Reply
 
Thread Tools Display Modes
 
Old 12-06-2015, 01:35 PM   #1
Bronze Member
 
Join Date: Dec 2015
Location: New Mexico
Posts: 49
Default Basic help please

We have purchased a Sprinter 170" extended with the 7' inside head room; and are building a Class B RV. Our intention is to install the Nations 270 Amp Alternator instead of a diesel generator. (We're doing our best to avoid propane.)

I understand the solar panels and controller, the lithium battery bank, and the shore power. We're prepared to install the high capacity inverter, etc.

My question (and it's hard to get info from Roadtrek when we're building our own): Does the 270 Amp Alternator feed the batteries, the batteries feed the inverter, and then on to the AC distribution panel? Or does the Alternator feed the inverter directly? And the batteries are charged from a converter fed from the AC panel?

I know this may sound basic to many, but my background is engineering on ships and boats and some of the new electrical/electronics equipment is an educational opportunity for me. Thanks in advance for your help.

tex4judy
__________________

tex4judy is offline   Reply With Quote
Old 12-06-2015, 01:43 PM   #2
Site Team
 
avanti's Avatar
 
Join Date: Jul 2013
Posts: 3,264
Default

Quote:
Originally Posted by tex4judy View Post
My question (and it's hard to get info from Roadtrek when we're building our own): Does the 270 Amp Alternator feed the batteries, the batteries feed the inverter, and then on to the AC distribution panel? Or does the Alternator feed the inverter directly? And the batteries are charged from a converter fed from the AC panel?
Typically, there is only a single DC system. I.e., the battery, alternator, inverter/charger, solar charger, and all loads are essentially all connected together. Think of it as a bus with all sources and sinks of current all connected in parallel. The battery in effect serves as a "load balancer" absorbing spare current when it is available and contributing it when necessary. The inverter/charger is a source when it is plugged in to shore power and a sink when it is inverting.
__________________

__________________
Formerly: 2005 Airstream Interstate (Sprinter 2500 T1N)
Now!: 2014 Great West Vans Legend SE (Sprinter 3500 NCV3 I4)
avanti is offline   Reply With Quote
Old 12-06-2015, 02:10 PM   #3
Bronze Member
 
Join Date: Dec 2015
Location: New Mexico
Posts: 49
Default Thank You

Your description is very helpful. So I can run DC current from the Alternator to the Inverter in the same connections where the battery is hooked up? And not worry about "unmanaged" charging of the batteries?
tex4judy is offline   Reply With Quote
Old 12-06-2015, 02:25 PM   #4
Platinum Member
 
BobB's Avatar
 
Join Date: Jun 2015
Location: Pennsylvania
Posts: 691
Default

Quote:
Originally Posted by tex4judy View Post
......and it's hard to get info from Roadtrek when we're building our own...
tex4judy
And you probably won't get any. Other manufacturers may be more helpful.


Quote:
Originally Posted by tex4judy View Post
I know this may sound basic to many, but my background is engineering on ships and boats and some of the new electrical/electronics equipment is an educational opportunity for me. Thanks in advance for your help.
tex4judy
Electricity is not my forté. BUT there are a lot of knowledgable people here. So my advice is - before you buy anything - work out the electrical design on paper, then post it here for review and comment. Much easier and cheaper to make mistakes on paper than in your new van.

See the thread "Roadtrek E-Trek Battery Replacement" and you'll get the idea.
__________________
BobB
'99 VW EVC
BobB is offline   Reply With Quote
Old 12-06-2015, 02:27 PM   #5
Site Team
 
avanti's Avatar
 
Join Date: Jul 2013
Posts: 3,264
Default

Quote:
Originally Posted by tex4judy View Post
Your description is very helpful. So I can run DC current from the Alternator to the Inverter in the same connections where the battery is hooked up? And not worry about "unmanaged" charging of the batteries?
Pretty much. At least that is what is commonly done, and it seems to mostly work out ok. You DO need to configure all the chargers so they are all singing from the same song sheet wrt charge thresholds, etc.

One issue that is a little subtle is where to put various disconnects, fuses and circuit breakers. There are non-obvious failure modes (e.g., suddenly removing the batteries from a running alternator) that can be nasty. This topic has been discussed here at length.
__________________
Formerly: 2005 Airstream Interstate (Sprinter 2500 T1N)
Now!: 2014 Great West Vans Legend SE (Sprinter 3500 NCV3 I4)
avanti is offline   Reply With Quote
Old 12-06-2015, 02:32 PM   #6
Site Team
 
avanti's Avatar
 
Join Date: Jul 2013
Posts: 3,264
Default

Just to be clear: The alternator doesn't literally connect directly to the battery. There needs to be a regulator/charger between them. Lots of people (including RT) use the Balmar MC614H, which is an excellent choice.
__________________
Formerly: 2005 Airstream Interstate (Sprinter 2500 T1N)
Now!: 2014 Great West Vans Legend SE (Sprinter 3500 NCV3 I4)
avanti is offline   Reply With Quote
Old 12-06-2015, 02:38 PM   #7
Bronze Member
 
Join Date: Dec 2015
Location: New Mexico
Posts: 49
Default

Perfect. Thanks. As I said, needing basic help.

You are also correct that there is good discussion here. Some have questioned running an A/C with the Secondary Alternator, but my numbers say it will start and run as long as the initial surge amps aren't too high. Any personal experience with that? The E Trek is set up that way.
tex4judy is offline   Reply With Quote
Old 12-06-2015, 02:41 PM   #8
Platinum Member
 
Join Date: Jul 2012
Posts: 2,240
Default

I agree with the idea that you document your design in detail and post it for review before you start buying stuff and building it. The devil is in the details in terms of wire size, circuit protection, balancing battery types/capacity, inverter size, and charging systems (solar, engine, inverter charger) with your energy usage profile. You can build up the system incrementally but a full design will help avoid finding out later you have issues.

There are examples of design schematics for similar systems you could use to start with.
gregmchugh is offline   Reply With Quote
Old 12-06-2015, 02:50 PM   #9
Site Team
 
avanti's Avatar
 
Join Date: Jul 2013
Posts: 3,264
Default

Quote:
Originally Posted by tex4judy View Post
Some have questioned running an A/C with the Secondary Alternator, but my numbers say it will start and run as long as the initial surge amps aren't too high. Any personal experience with that? The E Trek is set up that way.
I do it all the time. Trust your numbers. If you have a dedicated 270 amp alternator with properly-sized wiring, it is a no-brainer.
__________________
Formerly: 2005 Airstream Interstate (Sprinter 2500 T1N)
Now!: 2014 Great West Vans Legend SE (Sprinter 3500 NCV3 I4)
avanti is offline   Reply With Quote
Old 12-06-2015, 03:25 PM   #10
Platinum Member
 
Join Date: Aug 2010
Location: Minnesota
Posts: 7,566
Default

There are many, very detailed, discussions here about the different systems, how they work, and why folks chose to do them the way they do. Many of the questions you have brought out have been addressed from many different views, and that is a very good thing.

IMO, some of the important things to dig in to.

There are good reasons to chose a single alternator setup, and also good reasons to chose a standalone setup. It comes down to personal choice to some extent, how the van electronics react to big alternators, and if you feel the need to be able to stop the alternator charging to the coach. Especially with the lithium, I don't think a lot of the questions have for sure answers at this point.

The devil is in the details with charging, with AGM having one set of concerns, lithium a different set. Again, the lithium tech is new and not fully resolved, so most certainly will have to take a best guess on what is best, worst, OK on some of the issues. In all types of setups, it is possible to ruin batteries in a short time if done poorly. Environmental concerns have recently been a big topic for both hot and cold. Several folks are working on lithium systems on the forum, but only davydd has any real amount of time on them, and his time is still pretty short.

Interactions between all the systems have been proven to cause a lot of us issues. You have to have 3 charging systems that do what they are supposed to without keeping the other two from doing the same. Advanced RV appears to have put together a very sophisticated central control system to do that with the lithium batteries, but doing it with individual components will be tougher. Even with the much older AGM tech, there are very few components that play well together, and they still have oddities to them.

Above all, you will need to have a very good monitoring system, especially for initial checkout and tweaking.

IMO, the last thing you want to do is believe what the sales guys tell you about their stuff as we have seen piles of bad, distorted, and outright inaccurate information. Trust, but verify, as they say, no matter who says it.

Good luck on your project, it will be fun to see it progress!
__________________

booster is offline   Reply With Quote
Reply

Tags
basic wiring help, secondary alternator feed

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT. The time now is 10:35 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.