Lithium battery from electric cars for boat use

Discussion in 'OnBoard Electronics & Controls' started by Artem Klochko, Nov 17, 2019.

  1. BertKu
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    BertKu Senior Member

    Very nice set up. Forget a few threads with not too accurate information from other members. I love to know how easy it is to get such a nice Lithium set up. I bought a large number of 5 Ah , 3,32 Volt LiPo4 batteries and placed parallel in serial to only 12 Volt on top of my 24 Volt system. Sadly mine are round, thus quite a lot of space wasted. Yours are flat and save much more space. I am now planning to get more for a 48 Volt system, like all Telecommunication Industries/providers. Very safe, provided one does not clamp with the left hand the minus pole wet naked and the plus pole also naked with wounds. Your hand will contract, unpleasant but not deadly. How easy and at what cost did you purchase those? Sadly we have only a few electric cars in our country, not easy to get hold of them, thus we have to make power packs ourselves. Importing from China is a problem to get them transported to here, where I am living. Thanks for your interesting thread. Bert

    By the way: do a test. put lots of salt in warm water, put both your hands in it. You will probably measure similar readings with a Ohmmeter normal tap water: 200KOhm and with lots of salt in it : 60 KOhm i.e. with 48 Volt 24 Micro Ampere and with salt water 80 micro Ampere. The maximum the average a heart can withstand is 20 milliAmpere for AC. With DC it is substantial less because of the continuous cramping from the muzzles. It depends on how healthy the heart is. But who in his right mind touch DC with naked and with wounds in both hands DC battery terminals? Touching DC somewhere else? without shoes? naked? Well all the girls will have a ball.
     
    Last edited: Jan 23, 2020
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  2. BertKu
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    BertKu Senior Member

    I came across an interesting table, which explains the current for AC. Because AC moves through zero, if you are able to pull your body contact away from the electrical point, it means only 10 Millisecond contact. it totally depends on your reaction time.
    For DC, the problem is freezing from the first millisecond, thus how lower the body resistance, how longer your muzzles will freeze onto the electrical connection. I am unable to predict what other people reaction time is. Thus this table is also to certain extend applicable to DC.

    Effects of Electrical Current* on the Body 3
    CurrentReaction
    1 milliampJust a faint tingle.
    5 milliampsSlight shock felt. Disturbing, but not painful. Most people can “let go.” However, strong involuntary movements can cause injuries.
    6-25 milliamps (women)†Painful shock. Muscular control is lost. This is the range where “freezing currents” start. It may not be possible to “let go.”
    9-30 milliamps (men)
    50-150 milliamps Extremely painful shock, respiratory arrest (breathing stops), severe muscle contractions. Flexing muscles may cause holding on; extensor muscles may cause intense pushing away. Death is possible.
    1,000- 4,300 milliamps (1-4.3 amps)
    Ventricular fibrillation (heart pumping action not rhythmic) occurs. Muscles contract; nerve damage occurs. Death is likely.
    10,000 milliamps (10 amps)Cardiac arrest and severe burns occur. Death is probable.
    15,000 milliamps (15 amps)Lowest over current at which a typical fuse or circuit breaker opens a circuit!*Effects are for voltages less than about 600 volts. Higher voltages also cause severe burns. †Differences in muscle and fat content affect the severity of shock.

    Note: most contacts are between earth and life and the 20 milli-Ampere current safety device kicks in within 10 Milliseconds.

    Everybody is different and thus it is not an bad idea where your limits are. From hand to bare feet and left hand to right hand.
    The best is to put a handful salt in a basin with water (Or take seawater) and test your resistance in Ohms with an Ohm meter, accurate enough. Current = Volts /Resistance.
    Then it is easy to find out and give yourself a 100% safety margin. My limits are 60 Volt (charging DC) / 60 Kilo-Ohm. = 1 miliAmpere Good enough for me. Wounds? Yes it will increase the current. But I am not crazy and use gloves when dealing with DC > 48 Volt. Bert
     
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  3. Artem Klochko
    Joined: Dec 2018
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    Artem Klochko Junior Member

    I purchased a EV Bolt battery module (10 cells connected in serial or 36V mid charge, 180Ah) from China for ~800 USD plus delivery. BMS, case and contactor was created and connected everything in my country. IMHO BMS and this type of lithium must be insulated from humid environment at boat.
     
  4. BertKu
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    BertKu Senior Member

    Woowh that is a good price. If I take for shipping and taxes and importation cost 60% it means, 1280 dollar for 6,4 Kwh.
    Per KWh only 200 Dollar. I paid per KWh 630 dollar. Thanks I will investigate what it will cost me to get it here. Thanks very much. Bert
     
  5. Artem Klochko
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    Artem Klochko Junior Member

    Hi BertKu,
    I produce such batteries for my country customers currently. It is a: module + IP68 case + BMS + contactor 450A. Also I plan to try another EV module: 8s (29V) 240Ah - CATL cells, NMC chemistry (same as at EV Bolt battery). If you want to get a module or plug'n'play battery we can discuss this.

    In my opinion battery module inside the rugged case have better chance to be delivered without any damage to module.
     
  6. BertKu
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    BertKu Senior Member

    Thank you for the offer. Unfortunately most airlines do not allow to have Lithium batteries shipped with them for fire and explosion risk. That is my problem. For me the best would be per sea freight, but I have lost a few parcels and am careful. Let me think about it and will come back on your offer. Bert
     
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  7. Artem Klochko
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    Artem Klochko Junior Member

    Checked the battery inside after a year of use. Looks ok.
     

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  8. BertKu
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    BertKu Senior Member

    Are they LiFePo4 batteries or another type? Bert
     
  9. Artem Klochko
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    Artem Klochko Junior Member

    Hi Bert,
    this is another type of batteries - Li NMC
     
  10. BertKu
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    BertKu Senior Member

    Hi Artem, I am using LiFePo4 batteries because I can hit a nail in the battery and it will not explode. I am not too sure, whether that is the case with LiNMC batteries. Also they are 2,4 Volt versus 3,32 Volt and throw my chargers out. But it is a good price and maybe worthwhile to consider. Bert
     
  11. Artem Klochko
    Joined: Dec 2018
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    Artem Klochko Junior Member

    Li NMC cells is used at these electric cars: Nissan Leaf, Chevy Volt/Bolt, BMW i3 and others. It is most used li ion chemistry for EV starting from 2017 year.
    Li NMC cells produced by CATL, Samsung and LG conglomerates and others.
    Full specs can be read by link (Samsung cell for example) Samsung SDI 94 Ah battery cell full specifications - PushEVs https://pushevs.com/2018/04/05/samsung-sdi-94-ah-battery-cell-full-specifications/

    Full cell charge is 4.2V. For mentioned above Chevy Bolt module, which have 10 cells connected in serial, module full charge is 42V.
    As for your charger - I don't know if it can be adjusted. I using a chargers with trimming resistor that allow to change charge voltage +/- 10% from charger nominal voltage. My current charger you can see at photo

    P.S. yes, this chemistry can be dangerous if you try to overcharge it or punch with a nail. Thats why I use a reliable BMS (not chinese) and rugged case for module. Module itself is also have own durability.
     

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  12. BertKu
    Joined: May 2009
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    BertKu Senior Member

    Thanks so much Artem for the above info. Like so many Chinese information, a printing error and 2,4 Volt should read 4,2 Volt. That is good news. Yes indeed many Lithium chemistry combinations are tricky, but lucky LiFePo4 not. Thanks, great info to follow up.
    Bert
     
  13. Artem Klochko
    Joined: Dec 2018
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    Artem Klochko Junior Member

    Forgot to mention - Torqeedo company use lithium modules from BMW i3 (Li NMC) with same chemistry for use at water.
    Battery Technology - Torqeedo https://www.torqeedo.com/us/en-us/technology-and-environment/battery-technology.html
     
  14. gonzo
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    gonzo Senior Member

    According to their website, Torqueedo also uses LiFePO chemistry batteries. However, when you claim that they are the same as a BMW, you would need to know the chemistry of the electrodes and the electrolyte to be correct. Also, the percentage of each element.
     

  15. DCockey
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    DCockey Senior Member

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