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Carbon foam AGM batteries

Discussion in 'Technical Discussion' started by Delfin, May 20, 2015.

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  1. Delfin

    Delfin Member

    Joined:
    May 28, 2014
    Messages:
    52
    Location:
    Anacortes, WA
    This is a bit of a follow on to the thread on the noise level of the Northern Lights 5 kw genset. As mentioned on the prior thread, the drill here is to charge batteries and power a/c without running the 20kw. In trying to figure out where to put the batteries that have to move to make room for the genset I came across Firefly carbon foam batteries. This is relatively new technology - around 10 years - and while a bit pricier than other AGMs they have one characteristic that I wasn't aware of that others may find of interest as well.

    This feature is their ability to go through partially charged cycles without losing capacity, at least permanently. Where a traditional AGM will slowly die if you don't fully recharge it each time, these units won't (allegedly) sulfate with such use. As a practical matter what that means is that you can cycle them between 80% and 50% state of charge and as long as you bring them to 100% once every week or so you can supposedly get 3,600 cycles out them. Consequently, you can reduce run time on the genset because you aren't running it to slowly top the battery off after the bulk charge phase begins to taper off. I should be able to get by with a house bank of around half the size of the one I have now, saving a lot of space, because these can be drawn down fairly deep without the need to fully recharge them each time. You can essentially charge them long enough to replace what you use and as long as you fill them up completely every once in awhile, they will last a very long time. For a traditional AGM, that would not be a good usage plan. Disadvantages include only one size - 110 amp group 31 and around 20% more costly.

    Anyone else have experience or knowledge of this technology that contradicts my presumptions?