I have been talking with firefly privately...
Quote:
Originally Posted by thingstodo
If it's still lead .. with some minor sulphating issues ... and lead is still a heavy metal and is still poissionous ... and the battery's performance is comparable, but not quite as good as LiFePO4, but it costs just as much as LiFePO4
Where's the advantage? Am I missing something?
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These do not fail because of sulphation, much like the greensaver pack in my fathers minivan they fail from being charged, gradual water loss and separation of the active materials.
The advantage is that their RETAIL is $325, bulk discounts are less, so these do end up less than lithium or agm per usable wt/hr if you are the right buyer; and they are made in the US and recyclable here. Also the poisonis issue is moot, all batteries if mishandled don't belong in the environment, lead has the best recycling rate of any of the chemestries out there. Also they can tolerate a full FLAT 0 volt discharge and come back after 5 cycles
The fact that these are drop in replacements in a variety of motorhomes, standard vehicles and the like without anything special means they will offer 3x + life in those applications
The last reason would be to support an american battery startup in the hope that we can get multiple alternatives from them later down the road, lithium is not the end all. Having the masses get a reliable battery even if made of lead is a huge step forward. Also the companies goal was a CHEAP battery that also had better capacity and reliability, if they ever get to that point we will really have a compelling reason (cost) to go back to lead.
Whether these are compelling, I leave that to you. I think personally given what they have told me about the non-linear peukert which doesn't even start until 50amps then goes in a bell curve I think these are best left in cars, motorhomes and possibly home power. They have talked to me about a high amperage varient but honestly they start looking more like regular lead when you get to higher discharges like an EV experiences, the main reason is drop in compatibility and 3600 cycles under most DODs regardless of the conservative spec.
Quote:
Originally Posted by thingstodo
Why not go with LiFePO4 and get:
- stable performance that's been tested in use
- better cycle life (5000+ cycles to 60% DOD)
- higher current rating (10C or better)
- no discussion about weight - perhaps that is comparable as well?
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Stable performance is matter of perspective, in a on-bms uncontrolled chargin situation that many evs still have lead is better because it tolerates it.
That said firefly batteries DO NOT tolerate overcharge very well, how extreme that issue is remains to be determined. They do tolerate going flat and staying that way for months, which to me would make them great for motorcycle starting batteries.
Cycle life on lithium is a point of contention, just look at Nissans battery degredation issue, some work well others not so much, the firefly battery is typically rated at 3600 cycles by the way. Their curves are supposed to be conservative.
Firefly feels their low amperage battery would still perform better than my old fashioned 6v golf cart despite the exponential peukert but without real world tests I have no idea. They also feel I would get more range, which is possible but again it would vary even more with driving style and I guess with recovery time after runs because the batteries rapidly self charge to higher SOC after you let off the go pedal.
Ah well, unless someone blows a wad on them we won't really know for sure. I do know I can definately get lead batteries with a larger under load capacity but also at higher weight and with a shorter life for less money.
I will wait until they make a batch of high amerage batteries again and get a batch if the price is right (they do give a lot of discounts)
If they work and last better than the greensavers they may be worthwhile.
(7 of my 8 greensavers are still at 90% but one broke the casing
)
Cheers
Ryan
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