else here will know.

No solar. Nothing wrong with that. Depending on your use case, you could be just fine without it. But, it is not expensive and easy to do and gives you some wiggle room.

You have a few wiring sizes on the bus bars. If you can limit the number of sizes, your life will be easier. Not saying run 4 AWG everywhere, but you have 6, 8 and 10.

not sure if you expect to expand your system, but as shown, you total load would be under 25A DC (estimated). OTOH, you sized the breaker at 50A, so with that 6AWG would be right. And it would leave you lots of room for growth.

4AWG on the bus bars seems big. That would support 80A and I don't see any way your systems could move 80A (load or charge).

You are right to step up that long run from the starting bat. fuse to the Charger compared to the side going to the bus bar.

what's the output on that Samlex charger? 15A 110AC is 150A DC(ish). that 30A fuse connected to that long run at 10 AWG might be an issue. OTOH, if it only pushes <25A then it would be fine.
Thanks for the feedback ThomD.

Re: DC panel and chassis ground.
  • Perhaps it would be better to run the negative chassis ground from the bus bar vs. the house battery.
Yeah, I used the Blue Sea wiring guide to check gauge sizes. I'll double check my round trip lengths.
  • On the topic of round trip lengths. Using the B2B setup as an example, I would need to measure the length between both Negative Chassis Ground (correct?). So if I have ~20 ft. of positive, and X amount of length between both negative chassis grounds = round trip length.
The 20A dual usb charger will be pretty close to the fuse block, but I'll double check the round trip length here.

Re: battery monitor. Yeah, that was on my mind. Renogy has a monitor that is reasonably priced, or I could wire up a couple of Bayite monitors.

Re: bus bar wire sizes. Good recommendation.

My thinking on the 4 AWG was sized on the circuit breakers coming into the bus bar, and if I was running max dc loads and shore charging at the same time. I agree with you that 80A might be high, it's probably closer to 55A combined in the described scenario. Perhaps 6 AWG would be more appropriate here.

The Samlex has a max charging current of 15A.
 

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2017 159, w/dual sliders. SF Bay area
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I missed that you are relying on chassis ground to charge the vehicle battery. that is fine. Bus bar or battery post for that doesn't change the path. Busbar probably would be easier to do cleanly.

Yes, I think you round trip assessment is correct. It is the length of the actual wires that matter. The van chassis has trivial resistance provided you get good connections.

That USB charger will push 20A? Didn't know they came that high. I guess USB C will do it.

6AWG looks right for your busbars. You have a very light system, so the loads are relatively small.

But, you are committing to never putting in something like an inverter.

At 15A, that means you could take up to 4 or 5 hours to charge.

Having said all this, you are not giving yourself any room to grow the system. As long as you have a solid idea of how you will use the van, this can be fine.
 

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2014 Ram Promaster 2500, 136WB, 3.6L gas, High Roof
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Discussion Starter #8
Hi,
Good advice from ThomD.

I would think about whether you will want to add a fridge -- most people find the 12 volt compressor fridges to be a really good solution. As Thom says, the 100 AH battery would be marginal with a fridge -- the fridges use 40 to 50 amp-hrs on a warm day. Otherwise your loads are low and 100 amp-hrs should be OK.

I guess you are not planning to run any 120VAC loads in the van as you have no shore power connection? No problem with this as long as its what you want. If you do want to be able to run 120VAC loads, you could change the shore power battery charger for an inverter/charger which has the advantage of changing over from shore power to inverter power.

The Samlux charger is shown shown charging both your house battery and van battery - I've not seen that before but might be fine.

The BlueSea Circuit Wizard can be used to check all your wire gauges for both max current and voltage drop plus a few other things -- easy to use.

Gary
Hi Gary,

Thanks for the feedback.

Yeah, I did think about a fridge, but a good cooler will meet my needs.

Nope, no AC loads in the van. I will have a 15A 125v AC to plug the Samlex into. And I will probably install a power strip with circuit breaker in the van, so I have the option to run AC when connected to shore power.

Re: Samlex charging both the house and starting battery. I was following Fig. 5.1 in the Samlex Manual here that describes using 2 separate battery systems in RVs. It mentions, " If more than one battery systems are being used independently,
the system batteries will discharge to different levels. If system batteries are connected in parallel to charge from a single charger, a weak or a dead battery will drain the charge from the strong battery." Perhaps the keyword here is parallel, when in fact the setup is in series and the connection from the Samlex to the starting battery is not needed.
 

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Discussion Starter #9
I missed that you are relying on chassis ground to charge the vehicle battery. that is fine. Bus bar or battery post for that doesn't change the path. Busbar probably would be easier to do cleanly.

Yes, I think you round trip assessment is correct. It is the length of the actual wires that matter. The van chassis has trivial resistance provided you get good connections.

That USB charger will push 20A? Didn't know they came that high. I guess USB C will do it.

6AWG looks right for your busbars. You have a very light system, so the loads are relatively small.

But, you are committing to never putting in something like an inverter.

At 15A, that means you could take up to 4 or 5 hours to charge.

Having said all this, you are not giving yourself any room to grow the system. As long as you have a solid idea of how you will use the van, this can be fine.
It's a dual 12v/USB charger, the 12v socket is rated to 20A.

Re:15A shore charging, I'm estimating at 50% of 100Ah, 50A would take a litte more than ~3 hrs.

Point taken on ability to scale this simple system. It doesn't leave much room for growth, but I think it will meet all of my needs.

Thanks again.
 

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2016 136WB low roof diesel, converted to an RV by Sportsmobile, TX
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Does the Samlex isolate the 2 outputs? If not, you will pop the fuses and breakers when you start the van - the starter will try to pull from the house battery through the connection to the van battery through the Samlex.
Is that Samlex [email protected], or [email protected]? If the latter, you don't need or want a 30A fuse on the Samlex - you want to limit it to the max output of the Samlex - 15A.
I would also suggest a fuse between the battery and the bus bar - in case something shorts on the bus bar.
 

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Discussion Starter #11
Does the Samlex isolate the 2 outputs? If not, you will pop the fuses and breakers when you start the van - the starter will try to pull from the house battery through the connection to the van battery through the Samlex.
Is that Samlex [email protected], or [email protected]? If the latter, you don't need or want a 30A fuse on the Samlex - you want to limit it to the max output of the Samlex - 15A.
I would also suggest a fuse between the battery and the bus bar - in case something shorts on the bus bar.
Re: thread previous comment. I think the mistake here was reading for a parallel vs. series setup, and the Samlex to starting battery connection is not needed.

The Samlex can be powered from an AC power source of either 120v, 60 Hz (pre-set) or 230 V, 50 Hz (by changing configuration).

The Samlex has built in protections, including over load current limiting and reverse battery connection cut off (the output is internally fused on the DC side). The 30A fuses and breakers in the diagram are more of a backup to protect the batteries in case the Samlex failed. In this case, I wouldn't want them fused at the max current charge (15A), because they would be tripping every time I used the Samlex. Perhaps a 20A fuse would be more appropriate.

Re: fuse between battery and bus bar, thanks for the recommendation.
 

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2014 Ram Promaster 2500, 136WB, 3.6L gas, High Roof
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Discussion Starter #12
Hey All,

Thanks for the helpful discussions, v2 attached per notes below.

@ThomD, I double checked my round trip wire lengths, and have simplified wiring at the bus bar. It looks like I can use primarily 6 AWG and 14 AWG in this system. I also added a battery monitor, and I'm going to give the Victron Smart Shunt a try.

@GaryBIS I removed the Samlex from the starting battery.

@Wowbagger I installed a 60A circuit breaker between the bus bar and house battery, and stepped down the shore charging fuse from 30A to 20A at the bus bar.

Cheers
 

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2014, 138WB, High Roof, Gas, SW MT
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Hi,
If the positive bus bar is located right at the battery, you don't really need the 60 amp breaker at the battery because you already have breakers in all of the wires leaving the plus terminal.

With only 3 wires coming into the battery terminals, you don't really need the bus-bars at all -- you could just hook the wires directly to the battery terminals.

Maybe its already been mentioned, but a lot of people have reported problems with the cheap 12 volt breakers sold on Amazon -- I'd spring for the more expensive BlueSea or Bussmann breakers.

Gary
 

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Discussion Starter #14
Hi,
If the positive bus bar is located right at the battery, you don't really need the 60 amp breaker at the battery because you already have breakers in all of the wires leaving the plus terminal.

With only 3 wires coming into the battery terminals, you don't really need the bus-bars at all -- you could just hook the wires directly to the battery terminals.

Maybe its already been mentioned, but a lot of people have reported problems with the cheap 12 volt breakers sold on Amazon -- I'd spring for the more expensive BlueSea or Bussmann breakers.

Gary
Hi Gary,

Point taken on the 60A circuit breaker.

The bus bars will help keep things clean in the house battery box, and thanks for the recommend to purchase higher quality here, like BlueSea.
 

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Trying to learn so asking about the B2B connections. There is +in, +out, and -out. Is this correct? Thinking there are 4?
 

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Although you are keeping this really simple, I think a Battery Protect is worth dropping onto the load side. That way if you leave some load turned on over a few days when you aren't using the van it won't totally drain and wreck your house battery. That's especially useful if you have anything that has a thermostat or otherwise can appear to be off, but actually is energized and will consume energy when you aren't expecting it to. Having said that, I have had a similar system installed for the past five years without a battery protect and have not had any problems.
 

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You need either the breaker or a fuse at the battery, don't delete. I like fuses at batteries much quicker acting. Having a disconnect switch for the battery is important. If something happens you need a way to disconnect the main power source.
 

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Discussion Starter #18
Although you are keeping this really simple, I think a Battery Protect is worth dropping onto the load side. That way if you leave some load turned on over a few days when you aren't using the van it won't totally drain and wreck your house battery. That's especially useful if you have anything that has a thermostat or otherwise can appear to be off, but actually is energized and will consume energy when you aren't expecting it to. Having said that, I have had a similar system installed for the past five years without a battery protect and have not had any problems.
I've been contemplating a switch, and I agree, I think this would be a good addition to the system.

You need either the breaker or a fuse at the battery, don't delete. I like fuses at batteries much quicker acting. Having a disconnect switch for the battery is important. If something happens you need a way to disconnect the main power source.
Wowbagger also suggested a fuse between the battery and the bar. Perhaps better to be safe here.
 

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I think you mentioned using an AC power strip with breaker inside it, but if not you'll probably want a 15A breaker on the shore power AC.

For AC-DC charging take a look at the Powermax PM3 series; I got mine from donrowe.com. I've had an issue charging a LifePO battery bank with mine - they are better for charging AGMs - but Powermax gave me excellent support (and they're coming out with a PM2 for LifePOs at which time I'll buy one and sell my PM3-45LK).

Second the battery disconnect switch - they're $15 on Amazon.
 
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