Solar ring connectors to a 2 battery bank

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denmarc said:
I beg to differ. It is also said the chain is only as stong as its weakest link. Many places for a weak link to occur in a multiple battery set up. Your scenerio assumes a perfect "chain". Not reality. Too many variables.

In reading the thread word for word, it appeared to me the OP has 2 6v batteries. But he doesn't confirm that fact. He never says type of batteries he has. Sounds to me like everyone is guessing.

I think it's a good time to start again. Lets find out exactly what the OP has in place (Maybe pics?) and help this poor poster out.
Mark, I don't disagree that problems in the chain can be a problem but I don't assume perfect either, just well maintained and designed.

IMO the myth exists because people don't maintain their systems as often as they should or the builder went cheap.
 
'Myth' until, you know, tests and amperage readings are actually observed. http://www.smartgauge.co.uk/batt_con.html

I didn't want to continue this argument but, come on, you guys are taking your opinion a bit far; you're misinforming people. The industry disagrees with you.
 
Desert_Rat said:
'Myth' until, you know, tests and amperage readings are actually observed. http://www.smartgauge.co.uk/batt_con.html

I didn't want to continue this argument but, come on, you guys are taking your opinion a bit far; you're misinforming people. The industry disagrees with you.

While I don't disagree with the numbers quoted in your linked article, there is a "practical" realization to live with.  For our purpose, using multiple batteries to provide more amp/hours in our RVs.  The examples given in the article are splitting hairs....to the extreme.  The analogy that I would make is that if your car/truck battery was reading 12.6 volts, as measured with a perfectly calibrated volt meter and you engaged the starter to start the car/truck.....neither you or anyone else could tell the difference between that 12.6 volt battery starting the car and one that reads 12.5 volts.  It's no different that you common household voltage variations.  I can take a meter out to the breaker panel at my house and read one side of the 240VAC coming into the house and get 124.7volts to the neutral, then read the other hot line to neutral and get 124.2volts......can you tell the difference between the brightness of one light bulb being fed off of one side of the incoming power  vs.  another light bulb being fed off of the other phase coming in......with a .5 volt difference?

I work as a High Voltage Journeyman Electrician and some of the testing that we do on high voltage breakers and contactors for motor control, involve testing them for contact resistance, phase to ground resistance, and leakage current to ground which tests the amount of current flow to ground with specialized, highly calibrated test instruments.  I see readings that are so small that most people would simply ignore them or not even know what it meant.  An example of this....while applying 10,000 volts to a high voltage breaker, we measure the amount of leakage current to ground for that particular conductor of the breaker and sometime see as little as 1/10 of one micro-amp...that's  .0000001 amp of current.  Many times the resistance reading for that part of the breaker might be as high as 8 or 9 teraohms.....and one teraohm is equal to 1,000,000 megaohm....so suffice to say....a very high resistive value. 

So, I've said all of that ^^^^^ to say this.  For all intents and purpose of hooking up a charger to the battery bank of parallel batteries, it really doesn't matter where you hook it up for our practical use of the batteries in our RVs.  Are you really going to see that .0001 voltage drop?  Are you really going to see any performance degradation from it?  And furthmore, I quit reading the article when I rechecked their math and found some of his published numbers to be wrong.  .00012 (cable resistance for 20cm of cable) AND the additional .0002 (connector resistance) plus another .0002 connector reistance does NOT add up to what he said...  .0015 ohms.  The actual total resistance for what he is talking about...two connections and one length of cable is....  .00012 + .0002 + .0002 = .00052 not .0015.  And again, these are very, very, small resistance numbers that in real life, what we are using our batteries in the RV for, have no noticeable effect on our battery charging/usage. 

In my world of high voltage breakers and contactors when dealing with 2300V, 4160V, and 13.8KV, those small numbers in the micro amp and teraohm range have significant meaning and will determine whether or not a breaker will safely operate according to IEEE testing standards......in the real world of 12 volt batteries in an RV...........not so much

And then, to top it all off, the O.P. gave us the wrong information in the original post and stated that he had a parallel hookup for his batteries.  Turns out, he has two 6 volt batteries that are hooked up in series to provide 12 volts.....and we all know that Ohms law states that the current flow in a series circuit is the same throughout the entire circuit, and that amount of current flow is based on the applied voltage and the total circuit resistance.

Sorry for the very long-winded post, but I felt that some "practical" light should be shed on the subject and information given that will work for our purpose.

And a quick PS......I don't consider this discussion an "argument".  To me it is simply a discussion with the hope of coming to some conclusion for our practical use of batteries in our RV's.....a common sense approach if you will.
 
Good post

Not to argue  :) but:
The bottom battery provides 35.9 amps of this.
The next battery up provides 26.2 amps.
The next battery up provides 20.4 amps.
The top battery provides 17.8 amps.

Is substantial. That's 4 batteries connected in parallel, the 'bottom battery' having both leads connected to it.

Industry standard is connecting one lead to the first battery and the 2nd lead to the last battery, getting these improved, equalized results:
The bottom battery provides 26.7 amps of this.
The next battery up provides 23.2 amps.
The next battery up provides 23.2 amps.
The top battery provides 26.7 amps.

That's not to say that I totally disagree with you, because your point about it splitting hairs is accurate. The batteries will eventually equalize no matter how they're connected, and they're also gonna charge just fine. I think the proper wiring's point is that more stress is placed on the first example's first battery, so to protect your battery investment wire it our way iinstead.
 
Remember though, as I posted above, his resistance numbers didn't add up correctly, which tosses out the validity of what he is saying to a big extent.

Here's the part I'm talking about...
And furthmore, I quit reading the article when I rechecked their math and found some of his published numbers to be wrong.  .00012 (cable resistance for 20cm of cable) AND the additional .0002 (connector resistance) plus another .0002 connector reistance does NOT add up to what he said...  .0015 ohms.  The actual total resistance for what he is talking about...two connections and one length of cable is....  .00012 + .0002 + .0002 = .00052 not .0015.   

And honestly, unless he used some sort of highly calibrated and accurate Test instrument similar to the ones we use in our high voltage testing program where I work, his numbers may be flawed also.  I have no way of knowing that is the case though.  Just one of our contact resistance testers, which tests down to 1/1,000,000 of an ohm, costs well over $20K.  That is the type of test equipment that would be required to come up with some of the resistance numbers that he is touting.  They may very well have access to that type of equipment, again, I don't know.  But what I do know is that his math is flawed in the above quote, so in my book, he has lost some critical reliability with what he states.
 
This is what I was wanting to do and by no means am I a electrical engineer, who is wise to the ways of volts, amps and watts.

My camping will be done out west where there is normally ample hours of sun and 90% of this camping will be done without electrical hookups.

I don't have the trailer yet......but close to making a purchase.
The trailer "box" is 23 feet on the unit I am considering.

My useage would be minimal of 12V power.....I am single with no dogs, cats or any two legged companions.
Lighting, water pump, furnace fan if needed, refer electronics, electronic safety devices, OEM AM-FM-DVD player and the TV....along with a 600W inverter to power a laptop computer and various small electronic devices. Not all at one time.
I have zero need for a toaster, hair dryer, a Mr. Coffee maker or any other high draw electrical appliances.

Currently I camp in a truck slide in camper that has a 100W roof mounted solar panel feeding 2 Exide Edge 12V AGM batts in parallel, and is equipped with a 300W inverter that runs a laptop and a portable radio for hours on end with zero issues.

I was planning on getting a 120W GoPower portable solar panel setup to recharge the 2 supplied house batts on the yet to be purchased TT.
As an option before taking delivery of this new unit, I can change out the supplied batteries from 2 12V to 2 6V.

My tendency is to replace the supplied 12V batts (take off credit) with 2 Trojan T-105 6 volt units and wire in series to take advantage of increased Ah's and reported battery longevity, over 2 12V units.

Thank you and all comments welcome.




 
xrated said:
Remember though, as I posted above, his resistance numbers didn't add up correctly, which tosses out the validity of what he is saying to a big extent.

Here's the part I'm talking about...
And honestly, unless he used some sort of highly calibrated and accurate Test instrument similar to the ones we use in our high voltage testing program where I work, his numbers may be flawed also.  I have no way of knowing that is the case though.  Just one of our contact resistance testers, which tests down to 1/1,000,000 of an ohm, costs well over $20K.  That is the type of test equipment that would be required to come up with some of the resistance numbers that he is touting.  They may very well have access to that type of equipment, again, I don't know.  But what I do know is that his math is flawed in the above quote, so in my book, he has lost some critical reliability with what he states.

I think the additional '0' is just a typo but even if it's not, that bad math is applied to each of the 4 tested wiring schemes.
 
marcortez said:
This is what I was wanting to do and by no means am I a electrical engineer, who is wise to the ways of volts, amps and watts.

My camping will be done out west where there is normally ample hours of sun and 90% of this camping will be done without electrical hookups.

I don't have the trailer yet......but close to making a purchase.
The trailer "box" is 23 feet on the unit I am considering.

My useage would be minimal of 12V power.....I am single with no dogs, cats or any two legged companions.
Lighting, water pump, furnace fan if needed, refer electronics, electronic safety devices, OEM AM-FM-DVD player and the TV....along with a 600W inverter to power a laptop computer and various small electronic devices. Not all at one time.
I have zero need for a toaster, hair dryer, a Mr. Coffee maker or any other high draw electrical appliances.

Currently I camp in a truck slide in camper that has a 100W roof mounted solar panel feeding 2 Exide Edge 12V AGM batts in parallel, and is equipped with a 300W inverter that runs a laptop and a portable radio for hours on end with zero issues.

I was planning on getting a 120W GoPower portable solar panel setup to recharge the 2 supplied house batts on the yet to be purchased TT.
As an option before taking delivery of this new unit, I can change out the supplied batteries from 2 12V to 2 6V.

My tendency is to replace the supplied 12V batts (take off credit) with 2 Trojan T-105 6 volt units and wire in series to take advantage of increased Ah's and reported battery longevity, over 2 12V units.

Thank you and all comments welcome.

First of all, why change out the Exides for the Trojans? the energy storage on both is basically the same, and although I'd agree that the Trojan is a better battery I don't think it's $300 better. Assuming your Exides are good, I would keep them and buy a 2nd panel with the money. To run all that stuff you'll need at least another panel anyway.
 
Desert_Rat said:
First of all, why change out the Exides for the Trojans? the energy storage on both is basically the same, and although I'd agree that the Trojan is a better battery I don't think it's $300 better. Assuming your Exides are good, I would keep them and buy a 2nd panel with the money. To run all that stuff you'll need at least another panel anyway.
[/quote

The Exides are in the truck camper I have sold.....they are no longer in the equation. So the "why" does not apply.

I have already been told that "take off" credit for dealer installed run of the mill deep cycles would apply.
Ending up with $65 more each, or $130 for two Trojan T-105's. Instead of $300 more, it's down to $130 more with "take off" credit.

Based on my past use of a 100W solar panel and the dual Exides, and with my power requirements, a 120W solar panel seems sufficient.
 
The way to figure this out is to see what the amp/hour total is with two 12 volt batteries that the dealer would supply......add up the amp/hours from each battery and that is your total if they are hooked up in parallel.

Then, add look at the Trojan 6 volt batteries that will be hooked up in series and see what the amp/hour rating is on one of the batteries.  That will be your total amp/hour for that setup......
 
xrated said:
Well that changes everything.  You have no choice on where you put the terminals from the charger.... You do have a 12V charger.....right?

I am not going say the obvious. Enough said.
markbarendt said:
Mark, I don't disagree that problems in the chain can be a problem but I don't assume perfect either, just well maintained and designed.

IMO the myth exists because people don't maintain their systems as often as they should or the builder went cheap.

You're correct. I won't dispute that fact. Problem is reality and normal behavior can cost those particular people money. So be it. We don't disagree. We just have two different reasons for the same result. I can deal with that.
 
marcortez said:
Desert_Rat said:
First of all, why change out the Exides for the Trojans? the energy storage on both is basically the same, and although I'd agree that the Trojan is a better battery I don't think it's $300 better. Assuming your Exides are good, I would keep them and buy a 2nd panel with the money. To run all that stuff you'll need at least another panel anyway.
[/quote

The Exides are in the truck camper I have sold.....they are no longer in the equation. So the "why" does not apply.

I have already been told that "take off" credit for dealer installed run of the mill deep cycles would apply.
Ending up with $65 more each, or $130 for two Trojan T-105's. Instead of $300 more, it's down to $130 more with "take off" credit.

Based on my past use of a 100W solar panel and the dual Exides, and with my power requirements, a 120W solar panel seems sufficient.

Ah, that makes sense.
 
marcortez said:
This is what I was wanting to do and by no means am I a electrical engineer, who is wise to the ways of volts, amps and watts.

My camping will be done out west where there is normally ample hours of sun and 90% of this camping will be done without electrical hookups.

I don't have the trailer yet......but close to making a purchase.
The trailer "box" is 23 feet on the unit I am considering.

My useage would be minimal of 12V power.....I am single with no dogs, cats or any two legged companions.
Lighting, water pump, furnace fan if needed, refer electronics, electronic safety devices, OEM AM-FM-DVD player and the TV....along with a 600W inverter to power a laptop computer and various small electronic devices. Not all at one time.
I have zero need for a toaster, hair dryer, a Mr. Coffee maker or any other high draw electrical appliances.

Currently I camp in a truck slide in camper that has a 100W roof mounted solar panel feeding 2 Exide Edge 12V AGM batts in parallel, and is equipped with a 300W inverter that runs a laptop and a portable radio for hours on end with zero issues.

I was planning on getting a 120W GoPower portable solar panel setup to recharge the 2 supplied house batts on the yet to be purchased TT.
As an option before taking delivery of this new unit, I can change out the supplied batteries from 2 12V to 2 6V.

My tendency is to replace the supplied 12V batts (take off credit) with 2 Trojan T-105 6 volt units and wire in series to take advantage of increased Ah's and reported battery longevity, over 2 12V units.

Thank you and all comments welcome.
If I am understanding you correctly the two 12V batteries you want to change to the Trojan T105's are in the trailer you are going to buy.

Assuming the 12V batteries each have about 100-120AH capacity, swapping then to a pair of 6V golf cart sized batteries at 220AH each, you will NOT be increasing your AH capacity.  When you wire batteries in series the voltage adds but the total AH's stay the same.  When you wire the two 12V batteries in parallel the voltage stays the same, but the AH adds.

I agree with Desert Rat, I don't think Trojans are that much better to be worth the extra cost.  Go with a pair of Costco or Sam's Club golf cart batteries. 
 
AStravelers said:
If I am understanding you correctly the two 12V batteries you want to change to the Trojan T105's are in the trailer you are going to buy.

Assuming the 12V batteries each have about 100-120AH capacity, swapping then to a pair of 6V golf cart sized batteries at 220AH each, you will NOT be increasing your AH capacity.  When you wire batteries in series the voltage adds but the total AH's stay the same.  When you wire the two 12V batteries in parallel the voltage stays the same, but the AH adds.

I agree with Desert Rat, I don't think Trojans are that much better to be worth the extra cost.  Go with a pair of Costco or Sam's Club golf cart batteries.
Yes, doing the math is important.

One thing I really like about using 2 12volt batteries is that if one battery fails you can still have full voltage to work with, just with a reduced reserve.
 
AStravelers said:
If I am understanding you correctly the two 12V batteries you want to change to the Trojan T105's are in the trailer you are going to buy.

Yes you are correct....included in a new TT purchase.

I wanted to gain Ah's with the 2 6 volts over a pair of 12v's.
I am also having a difficult time locating the Ah rating of even an Exide Edge AGM battery.
DieHard is no help, as is Johnson controls.
I cannot decipher reserve cranking amps vs a straight up Ah rating.
Most 12V deep cycles I have seen are in the 80-90 hour Ah rating when I can find those specs.

One dealer has told me that they would give a "take off" credit of the dealer installed 12V deep cycle (brand/Ah's unknown) batteries normally included.
The quoted price for a Trojan T-105 would come to $65 each. Or $130 for two with this "take off" credit.

Would you opt to put in 2 Trojans at $130 for a pair if offered that pricing?

Incidentally.....the Costco site does not even give me a view of the various batteries online other than to say "Interstate"....no specs, no prices, no selections. The Interstate website is useless to find out Ah ratings. I get a mumbo jumbo to me, reserve CC amps in various time frames.
Frankly, I am going nuts trying to decipher it all.

Sam's club seems to sell batteries labeled as "Duracell" made by Deka Penn. Ah ratings is 215 I believe.

For what has been offered me, in writing, I will stick with the tried and true Trojans. I have yet to come across any significant number of adverse user reviews.

Maybe 6-8 years later (reported life span with proper maintenance) a Costco or Sam's club battery might make more sense.
 
http://www.exide.com/Media/files/Downloads/TransAmer/Products/Edge6pgMKTG27830_8-14.pdf
 

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