[time-nuts] Li Ion Battery for HP 5065A

[Bob kb8tq]

Hi

For 100 to 120 AH at 13.4V you will pay in the $900 to $1000 range (delivered) for the RV 
batteries with built in BMS. Capacity / price / current sale deal vary a bit manufacturer 
to manufacturer. Warranty also varies from <1 year to 10 years …..

Bob

> On Mar 8, 2019, at 2:32 PM, jimlux <jimlux at earthlink.net> wrote:
> 
> 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
> 
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