RV News RVBusiness 2021 Top 10 RVs of the Year, plus 56 additional debuts and must-see units → ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > THE OWNER'S CORNER FORUMS > Alpine Coach Owner's Forum
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 04-20-2020, 09:41 AM   #57
Member
 
fratermus's Avatar
 
Join Date: Jul 2016
Posts: 38
on mobile, please forgive clumsy formatting


Quote:
Originally Posted by Mark_K5LXP View Post
Sez the boost applies absorb voltage for 30 minutes.
Good catch, thanks for sharing.


> With banks in the hundreds of Ah (even just a couple GC-2's) you sit at absorb for several hours anyway, another 30 minutes isn't going to do a lot.


If the CC is claiming full charge by mid-morning it hasnn't Absorped for the requisite several hours.

> So if the controller had gone through a complete charge phase


probably didn't


> If the batteries weren't fully charged, then the net effect is zero since they're already in bulk or absorb phase anyway.

I'm suggesting it entered premature float. In that context a couple whacks of the button until current slowed to C/200 or whatever could be helpful.

Also consider the difference in panel output at Vabs and Vfloat in a PWM context.




> I wonder if the battery parameters are adjustable for this controller.


Preach! I'd much rather have configurable setpoints than a Boost button. :-)
fratermus 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 04-20-2020, 03:37 PM   #58
Junior Member
 
Join Date: Apr 2020
Posts: 4
Greetings hope everyone is well. I thought I should contribute because I have a similar setup.

500 watts and 4 200ah batteries. running at 12 volts Totaling 800ah with 40a mppt controller My batteries are designed to run down to 50% for max usage. So then at night or on cloudy days i would not exceed 50% usage. Before I stopped using electricity. So that would give me 400ah per day. I was told that in good conditions it would take 2 panels to charge 100ah about 4-6 hours to recharge. So I don't really have enough panels for the amount of batteries it would need to charge the batteries back based on their time table of 4-6 hours. But under optimal conditions this exceeds my capacity for usage anyway. The 50% of battery usage is to protect the longevity of the batteries under optimal conditions. So they don't get stressed and shorten their life span.

My controller is rated for max 520w panels at 12 volts. and about double that for 24 volts. So Then I could switch to 24 volts and double my wattage double the panels. This would be too much for my current space on my van. So I don't need and with my current needs would not need more than the 500 watts.

The reasoning I am using for not having enough panels for the amount of batteries is if there is not optimal conditions for a few days I will still have more than enough capacity for my usage and will not exceed the 50% drain on the batteries. I also have a 2000w shore power charger in case I need to recharge in a pinch.
Freerover726 is offline   Reply With Quote
Old 04-20-2020, 08:46 PM   #59
Senior Member
 
Join Date: Oct 2016
Posts: 2,860
Some quick math shows that your batteries would need 10 hours of charging time at the maximum 40A rating of the controller to recharge from 50%. 40A x 10h = 400Ah. The 500w panels are most likely reaching a maximum of 30A, so you’d be looking at 13-14 hours of charging time with no consumption during that time. Realistically, that’s 2-3 days of charging.

We have yet to install solar on our coach, but I would opt for more panels than necessary to recharge the batteries in the event of less than ideal conditions.
__________________
2005 Alpine Coach 36MDDS
2015 Grand Cherokee Diesel
RVPioneer is online now   Reply With Quote
Old 04-21-2020, 12:11 AM   #60
Junior Member
 
Join Date: Apr 2020
Posts: 4
Quote:
Originally Posted by RVPioneer View Post
Some quick math shows that your batteries would need 10 hours of charging time at the maximum 40A rating of the controller to recharge from 50%. 40A x 10h = 400Ah. The 500w panels are most likely reaching a maximum of 30A, so you’d be looking at 13-14 hours of charging time with no consumption during that time. Realistically, that’s 2-3 days of charging.

We have yet to install solar on our coach, but I would opt for more panels than necessary to recharge the batteries in the event of less than ideal conditions.
The info provided to me by the manufacturer was for 200 watts of panels for just 1 battery recharging 1 battery for 100ah. I have only about 55% of what is recommended for my batteries. My main focus is the reserve power. As I would only use possibly 150 amp hrs. per day max. Hence the extra batteries.

Thanks for the Info. Its good to know how long for a full recharge from just the 500 watts. That is very helpful.
Freerover726 is offline   Reply With Quote
Old 04-21-2020, 01:38 PM   #61
Member
 
fratermus's Avatar
 
Join Date: Jul 2016
Posts: 38
We all "pays our money and takes our chances" so I will not criticize any other man's rig. I will provide some thoughts below to muddy the waters for folks still in the planning stages.

Quote:
The reasoning I am using for not having enough panels for the amount of batteries is if there is not optimal conditions for a few days I will still have more than enough capacity for my usage and will not exceed the 50% drain on the batteries.
Oversized banks work well with multiple charging sources (generator/alternator/shore + solar), and generally poorly off solar alone. One strategy might be to generator/alternator charge in the morning until Vabs (or as high as the alt will go) then let solar carry it from there.

Being unable to charge batteries fully and regularly is the classic cause of lead-acid battery murder, and having an oversized bank makes it harder to get fully charged.

Although I don't necessarily recommend it for everyone I went the opposite direction and run an overpaneled, slim-reserves system (570w:220Ah). Doing something like this has its own set of challenges, but also rewards: it is full overcast and lightly raining right now and the system is making 152.92W. I'll finish absorption this afternoon instead of ~12pm, but it'll get the full charge.

Having said that....

Quote:
I also have a 2000w shore power charger in case I need to recharge in a pinch.
Getting on on shore power a few times a week and are doing full Absorption at those times the batteries should stay reasonably healthy. Or one could run Li or other chemistry that doesn't care about partial state of charge.
__________________
DIY campervan: Promaster 159" high roof
blog
fratermus is offline   Reply With Quote
Old 04-21-2020, 02:08 PM   #62
Senior Member
 
paul65k's Avatar


 
Alpine Owners Club
Join Date: Nov 2015
Location: Lake Havasu City, AZ
Posts: 1,466
Quote:
Originally Posted by fratermus View Post
We all "pays our money and takes our chances" so I will not criticize any other man's rig. I will provide some thoughts below to muddy the waters for folks still in the planning stages.



Oversized banks work well with multiple charging sources (generator/alternator/shore + solar), and generally poorly off solar alone. One strategy might be to generator/alternator charge in the morning until Vabs (or as high as the alt will go) then let solar carry it from there.

Being unable to charge batteries fully and regularly is the classic cause of lead-acid battery murder, and having an oversized bank makes it harder to get fully charged.

Although I don't necessarily recommend it for everyone I went the opposite direction and run an overpaneled, slim-reserves system (570w:220Ah). Doing something like this has its own set of challenges, but also rewards: it is full overcast and lightly raining right now and the system is making 152.92W. I'll finish absorption this afternoon instead of ~12pm, but it'll get the full charge.

Having said that....



Getting on on shore power a few times a week and are doing full Absorption at those times the batteries should stay reasonably healthy. Or one could run Li or other chemistry that doesn't care about partial state of charge.
Sounds like a feed strategy for you small camper/van application

In an Alpine coach, the smallest of which is 34' and most are even bigger the need for more solar to live in the fashion the coach was designed to deliver is more likely what the OP is after.

We over-paneled for the 100A MPPT solar controller we installed with 1600W of solar (@12V) and can add an additional 800W with the real estate we have. If we do this we'll likely either convert to a 24V system or add an additional controller (most likely) to handle the additional charging capacity for our 840Ah LifePO4 battery bank.

Our current set-up is perfectly adequate for our current needs including residential Refrigerator and we would really only need to upgrade if we do convert our AC units to a dual zone Mini-split ant some point in the future
__________________
Paul & Jean
2001 Alpine 36FDDS (74291) - 1600W Solar, 10,752 Wh (420Ah @24V) LiFePO4
2014 Jeep Wrangler Unlimited Rubicon
2006 Alpenlite 32RL - Sold
paul65k is offline   Reply With Quote
Old 04-22-2020, 12:02 AM   #63
Junior Member
 
Join Date: Mar 2016
Location: Ontario, CA
Posts: 20
Quote:
Originally Posted by Brianna View Post

So, in other words, can a 60A controller slam more amps into the batteries, or at a faster rate, than a 40A controller using the same battery bank and the same solar panels?
Depends.

With 600 watts of solar I chose a 60 amp controller. I later did the math and could have used the 40 with enough room to add at least 200 more. That would be much less intrusion in that cargo bay as the 60 is huge next to the 40.

My travel buddy has 800 watts of solar with a 40 and found it totally adequate . Long Before solar noon when his panels might out produce the 40 amps, his batteries are topped off and not using it anyway. By turning on every load in the place at solar noon we maxed him out at about 39 amps. One time only and in the name of science.
Tom48 is offline   Reply With Quote
Old 04-22-2020, 05:17 PM   #64
Senior Member
 
Pappion's Avatar
 
Join Date: May 2018
Location: Benson AZ
Posts: 328
Have not read all of the responses...
40 amp is the max output from the controller to the battery. Exceed this and the switchers Ferrite Toroid becomes saturated. Also the switching FETs may short and burn.
If it were 40A in at 96V, then it would deliver 320A at 12V. Your wiring would glow like a cigarette lighter.
__________________
2017 Winnebago Minne 2201DS TT
2010 Chalet XL1930 A-Frame SOLD
Retired Engineering Technician
Pappion is offline   Reply With Quote
Old 04-22-2020, 06:36 PM   #65
Senior Member
 
Join Date: Oct 2016
Posts: 2,860
Quote:
Originally Posted by fratermus View Post

Oversized banks work well with multiple charging sources (generator/alternator/shore + solar), and generally poorly off solar alone. One strategy might be to generator/alternator charge in the morning until Vabs (or as high as the alt will go) then let solar carry it from there.

Being unable to charge batteries fully and regularly is the classic cause of lead-acid battery murder, and having an oversized bank makes it harder to get fully charged.

Although I don't necessarily recommend it for everyone I went the opposite direction and run an overpaneled, slim-reserves system (570w:220Ah). Doing something like this has its own set of challenges, but also rewards: it is full overcast and lightly raining right now and the system is making 152.92W. I'll finish absorption this afternoon instead of ~12pm, but it'll get the full charge this afternoon.
Excellent information. There are many details to consider when devising such plans. Our individual needs are part of it, along with matching components that play well together and/or allow us to expand the system at a later date for minimal expense.

In the case of Freerover726, with 500 watts, a 40A controller and a max daily usage of 150Ah, a 200Ah Lithium battery may be a consideration when the LA batteries fail.

In the OP’s situation, the 40A controller would be the limiting component should more panels be added later. But they already have that piece of equipment, so when necessary, an hour or two of charging at 100A on shore power or the generator, followed by 5-6 hours of sunshine should fully charge the batteries.
__________________
2005 Alpine Coach 36MDDS
2015 Grand Cherokee Diesel
RVPioneer is online now   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


Similar Threads
Thread Thread Starter Forum Replies Last Post
And from the solar panels to the solar charge controller...... Rvlegaleagle Going Green 10 10-20-2017 03:57 PM
Solar Charge Controller 2009 Camelot Benjimommy iRV2.com General Discussion 0 01-19-2012 08:59 PM
Voltage drop from solar charge controller to batteries hdossett RV Systems & Appliances 8 09-15-2009 07:34 PM
15 Watt Solar Battery Charger Kit with 7 Amp Charge Controller bitterroot Going Green 1 07-23-2008 11:56 AM
Solar charger charge controller CC38EL Winnebago Industries Owner's Forum 15 08-23-2007 08:12 PM


All times are GMT -6. The time now is 11:29 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.