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Thread: Lithium batteries under bonnet

  1. #1
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    Lithium batteries under bonnet

    Quite a few are running lithium under bonnet,and have done now successfully for a few years.

    Anyone on here done it?

    Have a look at this link,snake oil?

    I will have to wait for Tim to chime in and shoot it all down in flames

    https://www.deepcyclesystems.com.au/...-dual-battery/
    Paul

    D2,D2,D2a,D4,'09 Defender 110(sons), all moved on.

    '56 S1,been in the family since...'56
    Comes out of hibernation every few months for a run

  2. #2
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    From the 'blurb' .................. "The DCS batteries are connected directly to the alternator which allows the batteries to swallow everything the factory 80Amp alternator can provide, which would be a maximum of around 60-70Amps. These batteries can recharge super fast and are designed to be able to recharge at a continuous 100Amps."


    So does this mean that the ability of the existing alternator to safely regulate its maximum output current is all that's stopping it from meltdown ?

    One (sometimes fatal) characteristic of LiFePO4 batterys is that they charge flat out ie. draw maximum available current from flat to fully charged so maximum load on the alternator all the (charging) time whereas a lead acid battery will charge at maximum current for a short period of time only with the charge current tapering off as the batterys charge level increases. With a LiFePO4 battery this can lead to alternator and sometimes wiring/connector failure as the vehicle electrical system may not be designed to withstand this sustained maximum load. Potentially even more so if charging multiple batterys simultaneously, though in fairness the dual battery system installed here may charge the batterys sequentially not simultaneously and have some sort of current regulation to prevent such a problem though the 'blurb' specifically states ...swallow everything the factory 80Amp alternator can provide.

    Deano
    66 SIIA SWB .......73 SIII LWB diesel wgn
    86 RR 'classic'......99 Range Rover P38a
    94 Defender 110..95 Defender 130 Ute
    96 D1 300TDi.......99 D2 TD5 (current)
    04 D2a Td5..........02 Disco 2 V8

  3. #3
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    Hi Paul and Deano, I would not trust that bloke as far as I could kick him with a broken leg.

    I worked with a company that bought the first of those lithium batteries into Australia.

    The cells were pretty good but the BMS was anything but good.

    I was asked by the company to test a batch of these batteries, which were made by the Optimum Battery Co in China.

    We sorted out the problems with the BMS and made some suggestion to the company in China.

    They happily adopted the suggestions and company who bought them in, started to form a Co-Op of small businesses, to buy bulk from Optimum in China, to keep prices down.

    One of the businesses approached was that mob.

    Next thing we know, he’s gone off the China and got an exclusive import arrangement with Optimum, and we were all supposed buy off him, at his make up price.

    Didn’t happen and in the end, it actually worked out well for us, because the original importer ended up sourcing an even better battery.

    As for that battery, as you pointed out dean, the maximum charge current is way too low, because most modern vehicles, not just Land Rovers, have high current alternators.

    If Lithium batteries are such great improvement over conventional cranking batteries, why is it that no major vehicle manufacture is using them.

    Regardless of what brand of Lithium battery you use as a cranking battery, there is a major chance they will cause some serious damage to your vehicle’s electronics.

    This can occur and has in Europe, where the lithium battery’s BMS has, for what ever reason, shut down and this takes the battery completely off line.

    This leaves the alternator running, and while the operating voltage will remain constant, all alternators generate voltage spikes, and these spikes can be as high as 60V.

    Your vehicle’s electronics can not tolerate such high voltages.

    With a conventional ( lead acid ) cranking battery, even a stuffed one, the battery acts as a massive spike suppressor and continually protects your vehicle’s electronics, even when the battery is stuffed.

    Add to this and while probably not a problem in most places in Oz, but lithium batteries do not like cold temperatures and can fail to operate when needed to start the motor.

    Also note, in most hybrids, while the main batteries are lithium, the motor’s starting battery is still a lead acid battery. WHY?

  4. #4
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    Tim,thank you for your reply.

    So the lithium is OK for the auxiliary,if set up correctly,but not advisable for the start battery?
    Paul

    D2,D2,D2a,D4,'09 Defender 110(sons), all moved on.

    '56 S1,been in the family since...'56
    Comes out of hibernation every few months for a run

  5. #5
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    I would not consider using lithium batteries as cranking batteries, until they sort out the drawbacks.

  6. #6
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    I read a report a few months ago by a university where they held Lithium batteries at different temperatures for extended periods.

    They found that if the batteries were held over 50c for extended periods they lost well over 50% of their cycle ability. You will note that just about all Lithium batteries state that he max temperature is 50C.
    AFAIR the desirable temperature was about 25C.

    I had planned to buy a Lithium as a house battery in the original D2 battery position, aided by a fan with a 10 minute timer. I have bought a Renolgy 20amp 12v/12v charger but not yet fitted it as it will need me to chop up the battery/ECU/jack location as it is BIG..

    After the Optimum debacle I would not buy a lesser battery than a Renolgy as they have been tested as true to description by a fanatical bloke in the USA. They are about $800 so out of my price point for now.


    Being obviously Gullible I have bought an Optimum 40amp in the early days before the Optimum fake outputs was known for the camper trailer and installed a 10amp DC/DC charger in the back of the car. I now doubt the 40AH claim. probably more like 18AH but still enough to run a small pump and LED lights.

    So if you are doing long trips in hot weather i would probably not put one in the engine bay.

    My new plan is to buy 4x100AH modules and fit them in a rear bin in the D2. A mob called Big Wei is also importing a long skinny 100AH but still out of my price range.
    Regards PhilipA

  7. #7
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    Hi Phillip and what is the reasons behind going to lithium?

  8. #8
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    Hi Phillip and what is the reasons behind going to lithium?
    I like to experiment while being conservative so that I don't throw away money.

    I was looking at 100-120AH lithium to run my old Engel fridge longer so that if camping on dull days that my solar set up doesn't fully recharge the battery I don't have to start up and drive .
    Also the weight saving.
    In the end I replaced my 100AH wet battery with a 120AH AGM in the original battery position. This should charge quicker than the wet battery and give me more time in camp.

    I originally bought the wet battery as a stopgap until Lithium prices came down, but it appears that only junk Lithiums are now cheap. Good ones are still at least $800 and more.

    The Optimum debacle taught me to be suspicious of all cheap Lithium batteries. I would be interested if anyone has access to an Australian test test of the cheaper batteries sold in Australia that shows that they have capacities as advertised. There is a bloke on you tube who seems to honestly check US Lithium brands but these are mostly different to those sold in Australia

    Regards PhilipA

  9. #9
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    Hi again Phillip and thanks for the reply.

    It depends on how you are charging the different batteries as to whether there is a real advantage to having lithium over AGMs.


    If you are using a DC/DC device for the AGM, then the charge time is not that much different, depending on how low you discharge either type of battery.


    If the AGM is being charged from your alternator, then if the AGM is in a low state, then it will recharge the bulk of the battery in a shorter time than the Lithium, which will still need to be recharged with a DC/DC device.


    As you have smartly stated, these cheap lithiums a very sus, and many would need to be a 120Ah size to replace your 120Ah AGM.


    A good quality 100Ah lithium could replace your 120Ah AGM.


    Experimenting is a good reason for trying lithium batteries and people like yourself, can then give others a fair and honest appraisal of what you find.


    Unfortunately, many people think they are going to get an advantage( based on grossly misleading advertising ) if they swap to a lithium setup.


    I get at least one phone call a week with people considering swapping to lithiums but it takes very like to show them they are going to be worse off and out of pocket in a big way.

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