Sprinter-Forum    
 

Go Back   Sprinter-Forum > Sprinter-Based RV's & Conversions > Sprinter RV's & Conversions Talk

Sprinter RV's & Conversions Talk Common features found in Sprinter RV's and Conversions.


 
Thread Tools Display Modes
Old 07-02-2019, 02:44 AM   #1
dwighttttt
 
Join Date: Aug 2016
Posts: 9
Thanks: 8
Thanked 1 Time in 1 Post
Lightbulb Electrical diagram review

Hi all,

I've got 2006 Dodge Sprinter 2500 144". I'm planning on adding an aux battery that charges off the alternator via isolator. I have pretty minimal usage requirements (lights, low power fridge, fan, laptop) that will likely only be running on/off throughout the day, if at all. I'm not so well versed in these sort of power setups but after a lot of research I think I've got a plan. I drew out a diagram to organize everything. Any feedback/suggestions/warnings/etc are welcome! Just trying to avoid blowing up the whole rig...

I've listed out the specific products, wire gauges, cable lengths, etc in the diagram. If there's anything I can add to clarify or make this easier to understand let me know!

Thanks!!!
Attached Images
File Type: jpg electrical-diagram.jpg (51.4 KB, 59 views)
dwighttttt is offline   Reply With Quote
Old 07-02-2019, 02:37 PM   #2
hein
Van Guru
 
Join Date: Jan 2011
Location: PacNW
Posts: 2,323
Thanks: 1,372
Thanked 1,805 Times in 1,022 Posts
Default Re: Electrical diagram review

Like the functional simplicity. A DC to DC charger might be a little better for getting a complete charge on your house battery. They are more expensive but there are some brands/models that also include an MPPT solar controller if you plan to add some panels in the future. We like/sell the Kisae DMT1250.

All the best,
Hein
DIYvan
__________________
2010 MB 3500 RV conversion.
hein is offline   Reply With Quote
Old 07-02-2019, 04:25 PM   #3
HarryN
 
Join Date: May 2010
Location: Pleasanton, CA
Posts: 2,363
Thanks: 537
Thanked 755 Times in 616 Posts
Default Re: Electrical diagram review

It is a simple design, but likely will not really work properly. In fact if you do it that way, you will be very unhappy. Sorry to tell you this.

In most vans, the single largest power consumer are the refrigerators, and that is where solar panels really help.

The house battery capacity is fairly low - that setup will run the fridge and indicated loads for less than 24 hours before needing multiple hours of driving to catch up. At least double the battery capacity.

The system will benefit greatly from 300 watts of solar panels or at a minimum a battery to battery charger. If you search on the poster "orton" he routinely suggests putting a small inverter on the starter battery, and using either a 120 vac - 12 volt charger, or a combo inverter charger to charge the house battery. This is a far superior option to an isolator based approach. Since your computer use is fairly modest, then this is sufficient for all similar loads.

I would avoid "all in one" products like the kaises. Stick with individual components as much as possible.

Your wire sizes are too small - where you indicate 14 awg should instead be 10 awg and the 2 awg should be 2/0 (also called 00 ) If the design is changed to instead use an inverter at the starter battery and a charger at the house battery, the wire size can drop to 10 awg instead of 2/0. One of the benefits of this is that you can use one wire size for the entire project and it will be much easier to install.

Consider to replace the master switch with a 50 amp breaker so it provides both switching and safety.

Perhaps purchase just about any other brand of inverter than the one you show. For example outback,

Sorry, don't mean to be critical, just help save you from wasting your hard earned money.

Take a look at these guys for components. Most of it is fairly decent and reasonably priced. Even their most econo / cheapo product offerings will work reasonably well.

https://www.solar-electric.com/marine-rv.html


Harry
__________________
Auxiliary Power for conversion vans

Instagram WirlNet

Last edited by HarryN; 07-02-2019 at 04:57 PM.
HarryN is offline   Reply With Quote
The Following User Says Thank You to HarryN For This Useful Post:
dwighttttt (07-02-2019)
Old 07-02-2019, 07:40 PM   #4
autostaretx
Erratic Member
 
autostaretx's Avatar
 
Join Date: Sep 2006
Location: Seattle
Posts: 17,348
Thanks: 3,041
Thanked 7,840 Times in 5,719 Posts
Default Re: Electrical diagram review

The 1.5 amp you list for the laptop is at 120vac ... so the draw from the battery will be ten times that: 15 amps.
(plus inverter inefficiencies).

True, it may not be asking for full power all of the time, but that depends upon what you're asking the laptop to do.
You might be able to find a suitable 12vdc-to-laptop adapter, and cut out the middleman (but keep an inverter for other duties).

AGMs don't like being drawn down below 50% state-of-charge (SOC).

You didn't specify your fridge's actual draw/useage/size ... so its daily needs could be anywhere from 24AH to 48AH.

With careful load management, i manage to get by with only a 67 AH AGM, but that's with 200 watts of solar and a 40 liter Engel: 2A intermittent, except in a 35 C situation when it was running 3A at a significant duty cycle (on/off time). But the sun giveth.
I'm also equipped for shore power (which handled the fridge overnight).

--dick
__________________
2005 T1N 118" Freightliner 2500 Passenger Wagon (2.7L, 15" tires, standard (short) roof)
Get YOUR Sprinter's full configuration datacard by entering your VIN to https://www.datamb.com/
http://diysprinter.co.uk/reference <-- lots of service documentation, Thanks to Jens Moller and Arnie_Oli
((as always: this post may go through a couple of post-posting edits... so maybe give it ten minutes before commenting))
autostaretx is offline   Reply With Quote
The Following User Says Thank You to autostaretx For This Useful Post:
dwighttttt (07-02-2019)
Old 07-02-2019, 08:26 PM   #5
Midwestdrifter
 
Join Date: Sep 2013
Location: Charlotte NC
Posts: 9,736
Thanks: 1,920
Thanked 6,456 Times in 4,082 Posts
Default Re: Electrical diagram review

I suggest doing a power consumption budget. Only then will you know if your battery and charging sources are correctly sized.
__________________
2004 T1N | Overland Conversion in Process Completed...For now... | 187,000 miles | 140" | High Roof | My Build Thread
Another Random Blog | http://VagariesAbound.blogspot.com
Midwestdrifter is online now   Reply With Quote
Old 07-02-2019, 09:12 PM   #6
OrioN
2008 2500 170" EXT
 
OrioN's Avatar
 
Join Date: Sep 2007
Location: Vancouver, BC
Posts: 9,961
Thanks: 558
Thanked 2,460 Times in 1,802 Posts
Default Re: Electrical diagram review

Quote:
Originally Posted by autostaretx View Post
The 1.5 amp you list for the laptop is at 120vac ... so the draw from the battery will be ten times that: 15 amps.
(plus inverter inefficiencies).

True, it may not be asking for full power all of the time, but that depends upon what you're asking the laptop to do.
You might be able to find a suitable 12vdc-to-laptop adapter, and cut out the middleman (but keep an inverter for other duties).

AGMs don't like being drawn down below 50% state-of-charge (SOC).

You didn't specify your fridge's actual draw/useage/size ... so its daily needs could be anywhere from 24AH to 48AH.

With careful load management, i manage to get by with only a 67 AH AGM, but that's with 200 watts of solar and a 40 liter Engel: 2A intermittent, except in a 35 C situation when it was running 3A at a significant duty cycle (on/off time). But the sun giveth.
I'm also equipped for shore power (which handled the fridge overnight).

--dick
Unless the OP is running a workstation notebook with say a modelling/render program plus a discreet GPU at full speed, he will never see it consume 15A dc (inverter load). Surfing and netflix are in the range of 2-3A dc.

I do the former on a slightly aged 2.8 GHz (3.45 Boosted) machine and peek at ~14A dc full out....
OrioN is offline   Reply With Quote
Old 07-02-2019, 11:19 PM   #7
dwighttttt
 
Join Date: Aug 2016
Posts: 9
Thanks: 8
Thanked 1 Time in 1 Post
Default Re: Electrical diagram review

Quote:
Originally Posted by HarryN View Post
The house battery capacity is fairly low - that setup will run the fridge and indicated loads for less than 24 hours before needing multiple hours of driving to catch up. At least double the battery capacity.
Quote:
Originally Posted by autostaretx View Post
You didn't specify your fridge's actual draw/useage/size ... so its daily needs could be anywhere from 24AH to 48AH.
I was looking at the 10801352 - 37QT PORTABLE ARB FRIDGE FREEZER. The website says the current draw is 0.85 amps/hour*
*Average power consumption tested at 37.4F cabinet temperature, 78.8F-87.8F ambient temperature range, test duration of 66 hours and supply voltage of 12V DC
https://www.arbusa.com/portable-frid...idge-freezers/
I'm assuming that's an average and may be higher but thought this fridge would have really low impact on overall battery usage. I was just assuming 0.85 * 24 would be the rough usage for a day. Thoughts? I am reading this incorrectly?


Quote:
Originally Posted by HarryN View Post
The system will benefit greatly from 300 watts of solar panels or at a minimum a battery to battery charger. If you search on the poster "orton" he routinely suggests putting a small inverter on the starter battery, and using either a 120 vac - 12 volt charger, or a combo inverter charger to charge the house battery. This is a far superior option to an isolator based approach. Since your computer use is fairly modest, then this is sufficient for all similar loads.
I need to research this more. Thanks for the tip.

Quote:
Originally Posted by HarryN View Post
Consider to replace the master switch with a 50 amp breaker so it provides both switching and safety.
Why 50 amps? The peak draw of the fuse block is 100A.


Quote:
Originally Posted by HarryN View Post
Sorry, don't mean to be critical, just help save you from wasting your hard earned money.
It's OK! That's why I posted. Taking criticism is easier than uninstalling/returning parts.


Quote:
Originally Posted by OrioN View Post
Unless the OP is running a workstation notebook with say a modelling/render program plus a discreet GPU at full speed, he will never see it consume 15A dc (inverter load). Surfing and netflix are in the range of 2-3A dc.
I think the diagram I put together is the most complex thing I would do on my machine.
dwighttttt is offline   Reply With Quote
Old 07-03-2019, 12:26 AM   #8
HarryN
 
Join Date: May 2010
Location: Pleasanton, CA
Posts: 2,363
Thanks: 537
Thanked 755 Times in 616 Posts
Default Re: Electrical diagram review

Quote:
Originally Posted by dwighttttt View Post
I was looking at the 10801352 - 37QT PORTABLE ARB FRIDGE FREEZER. The website says the current draw is 0.85 amps/hour*
*Average power consumption tested at 37.4F cabinet temperature, 78.8F-87.8F ambient temperature range, test duration of 66 hours and supply voltage of 12V DC
https://www.arbusa.com/portable-frid...idge-freezers/
I'm assuming that's an average and may be higher but thought this fridge would have really low impact on overall battery usage. I was just assuming 0.85 * 24 would be the rough usage for a day. Thoughts? I am reading this incorrectly?


I think the diagram I put together is the most complex thing I would do on my machine.
Let's do this in watts and watt-hrs to make your life easier.

Fridge ~ nominal (12 volts) x (~ 1 amp average draw) x (24 hrs) = ~ 300 watt-hrs consumption per day (can double on hot days)

Fan ~ nominal (12 volts ) x ( ~ 1 amp typical draw) x (24 hrs) = ~ 300 watt-hrs per day (also can double on hot days)

Lights - nominal (12 volts) x ( ~ 5 amps) x (8 hrs / day) = ~ 400 watt-hrs per day

Entertainment ~ 200 watt-hrs per day

Total = ~ 1200 watt-hrs per day of consumption.

____________
In a good size 31 XT AGM battery, you can routinely use ~ 50% of rated capacity, so:

(125 amp-hrs) x (12 volts) x (~50%) = ~ 750 watt-hrs of capacity

This is vs our estimate of 1200 watt-hrs of consumption per day, so at least 2x is suggested. 4x is better in case of cloudy days, but it depends if you are mostly having fun for a long weekend and minimal risk, vs living off grid in a difficult situation.

__________________________
__________________
Auxiliary Power for conversion vans

Instagram WirlNet

Last edited by HarryN; 07-03-2019 at 12:47 AM.
HarryN is offline   Reply With Quote
Old 07-03-2019, 12:34 AM   #9
HarryN
 
Join Date: May 2010
Location: Pleasanton, CA
Posts: 2,363
Thanks: 537
Thanked 755 Times in 616 Posts
Default Re: Electrical diagram review

In this area, the expected production of a solar panel on top of a van is roughly:

Expected power production per day = (50%) x (official rated capacity) x (6 hrs per day of useful production)

Your consumption plan is ~ 1200 watts-hrs, and using my initial estimate of 300 watts of panels:

(50%) x (300 rated watts of panels) x (6 hrs) = 900 watt-hrs, so actually just a tad short.

(50%) x (450 watts rated of panels) x (6 hrs) = 1350 watt-hrs - so potentially enough on a typical day but not by all that much. In the winter you could be short.

This of course assumes that the bulk of the power is from solar, which is not always the case.
__________________
Auxiliary Power for conversion vans

Instagram WirlNet

Last edited by HarryN; 07-03-2019 at 12:49 AM.
HarryN is offline   Reply With Quote
Old 07-03-2019, 12:38 AM   #10
HarryN
 
Join Date: May 2010
Location: Pleasanton, CA
Posts: 2,363
Thanks: 537
Thanked 755 Times in 616 Posts
Default Re: Electrical diagram review

Assuming that you buy a 1 kW inverter to pull power from the starter battery, and feed it into a 400 or 500 watt charger, then as you drive, it will take roughly:

- (1200 watt-hrs) / 500 watts = ~ 2.5 hrs of bulk charging

Plus another 2 hrs of finishing stage charging to complete

Combined with the solar though, a good 1-2 combo.
__________________
Auxiliary Power for conversion vans

Instagram WirlNet
HarryN is offline   Reply With Quote

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

Forum Jump



All times are GMT. The time now is 12:20 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2019, vBulletin Solutions, Inc.