Would you consider a Lithium Ion battery?

solar_dave
solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
16 kWh battery for under $2600?

http://www.gmpartsgiant.com/parts/gm-battery-20979876.html

The Charger section is only $830.
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #2
    Re: Would you consider a Lithium Ion battery?

    LiFePO4 batteries would be a great battery for off grid. They are happy with continual partial charge state.

    Problem is battery management. LiIon do not take overcharging and any imbalance between series connected cells must be mitigated with a charge balancer to top out slightly weaker cells without overcharging the already fully charged cells. This is non-trivial requiring secondary wiring to every cell to provide bleeding current on topped out batteries or supplimentary charging to cells not yet fully charged.

    During discharge, each cell must be monitored to avoid overdischarge on any single cell.

    I would be very careful about buying an automotive LiIon pack unless you are very familar with its internal workings. They are designed to work with their separate battery management computer system and it is quite complex. I believe the GM battery packs are made up of 288 mid-sized cylindrical cells similar to laptop battery arranged in parallel and series combination totally about 300 vdc and 16 kWH's. Each cell is about 55.5 watt-hour, or about 16 AH rating.

    From web:

    The battery pack stores 16 kW·h of energy but it is controlled or buffered via the energy management system to use only 10.4 kW·h of this capacity to maximize the life of the pack. For this reason the battery pack never fully charges or depletes, as the software only allows the battery to operate within a state of charge (SOC) window of 65% (range of 20% to 85% SOC), after which the engine kicks in and maintains the charge near the lower level. The minimum SOC varies depending on operating conditions. When more power is required, such as mountain mode, the lower limit of the SOC will raise to 45% to ensure there is enough power available.

    The Volt’s battery management system runs more than 500 diagnostics at 10 times per second, allowing to keep track of the Volt’s battery pack in real-time, 85% of which ensure the battery pack is operating safely and 15% monitor battery performance and life.

    The Volt's battery cells are produced by LG Chem in South Korea.
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #3
    Re: Would you consider a Lithium Ion battery?

    The safety issues would keep me away from Lithium, even if the pricing came down. Yes, the weight-to-power ratio is great which makes it perfect for mobile applications including phones and cars, but I still see stories of phones, laptops and cars bursting into flames. For a non-mobile application like PV I would consider flooded Nicad or good-old-lead-acid before any of the Lithium derivatives.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • boB
    boB Solar Expert Posts: 1,032 ✭✭✭✭
    #4
    Re: Would you consider a Lithium Ion battery?

    What little I have seen that would be a candidate for off-grid or backup power in any Li ion format already has battery charge management including balancing of cells and overcharge/temperature protection in the package. Haven't looked at this particular one but it's probably like that too ? It makes sense to me.
    Individual packages with multiple cells as far as I know are far and few between.
    Please let me know if you have found that this isn't the normal case.

    boB
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #5
    Re: Would you consider a Lithium Ion battery?

    Seems it will need a thermal management systems as well for best life and performance. 3.3 kW charging is recommended and I would think Solar could fit the bill directly. There are a couple guys working on that as a side project to put DC directly into the battery pack, I will keep tabs on the progress. Size wise 10.4 kWh usable seems real doable for a medium off grid system. As far as I know the balancing electronics is included in the pack.

    Is the price reasonable?
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  • DarkStar
    DarkStar Registered Users Posts: 12 ✭✭
    #6
    Re: Would you consider a Lithium Ion battery?
    solar_dave wrote: »
    16 kWh battery for under $2600?

    http://www.gmpartsgiant.com/parts/gm-battery-20979876.html

    The Charger section is only $830.
    Unfortunately that's only for the battery box, cells not included! ;)
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #7
    Re: Would you consider a Lithium Ion battery?
    DarkStar wrote: »
    Unfortunately that's only for the battery box, cells not included! ;)

    Actually no it is a complete battery assembly according to the Volt advisers.
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #8
    Re: Would you consider a Lithium Ion battery?

    Rarely are they in the package. At AH size needed for off grid a simple resistive dissipative shunt would draw way too much power generating a lot of heat (and waste during charging). The multi-cell automotive LiFePO4 starting battery have a low power resistive dissipative balancer that takes a long time to balance cells. This is acceptable for automotive starting but totally insufficient for repeative deep cycling off grid application.

    For off grid there has to be a bi-directional 3.6 vdc charger for each cell to efficiently push or pull currents around to balance cells. This is what commericial electric cars use.

    The simplest for off grid, that would be compatible with some existing inverter-chargers would be an active switching boost bleeder on each cell so when a given cell approaches its max charging voltage the switcher activates and bleeds current off and boosts its output voltage to the full battery stack for recycling.

    At typical off-grid currents the batteries should not even get warm. You don't have to worry about temp unless you are discharging or charging at multiple AH rates. Cars push and pull 5 times the AH rating. Try that with a lead acid battery.

    Another nice thing about LiFePO4 batteries is their recharge efficiency is in the mid 90%.
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,893 ✭✭✭✭✭✭
    #9
    Re: Would you consider a Lithium Ion battery?

    I have been able to buy a couple of XW inverters and 3 xw cc's from people who have tried to use Li Ion batteries offgrid.
    If the wind & sun store has them for sale then you should consider them. Even then I would wait another year!
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • mejustme
    mejustme Registered Users Posts: 17 ✭
    #10
    Re: Would you consider a Lithium Ion battery?

    Hi


    Yes I would but (currently) on a MUCH smaller scale.

    I do think that in time a lot of people will have solar panels on their roof and a LiFePo4 battery bank or similar.

    For now though, a 4 cell Motor cycle battery may be great for me to use for using 12 volt cooking with a small Solar panel. A 4 cell battery may get away without a BMS at least for a reasonable period.

    Neil
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,893 ✭✭✭✭✭✭
    #11
    Re: Would you consider a Lithium Ion battery?
    mejustme wrote: »
    Hi


    Yes I would but (currently) on a MUCH smaller scale.

    I do think that in time a lot of people will have solar panels on their roof and a LiFePo4 battery bank or similar.

    For now though, a 4 cell Motor cycle battery may be great for me to use for using 12 volt cooking with a small Solar panel. A 4 cell battery may get away without a BMS at least for a reasonable period.

    Neil


    Sure thing! You try this for awhile and be sure and report back! Remember if you get sore you can light a candle.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • mejustme
    mejustme Registered Users Posts: 17 ✭
    #12
    Re: Would you consider a Lithium Ion battery?
    Dave Sparks wrote: »
    Sure thing! You try this for awhile and be sure and report back! Remember if you get sore you can light a candle.

    Will do.

    Should be good.

    Gotta find the right battery first.


    Maybe a Ballistic 4 cell.

    Has anyone here used small LiFEPO4 batteries for 12 volt appliances?

    My issue is if the smallest Ballistic one (made for scooters) would be enough to use to cook without worry.

    It is meant to be 4AH lead acid replacement but it MIGHT be enough and for about $60 posted to Australia to be worth it for an experiment for off grid cooking.
    The next size up is also 4 cell and a 7AH lead acid equivalent as are others from Shorai and others but they cost enough to be more worrying if I toast the battery though they would work if the charging was right.


    Neil
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #13
    Re: Would you consider a Lithium Ion battery?

    What kind of wattage/kWH are you looking at from the battery? Just wiring up a battery that you can discharge at C*4 rate (28 amps if 7AH battery/battery pack) would require 10 awg wire and only give you 336 watts peak for ~15 minutes (or less)... What could you heat/cook with that amount of power and what appliance would you use?

    Even if you ran them at C*10 or ~1,200 watts--that is less than 6 minutes of power. One run in the microwave to reheat breakfast for one or two people? Over charge or over discharge the battery once and it will be dead (without BMS)?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mejustme
    mejustme Registered Users Posts: 17 ✭
    #14
    Re: Would you consider a Lithium Ion battery?

    Hi

    I use a 12 volt frypan but will also use other 12 volt appliances.

    A 12 volt frypan uses something between 140 and 180 watts to cook. (A 12 volt sandwich maker uses about 60 watts and takes about 15 minutes I think).

    I currently use a 7.2 AH agm battery with my frypan and it works well. I do think I am slowly killing this battery though but not only for the reasons most would think.

    I charge it with a 50 watt folding portable solar panel that is mostly just left in my window. This is about cooking at home off grid and being portable.

    The 50 watt panel at full sun is slightly too big current wise at full power for the battery. It also most of the time only gets a few hours summer sun a day in a westerly facing window. The drain on the battery is also larger than it would like I think but it has worked for a few months now and should for many more (I hope).

    I can cook twice on a good day as it is.

    There are limitations to what I cook but I pretty much cook the same as I do on my electric stove anyway.

    I think a LiFePo4 battery would be better for me because.
    from what I understand....correct me if I am wrong please..
    A) It can handle the power drain more easily.
    B) charges much faster (big plus for me and limited sun hours both at home and away).
    C) MUCH lighter. I also want to use this for camping and as a BBQ like situation....If a 4AH battery works, it weighs less than 300grams....I could put the battery in my pocket and stand in a bank Queue holding the pan and cook lunch while waiting (if I was dumb enough to).
    D) more USEABLE power for the same size.
    E) Will take the charge rate from my 50 watt panel at full sun.
    F) Does not mind being left discharged overnight

    All the meals I have cooked with it so far have taken between 4 minutes and about 15 minutes to cook so two meals for me in a day would only use around 40-50 watt hours. The pan is only 6 inches but very efficient and I need a lid without unlimited power available.

    The lack of a BMS on a 4 cell battery is the only real concern (other than not killing it if the battery is not enough with only 4 AH) but the battery is supposed to be a drop in replacement and is not sold with one. Some sites reccomend a BMS with the largest Ballistic motor cycle batteries bit they are 8 cells and more.

    I suppose to prolong life I could get a charger made for them that does have a BMS and run it every once in a while?? Thoughts??


    I am thinking a 4ah LiFePo4 battery fully charged would cooking me a meal and then charge quickly and cook a second.

    Neil
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #15
    Re: Would you consider a Lithium Ion battery?

    It sounds like it would meet your needs--And I would suggest looking into some sort of BMS setup. Would hate to see you kill a cell early.

    A good AGM would probably work OK at a much lower cost (a few good quality AGMs can take C*4 charge/discharge rates). I would be less worried about quick charging (from solar) unless you need that function.

    But, AGM's are going to be heavy. No way around that.

    Another option may be D Cell NiMH type cells (10 AH rated for ~$55 for an 8 pack). But fast charging NiMH has their own issues (monitoring heat/voltage to terminate charge).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mejustme
    mejustme Registered Users Posts: 17 ✭
    #16
    Re: Would you consider a Lithium Ion battery?
    BB. wrote: »
    It sounds like it would meet your needs--And I would suggest looking into some sort of BMS setup. Would hate to see you kill a cell early.

    A good AGM would probably work OK at a much lower cost (a few good quality AGMs can take C*4 charge/discharge rates). I would be less worried about quick charging (from solar) unless you need that function.

    But, AGM's are going to be heavy. No way around that.

    Another option may be D Cell NiMH type cells (10 AH rated for ~$55 for an 8 pack). But fast charging NiMH has their own issues (monitoring heat/voltage to terminate charge).

    -Bill

    Hi

    Thanks

    The sensible thing would be to buy something like a 15 AH AGM battery for home use (just for cooking) and a 7 AH eqiuvalent LiFePO4 for taking out and maybe overcast days if needed.


    But then again since no one would ever call me sensible......I think I may just get a 4 AH LiFePo4 4 cell Ballistic or similar and log how often I use it and how long it lasts before I toss it. Use it without a BMS to see if it is worth it to me. I think what will likely happen though is that it may not be a readily repeatable excersize because no two batteries willbe exactly the same and many might well last years without a bms and others could have the cells become very unequal very quickly. The larger the battery and the greater number of cells, the more likely that will happen quicker.

    A smaller battery SHOULD (this is a guess) last longer with just occassional use of a bms charger.

    Eventually I will get a slightly larger LiFePO4 battery and get a bms charger but first, I guess I should do this with the cheapest LifePo4 I can find that is 12 volts and at least 4 AH. I have been procrastinating too long on some of this stuff but there are so many toys I want to play with with so little money.

    I am hoping LiFePo4 12 volt batteries of very small size (less than say 15 or 20 AH) may be okay without a bms. If so they will be highly useable now if used CAREFULLY.....and used for larger size storage with bms and the works. For Inbetween size batteries for at least the next few years AGM would be my choice.

    I do think that for one or two people 12 volt cooking makes a lot of sense in some cases so this could be of use by many people off grid and for camping, the homeless and other uses. A family or group would find it harder off 12 volts.


    Neil
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  • oldchuck
    oldchuck Registered Users Posts: 7 ✭
    #17
    Re: Would you consider a Lithium Ion battery?

    I'm testing a 12V LiFePo4 60 AH battery now. It was very expensive, about $500 with an AC charger. The technology is nice compared with lead acid. The 4 cell battery is very light and easy to lug around. I hook it up to a 2500 W inverter and run a skill saw with it quite easily. It charges quickly and has a built in BMS. I'm seriously considering going for a 200-300 AH 48 V set up for solar storage. I'm thinking it would need it's own BMS but would I then need a charge controller too? Unsure how to hook it all up.
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  • DarkStar
    DarkStar Registered Users Posts: 12 ✭✭
    #18
    Re: Would you consider a Lithium Ion battery?
    solar_dave wrote: »
    Actually no it is a complete battery assembly according to the Volt advisers.
    The adviser you spoke to was mistaken. It's just the box, cells are individually priced.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #19
    Re: Would you consider a Lithium Ion battery?
    DarkStar wrote: »
    The adviser you spoke to was mistaken. It's just the box, cells are individually priced.

    I think it is correct as an assembly
    http://parts.nalleygmc.com/showAssembly.aspx?ukey_product=2949468&ukey_assembly=394291
    or
    http://www.gmpartsgiant.com/parts/gm-battery-20979876.html

    if you look at this thread the dealers are quoting $3k as replacement cost.
    http://gm-volt.com/forum/showthread.php?10746-Has-anyone-tried-to-purchase-high-voltage-battery-yet&highlight=battery+replacement
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