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Understanding camping batteries so you know what you are buying

Discussion in 'Camping Australia' started by T1 Terry, Nov 27, 2021.

  1. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,765
    Location:
    Mannum South Australia
    I'll try to start off simple and work my way up to the techo stuff. ;)
    If I'm going too fast, please tell me, but don't just switch off if you are already way ahead in the knowledge dept.
    If you don't agree with something I've posted, that's fine, but please try to be civil with your reply, no one gains when the fights start ... well, except for the bloke selling the popcorn :lol:

    Ok, first off, what makes it a camping battery a lot more expensive than a start battery.

    Camping batteries are generally called "deep cycle" batteries.
    What makes them different from start batteries is they are designed/built to hold a lot of potential electrical energy but the trade off is it can only do it slowly.
    They are built with thicker lead plates so the chemical reaction between the acid and the lead needs to happen not just on the surface, but all the way through the lead plate.

    A typical start battery has very thin plates as part of the design, just a lot more of them in each cell. This is designed so the chemical reaction takes place over a much bigger area allowing the electrical current to be created in a much larger volume, but for a much shorter time because the lead is much thinner, there isn't as much storage. The start battery makes a lot of amps available very quickly to power the starter motor. If the engine didn't fire up within a minute of cranking, there is something seriously wrong and just about all that high current is used up out of the start battery.
    On the flip side, the thin plate start battery recharges very quickly, again, because the lead plates are thin so the chemical reaction doesn't need to penetrate much below the surface. Because it is happening on both sides of the plate, it meets in the middle fairly quickly.

    A quick rule of thumb, in a 12v deep cycle battery, 100Ah capacity weight 30kg or more. This is the amount of lead required to store the 100Ah .... and they don't make light weight lead ;) If the battery the sales person is trying to sell doesn't meet this 30kg per 100Ah test, either look else where or do the calculation to understand what the real Ah capacity is so you can do an apples with apples comparison in regards to cost. Roughly, each kg = 3.3 Ah, if the battery weighs 27kg, it's true capacity is around 90Ah

    Have a read through this sellers info, a lot of it is very good, then get down to the specs at the end of the scrolling through and have a look at the battery weight ......
    https://www.ebay.com.au/itm/303695310840?_trkparms=ispr=1&hash=item46b5a6aff8:g:ptUAAOSwhoNhMGFl&amdata=enc:AQAGAAACoPYe5NmHp%2B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSzaVbXtmGxqmWnpn8RLN2q7yIHQegzMD8Qt2oGEm1oJ1OMWyHl%2Fv%2FlLwYrGlwvr5m1%2BQfYKVDaf7k6whd1zeEbO8zZuKpnDAWzQQvVa4OAxkSzkXg5SRwYiRkuHY1tQ4ZV%2Fq%2Fv6RMrBQh26yq9iK1JwP%2FVBOIDxUQ5nrkQ3KFk%2FeVNEVis0wNoqJlc67ZyJPeqPvI7e0Et%2FQk7kSiIMyB260aROcWlzHFKAUz3n6Um5CAlqo4QIs7AhPoI12pjayK0MwriKFfff1IVBKRHgIGjGJJM%2BzUIE8pP4IfQ80Tu8dFSMcT0vSUJVOr2mZLpSCdzBGl2feJpwhqOlR8kh8UuHbY%2BT1pwKEQ7uuSuJQCtuO%2B6UJDVxOEDjaO7Nuu3YO7VAs0KG64ienvaGwSeW42sLJSTrrKpfw%2B0OVpf3Js4vH5CiJ1vG4SnlsGU8egoI0JxU4ne%2B8D8TRefa4CHxABpVn5FKBdsfE9l7jmniVWHi1%2Fc8%2BQ0Ui7U2wQmXRAmNBSV2llRI1vkPgMoS44%2F3qOhtSYvBuWqG0xH35Gi%2Bbc8S9fC6k1erEZ%2Bp1BmgzW%2FfpVn3LdMJ1guamXmJxLu%2BfYJbRE6aEnsDTW%2FHZXpruRKbURZQ2p91ZYEH6LUoGpCZHT4H2xm9HV1%2FkrVknuIfBqw3NRf2iuNmtPke0OB3YsdSAWWbdphGAsLcq5BIV2bw%2Fwa3A6jCReU7Rw87IAdcJAY6lUsUuyZvePyHJTB1Fv%2FEtCXkAYY0OjGctNj1c9%2FnCVemDrbua%2B%2FPkfUL4ztz%2BtPhp3cGG5d2zlhYFAx3sXvSR8hMjDIMA5twBFbFxTJKzsDQ%2B65jyy86XjvmGSzhmTIQ%3D%3D|clp:2334524|tkp:BFBMxt7u9Ktf
    I'm not supporting or attacking this reseller, just using it as an example of the point I'm trying to get across

    T1 Terry
     
    Last edited: Nov 27, 2021
    nils likes this.
  2. oldman

    oldman Super Moderator Staff Member

    Messages:
    10,931
    Location:
    Avalon Beach NSW
    I've seen lots of talk regarding Lithium deep cycle batteries....
    Any chance of a quick rundown, (Dad joke...:rolleyes:), on the differences between battery materials ?
    ie pro's and cons ....
    Cheers,
    Mark
     
  3. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,765
    Location:
    Mannum South Australia
    Wow, you asked me not to get technical :lol: .... I'll start another thread for that one, it is a complex subject and the learning curve is near vertical, but I'll give it a go ....

    T1 Terry
     
    oldman likes this.
  4. oldman

    oldman Super Moderator Staff Member

    Messages:
    10,931
    Location:
    Avalon Beach NSW
    Ha ha haaaa....if it wasn't me, someone else would've asked sooner or later......
    Not really interested in the technical side, more a broad brush comparison and if one is better than the other and why....
    ie.In a comparison between different battery materials, which will hold charge longer and is it more expensive, or is it just a weight thing.
    It's all electrickery to me.....;)
    ...but I'm with you so far.....
    Cheers,
    Mark
     
  5. rstucke

    rstucke Well-Known Member

    Messages:
    1,937
    Location:
    Wamberal NSW AUS


    I hope not but you might be asking for more argument's
     
  6. oldman

    oldman Super Moderator Staff Member

    Messages:
    10,931
    Location:
    Avalon Beach NSW
    Definately not…..;)
    As an example, if I was asked about timber for structural purposes, I would advise using LVL over stick timber as it will span greater distances while supporting the same load, however it is more expensive.
    No need to go into the structural complexities of timber species, moment of inertia, slenderness ratio, modulus of elasticity etc etc.
    I’m just trying to get a general understanding about the different types of camping batteries and why I would choose one over another…..
    Cheers,
    Mark
     
    wombatventures likes this.
  7. cbus

    cbus Well-Known Member

    Messages:
    13,562
    Location:
    sunshine coast
    Guessing you mean lithium iron phosphate batteries and not lithium ion ?
     
  8. oldman

    oldman Super Moderator Staff Member

    Messages:
    10,931
    Location:
    Avalon Beach NSW
    Mate, I have no idea !
    Just heard snippets from others and trying to gain knowledge, hence the question ;)
    Always keen to learn from those that have more knowledge…..
    Cheers,
    Mark
     
  9. cbus

    cbus Well-Known Member

    Messages:
    13,562
    Location:
    sunshine coast
    LiFePO4 or lithium iron phosphate batteries are the ones generally touted as a replacement for lead/ acid batteries.
    I'll leave the details to Terry.
     
    oldman likes this.
  10. cbus

    cbus Well-Known Member

    Messages:
    13,562
    Location:
    sunshine coast
    Grantus, oldman and rstucke like this.
  11. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,765
    Location:
    Mannum South Australia
    Hate to bust any party balloons or rain on any parades, but this sort o thing has all been seen before.
    Yet another article written for impact rather than education .... the all important bit
    Testing also shows the coin-cell validation batteries last three times longer than lithium-ion versions.

    Now reread the article with that in mind, no reference to which member of the lithium ion family it will last 3 times long than .... like lithium titanate for example, has a cycle life of over 30,000 cycles and can be charged at 30 CA and discharged at 30 CA (30 times the rated capacity, so a 100Ah cell can be charged at 3,000 amps and discharged at 3,000 amps) ..... I call B/S on the claims that this :new" cell is better than something that is already in product and available off the shelf.
    Add to that, it is only a button cell made in a lab at the moment, yet they are trying to upsize it to EV replacement, around 40, 000 watt hrs and higher at the moment (40 kWh)
    I say, prove it with 12 mths testing and distance records like all EV batteries have had to do.
    There is a term for this sudden leaps in technology within the EV world "Vapour ware" lots of talk and money raising and then it disappears in a cloud of hot air.

    The lithium ferrous phosphate cell was first made in a production quantity back in 1996, but it was back in 1950 that the first lab samples for testing took place. No one had really heard of LiFeP04 as house batteries until 2011 when I started posting on forums across the world about my tests and findings in real world applications. So it took 15 yrs between production and me taking the next steps when it came to house battery use.
    The time frame for this lab tested button cell to reach a viable production size and quantity would need to be fast enough to beat any contenders that might hit the market before it gets that far, as well as developments in the technology that is already out there and proving itself. LTO or lithium titanate is the most promising "great new thing" at the moment, they just need to improve the energy density to push the LFP and LYP chemistries off the podium as the present day chemistry go to for EV batteries.

    T1 Terry
     
    David H likes this.
  12. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,765
    Location:
    Mannum South Australia
    OK, I've typed out a rough guide to lead acid batteries over on this thread https://forums.kombiclub.com/threads/lead-acid-or-lithium-which-battery.60472/ so I won't repeat it here.
    The first post is what to watch out for when buying any form of lead acid battery, so next might be how to recharge them.

    All variants of lead acid batteries suffer with high internal resistance. A rough explanation of resistance is the all too familiar electric bar heater. This is just a big wire wound resistor designed to turn 2400w @ 240v of electrical energy into 2400w of heat energy. All resistor or resistance converts one form of energy to heat energy. A compressor makes the compressed air hot, a restriction in a water pipe can cause heat just as a restriction in the flow of electrical energy causes heat.
    This is important to know so it helps understand a few of the down sides to using lead acid type batteries.
    Let's start with recharging. All lead acid batteries have a maximum charging current limit, deep cycle batteries even more so. This is because the electrical current is creating a difference in voltage between the plates and this causes a chemical reaction to take place. Basically, it pushes the sulphur out of the lead plate and back into the acid, you don't need to know the whole reaction process to get the idea that this takes electrical energy to achieve the chemical reaction. As a by product, some heat is generated so this is electrical energy lost to heat energy that you can't get back and needs to be wasted to the surrounding air. The other unwanted reaction is electrolysis between the two different voltage plates, this is the gas bubbles you see in a flooded cell, hydrogen and oxygen being released a the water molecule bond is broken. This uses some of the electrical energy as well and unless you feed this into a fuel cell, the electrical energy is lost as well.

    All this means, not all the electrical energy pushed into the battery gets stored for use later, up to 25% of it is lost. The faster the battery is recharged, the greater the losses, but there is still that limit as to how fast the battery can be charged before all these electrical energy energy converters can use up the electrical energy being pushed in. If this level is exceeded, the battery voltage will rise due to there being more energy there than can be used. Let this voltage climb too high and irreversible damage will be done to the battery.
    This upper voltage limit is between 14.4v and 14.8v, but on a flooded cell battery it can go as high as 16.8v to shed sulphation from the plate surfaces and to get all the sulphur out of the plates and into the acid. AGM batteries simply can not handle this sort of voltage because the recombiners in each cell can't return the hydrogen and oxygen back to water.
    The more sulphur removed from the lead and returned to the acid, the less chemical reactions can take place so the less electrical energy is used up by this process. To stop the voltage rising to damaging levels, the charging current must be reduced ... this is call the absorption stage. Depending how shallow the discharge was and how fast the charging was (how many amps) the sooner this stage is reached and the longer the absorption stage before dropping the votage to float level.
    Float voltage charging is for batteries that weren't discharged or are being charged with a device that runs 24/7. Solar charging and alternator charging don't fall into this category, the sun doesn't provide solar charging for much more than 8 hrs at the absolute max and alternator charging only occurs when driving or leaving the engine running, and this generally isn't a 24/7 event.
    This means, unless the battery wasn't discharged at all and was fully charged the day before, the float charge part of the cycle is just going to be wasted charging time.

    No doubt this will stir up some people and every one has the right to their own views of this matter.

    This brings up another hotly contended debate, whether to use a DC to DC charger. The logic I use is if the recharging voltage needs to be a constant 14.4v or 14.8v, the alternator is not going to maintain that voltage all the time you are driving. If it did, it would boil the start battery dry, the very thin plates recharge quickly, the thick deep cycle plated take a lot longer.

    T1 Terry
     
    nils likes this.
  13. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,765
    Location:
    Mannum South Australia
    First I'll tackle the portable solar panels. These generally come with a solar regulator mounted on the panel and a length of small diameter cable to go back to the battery.
    So, you unpack your nice new portable solar panel, toss the instructions over the left shoulder, get the panels set up facing the sun and connect the cables cable to the battery ..... and it doesn't seem to work .... so you go searching for the instructions :lol:

    Rule number one: The regulator is connected to the battery first and disconnected from the battery last

    Rule number two: If the solar can not be disconnected from the regulator, lay the panels face down, connect the battery, then stand the panels up facing the sun.

    To put the system away at night is the reverse. Either unplug the solar first, or lay the panels down or put them back in the bag. then disconnect the cables from the battery.

    The reason for this is the regulator needs to have a path for the current to go through and needs to know just what the battery voltage is, it can then start up all its functions. If the battery cable gets disconnected while to solar is still trying to push current into the regulator, the maximum solar panel open circuit voltage will try to find a way through the regulator and this will either freak out the solar regulator, or destroy it.

    OK, you've followed the instructions and the light is flashing on/off/on at the regulator. This is not telling you the whole thing is working well, what it is telling you is the cable between the regulator and the battery is too small for the job. What is happening is, the regulator sees 12v at the battery, so it turns the circuit on to allow the solar to flow through to the battery. The current (volts and amps) start to flow down the cable but the restriction in the under size cable won't let all the amps flow through to the battery so the voltage goes up at the regulator end of the cable. The regulator now sees anywhere up to 15v or maybe even higher, the regulator knows it should stop charging the battery at say 14.4v, so it disconnects the solar. Now there is no amps trying to get down the undersizes cable so the voltage drops back to the same 12v it read before, so it turns the solar back on ..... and so the cycle continues. The light flashes on/off but the battery doesn't appear to have charged much at the end of the day.
    There are two ways to sort this problem:

    a) the first way is to get much bigger cable to go between the regulator and the battery so the amps can get down the cable with very little restriction so the voltage doesn't climb to the point the solar regulator turns off.
    b) Take the regulator off the back of the solar panel and mount it as close as possible to the battery using cables thick enough to carry the amps the regulator says to can push out. If the cable length is shorter than your arm, 6mm auto cable will be enough for a 10 amp regulator. If you have a 20 amp regulator and/or the cable length is longer, use heavier gauge cable such as 8 B&S.
    I would recommend putting a fuse in the positive of this cable, I recommend midi fuses https://www.ebay.com.au/itm/254941924910?hash=item3b5bb90e2e:g:A6MAAOSwxjZgTsPK
    If there was a plug on the regulator to connect the battery cable, move this to the solar connections. Plug the long cable in and make sure to red goes to the red the other side of the plug and positive solar at the regulator, black cable matches up both sides of the plug and goes to the solar negative.
    Connect the non plug end of the cable to the solar cables you disconnected from the regulator (when you took it off the back of the panel) black to the black and red to the red.
    Now you can have the solar regulator connected to the battery all the time and just unplug the solar cable when you put it away each night.
    The gain is, the higher voltage from the solar panel will help to get more amps down the long cable to the regulator, the cable from the regulator to the battery is short and thick enough to do the job, so the solar should turn on when it sees the input from the solar and stay on all the time the panel is producing power from the sun. No more turning on/off/on and so on, and the battery will charge better.

    A bit of an explanation about cable selection.
    The actual current carrying part of 6mm auto cable is 4.3mm sq, the 6mm refers to the size hole you need to drill to get the cable through :rolleyes: such was the brain power of the automotive spare parts and accessory industry. If you need 6mmsq conductor, you are looking for 8 B&S or 8AWG cable.
    this is a very handy site to calculate what cable you need for the job.
    https://www.calculator.net/voltage-drop-calculator.html? material=copper&wiresize=0.3224&voltage=12.09&phase=dc&noofconductor=1&distance=14&distanceunit=meters&amperes=123.5&x=57&y=10
    select estimated resistance and put the numbers in, then calculate. The voltage drop in volts, voltage drop as % and voltage you could expect to see at the other end of the cable. The aim is loose as little of voltage as possible while keeping the cable size within a workable diameter. There is no value in putting welding cable between the 10 amp regulator and the battery :p

    T1 Terry
     
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