Where is the cheapest place to buy lithium batteries right now?

Discussion in 'OnBoard Electronics & Controls' started by DennisRB, Nov 1, 2014.

  1. DennisRB
    Joined: Sep 2004
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    DennisRB Senior Member

    I know I will be fine for lifep04, but not the batteries groper is talking about. I wont get a full charge with my controller so would need a more expensive one that goes over 15V. to get a full charge with limn2o4 I need 16V. Also I wonder if my panels which are rated to 18V will have enough potential difference to reach 16v to the batteries after the effects of heating, voltage drop, diode loss from shading etc. Seems limn2o4 batteries would be better suited to higher voltage panels and use MPPT.
     
  2. DennisRB
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    DennisRB Senior Member

    As you know I want to use some high power 240V electrical devices. So far I have found a decent high power inverter (8000w 36000w peak) which says it will run a compressor of up to 2500w. This has a reasonable price of around $500. Max voltage, like all inverters I have seen is 15 before it cuts off.

    Also my alternators would pretty much do nothing to charge to 16v. They seem to be set around 14v.

    I have to check my instruments and fridges.

    I would need to spend quite a bit to upgrade all my leds to voltages regulated units rather than cheap resistor LEDs.

    All doable. But costs need to be understood.
     
  3. BertKu
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    BertKu Senior Member

    No. Bert
     
  4. groper
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    groper Senior Member

    The solar panels would almost certainly not operate anywhere near peak efficiency with these limitations. led's will operate on an extremely wide voltage range, no problem there.
     
  5. DennisRB
    Joined: Sep 2004
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    DennisRB Senior Member

    No my LEDs wont be fine nor will most unless they have a voltage/current regulator circuit rather than only resistors. As I said I have cheap ones, which work fine in my application but WILL overheat and die over 15V. That's the difference between $1-2 leds VS $20-30 leds such as marine beam. That price per LED adds up on a 43 foot cruising cat.

    EG this will burn out at 16V. They are the last ones I purchased and get way hotter than I would like if I ever turn them on when I am charging at 14.5v. They are insanely bright.

    http://www.ebay.com.au/itm/40068807...eName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

    These should not get hot and will work great over a range of voltages. Still pretty decent price and should be fine for the task unlike the ones above.

    http://www.ebay.com.au/itm/27150073...eName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

    This is what many the marine industry says you should use. http://store.marinebeam.com/ read the part about cheap "dangerous" LEDs. Its a bit of scaremongering, but shows exactly why most LEDs lights do not work over a wide range of voltages. I have not had any probs at my voltages but I know for a fact the many of the ones I have will cook at 16V.

    Most LEDs you buy even for $40 at whitworths and the like fall into the category of the first $2 ones I posted which have no real regulation (unless they say something like "for use with 12v or 24v).

    Re my panels. I just checked out the specs which are as follows.

    Maximum power (W) 200
    Optimum power voltage (Vmp) 18.0v
    Optimum operating current (Imp) 11.12
    Open circuit voltage (Voc) 22.30v


    Looks like that should be fine :D

    I could always pair them in series with a MPPT controller. A more expensive controller with a higher max voltage setting would be required anyway.

    Still stumped for a good solution for the inverter.
     
  6. DennisRB
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    DennisRB Senior Member

    Anyone that has tried to buy LEDs from ebay will know how hard it is to search for something decent with all the fake adds and bad search tags. I used G4 LED 30V and found that as a good criteria and came up with this! Looks to be a regulated 12 x 5730 chip (very bright chips) for $2.79! I will buy one and post the results.

    http://www.ebay.com.au/itm/G4-AC12V...?pt=AU_Lighting_Fans&var=&hash=item5af8614404

    Anyway, this is a lithium thread. LEDs probably have threads all over the place already. Suffice to say even if your LEDs are not suitable for 16V there are cheap ones that are.
     
  7. groper
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    groper Senior Member

    Nevertheless , the suitability of the limn2o4 as a house bank for these reasons IS worth discussing. For some, due to the their current equipment , may find it more problematic to use them. For me and my equipment, it's not an issue as I run a 24v bank and would use 7cells as per Brianbne suggestion. We also run 44voc solar panels, not a problem to regulate down via the mppt.

    From what I have seen, the lifepo4 cells can't be had as cheaply as the limn2o4. This is likely due to the mass production and usage in commercial electric vehicles such as the nissan leaf. This will likely change in the short term as the leaf is supposed to have a new battery for next years model with higher capacity. Will it be a new chemistry or simply improved existing one? I don't know... At existing retails prices, a new limn2o4 battery can be built for $285 per kWh. For simplicity of comparison, that's a 12v 250ah battery for $1000. Edit price error.

    That's 220 amp hours usable capacity. A lead acid agm battery costs $500 for a 250ah. But that's only 125ah usable. Fr the same usable capacity, you would have to buy 2 of them and spend almost $1000. So the price is now almost on par with lead acid. In another 12 months, might even be cheaper.
     
  8. pdwiley
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    pdwiley Senior Member

    I haven't installed any electrical/electronic equipment yet so I don't really care. I was planning on a 12V system but could just as easily go to 24V. I'd already decided to have a separate battery & dedicated alternator for the engine so I don't have to consider swapping a starter motor.

    There should be a ton of 24V input inverters out there. I may fit a couple of small TEFC 240V 3 phase motors yet, still thinking over the pluses & minuses. Keeps the high power cable runs really short as 2.5mm wire is heaps for the 3 phase motors.

    As the cabin top is now installed I might start thinking on lighting etc. Definitely get the 24V rated LED lights.

    PDW
     

  9. DennisRB
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    DennisRB Senior Member

    PDW I would definitely go with 24V. For me it would be a no brainier on a new build. Its more efficient in many ways. Smaller cables (less money, weight and voltage drop). Chargers, and alternators etc are usually priced and sized for current. So for not much extra price and weight you get double the power. Eg a 150a alternator is putting out double the power at 24V vs 12. The same goes for solar controllers which can be half the amp rating. I provided links to cheap and good LEDs that will work for 24V.

    Then comes the limn2o4 batteries. There seems to be no voltage issue at 24V as there is with 12V. Plus it makes it even cheaper as you can subtract the price of one series cell to get to 24V...

    I checked my fridge and freezers. They work on 12-24. Seems my main issue will be the inverter. The prices you quoted are almost half that of lifepo4. I think waiting will be a good idea with the electric car market hotting up. Prices will be set to fall.
     
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