treatis on batteries.


Just keep it clean please....

Golden Jubilee
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Post Sat Mar 17, 2018 4:12 pm

treatis on batteries.

The attached is more info on vehicle batteries than most will want to read thru. I might help the recent poster about his battery problems. I make no excuse for it's length, it is not a subject that lends itself to brevity.

Batteries 101,102, 103

A long treatise on lead acid storage battery

For over 100 years we have relied on the simple cheap lead acid cell. It is neither the best nor the only battery. Edison cells, (iron cell) are longer lasting, but size and weight for a given output is higher on the Edison cell, so it is limited to stationary use. Lithium ion batteries are the new hot thing, and can provide lots of power in a small package.
The common lead acid cell is lead plates separated by an electrolyte (acid/water mix). It produces 2.2 volts fully charged, and is considered dis charged when the voltage drops below 2 volts. It is a secondary cell, meaning it can be dis charged and recharged many times, as opposed to a primary cell like a zinc-carbon dry cell which can be used once.
A battery is a collection of similar things, a gun battery is a bunch of cannons mounted near each other, a coke battery is a bunch of coke ovens mounted in a row. A battery as we know it is a series of cells in a row to make up an electrical storage “box” that we call a battery.
Lead acid batteries are very inefficient, one needs to greatly “oversize” the battery to be able to get useable amounts of energy out of it. They also require much more “input” to recharge than was removed when dis charged. The reason we still use it, is it is cheap and easy to mfg with easily available material.
Early batteries were in glass cells, glass could handle the acid electrolyte well, the cells were in a wood box and were “sealed” in with warm tar, which protected and held the cells in the box.
In the early 1900’s electricity was a new thing, and there was some fear of it. It was known that you could be electrocute someone. It is likely the reason early vehicles used the lowest voltage needed to get the job done.
Before the REA (rural electrification administration) most houses/farms out in the country didn’t have electricity, if you wanted lights or refrigeration you had to either burn some fuel or generate it your self. In fact most small towns in the Midwest and west had a municipal electric plant that generated that towns electricity. Many of these plants still exist. Most that do are “mothballed” and are not operational. They may become a valuable asset with our “modern” interdependent grid system. If something or someone attacked the grid, these plants could supply a town with there power.
Back to the farms of the previous century. In a city, you could sell more electricity in one mile then you could in 20 outside of the city. This ment it was not cost effective to bring power to the farms out in country. Farms worked with kerosene lamps and either ice gathered in the winter, or with Ammonia refrigeration when it was invented. As electrical appliances like refrigeration lights and radio became common “in town” the rural farms wanted the same. Battery power became the answer. There were many systems and voltages sold, 12 and 32 volts were the most common, but even 120 was used. The batteries could be re charged by wind (wind-charger and Jacobs were big mfg of wind powered chargers) and gasoline engines, Delco was a big name as were “tom-thumb and other lesser known. About this time electric start on farm tractors were becoming more popular, but most also retained the hand crank. Battery systems had many cells some in parallel to increase the current capacity and many in series to increase the voltage. Often the batteries were placed in the barn or shed, away from the house so the higher voltage the better it worked with the long runs of cable. 32 volts was the most popular and was used into the 60’s and beyond on ships. A lot of stuff was made in 32 volts, from radios to refrigerators, lamps, drill presses and just about anything else that you would find on the farm back in the 60’s and before. I bring this all up, to show that 12 volts wasn’t “discovered” in the mid fifty’s for vehicles, that other voltages, some much higher were being used before then. 64 volts is used on some locomotives.
A battery room of the 40’s and 50’s would have many glass cells (jars) in a rack, each cell being made up of many plates in a jar.
Once the REA strung power lines all over farm country, the need to self generate power went away and most of the battery systems were scrapped for there lead content.
There are still many uses for lead acid batteries. From railroad signals, out away from “land power” to UPS (uninterruptable power systems) etc. Industrial cells are often made in single cell (2.2 volt) and some in groups to make 4,6,12 and other voltages. They are often listed as having a 20 year lifespan.
Back to vehicles, 6 volt was chosen because it got the job done and there was no reason to go higher. In the 20’s and 30’s there were many electric vehicles and 64 and 92 volts were used (as well as other voltages), again to show that 12 volts was not a new “invention” in the 50’s.
To get back to the lead acid battery, each cell is 2.2 volt fully charged, so a “6” volt battery is 6.6 volts, a 12 volt is 13.2 and 24 is 28. for some unknown reason while 6 and 12 volt systems are refered as such a 24 volt system is refered to as either 24 or 28 volt system. 24 volt term is often used on ground based vehicles while 28 term is used on aircraft. A 32 volt system is four 8 volt batterys and a 36 volt is 3 12’s. A 64 volt system is again refered to as 64 or 72 volt (72 volt being the fully charged voltage of a ‘64” volt battery).
A lead acid battery produces voltage by a chemical process, a reaction between the electrolyte and the lead plates. How much current a cell can make is a function of the surface area of the plates exposed to the electrolyte. The more surface area the greater the capacity of the cell. Most cells are made up of multiple plates stacked in interposed positive and negative plates. With both sides of the plates exposed to the electrolyte and the plates interposed with each other, there is a lot of surface area in a cell. For most of the last 100 years the plates consisted of sponge lead, ridged and inflexible. Recently they have switched to a fiberglass substrate semeared with lead paste. This allowed for a more flexible plate. The Optima battery is a long plate rolled up like a jelly roll. It allows for a large surface area in a small package. For most of the past 100 years, a lead acid cell was/is a flooded cell type. This means there is enough liquid electrolyte to cover the plates. This allows the charge of the cell to be tested by takeing a hydrometer reading to get the specific gravity of the electrolyte. The more “dense” the higher the charge of the cell. In recent years absorbent glass mat or AGM battery have become more common, in these he electrolyte is held in the substrate of the plate, like being held in a sponge. This makes a battery that can be operated in positions other then level. These batteries are sealed and no access to the cells is provided.
For years the chemical make-up of the cells was the same, along with the electrolyte. In recent years that has changed, mostly to reduce water “consumption”, a byproduct of charging a flooded cell. More on this later.
Lead Acid battery has a big problem. It can store a lot of energy, but can only release it at a slow rate. In order to provide enough current to crank an engine it needs to be many times bigger than “needed”. Although a single 12 volt battery can store more than 10x the power needed to crank a big bore diesel, it take a minimum of 3 batteries and most semi’s have 4 to provide enough current at once to crank, and even then, they struggle in cold weather.
For over 50 years the way to rate lead acid batteries was ampere per hours or for short amp/hr’s . This is a measure of how many amps for how many hr a battery can produce without dropping below 2 volts per cell. While it is very accurate measure of capacity, it has some weaknesses. The amount of current available is not “linier”. A 1 amp hr battery means it can supply one amp for one hr or it can also mean a battery that can supply 10 amps for 1/10 of an hr, but a battery that can provide 10 amp for 1/10th of an hr would have to have more plate surface area. To be sure you are comparing apples to apples, most batteries are rated at the 20 hr rate. This means a 20 amp/hr battery can provide 1 amp for 20 hrs. The 20 hr rate is the most common std used, but be sure to check as some devious mfg give amp/hr rateing at some other rate like 40 or even 100) to make the battery look more powerful than it is.
The amp/hr rating make sense when dealing with deep-cycle battery, where the load is low but long lasting. When dealing with cranking loads, which are high but short lived, the amp/hr rating is less than ideal. Also 1000 cca (cold cranking amps) sounds a whole lot more impressive than 155 amp/hr, although the later has more stored energy. For the last 40-50 years starting batteries have been given a cca rating. This is the amount of current a battery can supply at 0 deg for 30 sec without dropping below 7.2 volts for a ’12 volt” battery. Yeah, there are a lot of “conditions” attached to that rating. Recently battery mfg have been advertizing “cranking amps, or the same thing as cca but at 32 deg to make there battery look more powerful. All an advertizing “slight of hand”! So a 1200 ca battery sound better than a 900 cca.
The truth is amp/hr, cca and ca all take plate surface area. Amp/hr also relies on depth of lead or lead paste on a plate, the more there is the higher capacity. Cca and ca need surface area alone. Modern starting batteries are designed to give a large jolt of current for a very limited time. Deep cycleing these batteries (long slow discharge) can ruin them in is few as 5 deep cycles. Modern charging systems are designed to work with these type batteries. They are designed to supply a short high current “recharge” then only supply a low amount of current (usually about 1/3 of the rating alternator) to cover the “running loads” of the vehicle. Prior to 1970 or thereabouts, charging systems were designed for the long slow charge, in part because batteries of that time were made more like deep cycle batteries, with limited ability to absorb high amounts of current. Early charging systems had more give and take between the battery and charging system. The battery provided power at low speed and idle, while charging system provided current at higher speed and recharged what was drawn from the battery at low speed. Until the mid 70’s when A/C became std equipment, most std charging systems, were around 30-40 amp regardless if it was supplied by an alternator or generator.
Jumping back to the 6 volt systems of old, early vehicles had very limited electrical equipment. Two headlights at 35 watts, a few watts for tail lamps, may be a heater fan and/or electric wipers. All together, less than 25 amps at 6 volts or ½ that at 12. A 30 amp generator was more than enough to cover this and still have some left over to recharge the battery. Most of the time, not everything was run at the same time, so there was plenty of current available.
By the mid 50’s more and more electrical loads were being placed on vehicles. The choice was to increase the 6 volt system (and double all size of cables, battery and copper in the charging system) or double the voltage and save money. In North America, the std voltage was upped to 12 volt, but in other parts of the world they were already using 24 volt for commercial vehicles. To be compatible with European Commercial vehicles and aircraft, our military chose 24 volt as the std for all military stuff. Only in motor coaches and transit buses in this country went with 24 volt systems.
Up until the ‘80’s that largest batteries were made in 6 volt packages. To get high amounts of cranking amps you only had two choices. Either use 6 volts in combination of series and parallel or use large heavy industrial/marine (8D) batteries. Until high amp cranking batteies were made in 12 volt ( group 31) to get 2000cca to crank a large bore diesel, Four six volts were used in two different ways. Either two groups of two batteries were used, the two batteries in each group were in series, the groups in parallel. (12 volt crank/run) The other way, and it was very popular thru the 70’s and into the 80’s, the two groups were used in series (to provide 24 volts) for starting and then placed in parallel for running and charging. Both of these methods provided the most cca in the smallest package at that time. Since 24 volt requires ½ the current for the same work as 12 volt, 1000 cca was enough to crank a large bore diesel @24 volt, and required less copper and could tolerate more resistance in the circuit.
Until the 80’s most batteries were not sealed, and required you to check the electrolyte every month or so and add water. This is because during charging, some of the water is broken into hydrogen and oxygen gas. To charge a battery, the supplied voltage must be over what it is fully charged at rest. Since the 80’s automotive battery and vehicle mfg have been working to reduce the amount water lost during charging. They have reached the point to where it doesn’t loose enough over its “lifetime” to need adding. All this is a compromise, lifespan vs. convenience. One way vehicle mfg have helped is by making the voltage regulator voltage setting much tighter. For the most part gone are voltage adjustment, only a fixed regulators are used. The battery mfg have changed the chemical make up inside the battery to minimize the water usage. Prior to the 80’s voltage settings was around 13.8 volts to minimize water usage in the older style batteries. With the change in chemical make up newer cars now are set at 14.2 volts, the newer chemicals require a slightly higher setting to re charge. Starting batteries which are subject to a quick high amp draw followed by a quick re charge, 14.2 works well. It does not work well for deep cycled batteries however. Fork truck, RV and some marine applications need a higher voltage to recharge deeply cycled batteries in the shortest time. For these batteries a four step charging system is ideal. Balmar and others make special regulators to make vehicle alternators mimic large expensive forklift chargers. The 4 steps are bulk where the majority of charging is done (where the voltage is around 14.6), absorption the finishing charge (where the voltage is slightly lower) float, where the fully charged battery is kept ready to go to work, and equalization where the voltage is raised above normal voltage to force cells that have a different level of charged to come up to full charge. Equalization has to be done with care, not to overheat or damage the cell, it can be done automatic or manually. Either way the temp and current must be closely monitored.
Ideally each cell would be charged separately. That way each cell can be charged until it has reached it maximum charge. Cells charged in series (like a battery) will only be charged to the level of the lowest cell. With today’s electronics it is possible to monitor and charge each cell individually. Electric cars and the Maxwell supercapacitor starting system do this. The cost doesn’t make sense with lead acid batteries being so cheap.
Back in the day of 6 volt vehicles, it was possible to replace individual cells in the battery, the lead tie straps between cells were removed, Tar was slowly heated to soften it, and the cell removed and replaced. It may have been part of the draw of the 6 volt system, only 3 cells to maintain or worry about.
If you read the instructions that come with a replacement alternator, they all say “charge the battery before installing the new alternator”. There is a good reason for this. Alternators are designed to replace the current used to crank the engine, and carry the running load. Starters pull a “surface charge” off a battery, but is far from dis charging it. They are not designed to run the vehicle and provide a long slow charge. 20-30 amps of running load and 20-30 amps of recharge will overtax and alternator over time and it can ruin a brand new alternator.
Here is a question. If you come out to your car, found you left the lights on over the weekend, how long does it take to re charge? Ask many, even mechanic’s they will say 30 min, may be an hour. Truth is more than 10 hours. It matters little if a 15 amp charger, or 150 amp alternator is used. 30 min or an hour will put a surface charge on the battery, may be enough to start the car, but will not recharge the battery. Only time, and it turns out that the amount of time doesn’t change much depending on the size of the battery. A larger battery needs a higher current, but the time it takes is about the same. The chemical process can’t be rushed. A lead acid battery will take a large amount of current for a very short time, within a few minutes the amount of current will drop to a lower level where it will remain for a long period, then slowly taper until the voltage reaches float.
I run a large deep cycle battery pack ( 620 amp/hr) when discharged less than ½ way (more than ½ the charge left) the current spikes at the capacity of the alternator (about 75 amps) than rapidly tapers to 35 amps or less (under a minute or so) it remains over 22 amps for a long time and takes more than 10 hr to reach “float”. A 25 amp home battery charger would charge the pack in about the same time. A discharged car battery would charge about the same, only the current readings would be different.
I had one car where the alternator was mounted in rubber bushings, it required a separate ground wire to charge, without it no charging would take place, and it wouldn’t turn on the charge light. The ground broke at one point and the car quit running. It took 18 hr on a 10 amp charger to fully recharge the battery.
Why is this important? With a 6 volt vehicle, it is easy to draw a battery down working on a hard to start truck. Just jumping it, or putting the battery on a charger for a few hrs will not do it, it needs more than 10 hrs on a long slow charge.
With a 6 volt system, with a generator, setting the voltage regulator at 7.4 will work well. While it is slightly higher than the original setting, with the chemical make up of today’s batteries, it works well. Chances are the vehicle will not be run for enough time to cause the battery to “use water”. It would take running continuously for more than 24 hrs to see water usage.
Some advocate using a 8 volt battery on a 6 volt system. There are many problems with this. 1st and foremost, a 6 volt charging system will not charge an 8 volt battery, it would need the voltage regulator set to over 9 volts to charge, and that brings other problems. The electrical components can handle a slight over voltage, but going that high will effect the life of the ign system, bulbs and gauges. You end up with a less reliable vehicle than fixing what was wrong to begin with. If you don’t raise the charging voltage in very short order the battery will be discharged.

This is likely more info than you ever wanted, but I did warn you at the beginning!
Last edited by cornbinder89 on Sun Oct 21, 2018 2:48 pm, edited 1 time in total.

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Post Sun Mar 18, 2018 12:35 am

Re: treatis on batteries.

I find this interesting, not only because of the vehicles, but also because much of this crosses over to Solar cell charging and the required "storage" capacity needed and that solar is figured in Amp hour.

Golden Jubilee
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Post Sun Mar 18, 2018 12:22 pm

Re: treatis on batteries.

yeah, running a large deep cycle battery pack has been an education. I also worked on electric Manlifts years ago. We had a big forklift charger that ran on 3 phase and had several stage charging. learned alot there.

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Post Sun Mar 18, 2018 10:30 pm

Re: treatis on batteries.

One of my "jobs" In Maintenance in the Army In Kansas and Germany was "battery" tech. I got to service and charge all sorts of batteries related to Tanks, 10 ton, 5 ton, and smaller vehicles. Was a different job and I learned a lot back in 71-77 before I went to Carpentry.

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Post Fri Mar 23, 2018 2:07 pm

Re: treatis on batteries.

Thanks, I found this extremely informative. It has answered some questions I've had for years and I like history too.

Golden Jubilee
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Post Tue Mar 27, 2018 2:50 pm

Re: treatis on batteries.

The newest thing in cranking is not a battery at all but a supercapacitor. It can store enough current to crank a big bore diesel in a package the size of one starting battery. It takes a minimum of 3 lead acids to do the job.
The Maxwell has a bank of capacitors a bit bigger than D cells, and a charging board to monitor temp and cell balance. This is important because they can have a thermal runaway and explode if overcharged.
I have one on my '83 9670. The blue "battery" is the Maxwell and the heavy starter cables attach to it alone. The other 3 deep cycles next to supply the trucks power for everything other than cranking. The heavy black wire (4 ga) feeds the truck, the red 8 ga wire on the Maxwell is what charges the unit.
Finally I included a video of a kid doing it the risky way, and just charging the capacitors directly
https://www.youtube.com/watch?v=GPJao1xLe7w
Attachments
Maxwell inside.jpg
Inside "guts" less charging board which sits in the recess
ESM-2a.jpg
Maxwell installed in my semi
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Golden Jubilee
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Post Tue Mar 27, 2018 10:47 pm

Re: treatis on batteries.

I really got a charge out of reading this
Gentle Men! you can't fight in here! This is the war room!

Golden Jubilee
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Post Wed Mar 28, 2018 8:42 am

Re: treatis on batteries.

bedrockjon wrote:I really got a charge out of reading this

I could do one on generators that might be more "exciting"
or I had a spark of an idea to tackle ignition systems
Started one on transmissions but it turned into a grind.
Should I stop now? I'll take a brake!

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Post Wed Mar 28, 2018 10:34 am

Re: treatis on batteries.

Brake systems are always a good topic! Gotta whoa before Go!

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