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 07-03-2019, 02:20 AM   #11
autostaretx
Erratic Member
 
autostaretx's Avatar
 
Join Date: Sep 2006
Location: Seattle
Posts: 16,824
Thanks: 2,951
Thanked 7,513 Times in 5,502 Posts
Default Re: Solar Power Needs Question

Quote:
Originally Posted by Bigskyvan View Post
Suggestions on my calculations or assumptions are more than welcome.
Just the tiny notational quibble that your loads aren't "4.5 amp/hr, 8 hrs / day = 36 amp-hrs"
There's no "per hour" on the initial number.
It's simply 4.5 amp, which will be multiplied by the 8 hours (per day) ... and that yields the 36 Ah per day.
As many teachers should've told you: keep the units straight.
(since what you wrote was "amp/hr * hr/day" ... the hours would've cancelled out (as written, not physically correct)).

--dick
p.s. MaxxFans draw a lot less power at any speed but "full"
__________________
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:
Bigskyvan (07-03-2019)
Old 07-03-2019, 02:34 AM   #12
marklg
 
Join Date: Apr 2017
Posts: 443
Thanks: 81
Thanked 183 Times in 147 Posts
Default Re: Solar Power Needs Question

Quote:
Originally Posted by Bigskyvan View Post
Now that I have my head tied in a knot. I'm starting to determine my power usage. I know there are many assumptions. Please comment on my assumptions/calculations on power needs before I dive into batteries and charging. Here's what I have:

Lights: 6 LED 3watt 5 hr/day = 7.5 amp-hrs
ARB 50: 2.3 amp/hr, 24 hrs/day = 55.2 amp-hrs (round up to 80 amp-hrs)
MaxxFan: 4.5 amp/hr, 8 hrs / day = 36 amp-hrs
Phone charger: 5 watt, 3 hrs = 1.6 amp-hrs
Laptop charger: inverter, 4 hrs/day = 30 amp-hrs

Total amp-hrs/day = 155 / day

Suggestions on my calculations or assumptions are more than welcome. THANKS
I did some actual measurements. Our fridge is propane, so it did not use much 12V. With an RV full of appliances that were used for meals, Microwave, Toaster, Keurig, LED lights, Fantastic Fan plus operation of a high power Ham Radio, we used between 72 and 100 Ah a day. A set of 500W nominal solar panels in the sun for much of the day fully charged the batteries each day. I don't have an MPPT controller, so with one of those, maybe 400W might be enough. It seems you are in the ballpark but even with the fridge, you may be a little high.

Certainly put as much solar on the roof as you can fit. Bigger panels are cheaper per watt. My van has a lot of stuff already up there, so I was limited and I deploy extra flexible panels up on the awning.

I have 400 Ah of Lithium batteries, so I can last 2-3 days with no sun.

Regards,

Mark
marklg is online now   Reply With Quote
The Following User Says Thank You to marklg For This Useful Post:
Bigskyvan (07-03-2019)
Old 07-03-2019, 03:28 PM   #13
Bigskyvan
 
Join Date: Jul 2017
Posts: 8
Thanks: 8
Thanked 0 Times in 0 Posts
Default Re: Solar Power Needs Question

Quote:
Originally Posted by autostaretx View Post
Just the tiny notational quibble that your loads aren't "4.5 amp/hr, 8 hrs / day = 36 amp-hrs"
There's no "per hour" on the initial number.
It's simply 4.5 amp, which will be multiplied by the 8 hours (per day) ... and that yields the 36 Ah per day.
As many teachers should've told you: keep the units straight.
(since what you wrote was "amp/hr * hr/day" ... the hours would've cancelled out (as written, not physically correct)).

--dick
p.s. MaxxFans draw a lot less power at any speed but "full"
Ah yes. Schooling was years ago. Thanks for correcting.
Bigskyvan is offline   Reply With Quote
Old 07-03-2019, 10:34 PM   #14
brownvan
2017 4X4 HR 144"
 
Join Date: Jul 2017
Location: 510 California
Posts: 82
Thanks: 9
Thanked 36 Times in 21 Posts
Default Re: Solar Power Needs Question

Quote:
Originally Posted by dorimontana View Post
Hi-
I have a 2017 cargo sprinter van. I am planning to buy an ARB 10800472 Fridge Freezer- 50 Quart, some string lights and would like the ability to charge lap tops and phones when the van is not running. It seems I am likely to need a supplemental power source but I don't know how much. Without supplemental power, I fear I could drain the car batters? Would be grateful for some advice. Thanks!
I've got the same ARB fridge and it pulls about 1 Amp-hour average in hot climates set at 33F.
(i.e. approx 24A per 24-hour period)

Last edited by brownvan; 07-03-2019 at 10:37 PM.
brownvan is offline   Reply With Quote
Old 07-04-2019, 02:59 AM   #15
mtncrawler
 
Join Date: Nov 2013
Location: Northern Colorado Front Range
Posts: 234
Thanks: 84
Thanked 62 Times in 48 Posts
Default Re: Solar Power Needs Question

I just installed the equivalent (Classic II - just color/bluetooth change) a week ago and will be anxious to see how well it does in my setup. I kicked it on tonight when it had an temp of 86 degrees F (and it was close to 90 today) - and set it for 41. In an hour it was down to 41 - and below. Drew around 5.5 amps and is now "idle" with a draw around .5 amps. Assuming it tapered off along the way. My SOC went from 100-98% in that time

I have 2, 6V, 220 AH Lifeline batteries setup with 200W of solar and a DC-DC charger.

I have similar "uses" lined up. A few USB's, a fan, the fridge, lights...nothing crazy. Anxious to see if I sized things sufficiently.

Last edited by mtncrawler; 07-04-2019 at 03:25 AM.
mtncrawler is offline   Reply With Quote
Old 07-04-2019, 01:01 PM   #16
HarryN
 
Join Date: May 2010
Location: Pleasanton, CA
Posts: 2,270
Thanks: 513
Thanked 726 Times in 594 Posts
Default Re: Solar Power Needs Question

Quote:
Originally Posted by mtncrawler View Post
I just installed the equivalent (Classic II - just color/bluetooth change) a week ago and will be anxious to see how well it does in my setup. I kicked it on tonight when it had an temp of 86 degrees F (and it was close to 90 today) - and set it for 41. In an hour it was down to 41 - and below. Drew around 5.5 amps and is now "idle" with a draw around .5 amps. Assuming it tapered off along the way. My SOC went from 100-98% in that time

I have 2, 6V, 220 AH Lifeline batteries setup with 200W of solar and a DC-DC charger.

I have similar "uses" lined up. A few USB's, a fan, the fridge, lights...nothing crazy. Anxious to see if I sized things sufficiently.
Life is easier if you do the calculations in watts and watt-hrs, at least for me.
__________________
Auxiliary Power for conversion vans

Instagram WirlNet
HarryN is offline   Reply With Quote

Tags
power

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 05:32 AM.


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