Go Back   iRV2 Forums > CAMPING, TRAVEL and TRIP PLANNING > Boondocking
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
 
Thread Tools Search this Thread Display Modes
 
Old 03-21-2013, 08:29 AM   #1
Senior Member
 
Join Date: Jun 2012
Location: Cheyenne, Wyoming
Posts: 275
How are you tracking solar harvest vs load?

Hello, my little sunsaver mppt shows me power harvested from my array, power sent out the charging circuit after the mppt thing, and power consumed by load. After subracting load power from charge power I have battery power consumption so the whole story. After watching my system for a few months now I realize it's not big enough. I have 220ah of battery in two 6 volt's connected in series. My understanding from all the great help I've received and great information I've read here is I need to produce 26 amps of charge current to properly charge and equalize these batteries. With this I'm looking at bigger charge controllers (and of course a bigger array) and can't find any way of tracking them with the detail I get from the little sunsaver. What say you guys?

For instance, the Bogart Engineering Trimetric 2025 simply watches current go into and out of the batteries. It's a battery monitor not a full solar system monitor. The Morningstar Tristar's show solar harvest via the modbus interface just like the sunsaver but not system load.
__________________

__________________
2016 Cougar XLite 26RBI
2015 F150 Lariat SCrew 4x4 3.5L Booster
unyalli 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 03-21-2013, 09:31 AM   #2
Senior Member
 
Join Date: Nov 2007
Location: somewhere in the west
Posts: 1,168
I say you do not need anywhere near that much amperage, and somewhere between 11 and 22 Amps would be sufficient, or somewhere in the C10 to C20 range if you are using flooded batts. Equalization is accomplished by bringing the VOLTAGE up higher than normal, and holding it there for some period of time, and personally have learned that if I bring up my Batts to the recommended charge level of 14.8 Volts daily, and hold that level for two to four hours, equalization is rarely needed. Ed
__________________

__________________
Ed-Sommers is offline   Reply With Quote
Old 03-21-2013, 09:49 AM   #3
Senior Member
 
Tony Lee's Avatar
 
Join Date: Sep 2012
Location: Peru heading for Brasilia, Brazil
Posts: 2,116
When is all said and done, it doesn't matter where the energy comes from or where it goes, but whether you have enough energy stored in the battery to provide your needs having regard for your likely input over the next couple of days.

Assuming batteries do need equalising - and that is not a universal opinion - they don't need equalising more often than every couple of months and maybe if the coach is on the move once in a while, never need it.
Equalising is probably rarely properly done with solar anyway unless you have a huge system capably of pumping the required current in for the time it takes, so it might be best left to a mains powered charger.
__________________
Tony Lee - International Grey Nomad. Picasa Album - Travel Map
RVs. USA - Airstream Cutter; in Australia - MC8 40' DIY Coach conversion & OKA 4x4 MH; in Germany - Hobby Class C; in S America - F350 with 2500 10.6 Bigfoot camper
Tony Lee is offline   Reply With Quote
Old 03-21-2013, 10:28 AM   #4
Senior Member
 
Join Date: Jun 2012
Location: Cheyenne, Wyoming
Posts: 275
Quote:
Originally Posted by Ed-Sommers View Post
I say you do not need anywhere near that much amperage, and somewhere between 11 and 22 Amps would be sufficient, or somewhere in the C10 to C20 range if you are using flooded batts.
Bare with me and let's see if I understood what I've read on this. The C20 rating for flooded batteries is the typical rating. When most deep cycle battery manufacturers state 220ah this is the C20 rate. I've also read I should charge flooded batteries at 10 to 13% of this rate or 22 to 28.6 amps. Where did I go wrong?
__________________
2016 Cougar XLite 26RBI
2015 F150 Lariat SCrew 4x4 3.5L Booster
unyalli is offline   Reply With Quote
Old 03-21-2013, 11:06 AM   #5
Senior Member
 
Mike_Harriet's Avatar
 
Join Date: Jan 2013
Posts: 776
My Blue Sky MPPT regulator/remote controller, gives me lots of info. About all I can comprehend. It's on my boat, but will work anywhere. I've got two 140W solar panels wired in series for 24VDC, and the regulator converts/ holds the output to the battery To 12-14.7 VDC. On a bright day I've gotten as much as 17.3 Amps to the battery bank. Series panel hookup also allows me to run smaller diameter wire with less line loss. Not a cheap system, but has worked flawlessly for 6 years in some very extreme conditions (salt water , high winds and rough seas)
__________________
Mike_Harriet is offline   Reply With Quote
Old 03-21-2013, 11:42 AM   #6
Senior Member
 
Winnebago Owners Club
iRV2 No Limits Club
Join Date: Apr 2010
Posts: 713
Not being computer literate, I can post here but thats about it, after having spent over 30 years in law enforcement there were several scams that would occasionaly work. Brings to mind the "Pigeon Drop or the "Bank Examiner" scam. Be just a little greedy and/or gullible and next thing you know your sitting at my desk wondering where your money went.

Latest one I heard of was to call certain area codes and get tied up with off shore crooks with astronamical per minute telephone charges.

Don G
__________________
Grimesy is offline   Reply With Quote
Old 03-21-2013, 07:18 PM   #7
Senior Member
 
SlyFox's Avatar
 
Join Date: Nov 2010
Location: Slocan Park
Posts: 228
Quote:
Originally Posted by unyalli View Post
Hello, my little sunsaver mppt shows me power harvested from my array, power sent out the charging circuit after the mppt thing, and power consumed by load. After subracting load power from charge power I have battery power consumption so the whole story. After watching my system for a few months now I realize it's not big enough. I have 220ah of battery in two 6 volt's connected in series. My understanding from all the great help I've received and great information I've read here is I need to produce 26 amps of charge current to properly charge and equalize these batteries. With this I'm looking at bigger charge controllers (and of course a bigger array) and can't find any way of tracking them with the detail I get from the little sunsaver. What say you guys?

For instance, the Bogart Engineering Trimetric 2025 simply watches current go into and out of the batteries. It's a battery monitor not a full solar system monitor. The Morningstar Tristar's show solar harvest via the modbus interface just like the sunsaver but not system load.
This is an excerpt from Handy Bob's RV Battery Charging Puzzle "Regardless of how much power you use, you need nearly 3% of your total battery storage amp hour capacity in charging amps in order to successfully charge those batteries. With less, you canít equalize. For instance, six batteries with 675 amp hours capacity require 20 amps charging (675 x .03 =20.25), which is three panels."

So by my calculations from what you have, 3% of 220 ah is 6.6 charging amps. So assuming your solar array is capable of this, you should be ok? Could it be the size of the wires from the array to the charge controller are not large enough and you are losing there?
__________________
2017 Ram 3500 Dually & 2012 Arctic Fox 29-5K Silver Fox Edition 5th wheel
Paul & Sheryl
SlyFox is offline   Reply With Quote
Old 03-21-2013, 08:03 PM   #8
Senior Member
 
Join Date: Jun 2012
Location: Cheyenne, Wyoming
Posts: 275
Well, I've read Handy Bob's guide and that's what got me interested and gave me my start. Here's an excerpt from Trojan's battery maintenance guide on Selecting chargers.

When selecting a charger, the charge rate should be between 10% and 13% of the battery’s 20-hour AH capacity. For example, a battery with a 20-hour capacity rating of 225 AH will use a charger rated between approximately 23 and 30 amps.

Problem is I've read more supporting documentation for the Trojan 10% to 13% than Bob's 3%.
__________________
2016 Cougar XLite 26RBI
2015 F150 Lariat SCrew 4x4 3.5L Booster
unyalli is offline   Reply With Quote
Old 03-21-2013, 09:34 PM   #9
Senior Member
 
Shadowcatche's Avatar
 
iRV2 No Limits Club
Join Date: Nov 2010
Posts: 1,218
You can get the whole picture in monitoring using a Trimetric or Vectron battery monitor and their computer interface. This would also let you monitor everything going into and coming out of the battery including engine power contribution. You can also use two MPPT SunSavers as they will play well together
__________________
Shadowcatche is offline   Reply With Quote
Old 03-21-2013, 10:35 PM   #10
Senior Member
 
SlyFox's Avatar
 
Join Date: Nov 2010
Location: Slocan Park
Posts: 228
Re-read about charger selection.

"Most deep-cycle applications have some sort of charging system already installed for battery charging (e.g. solar panels, inverter, golf car charger, alternator, etc.). However, there are still systems with deep-cycle batteries where an individual charger must be selected. The following will help in making a proper selection."

To me this means systems other than those listed need the listed charging requirements. Phone Trojan and get the real goods from them and clear it up in your mind.

Trojan also states that your batteries have to go 50 - 100 cycles before reaching full performance, has your system done this many cycles?

Give more details of your system and there may more detailed advice.
__________________
2017 Ram 3500 Dually & 2012 Arctic Fox 29-5K Silver Fox Edition 5th wheel
Paul & Sheryl
SlyFox is offline   Reply With Quote
Old 03-22-2013, 03:41 AM   #11
Senior Member
 
Join Date: Jun 2012
Location: Cheyenne, Wyoming
Posts: 275
Quote:
Originally Posted by SlyFox View Post
Re-read about charger selection.

I read this differently.
"Most deep-cycle applications have some sort of charging system already installed for battery charging (e.g. solar panels, inverter, golf car charger, alternator, etc.) so don't need a charger. However, there are still systems with deep-cycle batteries where an individual charger must be selected.

Quote:
Originally Posted by SlyFox View Post
To me this means systems other than those listed need the listed charging requirements. So some how the charging requirements for there batteries change depending on type of charging equipment?

Trojan also states that your batteries have to go 50 - 100 cycles before reaching full performance. Understood, what does this have to do with charging? This was information on battery performance, not charging requirements.

Give more details of your system and there may more detailed advice. Not required to answer my question. We don't need any system details for a discussion on battery charging which is not the topic here.
Thanks, Jeff
__________________
2016 Cougar XLite 26RBI
2015 F150 Lariat SCrew 4x4 3.5L Booster
unyalli is offline   Reply With Quote
Old 03-22-2013, 03:49 AM   #12
Senior Member
 
Join Date: Jun 2012
Location: Cheyenne, Wyoming
Posts: 275
Quote:
Originally Posted by Shadowcatche View Post
You can get the whole picture in monitoring using a Trimetric or Vectron battery monitor and their computer interface.
Sorry but I must disagree. Measuring power entering or leaving a battery via a single shunt will not tell me how much power the solar array produced and how much of that power went to loads.

Quote:
Originally Posted by Shadowcatche View Post
You can also use two MPPT SunSavers as they will play well together
This is interesting and was also stated in another forum so I'm starting to believe it. Only problem I see is load. While you may get away with connecting two sunsavers to the same battery bank in parallel I don't see anyone paralleling the load.

Thanks, Jeff
__________________
2016 Cougar XLite 26RBI
2015 F150 Lariat SCrew 4x4 3.5L Booster
unyalli is offline   Reply With Quote
Old 03-22-2013, 04:11 AM   #13
Senior Member
 
Join Date: Jun 2012
Location: Cheyenne, Wyoming
Posts: 275
I've found the Bogart Engineering Pentametric instead of Trimetric. The PM-5000-U data input unit is the brains of the outfit. Among other features it will monitor three shunts and two voltages. You can measure and log solar current and voltage, load current, and finally like the Trimetric current into/out of the battery and battery voltage. It internally calculates a bunch of other parameters like power in watts and power use over time to give the whole picture.

You also need some way of reading this data and controlling this device and they have four options. The wall mount display and three computer interfaces which are accessed with there software. The PM-101-CE Ethernet Internet Interface will connect to a wifi hot spot for instance and let you monitor the system with a wifi lap top. Or connect directly with twisted pair.
__________________
2016 Cougar XLite 26RBI
2015 F150 Lariat SCrew 4x4 3.5L Booster
unyalli is offline   Reply With Quote
Old 03-22-2013, 05:37 AM   #14
Senior Member
 
Shadowcatche's Avatar
 
iRV2 No Limits Club
Join Date: Nov 2010
Posts: 1,218
Jeff, I have a high voltage system with a panel intended for a grid tie system that typically put out more than 40 volts. This was a mistake on my part and came out of my ignorance when I found the panel used on ebay. What I have found is that it does better than it should, producing usable current with heavy shading i.e. in Big Basin Redwoods with VERY heavy shade We did not get below 70% SOC and that was made up the next day reaching 100% SOC. We have a large teardrop trailer with a 185W panel flat on the roof. Because of a number of factors size and where I had to put it I opted for a Victron Battery monitors - Victron Energy I also have a 140W Unisolar flexible panel that can be unrolled in the sun and feeding into a Steca PMW controller (will handle its higher voltage). All of this, the current from the converter and the tow vehicle pass through the Victron shunt and monitored by the meter. I am not using the load terminals on our Morningstar MPPT as that only monitors part of the used current, it would not handel the load from the Morningstar Sursine inverter, and none of the input to the battery other than from the solar panel. The trailer was designed for serious boondocking with all LED lights water filters that will take water from a lake or stream and make it potable. We have not stinted on comforts with XM radio flat screen TV and sat receiver, hot water heater, shower... This system will get an acid test this summer with 8 days on the nort shore of Lake Superior in a fairly heavily wooded site.
__________________

__________________
Shadowcatche is offline   Reply With Quote
Reply

Tags
solar



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


» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 02:56 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.