Wednesday, January 29, 2020
We will be attending the FMCA International Convention in Tucson, AZ March 26-29, 2020.
This will be our first FMCA rally. We have not yet received our packet for the event, but the FMCA has indicated that they have begun the mailing of packets.
Original material: https://roadtrek210.blogspot.com/
Sunday, January 19, 2020
|serving suggestion: parsley and parmesan cheese|
Chicken soup is something I could make in the Roadtrek. At present we don't because we don't take a slow cooker with us. However, here's the soup I made recently in a larger RV and the counter space available was similar to our 210P. I would probably put the cooker outside if the weather was dry....
One adjustment I would make in the Roadtrek is to braise the chicken in a cast iron pan. We don't carry a large stock pot, so cast iron would be the way to go.
Original material: https://roadtrek210.blogspot.com/
Saturday, January 18, 2020
Wednesday, December 4, 2019
Periodically I check the MPG we achieve. I do this for trip budgeting purposes. I don't trust the computer generated MPG display, but it is helpful, so I use the gas receipts. On a recent 2500+ mile trek I made a spreadsheet from the gas receipts and I thought I would share it here.
There are a variety of factors that impact the MPG. Some are:
- Driving habits
- Stop and Go
- Onan generator use
On this trek we were generally level, on interstate highways and I did the driving. I follow the speed limits and will stay in the right lane on divided highways with two lanes going in our direction. In urban areas I generally drive the expressway second lane from the right to avoid those who simply don't know how to merge, or exit. As a consequence our speeds are consistent with little hard braking or flooring of the accelerator. On this trek our highway speeds were usually 55-65 MPH. However there were long segments where the speed limit was 70-80 MPH. The initial day had about 40 minutes of stop and go 20 MPH on the expressway because of road construction and that decreased the MPG for the first segment at 55-65 MPH speed limits.
I do use 87 octane gasoline as recommended by Chevrolet. In portions of the west there is a choice between 86 and 88 octane. I usually fill up at about 1/2 tank level. I simply alternate fill-ups between 86 and 88 octane to keep 87 blend in the tank.
The weather was cool to mild for most of the trek, low of about 32F and high of about 75F. Little precipitation as our route allowed us to avoid some really unpleasant weather coming in from the West.
Perfect driving conditions as far as I am concerned.
From this trek with speed limits 55-80 MPH, I again observed the best gasoline mileage occurred at 55-65 MPH:
- 16.5 MPG - not bad!
At 80 MPH, which we encountered in the West, the mileage decreased:
- 11.0 MPG
- 15.2 MPG
Best mileage is achieved at 45-55 MPH, but we had few segments at that speed range on this trek, so I didn't attempt to calculate the MPG.
Original material: https://roadtrek210.blogspot.com/
Wednesday, November 27, 2019
|2550 miles to escape the cold|
We had been lingering in the midwest. It is always difficult to say goodbye to family, friends and acquaintances. Departing also means acknowledging the end of summer and the impending arrival of winter. But then a nasty, early winter storm appeared in the weather forecast and it was time to move on.
We assessed the weather patterns and I chose to travel a greater distance to avoid ice, sleet, and snow. So we packed and travelled a more southerly route. This included segments we had never taken before and it opened up some new possibilities. So we did our trip research and made overnight reservations about every 500 miles.
We both like to do some exploring, but freezing weather was predicted along much of our trek. So we opted to dispense with most of the sight seeing this time.
There are always surprises
We drove to I-65 and headed south. We didn't change our direction until we reached the Gulf of Mexico.
At Biloxi, MS we stopped at the Gulf Shores RV Resort. We arrived just before sunset on November 11, took a short walk on the beach and headed to dinner.
|Sunset November 11|
The weather front caught up to us overnight, so there was some rain, but mild temperatures, thanks to the Gulf waters. We took another stroll along the beach before departing the next morning.
|Biloxi Beach - very quiet morning|
|Ready to depart Biloxi|
|Baton Rouge, LA - Mississippi River|
|Lots of oil refining, chemicals and storage|
It wasn't long and we were in Texas:
Our first night in Texas was at a private, family run campground we've spent time at previously. We had a reservation and checked in. We were advised to disconnect our fresh water hose before retiring because there was a freeze warning. All well and good, we have experienced this many times. Then I asked "What about the bathrooms?" I was advised that all water in the campground would be turned off and the bath rooms locked as of 8:00 pm.
Well, that was a new experience! I've never been in a campground under a freeze warning where all of the fresh water services were shut down because of a freeze warning.
We have added this to the list of questions to ask when making reservations.
We dined at the Mexican restaurant across the street and had an excellent meal. LOL!
|At Lucy Tequilas - "the Jared"|
The night was uneventful and the low temperature was 33F. LOL!
Continuing on, we trekked to our next stop.
We spent a night at a KOA in Van Horn, TX. We've been at that campground before. Near freezing weather was predicted, so we put Reflectix in the windows. Our feathered neighbor didn't seem happy with the prediction. Freezing weather in this part of Texas is unusual in early November.
After a restful sleep, we got up early and prepared to continue.
|Van Horn Texas at Dawn|
Shortly thereafter we were on the downhill run and at a rest stop in Arizona.
This trek was different. We usually like to take our time and smell the roses. This trek we decided we wanted to avoid nasty weather and really cold. So we chose a route that accomplished that.
We made a few notes and hope to visit Biloxi again, in nice weather.
Original material: https://roadtrek210.blogspot.com/
Tuesday, November 5, 2019
|DC Voltmeter and Ammeter to monitor the coach batteries.|
I added this to improve upon the Roadtrek LED battery indicator.
If left on, it also provides a power reading and energy consumed.
|Roadtrek L-F-G-C battery display -|
4 LEDs lit indicates charging or fully charged.
The post points out what I've learned about my AGM batteries including limitations of the L-F-G-C battery display which is simple to read but can be misleading, as I discovered.
How do we use the Roadtrek if we're not in a campground? This is important because it influenced our battery decision. We do overnight in the Roadtrek off of the grid, but we don't do a lot of boondocking. If the temperatures are above freezing but cold we may run the generator and the heat pump. However, G and I have also slept in the Roadtrek in sub-freezing temperatures while off the grid and below the limit for the heat pump. We will then run the propane furnace if necessary and that requires 12VDC. If temperatures dip into mild sub-freezing overnight and we haven't winterized we will run the hot water heater on propane and the furnace. If we are on propane I don't think it is practical to run the generator continuously overnight and we usually don't. We rely on battery power.
What I discovered. I did not understand the limitations of that L-F-G-C Battery indicator and learned that "F" or "Fair" is really "Poor" because the batteries may be nearing depletion at that point.
I also learned that the Inverter Off-On switch didn't always turn off the inverter function of the Tripp Lite inverter/charger; that was a switch malfunction. It caused unexpected battery depletion.
I realized I had been mis-using my batteries. I didn't understand that the entire 220Ah or rated battery capacity is not available unless I want to seriously reduce the lifespan of the batteries. I also learned that repeatedly using the batteries below the "F" Fair indicator and until only the "L" or "Low" indicator was the only one illuminated was not good for the batteries, if I want longer battery life. My lack of understanding coupled with an inverter switch problem led to the early demise of my first set of AGM batteries.
I've learned about AGM batteries and when I replaced them I also investigated Lithium-Ion batteries (LiFePO4). I'll point out what I discovered about the AGM batteries in this post, but first, I decided that I would continue with AGMs because:
- 220Ah AGMs are sufficient for my use (approximately 110Ah to 170Ah useable - explained in this post).
- I have an Onan generator which I can use to provide power for coach appliances and charging.
- I was concerned about the low temperature charging restrictions of LiFePo4 batteries because my AGMs are mounted outside in the rear of the coach. That is the location I would use for LiFePO4 replacements.
- I did not want to open my wallet for the more costly LiFePO4 batteries.
- I decided to add a small 50W portable solar panel with de-sulfating 180W controller to help charging of the batteries. I concluded this was a better use of my money as compared to the LiFePO4 batteries. I may eventually put a 100W panel on the roof.
- I decided that adding a good DC voltmeter/ammeter to monitor the batteries would assist me in using them and avoid the earlier problems.
- There have been improvements in technology, and who knows, I may change my mind in 2-5 years.
I include a typical 12VDC energy audit at the end of this post.
My 2013 210P Roadtrek has two 6-Volt AGM lead-acid sealed batteries rated 220Ah. I use these on our treks in both warm and cold weather. We don't boondock a lot, but we do spend overnights off the grid. The numbers in this post are with those batteries in mind.
Some things I have learned
These lead-acid batteries can provide 4-6 years of good life, and sometimes more. But how they are used is a significant factor and determines how long they provide good service. Here are a few things to be aware of, and more on what the indicator in the Roadtrek is attempting to display and how it relates to what we observe with our batteries.
I don't think it is possible to reverse the aging of these batteries. It is possible to damage them.
How the batteries are used and discharged/charged is probably the single greatest determinant of how long these lead-acid batteries can provide good service. Battery life is determined by age and these cycles. We sometimes don’t get the life out of the batteries we may expect. I have two 6-volt AGM batteries. They are wired in series to provide 12V DC and can provide a maximum of about 220Ah (Ampere-hours).
What are DC Watts and Volts and Amperes?
These are important because they relate directly to our batteries. If we know the amperes our appliances and lighting are using we can estimate how long on a charge we can run them.
You can skip this and move on to the next section, but I think you will want to read this before you do an audit of your DC appliances and get a better idea of how much battery power you are using.
- Watts are Volts multiplied by Amperes. In our Roadtreks with 12V AGM batteries:
- 12V x Amperes = Watts; for example 12V x 5A = 60 Watts.
- Because we know watts and the voltage, we can calculate Amperes. For example:
- Watts divided by volts = amperes. A 100 watt DC appliance: 100W/12V = 8.33A
- An Ampere-hour is using one ampere continuously for an hour: 1A x 1 hour = 1 Ah
- 1.0A lights
- 0.8A charging phone
- 2.6A furnace and fan.
- 1.0 + 0.8 + 2.6 = 4.4A
- 4.4A x 1 hour = 4.4Ah
For example, let's say we left those appliances and lights on overnight, for 8 hours. Here is how much battery capacity they would use:
- 4.4A x 8 hours = 35.2 Ah
What use is knowing Ampere-hours? Ampere-hour (Ah) rating of a battery is a measure of how many amperes a battery can provide when discharging. One Ampere-hour is one ampere for one hour.
Unfortunately, a battery rated 220 Ah cannot provide 220 Amperes continuously for one hour. In watts that is 220 A x 12V = 2640 Watts total.
A 220 Ah AGM battery cannot be used that way. The more we attempt to pull from our batteries, the less Ah they can provide in a short period of time. I'm using the data provided by the manufacturer of my batteries, which is relative capacity. Relative capacity takes into account "battery fade" which normally occur to batteries as they age and are used:
- To get good battery life, these batteries should not be repeatedly discharged more than about 50%, and when discharged should be immediately recharged. In other words, one cannot get 220Ah out of these batteries if we want good life from them.
- A 50% discharge of 220Ah is 110Ah that we can use. The batteries must then be recharged. AGM batteries discharged repeatedly 50% and then recharged can provide about 1200 charge-discharge cycles. That’s the service life. Keeping batteries fully charged and not storing them partially discharged also is an aid to improved service life. Temperature also impacts service life, and temperatures above 77F reduce battery life.
- These batteries can be discharged repeatedly by 80% but that will reduce the life. A 80% discharge of 220Ah is 176Ah that we can use. AGM batteries repeatedly discharged 80% can provide 700 charge-discharge cycles. That is much lower than the number of cycles if we only discharge to 50%.
- Many battery manufacturers use a 20 hour rating for batteries. That is a more realistic and useful measure of battery capacity. For example, my AGM batteries are rated 220Ah, which implies continuous 220A for one hour. The actual 1-hour rating of the batteries is only 130A.
- The battery can, however provide a total of 220Ah over 20 hours of discharge. That is a continuous 11 amperes for 20 hours. But we should only go for 50% which is 5.5 A for 20 hours. This is to get better battery life.
- Over 10 hours, a typical night, the battery can provide a total of 210Ah according to my battery manufacturer. In other
words it can provide 210Ah/ 10 hours = 21 amperes continuously each hour for that 10 hours. But,
if we only discharge the battery 50%, of the 220Ah full rating, that implies about 110Ah/ 10 hours or only 11.0 amperes continuous discharge for 10 hours.
Conclusion: Over a typical night, my batteries could provide 11.0 Amperes each hour and provide good service life.
- These are the characteristics of the batteries in my Roadtrek when they were new. This capacity diminishes with battery age and use.
- There are differences between manufacturers, so it is best to check the specifications for your batteries.
- What does 1200 charge-discharge cycles mean? That's the number of times we can discharge and immediately recharge the batteries. For example, if you discharged the batteries to 50% and then fully recharged them once a day and every day, they could have a useable lifespan of 1200 days. 1200 days/365 days per year= 3.2 years battery life.
- If you did this every three days, then we would complete a cycle every three days, or 365/3 days = 122 cycles in a year. 1200 cycles/122 cycles per year = 9.8 years life.
- However, because of other factors including temperature, length of time the batteries sit in a partially discharged state, battery age, etc. it is unlikely we will ever achieve this in our Roadtreks. The manufacturer’s battery data is based upon ideal situations, including a temperature of 77F
- As the batteries age, even under ideal conditions, we may not get that 110Ah because the capacity of the battery diminishes as it ages. This is called battery fade. In other words the battery initially can provide 220Ah, but the actual capacity decreases over time. We notice this as a more rapidly falling terminal voltage, which we can see on the Roadtrek L-F-G-C display, which spends less time in the “Good" area. In other words, the display falls from C to G to F more rapidly than one would expect. That is an indicator of aging batteries with diminished capacity. Eventually we decide that the batteries don’t provide us with enough power to get through the night or whatever while powering our devices. We then get new batteries.
- Frequently discharging the batteries below 50% will further reduce the service life. For example, we can repeatedly discharge them to 80% (20% remaining). If we do this, the service life will decrease. My battery manufacturer states that discharging repeatedly 80% will reduce battery life to about 700 cycles. That is considered to be the lowest acceptable service life.
- At 700 cycles if we discharge and charge every 3 days (122 times a year), the batteries will have a useful life of about 700 cycles/122 cycles per year = 5.7 years. But we must also consider the aging of the battery, temperature and so on. These also reduce battery life.
There is a trade-off.
- We must decide between longer battery life, or more power from each charge, or a compromise. In practical terms we must choose between how long we want to power our DC appliances each time we discharge the batteries and how long a battery service life we want. We can’t get both maximum power for maximum time because the deeper we repeatedly discharge the batteries the shorter the service life. We notice this as how quickly the available power diminishes. Of course, we can replace the batteries every three years or so. That is a financial decision.
- If I use the "G" indicator and recharge the batteries when it goes out, then my battery manufacturer indicates that I can get about 800 cycles from my batteries if I discharge them to about 20-30% repeatedly.
- Important Note: I have not verified the Roadtrek indicator with actual measurements comparing the battery voltage to the indicator LED thresholds (I use a voltmeter and no longer pay much attention to the indicator). I'm using published information and it is my understanding that the “F” indicator is “ON” if the battery is above 11.2V, but the table for my batteries indicates a 0% Relative state of charge when the voltage decreases to 11.6V and completely depleted at 10.5 volts. The table provided by the manufacturer of the AGMs in my Roadtrek indicates 50% relative State of Charge = 12.35V and 100% State of Charge = 12.9 volts. I’ve seen other AGM charts and those batteries were in the range of 11.66V (20%) to 12.05V (50%) to 13.0V (100%).
- It measures battery voltage. This is an approximate indicator. A battery will give two different voltage readings. One reading if it is being discharged; the another is if it has rested (no discharge) for about 6 hours. The battery specification for “State of Charge” are usually for a resting battery. If a battery is discharged and then allowed to rest the voltage will usually increase. In other words, the battery may have more capacity remaining than the “L-F-G-C” indicator represents when we are in our Roadtrek and discharging the coach batteries.
- Use a voltmeter if we want a better idea of the condition of the batteries, so we avoid excessively discharging them. Avoid high temperatures because battery life decreases at higher temperatures. Measured life is usually at 77F and many batteries will lose half of their life if the temperature is 95F. Don’t charge if above 120F. Charge the batteries after every period of use. Don’t discharge more than 50%. All of these things improve the life of the batteries.
- We can add a voltmeter in the rear cabinet of a 210P to monitor the voltage.
12VDC socket in the rear of my 210P Inexpensive 12VDC digital meter
plugs into socket in photo above
Inexpensive 10 inch Splitter Cable for 12VDC
Use if we need two devices from a single 12VDC source,
such as the photo of the cabinet, above.
Dual, fused splitter with digital voltmeter
and USB sockets
As battery capacity diminishes what does that mean in practical terms if I want to boondock?
- There is a trade-off. Longer battery life, or obtaining more power from each charge. This is further complicated because as the batteries age, their capacity is diminished. The actual capacity of a 200Ah battery will gradually decrease to 190 Ah, 180 Ah, 170 Ah and so on. This is because the internals of the battery change as it ages. We usually notice this change because the voltage decreases more rapidly as the battery discharges.
- The beginning voltage of a fully charged battery will be that of the charger which is about 14.7 volts, this is called “surface charge” and this charge dissipates quickly as we discharge the battery. Both good and faded batteries will usually show a "C" when on the charger, and immediately after they are disconnected. That is deceiving and is not indicative of the actual state of the batteries.
- If an older 220Ah battery has a capacity that begins at 160Ah capacity then it won’t take very long to get to that 110Ah level which is the 50% capacity level of the new battery. We see this as a more rapid movement of the indicator as the indicator moves more rapidly from “C” to “G” to “F”.
Are there other things I should be aware of?
- Here is the short list. Batteries must be properly charged in accordance with the manufacturer’s instructions, automatic chargers are best. For golf cart batteries at 12V that usually means an Absorptive/bulk charge at 14.7 volts and a Float charge at 13.5 Volts. AGM batteries may be slightly different with an Absorptive/bulk charge at 14.4 volts and a Float charge at 13.5 Volts. My AGMs recommend an Absorptive/bulk charge range of 14.4-14.7V and a Float charge of 13.2-13.8V. Because the lead-acid batteries are chemical devices, there are other noticeable issues.
- Battery capacity is reduced at lower temperatures. A 200Ah AGM battery may have a capacity of only about 80% at 32F or 160Ah. However, that is at a discharge of about 20Ah (about 4A per hour for 5 hours).If we increase the to 40Ah, the capacity reduces to about 70% or 140Ah. (That provides a rate of about 8A per hour for 5 hours). However, we still have to watch the battery voltage to determine the actual condition, or state of charge. We can’t simply watch a clock.
- A 200Ah AGM battery is rated to provide that amount, 200Ah over 20 hours. It can provide 200Ah/20 hours = 10 amperes per hour continuously for 20 hours. But we would not want to exceed that 50% discharge limit if we want acceptable battery life. In practical terms, a 200Ah battery should be considered 100Ah. if that is so, it can provide 100Ah/20 hours = 5 amperes per hour continuously for 20 hours.
- If we increase the amperes used, then the time the battery can produce it will decrease. The same batteries will provide only about 170Ah over 5 hours, not the 200Ah rated over 20 hours. In other words, the more power we demand, the total amount decreases. That’s because these are chemical devices. If the batteries could provide 170Ah over 5 hours, that’s 170/5 or 34 amperes each hour at 100%. But if we allow only 50% discharge, we then can use only 34A x0.5 = 17 amperes per hour over the 5 hours. 17 amperes x 12 volts = 204 watts connected to the battery.
- If we use an inverter to get 120VAC from our batteries, we need to take into account the inefficiency of the inverter. In other words, if we run a 200W appliance at 120VAC on the inverter, the amount of DC power going into the inverter is greater than the AC power coming out. Simply turning on the inverter uses power, perhaps as much as 200W. To maximize battery power, leave the inverter Off if we don't need AC from the batteries. Tripp Lite suggests using 1.2 as an inefficiency multiplier:
- Begin with the AC amperes or watts of the 120V appliance. If 2.5A, then the watts are 120V x 2.5A = 300W.
- Then to determine DC amperes divide by 12V. 300W/12V = 25 DC Amperes.
- To estimate the battery Ampere-hours (Ah) required, multiply the DC Amperes x time x inefficiency. 25A x 4 hours x 1.2 = 120Ah. That’s a rough estimate and it exceeds the 50% capacity of a 200Ah battery.
- To determine amperes from an appliance using DC watts (such as a TV), simply divide the watts by 12 volts. For example for 100 watts: 100W/12V = 8.33 A
- Vehicle engine.
- Shore power.
- Onan generator.
- Underhood generator (GRU) - I don't have this.
- Solar panel.
The more depleted the batteries, the longer the charging time required.
- Using 120VAC and the Tripp Lite 750 Watt Power-Verter DC-to-AC Inverter/Charger, it can take 12 hours to completely recharge discharged coach batteries. This was confirmed by a factory technician. Furthermore, the charger has two settings: 10A and 45A.
- Using the Onan generator is the same as shore power because the Tripp Lite is used.
- Solar may take longer. This is determined by the amperes available from the solar panels. If a 45A Tripp Lite requires up to 12 hours, it is reasonable to assume solar may require more time because a 200W solar panel is providing about 17A. However, most RVs on solar don't draw down the batteries because during daylight hours the solar provides a part or all of the DC power requirements of the RV.
I need a 12V DC power budget. To do this we need to do an energy audit. That’s a way to determine how far my batteries can go before I run out of DC power, and then have to recharge
- To get maximum power available and maximize your batteries, it is better to use 12VDC appliances than 120VAC connected to the inverter because of the inverter losses.
- Add up the DC amperes to determine how much you use. Then calculate the Ampere hours to see how long your batteries will last before requiring a recharge.
- Add up the ampere requirements of all of the DC appliances and things in your RV. Product labels are reliable sources. Because there are differing options, I can't provide the Amperes required for each and every device. But I do provide a list with some approximations if I know what they are:
- Lighting 12VDC (LED uses less DC energy than bulbs and fluorescent) - Varies.
- Each LED light may require 0.25A.
- Lighting 12VDC fluorescent, single 20W bulb - 1.3 to 1.8A.
- Lighting 12VDC fluorescent, dual 20W bulbs - 1.8 to 2.2A.
- Propane detector 12VDC about 0.1A.
- 12VDC TV (about 32W or 2.7A).
- Amplified TV antenna - varies.Macerator 17A 12VDC when running.
- Water pump (varies with pressure and flow, possibly 5A 12VDC when running).
- Inverter 2A losses or more if ON.
- Roof fan - Fantastic Fan 3350 - 2.5A when running (varies with speed).
- Bathroom fan.
- 3-way Refrigerator 12VDC for controls - approximately 1 to 2A.
- 3-way Refrigerator on 12VDC cooling - approximately 20A.
- Dometic LCD single zone thermostat.
- 16,000 BTU Suburban Propane Furnace when running - 2.8A.
- 12,000 BTU Suburban Propane water heater - 12VDC Module board - 1.0A.
- 15 inch Laptop - estimated 90 watts 120 VAC.
- Smartphone charging - estimated 5 Watts @120V, 0.5A @ 12VDC.
- CPAP machine - varies.
(c) Copyright 2019 Norman Retzke "All Rights Reserved". See disclaimer notices.
Wednesday, October 30, 2019
|AGM Lead Acid batteries in my 210P. Mounted outside.|
Here's an update on lead acid sealed AGM batteries versus Lithium Ion (LiFePo4) as coach batteries in my Roadtrek. If you have a Chevy based Roadtrek, you probably have two 6-Volt 220Ah AGM batteries as I do.
Note: 1. I'll post an article about what we can expect from our batteries and my experience powering the stuff in my Roadtrek with AGM batteries since December 2013.
When we compare batteries, we usually look at these three types:
- 6V type GC2 golf cart batteries. These lead-acid batteries, are not sealed, and do require addition of distilled water from time to time. They also do vent gasses.
- 6 V type AGC2 AGM batteries. These are also lead-acid batteries, but they are sealed and require no maintenance.
- 12V LiFePO4 Lithium-Ion batteries. These are radically different than the golf cart and AGM batteries.
Trick question: Should one invest in LiFePo4 batteries or in Solar Panels? I won't attempt to answer that in this post. The answer lies in how much electrical power do you need to get through the night, when batteries are important, or use a generator.
In fact the real issue is making a useful comparison of electrical energy sources when off the grid. These include batteries, my Onan generator, and my solar panels. This is a somewhat unequal comparison, because my Onan can provide 2,800 watts of continuous power. That's sufficient to run my Air Conditioner and the Onan consumes about 25 ounces of gasoline per hour at low power and 55 ounces per hour at full power.
My point is, we are comparing energy sources, and the costs of those sources. This post will not compare the cost of solar panels and batteries to other sources.
Here is a quick comparison of batteries. I use Battle Born Battery as the Lithium-ion comparison because they seem to be a well made battery with a "10 year warranty". These would also work with the TrippLite inverter charger in my Roadtrek, with a change in settings to "Gel", because according to Battle Born "the battery prefers to bulk charge at 14.4 volts and float at 13.6 volts".
- GC2 and AGM batteries are both lead-acid batteries. One of the characteristics of these batteries is they should not be repeatedly discharged below 50% to get maximum life. So, my 220 Ah batteries can only really provide about 110 Ah of electrical energy if I want to get maximum life from my batteries.
- LiFePO4 type Lithium-ion batteries are radically different technology. So they are significantly lighter in weight than any lead-acid battery of similar capacity. They can be repeatedly discharged 75 to 80% without decreasing the life of the battery. They also can tolerate more charge-discharge cycles than the lead acid batteries. A 200Ah LiFePO4 battery can provide 160 Ah of useful electrical energy.
- LiFePO4 batteries cannot be charged if they are below freezing temperatures.
- LiFePO4 batteries are significantly more expensive than AGM batteries.
Here are some cost comparisons. I'm going to use two different AGM batteries and compare them to a "drop-in" Lithium-Ion battery replacement made by Battle Born Battery company:
- Amstron AP-GC2 6V AGM Deep Cycle Battery. This is rated 210 AH and is currently available for $209.99 at atbatt.com. List at $299.99. Two required to achieve 12V at list = $599.98.
- Deka 8AGC2 (8AGC2M) 6V Deep Cycle battery. Made in USA. This is rated 220 Ah and is currently available for $389.70 via Amazon. Two required to achieve 12V = $779.40.
- Battle Born 12V 100 Ah "drop-in" battery list $949 each. Two would provide 160 Ah of electrical energy versus 110 Ah for lead acid. This is considering a 80% discharge versus 50% discharge, which are the recommended maximums for these batteries. Price per battery $949 or $1,898 for two, which is required to achieve 200 Ah. However, if you are an Escapees RV Club member, you can currently get a 15% discount.
So what are the issues? A couple of years ago, I looked at the replacement of my two 6-V AGM batteries with Lithium Ion batteries. These were the issues I considered then:
- Available power. The Lithium-ion batteries can provide more electrical energy and more discharge-charge cycles. My AGM batteries can provide 110 Ah of useful electricity while Lithium-Ion which occupies the same space can provide 160 Ah. This is not trivial if one wants to boondock and could be an incentive to consider Lithium-Ion batteries.
- Temperature Restrictions. When I evaluated Lithium-Ion batteries a couple of years ago, I discovered that they should not be charged if the battery temperature is below freezing 32F (0 C). My 210P carries the batteries in an outside compartment. Because we do trek when it is below freezing, that was a serious impediment. The Battle Born batteries have a low temperature charging limit of 25F. The batteries are prevented from charging below 25F. However, they can continue to discharge until they reach a "low voltage limit" which is below 10 volts.
- Alternative Location. I even considered moving the Lithium-ion batteries inside of the coach as a means to get them above freezing, but that would displace useful space and add to the installation cost.
- Cost. Comparing the Deka AGM to the Battle Born the difference is about $1,118. Comparing the Armston the difference is $1,199.96.
- Weight. The Battle Born batteries are about one-half the weight of the AGM batteries. If weight is an issues, that reduction of about 60 lbs could be a significant factor.
- Warranty. Most AGM batteries can be expected to have a life of 5 years, or more. Some Lithium-Ion battery manufacturers offer a 10-year warranty. That means that one set of Lithium batteries is the equivalent of two sets of AGM batteries. This should be considered when evaluating batteries.
- Temperature and voltage affects - AGM. AGM battery specifications are under "ideal" conditions. These include an ambient temperature of about 77F, discharging to no more than 50% and then immediately recharging. That may not happen in the real world. AGM batteries do experience reduced capacity in cold weather. AGM battery life will also be reduced at higher temperatures. In other words, that 110 Ah available will decrease as the ambient temperature decreases and may be 25% less at 32F and 20 A discharge rate. Under high discharge rates the capacity is further reduced. There is a lot of data about AGM and other lead acid batteries because there are so many manufacturers and they have been in use for many decades.
- Temperature and voltage affects - Lithium ion batteries. Using Battle Born Battery data for their "drop-in" 100 Ah battery, they state that the "Output voltage is flat during most of the discharge cycle". Furthermore can provide "100 Amp Continuous Current". The company states that the batteries have low and high automatic temperature protection which shuts down the battery if temperature falls to 25F or a high temperature of 135F is reached.
- Lifespan. The AGMs in my Roadtrek are designed for about 1200 charge/discharge cycles if they are not discharged below 50%. According to Battle Born the lithium ion batteries "Approximately 75-80% of the battery capacity will remain after 3000 cycles in applications recharging at 0.5C or lower". The recharge "C" rating for a 200Ah battery is 0.5 x 200 A, or a charging rate of 100A. The lithium ion batteries will have much more life remaining than the AGMs after a couple of years of normal use. My AGMs should give good service for about 5 years, or longer. The Battle Born batteries will exceed that.
- "Useful Life". Lead-acid batteries experience a reduction in capacity as they are charged and discharged because of internal changes, primarily sulfation. This reduction can be significant. After a year of use, my AGMs experienced about a 10% reduction. So, my useful 110 Ah decreased to about 99 Ah. Since then my batteries have leveled out, based upon voltage after a moderate period of discharge. The lithium ion batteries retain their capacity for a longer period of time. That can be important if one needs every bit of electricity available in the batteries when new.
- Inside LiFePo4. I would have to give up some under the bed space, because the Lithium Ion batteries should not be charged if below freezing. In fact, the Battle Born battery internal battery management system prevents charging below 25F.
- Inside AGM. If I kept my two outside AGM batteries and added two inside, that would provide me with 220 AH of energy versus 160 Ah for the Lithium Ion batteries. In other words, I'd get about 38% more energy from four 6-V AGM batteries. However, those four batteries would weigh about 272 pounds. Two Battle Born batteries would weigh about 62 pounds.
- Inside AGM and Battle Born comparison. The above with four AGM batteries provides about 220 Ah at the best case at 272 pounds. If I added one Lithium Ion battery to total of three, that would increase the energy available to about 240 Ah. The weight would be about 93 pounds.
The show stopper:
When I considered AGM versus Lithium-ion, I had these issues and yours might be different:
- I wasn't willing to mount the LiFePO4 batteries inside the coach, because I didn't want to give up that space. That would be to keep the batteries above 25F while cold weather trekking.
- If I compare the normal life of AGMs (5 years or so) to the Battle Born LiFePo4 (10 year warranty) this changes the costs. To get 10 years of use from AGM batteries would probably require replacement after 5 years. In 10 years the two changes of AGMs is $779.40 each, for a total cost of $1,558.80 for Deka versus $1,878 for Battle Born.
- If I needed more overnight DC power, the Battle Born could be worth that extra $319. After all, considering the 10 year "warranty" life of the batteries, that's only about $32 per year.
For more about Battle Born Lithium Batteries:
Copyright (C) 2019 Norman Retzke, "All Rights Reserved"
Original material: https://roadtrek210.blogspot.com/