Reply
 
Thread Tools Display Modes
 
Old 07-17-2012, 07:10 PM   #1
Senior Member
 
GreyDawg's Avatar
 
Join Date: Aug 2009
Location: No fixed abode
Posts: 347
4D AGM battery capacity / solar panel to match?

Hi --

Sorry, but this is a very naive question....

When SMB-TX did electrical work on my homebrew in 2009, they added a 4D AGM battery ($495) under the van step, as they do with the RB-50 layout.

Now that I'm thinking about adding solar, I need to know the capacity of the battery. I can't find it on my receipt, nor can I find it on the SMB website.

Can anyone help?

Also, once the capacity is established, how do I figure out the correct size of solar panel to match the battery?

Thanks,
GreyDawg
__________________

__________________
GreyDawg
2017 T-250 MR 148" 3.7L cargo van. Slowly becoming a campervan...
GreyDawg is offline   Reply With Quote
Old 07-17-2012, 10:35 PM   #2
Senior Member
 
rockbender's Avatar
 
Join Date: Sep 2010
Location: Bend, OR
Posts: 799
Re: 4D AGM battery capacity / solar panel to match?

You are probably in the 180 - 200 ah range, depending on the specific battery. Someone else with more knowledge than I will chime in, but I'll try to share some basics from what I've learned from other folks here.

First off, your solar panel should be sized based off of your demand or usage, not so much your battery size - especially since an AGM can take quite a current load while charging (while standard wet / deep cycle batteries in theory shouldn't take on much more than C/10... C being your Ah).

Tell us what your power consumption is as well as the maximum number of days that you want to stay out without starting the engine and we can get a better idea of how much solar you might need.
__________________

__________________
Josh
2009 Express AWD, CCV Top & 50-ish home build. Daily driver/camper/kid hauler
rockbender is offline   Reply With Quote
Old 07-18-2012, 09:27 PM   #3
Site Team
 
daveb's Avatar
 
Join Date: May 2007
Location: Turlock Ca
Posts: 9,894
Garage
Re: 4D AGM battery capacity / solar panel to match?

Quote:
Originally Posted by GreyDawg
Hi --

Sorry, but this is a very naive question....

When SMB-TX did electrical work on my homebrew in 2009, they added a 4D AGM battery ($495) under the van step, as they do with the RB-50 layout.

Now that I'm thinking about adding solar, I need to know the capacity of the battery. I can't find it on my receipt, nor can I find it on the SMB website.

Can anyone help?

Also, once the capacity is established, how do I figure out the correct size of solar panel to match the battery?

Thanks,
GreyDawg
Your battery should be 200-220 AH as stated. Most of the loads that are needed to be figured in are always light loads that regulate on off or those that run in a continuous mode. Never worry about heavy loads like the microwave and measure amperage off things like the refrigerator, fans, or things like the light loads required to run the propane/diesel heaters. It seems like there isn't too much use for large panel systems that produce over 15 amps as most of the items I mentioned don't pull over a few amps each. The idea is to hold enough battery reserve to supply the big use items for short periods of time and light continous loads that run throughout the night. A 130 watt panel does a pretty good job for a single 4-D. I have two 4-D's and two 135 watt panels on my van. I would not go smaller than 50 watts using a 4-D battery.

The other factor is overcast. Some might need more panels just to get a light charge in on/off sun or fog but spending the bucks for an extra panel to get an amp or two might not be worth it.
Good luck
__________________
2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer

Sportsmobile 4X4 Adventures..........On and off road adventures
daveb is offline   Reply With Quote
Old 07-19-2012, 10:04 AM   #4
Site Team
 
Ford_6L_E350's Avatar
 
Join Date: May 2007
Location: Washington - Ridgefield
Posts: 4,725
Re: 4D AGM battery capacity / solar panel to match?

In reality, you don't need to match the solar panels to the batteries; you need to match your solar panels to your electrical load.

Mike
__________________
SOLD04 EB350 Custom Floorplan
6.0 PSD 4.10 Posi
Salem Kroger coil spring 4wd
SMB Trailer w/AT Air Suspension
Alaska to Key West, Labrador and more
130685 miles 16.65 mpg average

Prostate cancer survivor. viewtopic.php?f=8&t=11099
2015 VW GTI
Leaving CA for WA
Ford_6L_E350 is offline   Reply With Quote
Old 07-19-2012, 10:29 AM   #5
Site Team
 
daveb's Avatar
 
Join Date: May 2007
Location: Turlock Ca
Posts: 9,894
Garage
Re: 4D AGM battery capacity / solar panel to match?

Quote:
Originally Posted by Ford_6L_E350
In reality, you don't need to match the solar panels to the batteries; you need to match your solar panels to your electrical load.

Mike
My point is not matching the panels to the batteries affects the charge time. Too small of a panel setup can cause extended charge times with large battery banks especially during lower light conditions. If I use my microwave during the night and it pulls my two 4-D batteries down to say 60%, it will take much longer to recharge them than with a small panel setup. But I agree that there is a point where more might not be worth it.
__________________
2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer

Sportsmobile 4X4 Adventures..........On and off road adventures
daveb is offline   Reply With Quote
Reply

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

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by Sportsmobile SIP or any of its affiliates. This is an independent, unofficial site.


All times are GMT -6. The time now is 12:46 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
×