Battery Coach

LJ-TJ · October 18, 2017, 11:24 AM

I know, I know here we go again. Well the two 6 volt Trojans = 12 Volts just don't seem to be working out so I said

scrap'm. So I went out yesterday and bought a Huge AC DELCO 700 LTA 1400 CCA 450 RC 12 Volt Model 8D1400 88863847 Serial No 00091 Suppose to be out of a CAT tractor. I don't know I give up. If anyone wants to chime in.

legomybago · October 18, 2017, 12:01 PM

What happened to the Trojans?

LJ-TJ · October 18, 2017, 12:29 PM

Just wouldn't hold a charge. Drain down after a couple of movies to a point they wouldn't run anything. Pretty much watch a movie, no lights then maybe a reading light for 45 min. and then nothing. They were brand new. Took forever to recharge them. I got know idea.

I don't know how you guys get all this boon docking camping done. I've been very careful not to leave lights on or over use the batteries so who knows. Never tried to run the furnace. Speeking of which I'm going to pull today and see if I can figure out whats happening there. No any body looking for a cheep Winnebago.......Kidding just kidding. N:(

CapnDirk · October 18, 2017, 04:20 PM

What model number on the trojans? And what code is stamped into the lead on the negative post? I worked for a floor care machine company and did a couple hundred Trojan batteries.

DaveVA78Chieftain · October 18, 2017, 07:00 PM

Amp Hour Calculation Description

Amp hours per day = Amps x Quantity of item x hours of operation per day

Item	Amps	Qty	hours	= Amp Hours
Lights	1.5 amps	1	1 hrs	1.5 Ah
TV (19" color LED)	23 amps	1	4 hrs	92 Ah
VCR/DVD AC Mode	8.25 amps	1	4 hrs	33 Ah
Total Ah per Day	-	-	-	126.5 Ah

If you run the water pump or furnace or etc., this total AH used value only increases

200ah battery (2 6VDC Trojans) - While the voltage doubles for 2 6VDC batteries in series, the total AH available remains at the base level of 200AH of one battery. You to have two 6VDC battery bank pairs wired in parallel (4 batteries total) to increase AH to 400.

200 - 126.5 = 73.5ah left in battery (used 63% of available charge in battery)
Battery voltage @ 100% charge = ~ 12.7
Battery voltage @ 37% charge (100-63 = 37) = ~ 11.8VDC

8D battery = 250AH so 250 - 126.5 = 123.5AH left in battery (used 50% of available charge in battery)
Battery voltage @ 100% charge = ~ 12.7
Battery voltage @ 50% charge (100-63 = 37) = ~ 12.06VDC

The 8D battery is a starting battery for diesels so may not live as long as a pair of Trojan T-105 deep cell batteries

For long battery life, you should not drain the battery past 50%
You have to add more batteries to increase the available Amp Hours (AH) if you want longer usage times.

M & J · October 18, 2017, 07:49 PM

Hey. Dave got his moving rv back.

LJ-TJ · October 22, 2017, 04:52 PM

Sorry for taking so long to respond. Harvesting. Hey CapnDirk, The Trojan's I have are T-105's. CC016AA1325 E6 on the N post and 86 on the P post. CC016AA1328 ES on the N post. I tested the batteries individually and each one read 6volts. I tested both batteries together and got 12volts. When I tested both batteries with the charger on and they tested out at 13volts. It also read on the charger 13volts. I just went out after a few hours and checked the batteries with my fluk and they are now reading 14volts with the charger on them. i?? Hm?

DaveVA78Chieftain · October 22, 2017, 05:46 PM

TJ,
A 12VDC battery at full charge (100%) is ~12.7VDC (6VDC is ~ 6.25VDC). That is after the "surface charge" has been drained off (a minute or so of current drain or several hours of not being charged with no current drain) right after the battery is charged to 100%.

When you charge a battery, you have to use a charging voltage higher (e.g. 14.1VDC) than the current battery level is (e.g. 12.0VDC) so that you force a reverse current flow through the battery. A lead acid battery uses a chemical reaction to produce electricity. Current flowing out of the battery ( neg to pos post to run the light) is discharge. Current flowing into the battery (pos to neg post) charges the battery. Each current direction results in opposite chemical reactions which actually do remove and replace material on the lead battery plates. As time (charge cycles) progresses the battery gets weaker because the plate material flakes off and goes to the bottom of the battery and the electrolite solution weakens. . In order to get the battery up to 100% capacity (12.7VDC at rest), you have to keep charging (push the charge past 12VDC) it until the actual battery is around 14.4VDC (surface charge). Then you bleed of the surface charge (drop from 14.4 to 12.7vdc) to see the actual battery state.

QuoteDuring the constant-current charge (stage 1), the battery charges to about 70-80 percent in 5â€"8 hours; the remaining 30 percent is filled with the slower topping charge (stage 2) that lasts another 7â€"10 hours.

An old style linear RV converter took a lot longer to get to 100% because it constantly reduced the charge current as you got closer to 100% full. The newer RV converters (3 or 4 stage) maintains a constant current rate (stage 1) until the battery is ~70% charged). They then change to stage 2 to top off the battery. Stage 2 is the same as a regular linear RV converter. The newer converter then moves to stage 3 and drops the voltage to prevent boiling the battery dry (~13.1VDC). Older RV converters kept the charge voltage at around 13.6VDC which boils the battery dry. Older RV converters used a 13.6VDC charging voltage. Newer RV converters use a 14.6VDC charging which results in shorter charge top off times. The older 13.6VDC level was a compromise in an attempt to shorten the charge time but prevent the battery from boiling dry to quick once the battery was fully charged. The newer software controlled converters, can adjust their output (multiple stages) which allows shorter charge times and prevent battery water boiling.

All this is explained in infinite detail on that web site I pointed to above.

Lead Acid Battery Operation Videos

Remove Surface Charge (for our Canadian brothers)

And for those who just gotta know the whole enchilada:
Part 1 - Introduction to batteries 54 Minutes
Part 2 - Battery Discharge Characteristics 45 Minutes
Part 3 - Battery Charging Characteristics and Methods 34 Minutes

OK, between the post above and this one the only thing left is solar and power distribution stuff in at the top of the Coach Electrical Section

Schools out (reading homework assigned)

TerryH · October 22, 2017, 08:08 PM

Thank you, Dave. I was not aware of surface charge.
I always checked mine (with no draw, including phantom) with both hydrometer and voltage tester.
Had no knowledge that I should first drain off voltage to a minimal degree.
Am I correct to assume surface charge does not affect a reading from a hydrometer?

Thanks also for the 'Canadian' link.

:)rotflmao :)rotflmao

DaveVA78Chieftain · October 22, 2017, 08:25 PM

To the best of my knowledge, a surface charge does not affect a hydrometer test.
Battery water (electrolyte) is a combination of distilled water and sulfuric acid. A hydrometer measures the amount of acid that is diluted in the distilled water by comparing the density (specific gravity) of the electrolyte against the density (specific gravity) of pure water. As such, the surface charge is not an issue.
However, the specific gravity can be affected by temperature and how badly the electrolyte has been diluted by distilled water used to refill the cell. There are charts on the net to account for temperature (normally based on 77 degree baseline). Dilution can be controlled by not overfilling a cell, resulting in run off, when topping off a cell.

Rickf1985 · October 22, 2017, 08:27 PM

Surface charge has no affect on specific gravity.

TerryH · October 22, 2017, 08:36 PM

Thanks Dave and Rick.
Ideally, when checking my batteries (usually plugged into shore power, 3 stage charger) I would first check specific gravity taking into account temp and after bleeding off surface charge check the stored voltage?
After, of course, unplugging and disconnecting.

Oz · October 22, 2017, 09:43 PM

Deer in a headlight here... Hm?

What the heck is the actual question this topic is asking? i??

DaveVA78Chieftain · October 22, 2017, 10:00 PM

From my perspective, it started out is battery A better than Battery B for boondocking.
The problem is, battery selection and battery bank size revolves around multiple factors:
Type
Battery Bank Size (depends on what you want to do)
How to determine battery bank size
How to make your batteries last and prevent premature failure (excessive use do to not following simple rules)
Best charging method and why older methods result in poor results
All that plays in to what you should select and how to setup your rig to satisfy your needs and/or wants.
My attempt at least has been to keep people from throwing good money after bad and being disappointed at the result.

CapnDirk · October 22, 2017, 10:06 PM

Quote from: LJ-TJ on October 22, 2017, 04:52 PM
Sorry for taking so long to respond. Harvesting. Hey CapnDirk, The Trojan's I have are T-105's. CC016AA1325 E6 on the N post and 86 on the P post. CC016AA1328 ES on the N post. I tested the batteries individually and each one read 6volts. I tested both batteries together and got 12volts. When I tested both batteries with the charger on and they tested out at 13volts. It also read on the charger 13volts. I just went out after a few hours and checked the batteries with my fluk and they are now reading 14volts with the charger on them. i?? Hm?

105s would be at the lower end of a coach battery in my opinion. I recommend 125 or, 145s (my job had me replacing a few hundred) 105s just didn't hold up. If you think Trojans are expensive, they are! Our customers bought 6 145s at a time for their equipment to the tune of about $1200 a set.

Your 86 code is likely B6. First character month of year (skipping I since it looks 1) next the year. So your batteries are Feb of 2016 manufacture date. Have you checked for a drain?

Comparison of batteries.

LJ-TJ · October 23, 2017, 08:12 AM

Hey Dave your doing a great job don't stop now. So I've been beating my brains out trying to figure out why this is so difficult to some and not others. So this is what I've come up with.
When is a 12volt battery a 12volt battery. When I go to walmart and buy a 12volt battery for my car it's a 12volt battery. According to what I read and understand a 12volt battery that's 12volts is a dead battery. Throw it away. BUT a 12volt battery can be 12.1,12.5,12.9,13,14 then it's not a 12volt battery. I know those out here are getting tired and frustrated trying to explain this stuff to us in a way we can understand it and are probable tearing their hair out. Neofights like us, we really want to understand. We got the cranking power down for the chassis battery. Now we just got to square a way this boon docking thing. D:oH!

Rickf1985 · October 23, 2017, 09:47 AM

Quote from: LJ-TJ on October 23, 2017, 08:12 AM
Hey Dave your doing a great job don't stop now. So I've been beating my brains out trying to figure out why this is so difficult to some and not others. So this is what I've come up with.
When is a 12volt battery a 12volt battery. When I go to walmart and buy a 12volt battery for my car it's a 12volt battery. According to what I read and understand a 12volt battery that's 12volts is a dead battery. Throw it away. BUT a 12volt battery can be 12.1,12.5,12.9,13,14 then it's not a 12volt battery. I know those out here are getting tired and frustrated trying to explain this stuff to us in a way we can understand it and are probable tearing their hair out. Neofights like us, we really want to understand. We got the cranking power down for the chassis battery. Now we just got to square a way this boon docking thing. D:oH!

Maybe because you are so OLD!

Sorry, You opened that door so far I just fell through it!

:)rotflmao :)rotflmao :)rotflmao :)rotflmao

LJ-TJ · October 23, 2017, 10:05 AM

:)rotflmao That's all right buddy.I new you were just around the corner. I was just waiting. D:oH!

Rickf1985 · October 23, 2017, 01:45 PM

I can get away with it since although I am also old I am less old than a lot of you other guys.

LJ-TJ · October 23, 2017, 01:54 PM

So what your saying is your Jurassic not a fossil. D:oH! :)rotflmao :)rotflmao :)rotflmao

Froggy1936 · October 23, 2017, 04:54 PM

Nope TJ A 12V battery is a 12V battery when it is NOT a 6V battery or a 24V battery See its that easy , A dead 12V Battery is still a 12V battery ! Whats the Problem ? i?? i?? ?

Rickf1985 · October 23, 2017, 08:15 PM

Quote from: Froggy1936 on October 23, 2017, 04:54 PM
Nope TJ A 12V battery is a 12V battery when it is NOT a 6V battery or a 24V battery See its that easy , A dead 12V Battery is still a 12V battery ! Whats the Problem ? i?? i?? ?

Except when a 6 volt is two 6 volts and then it is a 12 volt but then you have a dead 24 volt which can be a 12 volt. But whatever you do watch out for those 16 volt batteries! :)rotflmao :)rotflmao :)rotflmao :)rotflmao

LJ-TJ · October 23, 2017, 08:52 PM

N:(

DaveVA78Chieftain · October 23, 2017, 09:07 PM

hang on, working on it

DaveVA78Chieftain · October 23, 2017, 09:54 PM

As far as the terms 6VDC, 8VDC, 12VDC, and/or 24VDC battery they are simply a way of expressing the battery size potential (a marketing strategy).
In actuality, each cell in the battery has the capability of producing 2.12VDC. A 12VDC battery consists of six 2.12VDC cells connected in series for a total of 12.72 VDC (6 x 2.12=12.72). That's why the term 100% charge = 12.7VDC.
A 6VDC battery (e.g. T-105) consists of three 2.12VDC cells connected in series for a total of 6.36 VDC. To get a 12VDC bank you have to connect two 6VDC batteries in series to get a total of six 2.12VDC cells connected in series (6 x 2.12 = 12.72VDC!)

As the battery is discharged, each cell voltage decreases as follows:

As I said before, battery water (electrolyte) is a combination of distilled water and sulfuric acid. The chemical reaction converts the sulfuric acid to Lead Sulfate which is deposited on the lead plates. This conversion results in the electrolyte moving closer to pure water. This depletion of sulfuric acid results in the specific gravity of the electrolyteto become closer to pure water which is how the hydrometer is able to read the charge capacity of a cell.

Cell capacity (amp hours) is governed by size and construction of the neg/pos plates in each cell. Larger plates = more energy (AH) that can be stored. Bigger gas tank = more gas that can be held = farther distance can be traveled. However, just like a car, the bigger the draw on the storage device (e.g race car engine), the shorter the distance that can be traveled due to decreased gas mileage for a given size tank. For a battery, the faster you discharge the energy (e.g a TV and VCR draw compared to a single light bulb draw), the faster the energy is pulled from the battery - ergo the faster the battery is run down.

For battery charging, there is a voltage level (~14.7VDC) where the the battery starts gassing. You can only push so much energy (current) to it at once before you start gassing (boiling) the electrolyte and run the danger of an explosion. Because of internal battery resistance, as the battery charge level increases this current threshold is more quickly reached and you have to cut back on how much current is pushed into the battery by the charger. This current reduction requirement is why it takes many hours to recharge the battery.

Now the moral of all this is:
1) You need to estimate how much energy you typically plan to use. Amp Hour Calculation Description
2) Now that you know what your typical AH is, you can then size your battery bank to meet your desired requirements. Please note for best battery life you should not draw your battery below 50% charge which means your ideal battery bank size (in AH) should be at least twice the size of your desired AH rate. (however, read on why it needs to be more like 3 times the size due to the typical 50 - 80% working range)
3) Now, charge time is where people get messed up. It can take 8 to 18 hours to recharge a battery to 100% capacity with a modern 3 stage charger. This is due to the stage 2 top off charge current reduction to prevent battery gassing. Typically most people only get through stage 1 on a daily basis which only gets the battery to 70 - 80% charge level. They then plug the rig in at home and get the battery completely charged back to 100%. Now if your read that carefully, you will deduce that your mainly keeping your battery between 50 and 80% charged on a daily boon-docking evolution. To do that actually means you have to fit your daily usage in the range. This is why Solar has been so popular as it not only recharges the battery but it also supplies much of that daily AH usage which helps you to reduce the actually battery bank size needed.

Now, this is where things like LED bulbs, using a DVD player, fridge on propane, and catalytic heater options might be a better options to help extend your battery availability time without having a very large battery bank.

100 gal gas tank
@ 30mpg = 3,000 miles traveled
@ 7.6 mpg = 760 miles traveled

125AH per day usage = 250AH bank size minimum for max 50% draw down; 400AH bank size minimum for 50% - 80% daily working range

250AH per day usage = 500AH bank size minimum for max 50% draw down; 800AH bank size minimum for 50% - 80% daily working range

I have four 12VDC 75AH batteries (300AH) on my rig plus a group 29 starting battery (maxed out space limits). PD9160 (60 amp) 3 stage converter that keeps the coach batteries at a comfortable 13.1VDC maintenance charge.