A123 7Ah "brick" LiFePO4 who is the vendor?Bert Kehrren
In a message dated 3/8/2019 4:03:53 PM Eastern Standard Time, [email protected] writes: On 3/8/19 5:38 AM, Bob kb8tq wrote: > Hi > > If you are headed into a “cost is no object” sort of battery backup bank for > the lab / shelter / cave > there are some interesting options out there. The RV world is very slowly > waking up to the fact that > big heavy lead acid batteries may not be ideal. For a ghastly amount of > money, you can now get > 12V 100AH “drop in” (no they are not drop in) Lithiums with fully integrated > BMS systems in them. > They *appear* to be safe and come with cute things like 10 year warranties . > Be aware that you > can buy a nice 5065 on eBay for what a couple of them will set you back ….. > I've used the A123 7Ah "brick" LiFePO4 that replace the standard Lead Acid - they weigh a LOT less, and cost a LOT more ($100 vs <$10) - They're pretty nifty devices. As you note internal battery management, built in (easily replaceable) 30A fuse, etc. They weigh about 850g (vs 2.6 kg) and work well at low temperatures (-20C) One peculiarity is that if you discharge them below minimum voltage, they cutoff and put out nothing. You have to put a charging voltage on them to turn them back on. This fouls up some "smart" battery chargers which use the "discharged" battery voltage to tell them that there's a battery connected. So we always had our smart chargers for day to day use, but had a couple wall wart trickle chargers around to turn the battery back on. 100 Ah would set you back well over a kilobuck. But, you would be able to lift it without you going over the OSHA 55lb/25kg "one person lift" limit. > In return for your massive cash outlay, you get a battery that does not > outgas or have the need > to be watered along with the plants. It has a much flatter discharge voltage > curve than a lead acid. > Their peak current vs voltage generally is better than a lead acid. The BMS > may impact this if it > is an issue in your setup. They also is a *lot* lighter / smaller for the > same amount of useful > capacity. The built in BMS *should* take care of all of the fiddly little > issues that might burn the > house down. Lots to like other than the absolutely giant hole in the wallet …. > > Bob _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
