Free 7 Day Trial RV GPS App RV Trip Planner Campground Reviews RV Maintenance Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > RV SYSTEMS AND TECHNOLOGIES FORUMS > Going Green
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 04-14-2021, 04:15 PM   #1
Member
 
Join Date: Feb 2021
Location: Duluth, MN
Posts: 41
Do I need a charge controller and battery monitor

Well the title pretty much says it all. I'm looking at getting a 100W setup that comes with a charge controller. The charge controller isn't anything fancy but it does give the basic info. Is it redundant to have both? I will be running a pair of grp 31 lead-acid batteries and boondocking up to about 5 days a couple of times a summer. There will be other boondocking trips but only for a couple of days at a time.

I haven't settled in on a panel just yet but I'm looking at an HQST one after watching a video by Will Prouse.

https://www.amazon.com/gp/product/B0...ZJD14Y8Y&psc=1
__________________
2008 Toyota 4runner V8
2012 Gulf Stream VISA 17RWD
birdsNboards is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 04-14-2021, 04:36 PM   #2
Registered User
 
Join Date: Nov 2005
Posts: 6,749
I am sure a solar "wizard" will be along shortly to explain--but 100watts is not much to control...but regardless, a controller is different from a monitor--controller helps ensure your panel doesn't over-charge your bats.....
Old Scout is offline   Reply With Quote
Old 04-14-2021, 04:52 PM   #3
Senior Member
 
Mid Atlantic Campers
Forest River Owners Club
Join Date: Oct 2013
Posts: 132
Use the charge controller
Think a bucket with a hose, turn on the water. If nothing to stop water flow, it overflows.
__________________
2015 FR grey wolf 27RR
2015 chevy 3500HD
kcmusa is offline   Reply With Quote
Old 04-14-2021, 06:05 PM   #4
Member
 
Join Date: Feb 2021
Location: Duluth, MN
Posts: 41
With just a couple of responses, I can tell that my question isn't really clear. Allow me to clarify. I know that it's not an "either-or" situation. I understand the monitor does not substitute as a charge controller but a charge controller can act as a battery monitor if the display gives some details. If I get a controller with a decently detailed display, is a battery monitor redundant.
__________________
2008 Toyota 4runner V8
2012 Gulf Stream VISA 17RWD
birdsNboards is offline   Reply With Quote
Old 04-14-2021, 06:45 PM   #5
Member
 
Join Date: Sep 2020
Location: Shrewsbury
Posts: 31
Quote:
Originally Posted by birdsNboards View Post
I understand the monitor does not substitute as a charge controller but a charge controller can act as a battery monitor if the display gives some details. If I get a controller with a decently detailed display, is a battery monitor redundant.
The charge controller knows what is going into the battery bank, but it doesn't know what is going out. So it may give lots of details, including an estimate of SOC (based on voltage), but it can't ever give you a true SOC for your battery bank.
dvspl is offline   Reply With Quote
Old 04-14-2021, 07:41 PM   #6
Senior Member
 
Join Date: Dec 2019
Location: America's Seaplane City.
Posts: 507
Boondocking without a battery monitor is kinda like driving a vehicle without a gas gauge. It can be done but life is easier with one.
__________________
1998 Safari Trek 2480.
'15 Kawasaki Versys650LT, well farkled
Mid Flowriduh
SteveJ. is online now   Reply With Quote
Old 04-14-2021, 07:47 PM   #7
Member
 
Join Date: Jan 2019
Location: San Diego
Posts: 88
An accurate voltage meter is all you really need. 12.1 volts, time to recharge.
__________________
Gary Kowal, San Diego, CA
2018 Winnebago Minnie Winnie 26A
2dr 2010 Jeep Wrangler toad
GaryKowal1 is offline   Reply With Quote
Old 04-14-2021, 08:25 PM   #8
Senior Member
 
Join Date: Oct 2015
Location: Washington
Posts: 1,038
There is a lot to unpack here and a few choices of what you want to accomplish.

First, you need a charge controller to keep from overcharging your batteries.

Next, 100 watts is only about 5-6 amps of charging, or about 2x what a trickle charger does. From what you propose to do that may be enough, but it is a fairly minimal amount of charge. It really depends on your usage.

With a small battery bank and a small panel any basic charge controller will work.

Next comes what you have to decide fits your needs, wants and budget best. Yes, a battery monitor that measures input and output can give you SOC figures. My last system with ~500 watts and 4 batteries did not have a monitor, my current system is 960 watts and 6 batteries which does include a monitor. In both systems I have always used voltage to monitor my system. I know it is not as accurate as SOC, but it works for my needs.

For the size of system you are proposing voltage should adequately meet your needs.
__________________
2014 Volvo 630 Tandem 2016 Chevy 3500 DRW, crew cab
2016 Fuzion 325T
675ah AGM, MSH 3012 inverter, 960w Solar
Nwcid is offline   Reply With Quote
Old 04-14-2021, 09:09 PM   #9
Member
 
BajaFog's Avatar
 
Join Date: Dec 2020
Location: Fort Collins
Posts: 33
I'm an idiot so...
You need more solar and better bats for 5 days off grid. Well, at least I would.
BajaFog is offline   Reply With Quote
Old 04-15-2021, 05:47 AM   #10
Senior Member
 
Join Date: Oct 2020
Posts: 299
Whether you need more solar or batteries depends entirely on what you want to run off them. Lights, occasionally the water pump, control circuit for propane water heater, control circuit for absorption fridge on propane? 100 watts is probably fine for 4-5 days in a reasonably sunny spot.

IMO, you don't really need the battery monitor in addition to the charge controller. A basic charge controller with a display will give you SOC and/or voltage of the bank, which is enough.
__________________
2021 Thor Four Winds 26B on Chevy 4500
atreis is offline   Reply With Quote
Old 04-15-2021, 06:30 AM   #11
Member
 
Join Date: Feb 2021
Location: Duluth, MN
Posts: 41
Thanks for all the replies folks. This will be my first solar set-up and I'm looking to keep it simple. Our power usage is very modest so I'm making the estimate that 100W would be fine. I've had a couple of folks claim that a pair of fully charged grp 31 batteries would last the trip, but I'm skeptical of that. Our usage consists of lights (all LED), water pump, and fridge. We'll also charge a couple of devices. Last year I had a pair of "worn out" grp 24 batteries that lasted us two days of normal usage.

Quote:
Originally Posted by dvspl View Post
The charge controller knows what is going into the battery bank, but it doesn't know what is going out. So it may give lots of details, including an estimate of SOC (based on voltage), but it can't ever give you a true SOC for your battery bank.
This comment makes it clear to me the advantages of having both. The controller can't tell me much/or anything about the draw on the batteries. The battery monitor is what tells me the amount of energy consumption. I think in my case, the monitor isn't really necessary but would be perfect to satisfy my curiosity, of which I have lots.

Before I take the plunge, I'll have to sell the small generator I hauled along last year to charge my batteries. I'm hoping the little Honda 650W will snag enough cash to mostly fund this new solar set-up.
__________________
2008 Toyota 4runner V8
2012 Gulf Stream VISA 17RWD
birdsNboards is offline   Reply With Quote
Old 04-15-2021, 09:49 AM   #12
Senior Member
 
Join Date: Oct 2015
Location: Washington
Posts: 1,038
Quote:
Originally Posted by birdsNboards View Post
Thanks for all the replies folks.

Before I take the plunge, I'll have to sell the small generator I hauled along last year to charge my batteries. I'm hoping the little Honda 650W will snag enough cash to mostly fund this new solar set-up.
You will have to make the choice for yourself, but I would not trade a generator for solar. While I love my solar it is not perfect and I still use my generator (built in) enough that I would not be without one.

What happens if you are relying on solar and it is cloudy? It rains? Your camping spot is more shaded then planned? You use more power than planned? Our last camping trip last fall we got snowed on and had no solar for 2.5 days. I have many trips where it rained and I had greatly reduced solar.

Again 100 watts of solar is only about 5 amps of charging at peak performance. Peak performance, depend on location, weather and time of year is only about 6 hours.

Running your generator 1-2 hours per day and using the camper charger would be much more reliable. Many people run for about an hour in the morning and about an hour in the evening.
__________________
2014 Volvo 630 Tandem 2016 Chevy 3500 DRW, crew cab
2016 Fuzion 325T
675ah AGM, MSH 3012 inverter, 960w Solar
Nwcid is offline   Reply With Quote
Old 04-15-2021, 11:45 AM   #13
Senior Member
 
Join Date: Feb 2018
Posts: 1,181
I had about 8 years of experience with a 5x8 converted cargo trailer. We used it to haul our astronomy and camping gear and it became a simple bedroom after the gear was unloaded at regional star parties.

I had a pair of 6 volt Trojan T105 batteries, 240 watts of solar, MPPT charge controller and 1000 watt inverter. It was enough power for the furnace, fantastic fan roof vent, red/white LED lighting, charging phones and laptop, personal evaporative cooler and Engel freezer. It also powered astronomy gear.

The inverter was only used to power a blender to make protein fruit shakes each day and a small vacuum cleaner.

The batteries were in great shape when I sold the trailer to a friend 3 years ago. He is still using the Trojan T105 batteries. They stayed in great shape because the overnight discharge was mostly about 30-40% max. The solar brought them to full SOC by about noon next day.

Having enough solar to regularly bring the batteries to 100% SOC will be the best thing you can do to keep lead acid batteries working well for a long life.

It isn't much harder installing 300 watts of solar vs 100 watts.

A battery monitor with shunt isn't mandatory but can provide a lot of information regarding the battery load of each item in your trailer and when it is time to start being conservative in the use of power to keep your batteries from discharging too far.
__________________
Jeff--
Arctic Fox 22G w/1440 watts solar/GMC2500HD Double Cab with Leer Cap w/265 watts solar
astrocamper is offline   Reply With Quote
Old 04-15-2021, 02:45 PM   #14
Senior Member
 
paul65k's Avatar


 
Alpine Owners Club
Join Date: Nov 2015
Location: Lake Havasu City, AZ
Posts: 2,135
Quote:
Originally Posted by GaryKowal1 View Post
An accurate voltage meter is all you really need. 12.1 volts, time to recharge.
I am sorry but this is just WRONG unless..........you remove all loads and I mean ALL loads (Disconnect batteries) for a minimum of 30 minutes, 60 is better, then and only then will you get true "Resting" voltage which is the only way to use voltage as a way to measure your State of charge.

Alternately a shunt-based battery monitor (~$120) for the Victron SmartShunt which is the best one out there will be like having a true gauge on your battery bank which will accurately measure charge in and power out of the batteries. A true battery monitor will also compensate for the Peukert effect which is the excess discharge you will encounter with high draw devices like a microwave or hairdryer.

Sooooo the answer is that you DO NEED a battery monitor if you really want to know what's going on with your batteries
__________________
Paul & Jean
2001 Alpine 36FDDS (74291)-1600W Solar, 13,440Wh (525Ah @24V) LiFePO4
2019 Jeep Grand Cherokee Trailhawk (Hemi)
2006 Alpenlite 32RL - Sold
paul65k is online now   Reply With Quote
Reply

Tags
battery, monitor



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Battery charging - different brand charge controller and inverter Shiba_Alex MH-General Discussions & Problems 6 10-31-2018 02:38 PM
One Charge Controller for House and Start-up Battery?? PeterCutter RV Systems & Appliances 7 11-26-2016 08:19 PM
Charge Controller & Inverter Battery Connection?? bproulx12 Class A Motorhome Discussions 2 12-15-2014 03:07 PM
Battery charge rate & absorb charge time loisjop Entegra Owner's Forum 0 11-01-2014 01:15 PM
15 Watt Solar Battery Charger Kit with 7 Amp Charge Controller bitterroot Going Green 1 07-23-2008 10:56 AM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 09:09 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.