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Topic: Lead acid battery 20% state of charge (Read 979 times) previous topic - next topic
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Re: Lead acid battery 20% state of charge
Reply #25 –
Two points:
1.  Portable and/or additional installed panels.  Where we camp in Yosemite in the fall, and elsewhere under canopy, there are no sunny spots nearby.  It's deep conifer forest.   More panels will not help.  Under mixed sun/shade conditions, our current setup is generally adequate, though portable or additional panels certainly would help at the margin.

2.  Battery capacity.  Is my logic flawed? 

The old batteries would not hold much of a charge, hence 3 generator sessions per day in Yosemite last fall and, therefore, the reason for replacing them this week. 

With my old 300AH batteries, I could consume 150AH before hitting the 50% discharge threshold.  With my new setup, I can consume 250AH before hitting that threshold.  The number of minutes of charging time per amp hour may be constant, but the frequency of generator sessions will be reduced.  I may need to run the generator once per day with new 300ah capacity, but only once every two days with 500ah capacity.  I can vacate the coach less frequently.  Also, I will be able to discharge to 25% and recharge vs. 50%  and recharge. 

My real goal is to cut the discharge cycle from 50% to 25% and to have increased reserve capacity as the batteries age and capacity drops. 

Ted
Re: Lead acid battery 20% state of charge
Reply #26 –
Quote from: Steve  - 
1) The shunt's distance from the battery does NOT affect its accuracy. As when properly connected ALL the battery current flows through it, it will develop the same voltage for a reading no matter its physical location. Proximity to the battery is important only due to the need to keep the high-current battery leads short for minimal losses, maximum current transfer.
I agree, to a point. Per Bogart's shunt FAQ:
Does the shunt need to be next to the battery? How far away can it be?
Even if the shunt is not close to the battery it will still measure the amps accurately. The main reason we say the shunt should be "near the batteries" is that the large cables to the battery need to be kept short to keep the voltage drop low to your loads and to charging sources. Since the shunt is in that path, it therefore will be near the batteries. The only slight inaccuracy that could occur if it isn't near the battery is that if the cable is too small, or the amps are really high there can be a little voltage drop that will cause the "volts" on the meter to read perhaps as much as a few tenths of a volt different than is at the battery. This error will be minimized if the cable is large enough to keep the voltage drop low.
Quote
2) Consider more smaller panels rather than one large one. This allows more mounting flexibility and reduces the chance of disabling the entire output if one panel is shadowed.
There's really only one place on my 20 foot LD's roof I would consider installing solar panels- in between the rear vent (removed the swamp cooler) and the escape hatch. There are rails from a now-removed roof-top box already installed in this space, which makes mounting easier and more secure. There's only so much space on the short roof for flat-mounted panels to avoid shading from the vents. That said, I haven't purchased the panel(s) yet, so I'm not married to any one configuration yet. If one panel will do the trick, that's where I'll stop. If not, I'll look at adding more. Shipping for panels to Alaska can be expensive, and often they arrive damaged, so I'm paying the premium from a local supplier. "Free" shipping rarely applies for bulky items, even from places like Amazon.
The main idea is to keep the batteries topped off. During most of the summer, our battery drain will be the lowest and daylight will be the longest. In the spring and fall, we will either be plugged in at a campground or charging via generator/solar.
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3)Among quality controllers, the price differential between the two is not that great, but the MPPT will bring the batteries up more quickly.
The price differential I've seen would purchase another fixed solar panel or get me most of the way towards a good portable panel/cabling, which would make up the difference between the control methods in a system this size and add flexibility. If we were talking about more than 400W (which I will never go to on this vehicle), MPPT might make a difference.
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4) Matching ANY charging system - solar controller, converter, etc - to the charging source is not as vital as matching to the needs of the battery technology. All charging devices should be optimized to match the needs of your AGMs.
And that's why the TM 2030 is so important. That will allow me to optimize the charging parameters for my batteries to ensure stages are properly configured. The SC 2030 is easier to configure when it's paired with the TM 2030.
 
The more I know about how my battery reacts to usage and how quickly the system can recover from loads under varying conditions, the better I can make the best use of the equipment I have. Too many people go with the default they were given, and then wonder why they're running their generators all of the time.
1983 20'
Re: Lead acid battery 20% state of charge
Reply #27 –
Quote from: LD-TED  - 

2.  Battery capacity.  Is my logic flawed? 
With my old 300AH batteries, I could consume 150AH before hitting the 50% discharge threshold.  With my new setup, I can consume 250AH before hitting that threshold.  The number of minutes of charging time per amp hour may be constant, but the frequency of generator sessions will be lower. 

We had the same same experience as you with limited or no solar battery charging, when camped in deep shade or in the winter.
I hate running the generator so to expand the battery capacity, I built a steel cradle to hold four T-105s batteries, hanging them below the floor.
The bigger battery pack allowed us to go for several days, in shade, without needing to charge..

When we do need to charge, I want to minimize the generator run time so the the stock 45-amp converter with replaced with a 70-amp converter. You should consider doing something similar.
With the 500-amp/hr AGM battery pack, you can significantly cut the generator run time by installing a much bigger converter, the battery can easily handle a 100+ amp charge, when discharged .
The generator produces up to 30-amp of 120-VAC power, so you also have the option of using an external battery charger along with the converter.
Use as much the 30-amps as possible to reduce run time.
While running the generator, make sure to charge all your devices at the same time, no need to waste watts.

Larry

Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Lead acid battery 20% state of charge
Reply #28 –
Quote from: Larry W  - 
We had the same same experience as you with limited or no solar battery charging, when camped in deep shade or in the winter.
I hate running the generator so to expand the battery capacity, I built a steel cradle to hold four T-105s batteries, hanging them below the floor.
The bigger battery pack allowed us to go for several days, in shade, without needing to charge..

When we do need to charge, I want to minimize the generator run time so the the stock 45-amp converter with replaced with a 70-amp converter. You should consider doing something similar.
With the 500-amp/hr AGM battery pack, you can significantly cut the generator run time by installing a much bigger converter, the battery can easily handle a 100+ amp charge, when discharged .
The generator produces up to 30-amp of 120-VAC power, so you also have the option of using an external battery charger along with the converter.
Use as much the 30-amps as possible to reduce run time.
While running the generator, make sure to charge all your devices at the same time, no need to waste watts.

Larry

Ah, Larry, you don't remember, which is not surprising, but I followed your advice years ago and replaced the stock converter with the one you recommended and reported back that that upgrade alone cut the charging time in half.  And we always charge electronic devices when the generator is running.

As a side note, when Rod M. installed the new AGMs this week, he upgraded one of our fluorescents to LED so I could see how it's done.  Very nice, warm 3200K units, easy to retrofit ($15/tube; $30/lamp).  I just received 8 more and will shortly have all 5 fluourescents replaced with LEDs.  In the past we never used the fluourescents for more than 5 minutes unless we had plenty of sunshine or shore power.

Ted
Re: Lead acid battery 20% state of charge
Reply #29 –
Quote from: Alaska Mike  - 
I agree, to a point. Per Bogart's shunt FAQ:
Does the shunt need to be next to the battery? How far away can it be?
The only slight inaccuracy that could occur if it isn't near the battery is that if the cable is too small, or the amps are really high there can be a little voltage drop that will cause the "volts" on the meter to read perhaps as much as a few tenths of a volt different than is at the battery. This error will be minimized if the cable is large enough to keep the voltage drop low.
No. There will be voltage drops along the cable due to its resistivity, and this will affect the current from a fixed volltage source. However, whatever that current is, it will be accurately read by the shunt, whether 6" from the battery or 60' from it. The battery monitor will accurately measure and indicate current into and out of the battery, regardless of cable length.

Steve
2004 FL
2013 Honda Fit
Re: Lead acid battery 20% state of charge
Reply #30 –
Quote from: Larry W  - 
While running the generator, make sure to charge all your devices at the same time, no need to waste watts.

Actually, this advice applies well to solar charging too. Charge your devices and shift your 12V tasks to prime solar hours too to optimize use of that resource. This is most significant when solar will fully charge your battery bank well before the sun goes down...

Steve
2004 FL
2013 Honda Fit
Re: Lead acid battery 20% state of charge
Reply #31 –
"whatever that current is, it will be accurately read by the shunt, whether 6" from the battery or 60' from it."

Steve nailed it. Voltage can vary, but current is the same throughout the circuit. (A tip of the hat to Herr Doktor Professor Kirchoff. ;-)
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Lead acid battery 20% state of charge
Reply #32 –
Since Alaska Mike was referring to a voltage inaccuracy when measuring it at the shunt, note that the resistance of 2 gauge wire 6" long would be 0.0001 Ohms. A current of 50 Amps would cause a voltage drop at the shunt of 5 mV. The resistance of a 60' run would be 0.009 Ohms. The voltage drop here would be 450 mV. Thus, a battery voltage reading would be off by 4 tenths of a Volt. The moral is to keep the runs as short as possible - for many reasons.

However, a battery voltage reading is not generally that useful except as an indicator of battery problems. As far as maintenance, the current reading is what counts, as that is what the monitor uses to integrate state of charge. In my case, I missed an important warning of impending battery doom recently by NOT paying attention to the battery voltage. When problems appeared after dark despite a full charge indication, I DID check the battery voltage - 11V. Shorted cell.

Steve
2004 FL
2013 Honda Fit
Re: Lead acid battery 20% state of charge
Reply #33 –
Quote from: LD-TED  - 
Quote from: Larry W  - 
We had the same same experience as you with limited or no solar battery charging, when camped in deep shade or in the winter.
I hate running the generator so to expand the battery capacity, I built a steel cradle to hold four T-105s batteries, hanging them below the floor.
The bigger battery pack allowed us to go for several days, in shade, without needing to charge..

When we do need to charge, I want to minimize the generator run time so the the stock 45-amp converter with replaced with a 70-amp converter. You should consider doing something similar.
With the 500-amp/hr AGM battery pack, you can significantly cut the generator run time by installing a much bigger converter, the battery can easily handle a 100+ amp charge, when discharged .
The generator produces up to 30-amp of 120-VAC power, so you also have the option of using an external battery charger along with the converter.
Use as much the 30-amps as possible to reduce run time.
While running the generator, make sure to charge all your devices at the same time, no need to waste watts.

Larry

Ah, Larry, you don't remember, which is not surprising, but I followed your advice years ago and replaced the stock converter with the one you recommended and reported back that that upgrade alone cut the charging time in half.  And we always charge electronic devices when the generator is running.

As a side note, when Rod M. installed the new AGMs this week, he upgraded one of our fluorescents to LED so I could see how it's done.  Very nice, warm 3200K units, easy to retrofit ($15/tube; $30/lamp).  I just received 8 more and will shortly have all 5 fluourescents replaced with LEDs.  In the past we never used the fluourescents for more than 5 minutes unless we had plenty of sunshine or shore power.

Ted
 Very nice, warm 3200K units, easy to retrofit ($15/tube; $30/lamp).  I just received 8 more and will shortly have all 5 fluourescents replaced with LEDs.  In the past we never used the fluourescents for more than 5 minutes unless we had plenty of sunshine or shore power.

Ted, what brand and source did you use for your LEDs? Did you replace both tubes in the fluourescent fixtures?

Chris
Formerly: 2002 30' IB
Re: Lead acid battery 20% state of charge
Reply #34 –
Quote from: Steve  - 
Since Alaska Mike was referring to a voltage inaccuracy when measuring it at the shunt, note that the resistance of 2 gauge wire 6" long would be 0.0001 Ohms. A current of 50 Amps would cause a voltage drop at the shunt of 5 mV. The resistance of a 60' run would be 0.009 Ohms. The voltage drop here would be 450 mV. Thus, a battery voltage reading would be off by 4 tenths of a Volt. The moral is to keep the runs as short as possible - for many reasons.

However, a battery voltage reading is not generally that useful except as an indicator of battery problems. As far as maintenance, the current reading is what counts, as that is what the monitor uses to integrate state of charge. In my case, I missed an important warning of impending battery doom recently by NOT paying attention to the battery voltage. When problems appeared after dark despite a full charge indication, I DID check the battery voltage - 11V. Shorted cell.
Thanks Steve- that's exactly what I was talking about. Knowing the voltage at the battery instead of at some random point along the wiring allows a battery monitor to better do its job.
 
For the size of my system, I'm way overbuilding the backbone. Part of this is to avoid having to re-run wiring many times as I modify the system to suit my needs. So, when I moved my coach battery(ies) from the engine compartment to the rear of the vehicle under the driver's side bench, I ran 2/0 arctic-grade welding wire to keep loss from the alternator to a minimum. In retrospect, that seems silly given the addition of a generator and eventually solar, but I would have killed my batteries trying to maintain them off of the alternator with the original 4ga wire. At the very least, now when I'm driving, I'm charging. Probably the most expensive Ah ever. Excellent quality wiring, connectors, terminal blocks, and other bits and pieces has added up, but it has also allowed me to adapt as plans changed. Most of it will probably be removed when (if) I ever sell the Lazy Daze and transferred to the new RV/camper.
 
I still haven't decided on the size/number of panels I'm going to use. The low angle sunlight up here means shading is a real concern, even in the long, bright days of summer. That escape hatch throws some long shadows when open. Going with a couple 100W panels instead of a single 150W panel would help somewhat, so that bit of advice is being considered carefully.
1983 20'
Re: Lead acid battery 20% state of charge
Reply #35 –
Harry, I am surprised you are paying $50 a night.  Phoenix AZ - big destination, in town, is only $36 a night (including tax) even at very nice places with lots of activities, further outside of town is cheaper (but filled up now).
I don't even like paying $36 a night, I would not pay $50 either - unless a very nice dinner and a show was included.  :D
Though I found one that does $15 dry camping with dump (e.g. no electricity, not sure if it has water), just "parking lot" kind of place but had laundry and showers/bathrooms.

Many places let you do a dump & fill water for $10/$15 - truck stops (Loves, Pilots, likely others), rv storage lots, and rv supply stores (like camping world or state trailer).  Some calling around might be useful.  Note:  When we ask about potable water, we have gotten some answers like it is city water but:
It is not run thru the filtration system we use inside our store (e.g it is tap water), or
because it is close to sewer we have to label it non-potable (I thought  huh, rv parks have sewer right next to the water spigot, do they have a problem with water pipe leakage so sewer leaks out and into the water spigot?).
So asking and making sure it is fine with you is suggested.
Jane & Scott
Currently have a 1989 TK  LD we did a lot of upgrades on.
Bigfoot 25RQ Twin on order with early summer 2024 ETA

Our smartphone autocorrects into very poor English.
 We disclaim the illusion of ignorance this creates as we have enough ignorance we rightly claim.
Re: Lead acid battery 20% state of charge
Reply #36 –
Quote from: JandS2  - 
Harry, I am surprised you are paying $50 a night.  Phoenix AZ - big destination, in town, is only $36 a night (including tax) even at very nice places with lots of activities, further outside of town is cheaper (but filled up now).
I don't even like paying $36 a night, I would not pay $50 either - unless a very nice dinner and a show was included.  :D
Though I found one that does $15 dry camping with dump (e.g. no electricity, not sure if it has water), just "parking lot" kind of place but had laundry and showers/bathrooms.

Many places let you do a dump & fill water for $10/$15 - truck stops (Loves, Pilots, likely others), rv storage lots, and rv supply stores (like camping world or state trailer).  Some calling around might be useful.  Note:  When we ask about potable water, we have gotten some answers like it is city water but:
It is not run thru the filtration system we use inside our store (e.g it is tap water), or
because it is close to sewer we have to label it non-potable (I thought  huh, rv parks have sewer right next to the water spigot, do they have a problem with water pipe leakage so sewer leaks out and into the water spigot?).
So asking and making sure it is fine with you is suggested.

I'm guessing this belongs on another thread?

Jim
Re: Lead acid battery 20% state of charge
Reply #37 –
It is on this thread because we are being forced to adapt coaches that have limited solar and battery capacity to free camping with satelite TV and such power hogs.

I spend my summers in and around Silverton, Colorado, and today I cannot get a seasonal or monthly rate, only a daily rate, and it is $50/night in one park and nearly that in the others. That is $1500/mo and we used to pay $500.

I have installed the cat heater but I don't know how well it will work at 9300ft. One reference says it won't so we will see. One way to cope is to discharge the limited battery bank below 50% and we are back to the thread title.

At the end of the summer I'll report how it went. The spring will be spent in Moab, Utah. The problem there is the parks are full. Free camping readily available. I admit I'm getting used to the cost of no fee camping!
Harry 2006RB
Re: Lead acid battery 20% state of charge
Reply #38 –
Quote from: hbn7hj  - 
It is on this thread because we are being forced to adapt coaches that have limited solar and battery capacity to free camping with satelite TV and such power hogs.

I spend my summers in and around Silverton, Colorado, and today I cannot get a seasonal or monthly rate, only a daily rate, and it is $50/night in one park and nearly that in the others. That is $1500/mo and we used to pay $500.

I have installed the cat heater but I don't know how well it will work at 9300ft. One reference says it won't so we will see. One way to cope is to discharge the limited battery bank below 50% and we are back to the thread title.

At the end of the summer I'll report how it went. The spring will be spent in Moab, Utah. The problem there is the parks are full. Free camping readily available. I admit I'm getting used to the cost of no fee camping!

When I look back at your original post I now see the reference to camping costs. Based on what I've been reading the past couple of years on rvtravel.com increased costs and packed campgrounds is what we should expect. They sold over half a million new units in 2017 and over 400K in 2016 which are record numbers. Chuck Woodbury, who is in charge of that site is full timing and talks about this issue a lot.

Too many folks us included have been selling the idea of RVing and full-time travel.

Jim
Re: Lead acid battery 20% state of charge
Reply #39 –
The new RVer soon discovers his new, high dollar, RV functions very poorly if not plugged in on a daily basis. Those folks are filling the RV parks. When the parks fill up they run their generators all evening just to watch TV.

I would prefer to plug in. It makes things so much easier, but my opportunities to do so are more and more limited. Again, I can pay the $50/night, but this year I've put the limit at $20/night. There won't be many/any opportunities for electrical power at $20/night.

Free camping faces another problem in phone signal access. With broadband we don't need wifi anymore but mountains or the Canyonlands area have camping areas with no signal. With a booster many areas do have signal.

I'm not new to this game but have been at it for 35 years. There is a difference between being a weekend warrior and a seasonal RVer. I'm just trying to deal with the economic changes. We need a battery like lithium without the temperature problems. It will arrive.

This will be a year of transition. Maybe I'll decide to pay the money, maybe I'll turn the iPad off in the evening and log in when I go into town, Maybe I'll get reservations for next year and let others cope with power problems. I won't decide to stay home.
Harry 2006RB
Re: Lead acid battery 20% state of charge
Reply #40 –
If this correction in the stock market starts to stretch out and becomes a bear market (20%+ drop) and lasts for awhile all these folks who bought their new RV’s with nothing down will be dumping them left and right and all will be right with the RV world. 🤓

I’ve never cheered for a bear market before but honest to God I would be fine with it now.
Ruby, the red 2004 26' RK hauling Dave and Kristine hither and yon
Re: Lead acid battery 20% state of charge
Reply #41 –
Quote from: hbn7hj  - 
The new RVer soon discovers his new, high dollar, RV functions very poorly if not plugged in on a daily basis.
The new RVer soon discovers that it's a relationship, not an object. It takes work to maintain a relationship.  ;)
Joel & Terry Wiley
dog Zeke
2013  31 IB   Orwan   / 2011 CRV Tow'd LWEROVE
Re: Lead acid battery 20% state of charge
Reply #42 –
"I’ve never cheered for a bear market before but honest to God I would be fine with it now."

Gotta confess I had the exact same thought! Pretty funny.

What would be nice is something that put out 300 watts of electrical power, uses propane, is silent and small, and can run 24/7. The EFOY fuel cell would do it but the fuel is unobtanium, very expensive and it is a bit large. I'll just have to settle for a Honda EU1000i on propane to run when needed.
Harry 2006RB
Re: Lead acid battery 20% state of charge
Reply #43 –
Quote from: hbn7hj  - 
What would be nice is something that put out 300 watts of electrical power, uses propane, is silent and small, and can run 24/7. The EFOY fuel cell would do it but the fuel is unobtanium, very expensive and it is a bit large. I'll just have to settle for a Honda EU1000i on propane to run when needed.

Sadly, we have been promised LPG fuel cells for years.
Yes, You Can Buy This Home Fuel Cell | Popular Science.
Reading Popular Science since I was kid, I have had a lot of disappointments, so many 'amazing' inventions have gone nowhere.

EFOY fuel cells have been around for many years but the lack of readily available pure Methanol and the high overall cost doomed its adaptation. To really be practical, a separate onboard methanol tank would be needed.
I want a fuel cell that burns a fuel that is already carried, either gasoline or propane.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Lead acid battery 20% state of charge
Reply #44 –
Quote from: huskerblue  - 
If this correction in the stock market starts to stretch out and becomes a bear market (20%+ drop) and lasts for awhile all these folks who bought their new RV’s with nothing down will be dumping them left and right and all will be right with the RV world. 🤓

I’ve never cheered for a bear market before but honest to God I would be fine with it now.

Just a thought. I'm guessing many of the RV parks (especially newer ones) have probably been built with leveraged financing. Between that and the lack of business from all those new, shiny mass-produced RV's if the stock market were to get too bad, many of the RV parks themselves could go out of business. The ones that do remain will jack up their prices due to higher demand.

But since everyone is saying the fundamentals of the economy are strong, this is just a moot thought, right!?  :)
Greg & Victoria
2017 Mid-Bath  “Nocona” towing a manual 2015 Forester
Previously a 1985 TK
SKP #61264
Re: Lead acid battery 20% state of charge
Reply #45 –
Stock market is not a judge of today’s economy, it is lead indicator of what folks think things will look like 12 months or so from now. As Gretzky said, “I’m a great hockey player because I skate to where the puck is going to be, not where it is now.”

Your take on some Rv Park operators going down is a good point. Then again, with a LD we can go off and camp wherever the heck we want for free!

Dave
Ruby, the red 2004 26' RK hauling Dave and Kristine hither and yon
Re: Lead acid battery 20% state of charge
Reply #46 –
Quote from: huskerblue  - 
Stock market is not a judge of today’s economy, it is lead indicator of what folks think things will look like 12 months or so from now. As Gretzky said, “I’m a great hockey player because I skate to where the puck is going to be, not where it is now.”

Your take on some Rv Park operators going down is a good point. Then again, with a LD we can go off and camp wherever the heck we want for free!

Dave

You can but we are seeing more and more people at boondocking spots. All those people gotta park those shiny new RVs somewhere.

Give you some examples. There is a beautiful spot that overlooks the Grand Tetons we found a few years ago. It has subsequently been listed online and is now packed. A ranger commented on the increased traffic to that location. Another off 395 has been closed.

Jim
Re: Lead acid battery 20% state of charge
Reply #47 –
If I may veer into a stock market observation -- only two things drive the market - greed and fear.   Greed to get more money today and fear you are going to loose the money you have.   Each day is a new day with no relationship to yesterday or tomorrow.  

In my not so humble opinion the only way to make money in/on the stock market is to bet with the house.   They know more then we will ever know or get to know.
personal fine art photo stuff
TF Mack | Flickr
It's all good .......
2014 Twin King
 
Re: Lead acid battery 20% state of charge
Reply #48 –
Although the stock market is tempting to discuss in these volatile stock exchange times, let's move back to the original topic of this thread, please.

Chris
Formerly: 2002 30' IB