Lithium Batteries

Discussion in 'General Camping Discussion Forum' started by justwork, Mar 25, 2020.

  1. justwork

    justwork Active Member

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    For the last year I’ve been researching a grid tied solar electric system with batteries for night and backup. Overall solar is affordable but the battery cost, nope, batteries will almost double the cost.

    I did find these awesome lithium batteries on ebay, they’re 12V and 40 amp hour, two of these in parallel would be fantastic. You can find them as cheap as $150 a battery. They’re used BUT a solar guru on YouTube tested two random ones and they were still above %90 capacity. Some batteries when you buy them brand new don’t have %90 capacity.

    the batteries are called Valence, they’re used in medical devices.
     
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  2. justwork

    justwork Active Member

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    To be clear, two in parallel would be great for a pup, not a solar powered house...
     
  3. generok

    generok Well-Known Member

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    Lithium units have great performance, but personally I can't justify the expense for weekend warrior use like I currently do. If you had a specific high performance need for full-time live-in boondock operations, maybe. I haven't run the numbers, but my gut tells me it's less expensive to invest in more solar panels, and use wet cell or even AGM batteries, than it is to go lithium at this time.

    That's pretty cool that there are some used lithium batteries out there. Might allow for some experimentation.

    Thanks for sharing it!
     
  4. joet

    joet Well-Known Member

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    Keep in mind you stated the pair will give 40 AMP HRs of which 20 can be used. I would do and energy audit first.
    A Group 24 wet cell will give more AMP HRs
     
  5. justwork

    justwork Active Member

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    Oh I realize these are not perfect. 80 amp hours, 2 40amp hour batteries in parallel, this would be much less capacity then I currently have. However per kWh these lithium batteries are actually cheaper compared to cheap wet cell batteries. Currently I have 2 group 31 which give me 240 amp hours. However, this is way more capacity then I need. I’ve been on 5 day boomdocking trips and only used about %30 capacity. This is from my Victron battery monitor.

    I believe I paid $250 for EACH of my group 31 SLA batteries. So $500 total. I could get 4 of these lithium batteries for that price. 4 in parallel would give me 160 amp hours. That’s plenty.
     
  6. bearman512

    bearman512 Well-Known Member

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    If they have a good BMS installed you can draw these batteries down to 10% with no damage and they actually like this. I have a 125 ah Torque 12v battery that has a internal BMS and it is a drop in battery. It actually has a top ah charge of 136 after charge is complete. I have 750 watts of 24v solar and a li40 renogy MPPT controller if I use 50% over night it will be back at full in about 2.5 hours.
     
    Last edited: Mar 25, 2020
  7. justwork

    justwork Active Member

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    It does have an internal BMS, and when the batteries are connected through the attached cables the batteries talk to each other and will balance properly.
     
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  8. BillyMc

    BillyMc Well-Known Member

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    Thought about it, but can't justify the cost. I run one Duracell Group 31 flooded battery with 105AH. After three nights we barely put a dent in it's capacity.
     
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  9. JimmyM

    JimmyM Well-Known Member

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    You don't apply the 50% "rule" (which is garbage in our application anyway) to lithium batteries. Use the 90% rule for lithiums.
     
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  10. MNTCamper

    MNTCamper Well-Known Member

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    Group 31 Deep cycle FLAs are $80 at Sam's on sale and $100 regularly. There is no reason to pay much more than that for batteries. Unless there are weight or size considerations, there is no reason to go with lithium at this point, there are much more cost effective options out there.
     
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  11. joet

    joet Well-Known Member

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    Even using the 90% rule and at $150 per battery wet cells will out preform when comparing amp hrs. to cost. Remember these are just 40 amp batteries.
     
  12. JimmyM

    JimmyM Well-Known Member

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    Definitely. Agreed. Nothing will beat a flooded lead acid battery for AH/$. I was speaking to the 50% rule "accepted without any analysis" trope.
     
  13. GreyFox

    GreyFox Well-Known Member

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    For you perhaps but many others of us have moved on to AGM and would never go back to flooded despite the higher cost of a sealed, maintenance free battery.
     
  14. rabird

    rabird Howdy!

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    Brother (TT) went from marine to AGM to Li in 3 years.
    I showed up with portable solar panels and his G24 and Odyssey were @ 11.8v.
    He went to 4 100ah AGM and all was fine with 300w roof top solar.
    Decided 3 Li battle borns was the way to go! Still fine.

    With my new to me trailer with hydraulic lift, a dual post G24 fits nicely.
    BattConn.jpg

    took a week + with various chargers to get a decent hydrometer reading.
     
    Last edited: Mar 26, 2020
  15. justwork

    justwork Active Member

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    I think when my SLA batteries are toast I'll be picking two of these lithium batteries up. Weight is a lot less, and my tongue weight is already up there with my E3. Plus I can run these way down and not worry about damaging the battery. Also a lot smaller so I will be able to fab up a nice compact battery box. To each their own.

    In the mean time I wont complain about my SLA deep cycle batteries, they do everything I need, just take up a lot of space on my toy deck.
     
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  16. rabird

    rabird Howdy!

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    possible NON issue, the Li BMS may not let a cold battery charge, <0C/32F. Mount em indoors!
     
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  17. FARfetched

    FARfetched Well-Known Member

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    We use Li-Ion batteries in some of our products. Since I was documenting the charging system, I had to do a whole bunch of reading about them. Learned a whole bunch of stuff. They're definitely temperature-sensitive.
     

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