1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Batteries

Discussion in 'Fuel System & Electrics' started by Jon Baldwin, Feb 2, 2021.

  1. 1500king

    1500king Well-Known Member

    Messages:
    1,568
    Location:
    Adelaide, SA
    You don't need a big starting battery. The starter on a healthy 2.0 only pulls 65A. Save your money for a Lithium/solar/Alt controller needed for a lithium auxilliary battery..
     
    syncro and Mordred like this.
  2. drivesafe

    drivesafe Active Member

    Messages:
    234
    Hi again Noisyjohnny and out of curiosity, why are you thinking of going for a Lithium Auxiliary battery?
     
  3. noisyjohnny

    noisyjohnny New Member

    Messages:
    2
    Location:
    Melbourne
    I run out of power on a 100 AH AGM battery because I can only get 50 AH use out of it an I need 48 A per 24 hour which isn’t enough even with 180 W solar blanket to top up. With a 100 AH lithium I can get 80 ah useful power, faster recharge (with the right charging system), with less weight in the same space. I am expecting the life of a lithium battery will be much greater and therefore justify the higher initial investment. I have replaced the AGM battery twice in 3 years and loooking to go off grid longer so I need a better solution. I appreciate the input from this forum.
     
    drivesafe likes this.
  4. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,552
    Location:
    Mannum South Australia
    A quality lithium 100Ah battery will supply all 100Ah without dropping below 12v while under a 50 amp load. We service and test the battery system we install every 3 to 4 yrs, up to the customer when and even if they bring them back in for a service. We capacity test them at the 2C rate the cells are capacity test at in the factory and offer another 3 yrs warranty if the battery comes up as still having the advertised capacity. The oldest set that operates 24/7 as a house battery was 8 1/2yrs old when it came in for the last service, 200 amp load on a 400Ah battery and after 2 hrs the cells were all still above 3v and battery above 12v while still under the 200 amp load. The factory testing pulls the cell voltage down to 2.5v under load, so after 8 1/2 yrs of full time service this battery pack still has more than the advertised capacity when discharged to 0% of its advertised capacity. Every system we have serviced has passed the same test, the most recent, 3 1/2 yrs full time service delivered 420Ah before any cell group dropped below 3v.

    We also recently found a Sinopoly 100Ah cell packed away in a box when we moved from Lake Illawarra to Mannum. We traced back to the batch we purchased from an abandoned electric vehicle conversion 7 yrs ago, the batteries had been in their boxes for 3 yrs when he decided he wasn't going to find the time to finish the conversion, so that makes them a minimum of 10 yrs since manufacture. The cell is still at 3.388v, the same as the the cells in the sealed boxes 7 yrs ago.

    These 2 real life tests show the loss of capacity over time to be B/S and the 10 yr shelf life is also B/S .... just nonsense put out by the lead acid battery sellers in an attempt to discredit lithium technology.

    T1 Terry
     
  5. drivesafe

    drivesafe Active Member

    Messages:
    234
    Hi John, and first off, your 100Ah AGM will deliver at least 80Ah, as all modern AGMs can be safely discharged down to 20% SoC and many new AGMs can be safely discharged down to 0%.
    A good battery I have been using and testing for some time now, is the SSB HVT range ( the HVT-70ZZD is the same as your 100Ah AGM ). These batteries are both cranking batteries and deep cycle batteries.
    But if you are only cycling your battery to 50% SoC and getting about 18 months of use from a battery, you are doing something very wrong, and the most common cause of such short life spans is lack of maintenance when the battery is not in use.
    Also note, as you will need to use a DC/DC device to recharge your lithium battery, and because you have such a small alternator, it will take you much longer to recharge the lithium then at will to recharge a cranking battery type AGM.
    IMO for far less cost, you will have a better setup just using the right type of AGM.
     
    Last edited: Feb 22, 2021
  6. drivesafe

    drivesafe Active Member

    Messages:
    234
    Also John, can you post up the brand of lithium you were considering.

    There are some really terrible quality lithium batteries out there now, and some actually have such bad specs that many AGMs will actually give better performance.
     
  7. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,552
    Location:
    Mannum South Australia
    Edit: some other takes on the information above:

    1) It may be possible to discharge an AGM battery down to 20% SOC or even 0% SOC, it is the voltage under load that is significant. A phone call this morning from a customer who bought a DC to DC charge from us because his AGM batteries were not recharging sufficiently from direct alternator charging to run his fridge over night, told me he was still having problems with the fridge cutting out when the battery rested voltage dropped below 11.8v. I asked him to check the voltage at the fridge without the fridge running and when it started up. 12v not running, 10.5v momentarily before the fridge cut out again and the voltage slowly crept back up to 12v, then the cycle repeated. Measure at the batteries, 12v dropping to 11v then climbing back to 12v again.
    Car engine running, the charge current was now the full 40 amps, not less than 1 amp that we measured when testing the system when he first came for use to see what the problem was and ask about replacement batteries.

    2) you don't need a DC to DC charger to recharge lithium batteries, you need a DC to DC charger to control the maximum current the alternator has to supply. An AGM battery will only accept a high charge rate for a short period before the voltage jumps up to the regulated voltage, then the current is reduced to control the voltage. A quality lithium battery will accept the charge current as fast as it can be supplied until it is fully charged ... it will actually continue to accept the same high current if the voltage high enough until it fails due to over voltage overheating boiling the electrolyte. This is why a BMS is required, to save the lithium battery from its own greed for charging current as well as its ability to supply current until the cell is so discharged it starts to eat itself in an attempt to still supply the current demand.

    3) You are correct about AGM batteries needing to be maintained at a fully charge state when not in use to prevent them sulphating, not a problem for lithim batteries, in fact, they don't like being held at 100% SOC for long periods ... we are talking day/weeks mths at 100% SOC, not a few hrs.

    4) You are correct about the lower initial cost, but that soon turns the other way once the AGM battery has to be replaced yet the lithium battery would still be doing its job without an issue.

    5) Agree about the poor quality lithium batteries out there in the market place, some are absolute garbage .... just like a genuine 100Ah deep cycle AGM battery, weight tells a lot, 100Ah @ C20 discharge rate (5 amps for 20 hrs) it will weigh between 30kg and 32kg, they don't make light weight lead. A genuine 100Ah @ C2 discharge rate (50 amps for 2 hrs) LFP or LYP chemistry lithium battery, it will weigh around 16kg, more if they claim there is a BMS in the battery case, that is just how much the combined weight of what is required to store and deliver that much energy, it can't be made lighter than that without reducing the capacity. The usual trick is to measure the capacity at the same C20 rate as used for an AGM battery (5 amps until the battery drops to below 10v and the BMS disconnects the battery) that many hrs x 5 amps is their claimed Ah capacity. A lithium battery that has it's capacity measured using a C20 rate wouldn't give you much better service than a quality 32kg AGM 100Ah battery. If they won't tell you the C rating or amps load the capacity of the battery was measured at, look for another supplier ... this goes for AGM batteries as well, I've seen them rated at 100Ah @ C100 rate (1 amp for 100 hrs) maybe 80Ah @ a C20 rate on a good day.

    T1 Terry
     
    Last edited by a moderator: Feb 27, 2021
  8. drivesafe

    drivesafe Active Member

    Messages:
    234
    Edit: in response to previous comments:

    No vehicle built before 2004 needs any form of DC/DC device.
    DC/DC devices were first developed here in Australia, to get around the problem of voltage drop at house batteries in caravans, because the clowns making the caravans or installing the cabling ( read wires ) in the tow vehicles, were running grossly undersized WIRES.
    It had nothing to do with alternator voltage.

    edit: to clarify, voltage drop in small cable sizes at long lengths is a major factor in low voltage issues and as a result charging issues. A DC/DC converter will increase the voltage but also draw more current so some power wis wasted. It may be cheaper to increase the cable size or shorten the run to reduce the voltage drop rather than add another unit.
     
    Last edited by a moderator: Feb 27, 2021
  9. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,552
    Location:
    Mannum South Australia
    Wow, Tim, straight for the throat like the old days :lol: The owner of the vehicle was standing there with me when I did the tests to prove the alternator alone was not recharging his batteries and this confirmed what he suspected.
    Just like water needs to flow down hill, you can't make electrical current flow unless it is moving from a higher voltage to a lower voltage. Are you now refuting the fact that AGM battery terminal voltage increases as it charges? Are you claiming that if the wire is thick enough resistance no longer exists so there is zero voltage drop along the length of cable?

    T1 Terry
     
  10. oldman

    oldman Super Moderator Staff Member

    Messages:
    9,754
    Location:
    Avalon Beach NSW
    Let’s keep the personal attacks out of this thread please....
    Between the barbs, there’s a lot of great information for us battery ludites to process and learn from.

    Cheers,
    Mark
     
    Last edited: Feb 23, 2021
    syncro and tintop like this.
  11. robmich

    robmich Active Member

    Messages:
    555
    Location:
    buff point
    i fitted a 70ah AGM battery connected via a VSR to run my fridge, still going strong after 4 yrs if i am camped for more than a day or 2 i plug in a portable 100 watt solar panel i have never come close to running out of power i believe people tend to over think the whole battery thing, keep it simple is my advice
    Rob
     
  12. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,552
    Location:
    Mannum South Australia
    Lead acid batteries are great for those who don't have high current requirements and don't require a lot of stored capacity each non charging cycle, whether it by by alternator (with or without DC to DC assistance) or solar.
    AGM type lead acid batteries do not suit a hot environment , the heat tends to add to the water evaporating out of the electrolyte and being lost from the battery. The recombining technology in an AGM battery just just as it indicates, it recombines the hydrogen and oxygen that is split from the water during the electrolysis action that is a by product of recharging any type of lead acid battery. This technology can not replace water vapour lost from the cells and as part of the process creates heat itself, just adding to the heat build up in the battery.
    This is why flooded cell type lead acid batteries are prominently used as start batteries under the bonnet beside the hot engine in a typical vehicle.
    This could be part of the problem noisyjohnny is experiencing that is causing the shorten battery life, but I expect it is more along the lines of energy requirement exceeding the stored capacity in the battery after the first night free camping. The advertised capacity of any battery is measured from the 100% charged state and this takes a lot longer to achieve than many people think when it comes to lead acid batteries. Just because the voltage reaches 13.8v doesn't indicate the battery is 100% charged when it comes to lead acid batteries, it doesn't even mean 100% charged for a lithium battery, it is the actual rested cell voltages that indicate if a lithium battery is fully charged and the acid specific gravity for a lead acid battery.
    Individual cell voltages for a lithium battery isn't really possible for one of the "drop in" type lithium batteries that is built to look like a lead acid battery, built that way so people are more accepting that they will simply replace their old lead acid battery.
    Acid specific gravity measuring is a bit of a dark art, carries the risk of acid spills and clothing/skin burns and is only possible with flooded cell batteries, not AGM, Gel or lead crystal.
    The old high load starter battery tester that puts a high current load across the battery terminals and measures the voltage drop is designed for starter batteries, not deep cycle batteries, so don't let the battery testing person put one of those on your deep cycle battery, if it didn't have a problem before the test, it will afterwards ... deep cycle batteries are not designed to deliver that high current for a short period, they are designed to deliver a much lower current for a much longer period. There are higher tech battery testers on the market, but not all of them are accurate. I tested two deep cycle batteries with an evil bay purchased unit and it claimed both were 2% capacity and required replacement, yet the voltage under a C20 load test over time showed that one battery would recover with a regurgitation charging regime to clear the plates surface sulphation, the other was as dead as a brick, so be wary of the "high tech" battery testers as well.
    The tried and true test for any battery no matter what chemistry, find out the "C" rating it was rated at, generally C20 for lead acid deep cycle batteries which means the advertised capacity divided by 20(hrs) e.g. 100Ah C20 rated is 5 amps for 20hrs, then apply that load to a fully charged battery and watch for the voltage to drop to 12v and how many hrs that takes. For a lead acid battery that will indicate the remaining capacity till the battery reaches the 50% capacity level ... yes, it can be discharged to a lower voltage but generally a 12v appliance wants 12v or better, this includes stereos, TV's and fridges/freezers ... and yes, they do have cut out that can be set by the user and often that goes down to 10.5v, but that lower voltage is to protect the fridge compressor and electronics, not the battery, they just don't work well at any voltage much below 12v.
    Lithium batteries are a mine field full of scammers, so be very careful. If there is no "C"rating supplied with the advertised capacity, the maximum amps and continuous amps listing is not the "C"rating the capacity was measured at, so don't let the seller try and pull that one on you .... if the won't give you a "C" rating or "CA" rating (the advertised capacity divided by the number is the load, divide the advertised capacity by that number and that is the number of hrs the battery will supply that load before the 100% of the advertised capacity is drawn off) e.g. 100Ah 0.5CA rated means 100/0.5 = 50 amps, 100/50 = 2 hrs, so the manufacturer says the battery will supply 50 amps continuous for 2 hrs and still retain 12v while under load .... This is a serious capacity test, it also means that if the load was less than 50 amps the battery could supply the load for more than 2 hrs and therefore the capacity measured at a lower load would be greater ....... something I mentioned previously, beware of the lithium seller who tries to sell a 100Ah battery tested at the C20 rate, in a proper lithium battery test it would probably fail under load but even if it could deliver the 0.5CA load, it certainly wouldn't deliver it for 2hrs before it dropped to the 12v mark while under load.

    And just for Tim, no, I'm not trying to sell anyone a battery, we don't sell batteries as such, we design and install off grid power systems to mobile and non mobile homes .... and we are very busy so we must be doing something right :lol:
    My wife has written a very helpful plain speak website T1lithium.com.au if you want to learn more, this is also not a business plug Tim, but offered as an assistance tool for those who want to learn more. As I said, we are very busy, so don't expect you can email or ring and book in a weeks time, but I don't do that part, it is my business and she handles that part, I'm the slave labour :eek:

    T1 Terry
     
  13. cbus

    cbus Well-Known Member

    Messages:
    13,053
    Location:
    sunshine coast
    Except a big battery gives plenty of reserve if you have a bad starting issue in the boonies.
    Plus lasts longer due to less cycling on hard starts or when it starts deteriorating.
    Pick them up at less than a RACQ or Repco small battery by thinking ahead and buying with a good discount.
    Just extra insurance ;)
     
  14. drivesafe

    drivesafe Active Member

    Messages:
    234
    Thats strange, considering companies like Land Rover and Mercedes Bends and other European vehicle manufactures have been using AGM cranking batteries for over a decade now. And as most are located under the bonnet, so where did you get your info from?


    For a starter, as most lithium batteries are sealed, Lithium batteries will sit at 13.2 to 13.3v, regardless of whether they are 20% charged or all the way to 100% charged, and you can NOT use lithium battery voltage as an indicator of the state of charge of a lithium battery.

    As for SPECIFIC GRAVITY of a lead acid battery. Again, how do you achieve that these days as most lead acid batteries, be they AGM or Wet Cell, and now sealed.


    [QUOTE="T1 Terry, post: 692199, member: 5767”]generally C20 for lead acid deep cycle batteries. T1 Terry[/QUOTE]
    The C20 rating is the international standard for ALL LEAD ACID batteries, deep cycle and cranking batteries.

    If a battery has an Ah rate marked on it, and no other info, it is a C20 rating for that battery and no other info is required.
     
  15. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,552
    Location:
    Mannum South Australia
    Sorry Tim, your not very well informed on the topic you have tackled, clearly shown by the volume of incorrect information you posted. Starting batteries are rated at RC and CCA, Ah are for deep cycle batteries, there might be some trying to fill all the requirements so they have all the ratings, CCA, RC and Ah, but not being designed for yo perform any of the tasks specifically, they sort of generally do the job ... a bit like "one size fits all". Compare the specs between a quality deep cycle battery such as a Concorde and the equivalent capacity cross over battery and it is clear to see the difference between something designed to do the job and the "One size fits all" approach.
    As for all deep cycle lead acid batteries being rated at C20 ... a tad more research is required Tim, they range from C10 to C100, good quality is at the C10 end of the scale, those trying to pull a swifty use the C100 end of the scale. If the manufacturer/seller does not specify the C rating, ask for it, if they can not provide documentation from the manufacturer that verifies the C rating, look else where is my advice.

    Drop in lithium batteries are sealed, they make up one section of the market and yes, this section of the market is flooded with them .... buyer beware ..... if you can't check the cell voltages or the terminal connections, it's a problem waiting to happen.
    Lithium batteries will sit at 13.2 to 13.3v, regardless of whether they are 20% charged or all the way to 100% charged

    No idea where you got this bit of mis-information from, but it is incorrect. The fact is, unless the cell voltages can be read and they are all better than 3.5v rested, the battery is not actually 100% charged because not all the cells are 100% charged. 3.45v in each cell rested does indicate above 99% charged so close enough for general day to day use, but for genuine capacity testing, every cell must be saturation charged.

    As for specific gravity testing, thank you for backing up my point, those in the industry that remember the old days of Telecom flooded cell battery banks that acted as the back up or full time power supply for remote exchanges can verify that the only accurate method of determining the cell state of charge was by specific gravity testing of the acid. Voltage can be very misleading, a heavily sulphated cell will hold a high surface voltage yet the actual Ah capacity of the cell is very little, spread across 6 cells in a battery that can't be accessed to measure cell voltages under load and the real state of the battery is limited to the poorest cell and little can be done to rectify the problem, the whole battery is destined for the scrap yard.

    With a lithium battery or a lead acid battery built from individual cells, is a cell becomes problematic, it can be replaced at a much cheaper cost than replacing the whole battery.

    T1 Terry
     
  16. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,552
    Location:
    Mannum South Australia
    Can't argue with that, but a quality 100Ah LFP or LYP lithium battery can provide the full 100Ah @ 100 amps for 1 hr if required. If the starter motor draw is 65 amps that means it could theoretically crank the motor for 1 1/2 hrs and still retain the full 12v while cranking ..... I have my doubts the starter would last that long but say a 1 min crank with a 5 min rest to cool, 90 mins actual cranking and 450 mins resting, that's 9 hrs in total, probably close to driving the vehicle to the workshop on the starter :lol:

    T1 Terry
     
  17. cbus

    cbus Well-Known Member

    Messages:
    13,053
    Location:
    sunshine coast
    Have used starter to clear an intersection more than once ;)

    I haven't got a clamp for amps so would be interested in an actual reading while cranking.
    The 65 amp sounds theoretical for 1 HP starter.
    Then they are only about 60% efficient.
    Add circuit losses from bad connections and an older standard 44 Ah battery can struggle to survive a non start diagnosis or flooded engine pretty quickly.

    I know everything should be up to scratch but that's not always reality in kombis .
     
  18. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,552
    Location:
    Mannum South Australia
    Yes agreed :lol: The 13.8v charged from a quality lithium battery will not sag below 13v even under a 1C load, (100 amps from a 100Ah battery, so the engine spin speed is much faster and really helps on the cold wet morning where you really want the engine to fire up first time ..... these are the morning when the tired lead acid start battery will drop its voltage to 10v under cranking load resulting in a very poor spark in the basic points/coil ignition system. Add in the length of rather small cable that runs from the back to the front to get to the ignition switch, then all the way back again to the coil, the voltage at the coil on one of those slow cranking speed cold and miserable mornings can be very low and barely enough to create a spark across the worn plug electrodes.

    T1 Terry
     
  19. Jon Baldwin

    Jon Baldwin Member

    Messages:
    85
    Location:
    Goonellabah Australia
    What do you guy's think of the CATL 3.2V 310Ah, $88/ PCS ( QR code intact) ? these are from Alibaba freight to OZ is about as much as the batteries but still significantly cheaper than buying them here
     
  20. David H

    David H Well-Known Member

    Messages:
    6,296
    Location:
    newcastle
    All good until it goes wrong Jon;).
    Return policy not in your favour:(.
    Cheers
     

Share This Page