Reply
 
Thread Tools Display Modes
 
Old 12-04-2016, 06:33 PM   #1
Mini-Skoolie
 
Join Date: Dec 2016
Posts: 43
Electrical Overview (connecting Alternator, Shore, Generator and Solar)

Hi, I'm looking for a description and diagrams for how all of the power inputs tie into a single system to charge the house batteries. If I'm connected to shore power, my solar panels are still pulling in power. If I'm boondocking, my solar is primary, but I may be running a genny on occasion. As I drive, my alternator and solar are providing power. I may even be driving a long distance in bad weather and have to run the genny to power my fridge/freezer for food safety. All of this to ensure my batteries do not drop below 50% charge or receive too much of a charge. How does al of this tie together in a design? Can someone point me in the right direction so I can figure out what I need to start with. If I build my system as I want it, it needs to support generator, shore power and alternator from day one and be able to add solar in the future. Thanks
PappySki is offline   Reply With Quote
Old 12-04-2016, 07:02 PM   #2
Bus Nut
 
AlleyCat67's Avatar
 
Join Date: Oct 2013
Location: Music City USA
Posts: 737
Year: 2005
Coachwork: Thomas
Chassis: Freightliner
Engine: Detroit MBE906
Rated Cap: 72
Here's a diagram that is way simplified but shows how I think all these things should tie together to form a complete 4 way charging system.... there are things I did not include that will need to be added but since this is just a very basic overview I didn't go into too much detail.



Couple of things I should mention....

1) On the AC side, make sure your inverter INPUT is coming from your main AC load center, and connect the OUTPUT to a separate subpanel. That way you prevent your inverter output from feeding back into itself, plus it ensures the charging circuit is OFF when no external AC source is connected.

2) On the DC side, make sure you turn OFF your solar charge controller when charging from the bus alternator. I'm not sure it would damage it if power is coming in from the panels with nowhere to go but better not to chance it. And also make sure the charge controller is OFF if using shore/generator power to charge them.

If I have made any gross errors I'm sure someone will call them out.
__________________
My bus - Jasmine - External Build Website - YouTube Channel - TN/KY Meetup Group
As a level 1 burglar, Bilbo got a pony when he accompanied the level 60 dwarves on the Smaug the Dragon raid. Those powerlevelers probably invited him solely so he could trigger fellowship attacks for them.
AlleyCat67 is offline   Reply With Quote
Old 12-04-2016, 07:21 PM   #3
Mini-Skoolie
 
Join Date: Dec 2016
Posts: 43
DC-Side

Thanks AlleyCat67. On the DC side of things, is it possible to feed the alternator output and solar into a single charge controller to eliminate the need to the transfer switch?

As for the AC side, it seems pretty straight forward to me. 120AC is 120AC, doesn't matter if its from the generator or the shore power. For this, I just need a big frankenstein switch and have Igor throw it to switch between shore and generator. Doesn't matter if both happen to be running/connected as the switch will only allow one to feed my system.
PappySki is offline   Reply With Quote
Old 12-05-2016, 03:00 AM   #4
Bus Nut
 
AlleyCat67's Avatar
 
Join Date: Oct 2013
Location: Music City USA
Posts: 737
Year: 2005
Coachwork: Thomas
Chassis: Freightliner
Engine: Detroit MBE906
Rated Cap: 72
I'm not sure if they make charge controllers that can handle more than one input... if they do that would simplify things a bit as the controller/transfer switch would be combined in one unit.

On the AC side of things, yes you're mostly correct..... there IS a slight difference between shore and generator power, in that some generators put out a modified (square) sine wave where shore power is pure sine. You don't want both connected at the same time but the transfer switch prevents that, just as you said. Transfer switches come in both manual and automatic varieties, which one you go with is a purely personal choice.
__________________
My bus - Jasmine - External Build Website - YouTube Channel - TN/KY Meetup Group
As a level 1 burglar, Bilbo got a pony when he accompanied the level 60 dwarves on the Smaug the Dragon raid. Those powerlevelers probably invited him solely so he could trigger fellowship attacks for them.
AlleyCat67 is offline   Reply With Quote
Old 12-05-2016, 07:34 AM   #5
Mini-Skoolie
 
Join Date: Dec 2016
Posts: 43
Thanks again. So how does the Battery Control Center figure into this...or do bus conversions have a BCC? My RV has one and I only know about it because an automatic switch failed and allowed the Chassis and Coach batteries to remain connected. This resulted in both sets of batteries dying on our last trip. Not sure if the starter killed the coach batteries or the constant drain from the coach killed the starter battery first. After a bit of research, I discovered that the BCC has a swich taht is supposed to allow both batteries to be connected only when the alternator is providing a charge. Otherwise, they are supposed to be separate.
PappySki is offline   Reply With Quote
Old 12-05-2016, 07:52 AM   #6
Bus Nut
 
AlleyCat67's Avatar
 
Join Date: Oct 2013
Location: Music City USA
Posts: 737
Year: 2005
Coachwork: Thomas
Chassis: Freightliner
Engine: Detroit MBE906
Rated Cap: 72
It would only have such a beast if you add it yourself. If you do decide to wire the house batteries and coach batteries together it would probably be better to install a MANUAL switch in the connecting line somewhere, so it would take a deliberate action to connect them when you start the engine (but don't forget to turn the switch OFF when you shut down).
__________________
My bus - Jasmine - External Build Website - YouTube Channel - TN/KY Meetup Group
As a level 1 burglar, Bilbo got a pony when he accompanied the level 60 dwarves on the Smaug the Dragon raid. Those powerlevelers probably invited him solely so he could trigger fellowship attacks for them.
AlleyCat67 is offline   Reply With Quote
Old 12-05-2016, 08:35 AM   #7
Mini-Skoolie
 
Join Date: Dec 2016
Posts: 43
Simplified Charging System Diagram v2

So would it make sense to add a separate transfer switch before the batteries to switch between DC and AC battery charging sources? This would allow only one source of power to feed the batteries at a time. You have the Genny/Shore power switch on the AC side and the Alternator/Solar switch on the DC side. These connect to a AC / DC Transfer Switch just before the batteries. This final transfer switch would actually feed into a shunt where my battery monitoring would occur. If I'm ever not seeing voltage, chances are one of these switches needs to be flipped.
Attached Images
File Type: jpg Simplified Charging System v2.jpg (45.3 KB, 35 views)
PappySki is offline   Reply With Quote
Old 12-05-2016, 10:07 AM   #8
Bus Geek
 
Tango's Avatar
 
Join Date: Mar 2011
Location: Houston, Texas
Posts: 6,029
Year: 1946
Coachwork: Chevrolet/Wayne
Chassis: 1- 1/2 ton
Engine: Cummins 4BT
Rated Cap: 15
Well dang...can't get the layout/plan to open.
Tango is offline   Reply With Quote
Old 12-05-2016, 11:07 AM   #9
Mini-Skoolie
 
Join Date: Dec 2016
Posts: 43
I keep getting an error when I try to upload it. Take AlleyCat67's diagram, move the Battery Bank down and put a new Transfer switch where the batter bank is current drawn. This allows you to switch between the DC system (Alternator/Solar) and the AC system (Generator/Shore). With this switch in place, it isn't physically possible for the batteries to be charged by more than one source at the same time.
PappySki is offline   Reply With Quote
Old 12-05-2016, 11:28 AM   #10
Bus Crazy
 
Join Date: Feb 2012
Location: Salt Lake City Utah
Posts: 1,321
Year: 2000
Chassis: Blue Bird
Engine: ISC 8.3
I don't see the v2 drawing either. But with regards to the first sketch from AlleyCat67, the transfer switch on the DC side will almost certainly prove unnecessary. Each of those charging sources (mains charger, solar, alternator) should be independently regulated such that they'll work it out amongst themselves if more than one is energized and willing to charge the batteries. The only point of concern might be that the batteries themselves will have some maximum recommended charge rate; with a combination of independent chargers operating in tandem you might conceivably exceed that charge rate. That could cause the batteries to run warm, off-gas, and possibly shorten their life (or at least accelerate the maintenance interval).

The switch mentioned in that last post could prevent this. It could also be avoided through use of a manual-start mains charger rather than automatic, as well as some consideration of what to actually expect from the solar system vs battery bank size. If the solar system is relatively small, or at least its output could be expected to be low while the engine is running (ie, the bus is underway) then maybe it isn't something to stress over.
family wagon is offline   Reply With Quote
Reply

Tags
alternator, batteries, generator, shore power, solar

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


» Virginia Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 11:31 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.