New Voltmeter-Ammeter-Wattmeter for AGM batteries - Part 2

New Ammeter-Voltmeter-Wattmeter

September 15, 2017: Added short video clip

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Short video:

New Ammeter-Voltmeter-Wattmeter

See Part 1 for the background information about the AGM batteries in my roadtrek 210P:

http://roadtrek210.blogspot.com/2017/08/new-voltmeter-ammeter-wattmeter-for-agm.html

Why add a digital voltmeter-ammeter?
The decision to add a digital meter was easy. Then I proceeded to decide upon the type of meter. I had seen a FMCA Roadtrek Chapter Cyberrally post about how someone added a digital meter and I wanted to do the same.

Finding a meter wasn't all that difficult. A meter which stored "Ampere Hours" would have been ideal, but I opted for a digital voltmeter-ammeter-wattmeter. The selected meter also included adjustable alarm points for high and low voltage. That would be useful for monitoring low battery voltage, or a point at which I wanted to pay closer attention to battery draw.

I ordered the meter ($15.99 at the time) with DC shunt. I wanted to connect it directly to the battery so I could monitor battery voltage even with the battery disconnect "off". A switch and protective fuse was necessary. The parts list included:

1. Meter with 100A shunt
2. Off-On switch
3. Case for meter and switch (Case dimensions: 5-1/2" x 3-1/8" x 1-1/2")
4. 25 ft. 4-conductor cable
5. Automotive fuse holder (I used a fuse from my kit)
6. Miscellaneous connectors.
7. Note: for details, see the parts list at end of this post. 

The most difficult part for me was determining where to mount the meter. I had decided that I wanted a surface mount case, so I could remove the meter in the future and leave no trace. Determining how to run the 4/C cable was also a bit of a challenge. I decided to route it behind the fiberglass side panel, into the coach along side the door, then behind the side panel and exiting just below the 120VAC/12VDC power distribution center. This required the temporary removal of the rear passenger seat. Lots of screws.

Passenger seat removed, propane furnace exposed

With the passenger seat removed, it was possible to remove the side panel, and pull the cable behind the panel. I pulled the cable from the battery compartment to the passenger seat area, and re-assembled the interior panel. I left a foot lomg "pigtail" for connecting the meter.

Cable at Passenger Seat

I then mounted the rear of the meter case to the wall. I used 3M Dual Lock™ General Purpose Reclosable Fasteners. Note the female electrical connectors on the cable from the battery compartment:

Base of Meter Case

I assembled the meter in the case. Marked the case and cut the opening with a Dremel tool and cutting wheel. I used connectors so I can remove this if necessary. The "female" end goes on the cable from the battery compartment. The "male" end is in the meter case. This is so there should not be any exposed live parts if I pull the meter, even if the fuse at the shunt is intact.

Meter and Off-On switch in case

This is the front of the meter and switch, assembled in the case:

Front of meter case with Off-On switch

I mounted the meter to the case mounted on the wall:

Meter case mounted to the wall

This is the shunt, which was supplied with the meter. For the meter I purchased the shunt is connected between the negative battery post and the negative conductor. The shunt is rated 100A/75mV. The shunt is actually a precision resistor and the higher the current flowing through it, the higher the voltage drop across it. The voltage drop is 75 millivolts at 100 amperes.

Shunt

The shunt was installed in accordance with the manufacturer's instructions. A right angle screwdriver is helpful for installing the wiring to the shunt (I used a phillips).

CAUTION - Installing the shunt requires removing the negative battery lead. Exercise great care not to short a tool from negative to the nearby positive terminal. DEATH OR INJURY CAN RESULT. Be sure there is no battery load when doing this procedure.

The shunt is connected directly to the negative battery post. The black (Negative) cable is connected to the other side of the shunt; the yellow arrow points to that connection. Three of the leads of the 4-conductor cable is connected to the shunt. The fourth conductor goes to the red (Positive) battery terminal.  I installed an automotive fuse between the positive battery terminal and the lead going to the meter. That is to protect the wire in the event of a short circuit

CAUTION - A properly sized fuse is necessary to protect the wire in the event of equipment failure or short circuit. Fire, damage,  injury or death can result from an unprotected circuit.

Shunt installation and automotive fuse on positive battery terminal

With the installation complete I threw the "Off-On" switch to the "On" position.

I checked the display using a precision digital VOM. I measured the mV at the shunt and calculated the meter reading. The meter agreed.

Meter Setup
The meter has alarm points and some options:

1. Set backlight off or on. The default is "on".
2. Set voltage alarm threshold. The meter includes both "high" and "low" voltage alarms. These are set independently. The presence of an alarm flashes the backlight alternating "off" and "on". I set the low voltage alarm at the 50% DoD level for my coach batteries.
3. Set the measuring range. This meter will work with a 50A/75mV shunt or a 100A/75mV shunt. I set this to match the installed shunt, which is 100A/75mV.
4. Energy reset. The meter will accumulate and store kilo-watt hours (kWh). This value can be reset to zero.  

Meter Limitations
The meter is a DC meter. This means that the ammeter measurement is polarity sensitive. The meter as connected can only measure discharge current from the battery across the shunt. When charging the meter displays 0.00 amperes. However, by reversing the connections it is possible to measure charging current. I tried this and it works.

It was interesting to watch the Tripplite inverter/charger step through the charging levels. I may add a DPDT switch for this purpose, but it is completely optional. I've monitored the Tripplite by watching the AC current; as the Tripplite throttles back the AC current decreases. However, other 120VAC loads will mask that.  It is also possible to pull the compartment cover over the Tripplite and observe the charge state LEDs:

Green = Full Charge

Detailed Parts list, my cost $36.45 plus tax and any shipping:

1. MICTUNING DC 6.5-100V 0-100A LCD Digital Display Ammeter Voltmeter Multimeter Volt Watt Power Energy Meter Blue with 100A/75mV Shunt, Part No. MIC-DVG-015.
2. Serpac black plastic case, model 151i, BK.
3. Rocker switch, Philmore No. 30-882.
4. 4-conductor shielded cable, 24 AWG. (Use #22-24 AWG; smaller AWG is easier to pull).
5. Insulated terminal disconnects, male and female (from toolbox, not included in price total).
6. Fuse and fuseholder to protect the wire from the meter to the (+) positive battery terminal. Size of the fuse is determined by the size of the wire. 

New Voltmeter-Ammeter-Wattmeter for AGM batteries - Part 1

Earlier this year I replaced the AGM batteries in the Roadtrek with new AGMs. I decided against lithium (LiFePO4) batteries for the time being. For one thing, I hadn't decided which real estate I would give up. I wasn't sure I'd put them in the battery compartment as it is outside the rig and uninsulated.

I've posted on social media (G+ and FB) that I wasn't happy with the 4-point L-F-G-C "idiot light" arrangement in the Roadtrek, in particular because I discovered that the "G" or "Good" indicator was illuminated even when the batteries were below 50% depth of discharge (DoD).

What was my issue? It was about battery life and capacity. To get optimal life from AGM batteries most experts recommend not allowing the battery to regularly fall below 50% state of charge (SoC). The "G" or "Good" LED extinguishes below that level. The "F" or "Fair" light on the Roadtrek is below that. A simple plug-in digital meter was an option and one can be purchased for between $5 and $15. Here's one:

12V Plug-in digital Voltmeter

Our rental rig had such a simple meter, and I could plug one into the rear cabinet above the entertainment center in our 210P, which had a cigarette lighter for the 12V amplified antenna. I added a "Y" connector for this purpose. However, I also wanted an ammeter and a wattmeter, but I didn't want to spend the amount necessary for a Trimetric and I wanted something easy to install.

Here's the 12V connector I used to install a "Y" cable. That allowed me to connect a meter in addition to the 12V TV antenna amplifier. But viewing the meter in this location isn't very convenient.

Location of simple plug-in digital meter connector:

12V Connector in rear compartment

Installed and functional digital meter:

New Digital Meter

Battery Life Issues
All of this is really about getting full value and maximum capacity from the batteries. As AGM batteries age, they will lose capacity. Such batteries have specifications based on specific conditions, such as an ideal temperature of 77F. AGM batteries operate on chemical principles, and chemistry is influenced by temperature.

I had noticed that, after 4 years the batteries in the Roadtrek didn't seem to be able of providing the desired voltage for the time I wanted to use them "off the power grid". That indicated a loss of capacity.

The entire point of adding a digital voltmeter-ammeter is to get a better idea of the condition of the coach batteries. Even better than battery voltage is specific gravity, but that can't be readily determined. Below is a table for my current batteries which provides some idea of the life of the batteries when discharged repeatedly to certain levels of DoD (depth of discharge). As can be seen, the 50% DoD provides about 1200 charge-discharge cycles. Decreasing to 80% DoD provides a life of about 700 cycles. Avoiding DoD below 50% provides a good compromise between battery life (cycles) while providing adequate capacity.

The problem we face is that to extend battery life we either use them less (fewer cycles per year means more years of service before reaching end of life). Or, we can reduce the DoD. As noted in the table below, if the DoD is only 20% it is possible for a battery to provide 3600 charge-discharge cycles. Of course, to achieve only 20% DoD requires much less use of the available battery capacity.

Why Measure Battery Volts and Amperes?
How long can we run things in the coach on batteries and avoid discharging the batteries below 50% DoD? The ammeter and voltmeter with the tables for our batteries can be an aid to this.

For example, my batteries can provide 18.33AH for 12 hours. However, that is to 100% discharge, which is what I want to avoid. 50% DoD will allow a draw for only about half that time, or about 18.33AH for 6 hours.  Or, I could reduce the load and extend the time. If I really need to run solely on batteries for 12 hours, my batteries can provide about 9 amperes per hour:

                                           220AH/12H = 18.33A
                                           18.33A x 50% = 9.165A

The times are approximate. If we have an ammeter we can determine what the actual current draw on the batteries are. If we have a voltmeter. we can determine the state of charge of the batteries.

Battery Life and Charge-Discharge Cycles

Depth of Discharge - New AGMs

Using the Voltmeter
The digital voltmeter will provide an indicator of the state of charge (SoC) of the batteries. "OCV" is open circuit voltage, or the state when the batteries are not connected to a load:

Relative State of Charge @ 77F - New AGMs

Note that SoC tables may vary. Here is a "typical" AGM table, which differs from the chart above.

Typical AGM battery SoC table

Battery Life 
Taking care of batteries and extending their life will obviously reduce costs. They are expensive. 220AH of AGM batteries is about $450 to $600. However, the other desireable thing is capacity. I want to be assured that the battery is capable of providing the amperes I need for as long as I need them. A battery with reduced capacity may not be able to do that.

Capacity is the ability of a battery to deliver the amount of power it was designed to do. Over time, battery capacity will decrease. As the battery nears end of life, it's capacity will diminish significantly. The batteries I have are designed to provide 25A @ 460 minutes  (7.7 hours) when new. As the batteries lose capacity, they will provide 25A but for shorter periods of time. And as the battery discharges, the voltage will decrease. A battery with diminished capacity will experience more rapid voltage fall-off. DC power is volts x amperes. As the voltage diminishes, so does the power if the amperes are constant.

While extending battery life does reduce operating costs, I am more interested in having the desired capacity available to me.  My batteries are rated 220AH. That means that they can continuously provide about 18 amperes for 12 hours, if they can provide full capacity (see notes):

220AH/12H = 18.33A.

Real World Capacity
The capacity achieved is based on battery condition, ambient temperature and other factors.

As noted above, the 12 hour rating for my AGM batteries is 18.33A.

In the real worlds AGM battery capacity does gradually decline, and by 700 cycles capacity decrease to 50-60% is usual. That means that the above number will gradually decrease:

• New AGM battery (80-100% capacity) = 18.33A for 12 hours
• Battery after 400 cycles (80% capacity) =  14.7A for 12 hours.
• Battery after 700 cycles 50-60% capacity = 9.2A for 12 hours

Lithium batteries also have a gradual reduction in capacity, but generally a 220AH battery:

• Lithium battery after 400-500 cycles (80% capacity) = 14.7A for 12 hours. 

Note: The above numbers are based on battery manufacturer published data and this information does vary from manufacturer to manufacturer. It is important to realize that battery data is usually under ideal conditions such as 77F temperature. AGM battery capacity decreases as battery temperature decreases and can perform (charge and discharge) over temperature ranges of (-)4F to 104F. Lithium batteries generally can operate with charging temperature of 32F-113F and discharge temperatures of (-)4F to 140F. Electric vehicle and experimental data indicates that high environment temperature could accelerate the aging of LiFePO4 batteries, while low temperature could reduce output power capability. Data suggests normal life can be achieve if operated in the range 50F to 104F.
However, it is important to check with each manufacturer for their specifications.

Battery Life based on Depth of Discharge
A well maintained AGM (absorbent glass mat) battery has a life of 6-8 years. Average life has been stated to be 3-5 years. If not maintained, that will diminish to 2-4 years. Note that it really is charge-discharge cycles that are the limit. Battery manufacturers assume a certain number of such cycles in a year. That assumes optimal temperatures of 77F and that the batteries are immediately charged to 100% immediately upon the end of the discharge cycle.

For example, with 50% DoD my batteries are designed to provide 1200 charge-discharge cycles:

1. If used every day, a battery will experience 365 cycles per year.  Under such use, the batteries have a service life of 3.2 years. 
2. If a charge-discharge cycle occurs every other day, or about 180 times a year, the same batteries could provide a service life of 6.7 years. 
3. If a charge-discharge cycle occurs every three days, or about 120 times a year, the same batteries could provide a service life of 10.0 years. 

 For example, with 80% DoD my batteries are designed to provide 700 charge-discharge cycles:

1. If used every day, a battery will experience 365 cycles per year.   Under such use, the batteries have a service life of 1.9 years.  
2. If a charge-discharge cycle occurs every other day, or about 180 times a year, the same batteries could provide a service life of 3.9 years. 
3. If a charge-discharge cycle occurs every three days, or about 120 times a year, the same batteries could provide a service life of 5.8 years. 

How does one "maintain" a maintenance free battery?

1. Recharge as soon as possible after use - preferably within 24 hours.
2. Recharge the battery properly.
3. Use a "smart" charger.
4. Battery should not be charged if the core temperature reaches 120F (49°C).
5. Avoid discharging below 50% SoC (state of charge).
6. When recharging, recharge to at least 80% SoC before beginning another discharge cycle. 
7. Charge to 100% as often as possible. 
8. Avoid heat; heat shortens battery life. Each 15°F (8C) rise in temperature reduces the life of the battery in half.
9. Know the correct state of charge (SoC). Knowing this will help to extend overall cycle life. A battery monitor is worthwhile and use one that is accurate.  

Battery Cost 
There is a cost to overtaxing batteries, as noted above. Best case is a battery with 50% DoD, and that yields 1200 cycles under best conditions. As noted above:

1. If used every day, or 365 cycles per year or a service life of 3.2 years.  The cost is $140 per year ($450/3.2)
2. If a charge-discharge cycle occurs every other day, or about 180 times a year, the same batteries could provide a service life of 6.7 years. The cost is $67 per year ($450/6.7).
3. If a charge-discharge cycle occurs every three days, or about 120 times a year, the same batteries  could provide a service life of 10.0 years. The cost is $45 per year ($450/10).

 For example, with 80% DoD, which provided more AH, but sacrifices battery life:

1. If used every day, a battery will have 365 cycles per year.  At 80% DoD, my batteries are designed to provide 700 cycles.  Under such use, the batteries have a service life of 1.9 years.  (Cost is $236 per year)
2. If a charge-discharge cycle occurs every other day, or about 180 times a year, the same batteries with a life of 700 cycles could provide a service life of 3.9 years. (Cost is $115 per year).
3. If a charge-discharge cycle occurs every three days, or about 120 times a year, the same batteries with a life of 700 cycles could provide a service life of 5.8 years. (Cost is $78 per year).

Notes: 
Ampere-Hours. An amp hour (AH) rating is a rating usually used on deep cycle batteries. It is an ampere rating taken for 20 hours. For a 100 AH rated battery a load may draw 100AH from the battery for 20 hours.For such a battery, that's about 5 amperes an hour. 100AH/20H  = 5A).

1. The total time of discharge and load applied is not a linear relationship. As the battery load increases the actual capacity decreases. For example, a 100 AH battery with a 100 amp load should provide one hour of runtime. But it won't. The capacity of the battery will be severely reduced.
2. Each battery manufacturer provides AH data under various loads. For example, here is the table for my batteries, with a final voltage of 1.75V per cell (3 x 1.75 = 5.25V, or a dead battery):
1. 20 hours = 220 AH
2. 10 hours = 210 AH
3. 5 hours = 190 AH
4. 3 hours = 175AH
5. 2 hours = 155 AH
6. 1 hour = 130 AH

Using the AH from the battery table, a rough guide for capacity can be determined. For example, 10 hours = 210AH. To achieve a 50% DoD, 210 x 0.5 = 105AH realized capacity. To achieve a 80% DoD, 210 x 0.8 = 168 AH realized capacity.  However, these figures are approximate and are based upon a new battery and 77F. The approximate condition (state of charge, SoC) can be determined with a voltmeter.

Using the above, the 10 hour ability of the batteries is actually about:

10 hours, 50% DoD = 105AH/10H = 10.5A.
10 hours, 80% DoD = 168AH/10H = 16.8A.

Note that the above information is in accordance with the battery data provided by the manufacturer of my batteries. The actual data will vary by manufacturer.

August 10, 2017 added and expanded "real world" battery life data.

Current Project - Adding a DC Voltmeter-Wattmeter

Updated August 4
I completed the install yesterday. I did install a fuse at the coach batteries. I'll post a more complete blog in the future on the details of the install. The meter works well. I set the low voltage alarm at 12.1V (about 50% depth of discharge, or DoD). The meter is very accurate. I measured the voltage at the coach batteries and compared to the display. I also measured the mV at the shunt and compared to the ammeter display (has a 75mV shunt). After charging the coach batteries I killed the AC to the coach and with the meter powered, the fantastic fan at speed 1 and an overhead fluorescent on, this was the display. The battery voltage is high because it has some surface charge:

Voltmeter-ammeter-wattmeter with voltage alarm

Updated August 1

Meter in Case, with DC power "Off-On" switch

Making progress. The cabling is in, the shunt is mounted, and I've wired the meter case. I should complete in another hour or so. However, today (August 1) it was overcast and so I worked on the travel trailer; I'm using Meguiar's® Fiberglass Oxidation Remover on the cap. Got about 70% complete before the rain came in. I'll be working on that for another couple of days, weather permitting. Can't do this in the sunlight, or the rain. After completing with the Remover I'll be using No. 45 Polish followed by No. 56 Pure Wax.

Today I wired the meter case, and assembled jumper cabling to extend from the coach batteries to the cable run to the meter.



Original Post, July 28, 2017:
Current project is to put a decent DC electrical meter into the 210P, to monitor the coach batteries.

The 4-LEDS (L-F-G-C) or "Low-Fair-Good-Charging" indicate G "good" at 11.95V, which is not good IMHO. I really don't know the point at which the G indicator goes out, and the F "fair" indicator is illuminated. I don't think I want to find out.

Why my concern? The 11.95V which the LED "G" indicates "good" charge level, is actually a 40% charge level (60% DoD, or "Depth of Discharge") for the AGM coach batteries. Why do I consider that to be a problem? To get best life out of the AGMs it is my understanding that one should not repeatedly discharge below 50%, although these batteries can be discharged 80% (11.66V). The bad news? Doing so repeatedly will shorten the life. How much? As much as 50%, or a 5-8 year battery will make only 2.5-4 years.

So I'm interested in knowing the DoD and a good voltmeter will tell me that. My 210P has the AGM coach batteries, and I replaced the first set a few months ago; they were about 4-1/2 years old.

Is there an alternative approach? I considered just adding meter jacks, but G would have had some difficulty with that, so I'm putting in a digital ammeter-wattmeter. Probably the most difficult was determining how and where to mount it, because routing the cabling is a real pain. After figuring it out I purchased the parts. Should be up and running in a few day, assuming I find some time to complete.

Tire Carrier Surface Finish Issues - Rust!

Yakima Bike Carrier - No Rust after 10 years

The photo above is not directly related to the issue with the tire carrier finish. But this is the best place to put it on the blog. I added this photo of the bike rack on the rear of the Roadtrek. It is a Yakima "KingPin 4" which can accommodate up to four bicycles.  We normally travel with two.

The Yakima shows no rust, after 10 years. It has a powdered finish and Yakima obviously does a great job. No rust of any kind on this bike carrier after about 11 years!

I purchased this adapter in 2006 for our Malibu Maxx and use it on both vehicles. I added a hitch adapter to match the hitch on the 210P to the 1-1/4" hitch on the bike rack. This moved the rack out.

As shown in the photo, I can open the right rear door of the Roadtrek with the rack on the Roadtrek. Very convenient.

Comments March 1, 2017:

1. A reader suggested I consider using "Corroseal" which is a rust inhibitor.  Thanks for the tip, Wanda!  "Corroseal® is a water based rust converter combined with a non pigmented high quality latex metal primer. The converter segments turn rust into a barrier layer of black non rusting magnetite. The metal primer acts as a bonding agent for oil-based intermediate and finish coatings of epoxy, enamel, acrylic, polyurethane and moisture-cured urethane...."  http://www.corroseal.com/technical/technicaldata.aspx
2. I used Rust-Oleum® Stops Rust® Rusty Metal Primer. According to the manufacturer this "stops rust and prevents corrosion. Apply to heavily rusted metal (use Rust-Oleum® Stops Rust® Clean Metal Primer on clean or lightly rusted metal). Bonds tightly to rust to form a surface top coats can adhere to."

Original Post February 27, 2017
The surface of the metal tire carrier on my 210P began to show some distress about two years after purchase. Paint flaked off to show rust underneath. This became quite extensive by the third year.

I really don't know what grade of steel, or surface finishing was used. It appears that there was no metal primer, but that is difficult to determine. Let's just say that the black paint and the primer were identical, because the paint flakes were black throughout, with rusty metal beneath.

I prepared the surface by cleaning with mineral spirits. I then used a stiff wire brush and a wire wheel to remove as much loose or flaking paint as possible, and also removed as much surface rust as I could. However, it would take a lot of grinding to get to polished metal. I also did not want to disassemble the unit.

Here's what it looked like after the first pass of cleaning. The first was by hand with a stiff wire brush, to remove as much loose paint as possible:

Here is how it looked after using the wire wheel with a 3/8 drill and before cleaning. Soon I'll be applying a primer:

After doing this I cleaned the surface again with mineral spirits, allowed to dry and then with a tack cloth. I did have to open it and flip it several times, and I used a wooden shim to keep it from closing (going to a 90 degree position).

I wanted to assure that all loose rust and paint had been removed. I decided against using a spray primer, choosing a brush-on "Rusty metal primer". I painted it partially on a table, let that dry overnight and then completed by sliding it partially into the center hitch of the Roadtrek:

I let it dry in the horizontal position, then closed it partially and that allowed me to paint other areas. I used a wooden shim to hold the hitch in position (shim removed for this photo):

I used brush-on black enamel as the final coat of paint. I used a shim to hold the rack in the partially dropped position. The arrow in the photo points to the shim, which is a piece of scrap with partially black surface:

Here's the finished tire rack. I didn't put a finish coat on the section that slides into the receiver; it will simply be scraped off when inserting it:

While I was at it, I painted the hitch parts on the Roadtrek that were showing some rust. Same procedure as the rack; clean, wire brush, prime and then finish coat.

We'll see how well this does. I hope it slows the rust down.

Coach Battery Replacement

My Roadtrek which I could name "Tried and true" or "Rock steady" continues to perform. But there is maintenance to do. Some of this is preventative.

It became apparent that I needed to replace the coach batteries when one of them dropped to 0 volts. It had shorted, I guess, because the bank was at 6.5 volts, which was the voltage across one of the batteries and also the voltage across both. One battery seemed to be doing okay and the other was a tag-along. Just like America, 50% are doing the work and the other 50% is contributing nothing. beyond lip service.

I was aware that the batteries were not able to deliver the designed capacity. Capacity is the ability of a battery to provide the required power (watts) or ampere-hours for the required amount of time. My coach battery capacity prior to the 0 volt failure was below 50%, even though they measured suitable voltage on the indicator in the Roadtrek.

My batteries achieved a life of 4 years. Well maintained AGM batteries can go for 6 years, or more. I use a 50 watt solar panel with de-sulfating controller to maintain the batteries when off of the grid. My measurements indicate this is sufficient when storing the Roadtrek. On a sunny day the batteries will reach peak voltage. After a couple of cloudy days the voltage might decrease to about 80% as an indicator of "state of charge." I take my measurements early in the morning, prior to sunrise and after sufficient time to dissipate any "surface charge."

I'd done a lot of research including opening a discussion via the FMCA Roadtrek International "cyberrally" email.

I'd also designed a LiFePO4 system, should I want to upgrade to a lithium battery system. However, I decided at this time that going with AGM battery replacement was the prudent thing to do. More on that decision in a future post.

I was spending some time in the Tucson AZ area, so I found a distributor who carried the 220Ah 6-volt AGMs I was interested in and would install them for an additional $30. The total price was irresistible.

One thing we observed was the ends of the crimp connectors showed some oxidation. Is that a problem? The oxidation is higher resistance than bright copper, and over time that oxidation will creep up the wire. Resistance is a voltage loss and a source of heat. After cleaning, the ends were again shiny copper.

The installer then applied liquid plastic via a glue gun to seal the end of the connector. This should prevent further oxidation.

The new batteries included lifting means. One of the reasons I didn't do this was the fact that the old batteries didn't have such a means. I was faced with either purchasing a strap, or wrestling with 63 pound batteries. I've stored the lifting means in the compartment with the batteries.

Here's the completed installation:

After several weeks of monitoring the battery voltage, and with the solar panel connected, it seems the new batteries are doing well, achieving maximum terminal voltage and sustaining it into darkness.

My Roadtrek which I could name "Tried and true" or "Rock steady" continues to perform.

Adding Interior LED Strip Lighting to RV

We like the lighting of the 210P, which includes LED spots and fluorescents. But in the evening we wanted dimmable and "surround" light. So in June of [2015] I purchased and installed strip lighting.

I purchased a strip of LEDs 16.4 feet in length, with power supply, remote control and sensor for the remote. The cost was about $22 and today a similar strip can be purchased for less.

The first decision was where to mount the power supply. I could have gone direct DC, but decided on using the 120VAC supply that came with the strip. [Note: Some of the LEDs are designed for 12VDC and are intolerant of the higher voltages which can occur in RVs. I decided to use the AC/DC power supply which provides a stable DC voltage to the LEDs].

For the location of the power supply I had two easy choices. One location was above the entertainment center and the other above the kitchen galley. I chose the kitchen galley because it provided a better "line of site" for the remote.

As is true for all of my projects I determined what plugs into what before I attempted the install. I powered it up and confirmed operation on a tabletop. I also checked the length of the LED strip and how far it could reach. I'd made measurements prior to purchase, but the saying is "measure twice, cut once." This is before doing any drilling, etc. I had measured the length of the ceiling perimeter in the Roadtrek, The strip would reach from the extreme edge of the cabinet above the kitchen area, around the rear and to the armoire with about a foot to spare. I removed the plastic cover of the heat pump/AC so I could run the strip beneath it. The strip has a sticky back and adheres easily to the cabinetry.

Before installing I plugged it all together on a table and powered it up. I verified it all works before installing.

Here's the package:

Here are the electronics included in the package. Not shown is the remote or the spool of LEDs. This is a power supply and control module. The module includes a sensor which responds to the remote:

Here's the sensor that must have "line of sight" to the remote control. The sensor is one of the leads going to the white box in the above photo. The control included detailed instructions of what to plug into what, so I won't duplicate that here. The important this is this. The sensor must be installed outside of any cabinet so the remote will work.

Here's the second lead from the white control module. This lead goes to the LED strip. If you enlarge the photo you will notice a raised arrow. This must be aligned with a matching one on the mating connector of the LED strip. I needed to drill a hole large enough to accommodate this connector and the sensor.

Using a hand drill, I drilled a hole large enough through the cabinet to accommodate both connectors, but no larger than necessary so as not to reduce the strength of the cabinet. Here is what it looks like with the LED strip in place. The sensor was pushed into the hole from the rear and projects slightly into the room.

I also fed the LED connector through the hole and into the cabinet. It is probably easier to do the LED first. As I unrolled the LED strip I removed the backing about 3 inches at a time and pressed it onto the cabinet surface. The strip has a sticky back. At the heat pump/AC I removed the cover and ran the LED strip under it and around. It reached all the way to the armoire.

Here's a close-up. You can see the sensor projecting into the room:

Here's the cable and connector from the LED strip, Ready to install the control module and connect.

To get the strip around corners I used two techniques.  I used a razor knife to cut the plastic lens at exterior corners. This allowed for a sharp 90 degree bend. For interior corners I simply rounded the LED strip. Of course, I could have chamfered the inside corners, but I decided the benefits outweighed the time spent:

Ready to mount the electrical components:

Drilling the mounting holes for the screws to hold the electronic control module in place:

Connecting the LED strip to the control module. Be sure to observe the polarity markings:

Ready to mount the power supply:

I used sticky bases for cable tie-wraps to mount the power supply (See Note 1). These tend to loosen and perhaps one day I'll do this with screws. After mounting I plugged the power supply into the controller and into the AC outlet:

In the above photo, you will notice the sensor hanging in space. I simply pulled on the cable, drawing it back toward the hole. It projects about 1/4 inch from the front of the cabinet. Not noticeable,

Here's the remote:

Here's a close-up of the LED strip. It can be cut at the copper areas to shorten it, but I chose not to:

Here is the same strip illuminated as "white" and at maximum brightness:

Here we are, at night with the strip set to white light and moderate intensity:

Notes:
Per reader question. The "sticky base" I used for the cable ties is a square plastic mounting base with foam sticky backing. The cable tie can be threaded through this. These bases tend to loosen under high heat when attached to non-smooth surfaces (>90F per my experience). See the photo: