Portable Solar and Monitor Location

[thoer]

Larry, your post pretty well sums up what seems to be an inherent conflict with the all in one kits. I am by no means an expert, and am still at the exploration stage, deciding if solar is worthwhile for our situation. So I hope Paul will provide better answers as he has done far more research into this than I have.

From what I have read, the oft quoted solar expert Handy Bob seems to say that batteries suffer early death and are never fully charged unless they are always charged at voltages prescribed in charts like the one Seldonseem provided for us.

Again, my inexpert opinion, is that the solar kit manufactures make nice handy portable systems that do indeed provide charge and give folks more useage. But the charge they provide does not seem to meet the requirements of battery companies and solar experts. (But then again, the OEM converter charger in my trailer is regarded as far from ideal too)

So, it seems to come down to cost tradeoffs. My personal opinion for our situation, is leaning toward the fact that solar will only be occasionally used so I want something I can easily carry in the back of our truck. The portable kits supposedly will cause some unspecified shortening of battery lifespan by not charging ideally, but apparently so is my OEM converter charger......

Mounting the controller close to the batteries seems to me to be a relatively easy possibility to minimize voltage drop, but I am far from any decision.

(I did buy one of these Battery-Tender-022-0142-DL-WH and use it while our trailer is in storage as it supposedly puts out all the correct cycles and voltages....but I am sure it is probably far from ideal too... I think I'll just go make some homebrew.)

[Jubal]

"Jubal has taken a different approach and replaced his WIFCO with a Progressive PM4-45 MBA controller".

I installed this power converter:
To maintain the battery charge in storage using a 4 stage charging strategy which includes a stratification/desulfation stage.
To fully charge the batteries (within a resonable amount of time) after they are depleted from dry camping using shore power or a generator during a trip if needed.
To eliminate the need for a auxillary remote charger.

[fudge_brownie]

All of you have made very valid points. First, Eric’s consideration of how you are going to use the solar unit is critical to what to buy. Let’s look at some scenarios: If you are going to be using it for a maximum of four nights at a time before connecting to shore power or driving 8+ hours the three kits that Larry has listed will work. For that matter, they will always work; it is a matter of what will work best.

The other side of the equation would be those situations where you are relying on solar power for more than four days. These might occur in national parks, forests or state facilities without shore power. On a recent trip to Yellowstone and the Tetons we were without shore power for almost two weeks, a short drive did some charging. In these scenarios you will possibly have cloudy days that will affect charging, you may be off season and using furnace more, showers might be in the trailer so the pump will draw more battery. In any case, it is at this time that you will want the most battery. Here is where the higher charge rates and increased charge in the battery will come into play. I think battery life will be extended

Larry has come up with an excellent list of portable solar units. I had only seen one of these before. The two I did not see were quite impressive, that being the GPElectric and Samlex. I purposely did not look at price, which is not part of this consideration. I think Larry summed it up best with his observation that these units all fly in the face of keeping the controller within 1-2 meters of the battery. Here are some calculations based in the Samlex unit. The controller will put out a charge rate of 14.6 VA in the absorption stage, not far off from the recommended 14.8 VA. But now we connect the supplied 32' extension cable and using the voltage drop calculator and using 14 AWG wires we find ourselves with only 14.31 VA at the battery. Replacing that wire with a 12 AWG will bring the voltage to 14.41 at the battery. Ten AWG is an option; we would now have 14.48 VA at the battery.

The Samlex unit is nearly identical, they have a lower starting voltage of 14.4 VA but use a 12 gauge AWG wire on 16' of cable. This gives them 14.3 VA at the battery. You probably should not opt for the 30' extension cable, that will give you 14.13 at the battery. The Solarland unit does not provide enough information to make any conclusions.

In summary, Larry is correct, these units are nice kits, particularly the GPElectric and Samlex but they cannot venture far from the battery and it is best not to use the 30 ft cables they provide. And Eric is correct in stating that your camping style should affect your selection of solar. There are two work a rounds to bring these panels closer to optimum, replace the cables from the controller to the battery with a minimum 10 AWG cables or remove the controller from the panel and place it next to the battery, then use 14 AWG wire to connect the panel to the controller.

I do no want to be critical of this as an option and believe it is a good option providing you know what you are getting. I would like to restate what I plan to do if I ordered today. I will use the following:

- 100 Watt suitcase panel from solarblvd – throw away the attached controller.
- Xantec C35 controller – non digital model. This unit has selectable voltages for absorption, float and equalization stages. Installed inside the Escape battery compartment near the battery boxes. I will set for 14.8 VA
- Some type of marine connector on the outside of the Escape to plug in the solar.
- Three prong 15 amp grounding connector and plug. Often used as replacement connectors on extension cords. These connectors will allow me to insert a standard extension cord of varying lengths between my panel and outlet on the trailer. These cords will double as connectors to shore power if the campground power pole is not accessible with the built in cord.

I am estimating a cost of $310 US with shipping, assuming I have the extension cords.

Now, I am going to look up the cost of the GPElectric and Samlex units.

[thoer]

Paul, as always, thanks for the well explained info. What do you make of those voltages requirements in that Interstate chart for dual 6v's- it calls for voltages as high as 15.6 in one cycle?

(I like your solution and would probably go with it, if I could get myself to drill that access hole )

[fudge_brownie]

Drilling that hole would give me cold chills. I'm glad you have to get over that one.

Those Interstate charge levels are from their official web site and table. I believe those of us with older dual six volt batteries, not sure when the change over occurred, have Interstate U2000 or U2200. I believe those have now been replaced by Interstate GC2-XHD. The recommendations are a little different, depending on the model. but all are over 15 volts. For the U2200 it is 15.5 VA for absorption stage, the GC2-XHD are at 15.3 VA

And to think the built in WFCO charger is charging at the rate of 14.4 VA, but according to some reviews it never gets to that rate, instead uses 13.6 VA. Big difference between 13.6 VA and what Interstate recommends for my batteries of 15.5 VA.

Now we could get into a discussion, is that what I really should charge them at? I had to check, the Xantec C35 does go to 15.5 VA. Since that is the recommendation by Interstate and the controller would do it, I will use their advice.

[thoer]

Paul - are you getting something instead of the WFCO in your 21?

[Stargeezer]

Originally Posted by fudge_brownie

Drilling that hole would give me cold chills. I'm glad you have to get over that one.

Those Interstate charge levels are from their official web site and table. I believe those of us with older dual six volt batteries, not sure when the change over occurred, have Interstate U2000 or U2200. I believe those have now been replaced by Interstate GC2-XHD. The recommendations are a little different, depending on the model. but all are over 15 volts. For the U2200 it is 15.5 VA for absorption stage, the GC2-XHD are at 15.3 VA

And to think the built in WFCO charger is charging at the rate of 14.4 VA, but according to some reviews it never gets to that rate, instead uses 13.6 VA. Big difference between 13.6 VA and what Interstate recommends for my batteries of 15.5 VA.

Now we could get into a discussion, is that what I really should charge them at? I had to check, the Xantec C35 does go to 15.5 VA. Since that is the recommendation by Interstate and the controller would do it, I will use their advice.

We may be getting too technical, but here goes anyways... I'm wondering Paul, if the 15.5v refers to "equalizing" the batteries? If so, then this is different from regular charging, especially through solar. Equalizing is periodic "topping up" of battery capacity and correcting cell capacity differences.

Electrolyte stratification can occur in all types of flooded batteries. As the battery is discharged and charged, concentration of sulphuric acid becomes higher at the bottom of the cell and lower at the top of the cell. The low acid concentration reduces capacity at the top of the plates, and the high acid concentration accelerates corrosion at the bottom of the plates and shortens battery life. Stratification can be minimized through equalization by raising the charging voltage so that the increased gassing and bubbling agitates/stirs the electrolyte and ensures that the electrolyte has uniform concentration from top to bottom. The stirring action also helps to break up any lead sulfate crystals, which may remain after normal charging.

During normal charging, temperature and chemical imbalances prevent some cells from reaching full charge. As a battery is discharged, the cells with lower voltage will be drained further than the cells at the higher voltage. When recharged, the cells with the higher voltage will be fully charged before the cells with the lower voltage. The more a battery is cycled, the more cell voltage separation takes
place. In a healthy battery, all the individual cells will have the same voltage and same specific gravity. If there is a substantial difference in the cell voltages (0.2 V or more) and in the specific gravities (0.015 or more) of the individual cells, the cells will require equalization. Equalizing batteries helps to bring all the cells of a battery to the same voltage. During the Equalization Stage, fully charged cells will dissipate the charging energy by gassing while incompletely charged cells continue to charge.

Equalizing temporarily elevates the charging voltage of the entire battery string above the normal "float" voltage. The elevated charging voltage allows all cells, including the weak ones, to accept more current from the charger than they would at float voltage. A consequence of the elevated equalize voltage is that all cells in the battery are overcharged. This is acceptable for short periods provided the battery has sufficient electrolyte.

Overcharging greatly increases the rate at which the water in battery electrolyte is electrolyzed into oxygen and hydrogen gas. Since low electrolyte level will permanently damage the battery it is important to limit when, and for how long, the battery is charged at the equalize voltage.

Therefore Paul, if you set your normal charge (through over ride) to equalization, you may do your batteries more harm than good. On the other hand, occasional equalization, may lead to longer battery life.

To get the batteries occasionally equalized, one would think that ETI has done their homework and have matched their standard converter offering to the battery options (12v & 6V) provided.

My intent was not to pontificate, but the solar option is not cheap... For what it is worth, I believe that battery charging with solar and equalizing charging are two separate issues. But I've been wrong before!!!

Thanks,
Larry

[thoer]

Larry - very interesting - thanks

[Dave Walter]

Originally Posted by fudge_brownie

Thanks to Bob, SantaCruzer there is a better device to use when connecting your portable solar to the Escape. Called a "deck connector" it is for marine applications using two wires that are polarized. Bob pointed out the below model from the West Marine catalog.

Looks like you need the male plug on your Escape and the female plug on the cord from your panel. Maybe something like this one.

[gbaglo]

Portable battery chargers may or may not have an Equalization option.
Mine doesn't, but in a video on the Trojan Battery site, they say that you can achieve the same thing by unplugging the charger and plugging it back in. So, I gather that after it is indicated as fully charged, you unplug and after a short time, plug it back in.
Unfortunately, there doesn't appear to be any clarification of the process elsewhere on the site.
Talked to my mechanic about "equalizing" and in his experience, it didn't make a difference on a under-performing battery. Maybe, by the time you notice poor performance, it's too late.
So, maybe just put the battery (s) on an auxiliary charger ( with equalization phase ) from time to time.

[fudge_brownie]

Larry,
That was a very good description of the equalization stage of battery charging. I understand what it is doing, I am not sure I understand the long term results. Your question made me go back to the Interstate website and check the numbers and it is very clear that the recommended levels for charging Interstate batteries are significantly higher than similar numbers for Trojan.

For the bulk charge rate, that is applied when the battery is below 80% charged, the rate of charge is 14.4 VA. Once the battery reaches 80% charge Interstate recommends a charge of 15.5 for 2-4 hours, they call this the absorption stage. In addition they call for voltages even higher, that of 15.6 for the equalization stage that you so ably described. The final charge rate is 13.2 for maintenance or what some call a trickle charge.

All this is being done by something called a smart charger. What are smart chargers? The primary requirement of a smart charger is it has the ability to communicate and measure conditions on the battery and then make adjustments. It is preprogrammed to look for certain benchmarks and then automatically perform a switch. Most solar controllers are smart with 3 or 4 stages, the built in charger in the Escape from WFCO is smart and has three stages. Many homeowners have a portable battery charger that works off household current. Some many be smart, some are for only one stage such as a trickle charge and some may have buttons or switches to move between stages.

All smart chargers are going to make these transitions automatically, temperatures can come into play, so some solar controllers have options for temperature sensors to adjust for such changes. Some smart chargers do not have the equalization stage. The big variable on smart chargers, and this is the key statement to this discussion, is only a few are adjustable as to voltage rates. Most are preprogrammed to perform their events at a certain voltage and you have to live with that setting. If you take anything away from these pages of posts let it be that you will benefit from a solar controller that you can control and adjust voltages. The battery discussion points out how under charged we are leaving our batteries with chargers and controllers that do not provide the voltages that are recommended.

[jamie beers]

Paul, thanks for all these posts. If I'm reading everything correctly ( and being a newbie, chances are I'm in error), the rates you just posted are not reached by the Tristar TS-45, which is apparently one of the desirable controller options.

Well, at least not reached by any of their pre-programmed selectable options, and I don't seem too interested in delving in further and doing my own software customizations.

From what I've read on Trojan batteries, their recommended rates are slightly lower. The available options for the TS-45 do seem to match up nicely with the Trojan numbers I've seen.

My foggy mind seems to have come up with 2 choices: (a) get an Interstate battery that's better than a Trojan battery, but one that I can't optimally charge, or (b) get a Trojan T-105 that I can optimally charge.

Am I way off base here? j

[fudge_brownie]

I think you have it correct. I sympathize with you on reading the TriStar user manual, or any of these user manuals for that matter. Yes, short of a software customization, it appears the TriStar peaks out at 15.0 VA.

I just finished reading about differences between Trojan and Interstate batteries, trying to see if there is a valid review that distinguishes one as better. All I could find was anecdotal comments, like mine lasted 8 years and I had one bad cell etc. There does not seem to be a difference between them that could be measured and validated. I have an email into ETI asking if the Trojans are available on a new trailer delivery.

Now I am not so sure it matters which one.

A third alternative would be to find a replacement for the TriStar that does reach the desired levels. I have only considered the TriStar and Xantec, the Xantec claims to do it. There maybe others.

I have heard the claim that keeping a battery above 80% charge, rather than the 50% that we all live and die on, will result in longer battery life. No proof, just a claim,

[jamie beers]

Thanks very much for replying. I seem to feel most comfortable with the Tristar, so I am thinking T-105. I would be interested in any feedback from ETI about the Trojans.....batteries.

j

[gbaglo]

I went with Trojan, even though they have lousy graphics and are a ugly brown colour.

[thoer]

Originally Posted by gbaglo

I went with Trojan, even though they have lousy graphics and are a ugly brown colour.

That's it then - I'm sticking with Interstate!

[Stargeezer]

For me, this has been a great discussion. One last shot... after reading the last post... #56, I spoke with a vehicle tech acquaintance of mine who retired a few years ago. He stated that no charger can determine a batteries charging specs. Most mechanical shops have chargers that can be programmed by the techs to the specs of a specific battery. This includes all stages... bulk, absorption, float & equalization. Interesting though, he said that the chargers are mainly used to set-up a new battery for installation (out of the box, through the charger and then into the vehicle). This includes crank as well as deep cycle batteries. When it comes to batteries that have been used for some time and are showing signs of failing, this commercial charge can help in giving the batteries a little more life. Unfortunately, in most cases, the disease that the batteries have at this point is terminal and it is best for them to get their affairs in order... they're not long for this world!

His two suggestions... find out from current owners what batteries they have had, how long have they had them, how much and how have they used them (including charging... online & storage) and like that "goofy bunny", do they just keep going & going! His view is... if there hasn't been a "tsunami" of quick battery burn out, then chances are very good that ETI has designed a very good converter/solar/battery configuration.

Second suggestion... take them out occasionally and have them "blasted" in a battery (mechanical) shop. How often... yes!

I'm done...

Travel Safe...
Larry

[padlin]

If anyone is interested and not seen it before, the site referenced below has a couple calculators that are useful for calculating proper solar array size and orientation. Quite a difference in the roof mount "flat" orientation as compared to optimal angle if adjustable.

Solar Irradiance - calculate the solar energy available on your site

Solar Angle Calculator | Solar Panel Angle Calculator

[FMLNM]

Nice! For the SW it looks like not too much different between optimal angle and flat installation except for the winter months (Nov-Feb).

[fudge_brownie]

Dave and Fran
The same numbers hold true here in Wisconsin. If you have sun, flat is almost better than an angle in June and July. The bigger variable for us is tree cover. With the state heavily forested, having portable solar has distinct advantages over roof top mounted.