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

[Bob kb8tq]

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 …..

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

> On Mar 8, 2019, at 6:43 AM, ew via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> For my frequency stand alone setup opposite the rest of the lab I have a 100 A 12V AGM/Inverter/Resonsnt Transformer that will power the setup for 10 hours, but like you I like remove the HP 5065A powered up. Did consider a similar system for the HP 5061B but have not and most likely will not touch it.I am concerned about fire but I have more than 10 in one form or the other Li Ion batteries in the house. The Battery is inside the frame that comes with the unit. Starting with a quality product, slow charging and dual max voltage control and dual low voltage shut out risk is very low. Changing the Zener in the 65 reduces the output from 33V to 29.5V. The 65 cut out of 21.5V is perfect for 7 batteries. Charging will be close to C/20.  Most problems out there seem to be do to over charge and temperature rise. Multiple tests will be done with the pack outside the unit to allow close monitoring.The main reason for my posting is the pile of junk batteries and finding a reliable source.in the US.
> Bert Kehren
> In a message dated 3/7/2019 8:24:09 PM Eastern Standard Time, jltran at att.net writes:
> 
> Bert,
> 
> I'm interested in your quest.
> 
> I'm interested in batteries for not only the 5065A but also the 5061A and B.  I was thinking of an SLA for the 5061's.  I like the idea of being able to move the units without having to also move a separate battery backup system simultaneously.
> 
> What have you come up with and how have you addressed the potential for catastrophic failure of a Lithium Ion battery?
> 
> Hope all is well.
> 
> Joe
> 
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at lists.febo.com] On Behalf Of ew via time-nuts
> Sent: Thursday, March 07, 2019 3:37 PM
> To: time-nuts at lists.febo.com
> Cc: ew
> Subject: [time-nuts] Li Ion Battery for HP 5065A
> 
> 
> 
> Having recently acquired a HP 5065A with clock I decided to put a battery in it. My choice is 5000 mA Lithium Ion. Having in the past very good experience with a Florida vendor, was first choice. Sadly he is going out of business. 90+% out there is junk, have 26650s with 1800 mA. Last week finally located a reliable vendor, purchased seven 21700 Samsung B50s, reasonable price. 21700 is a better fit in the 50 X 65 X175 mm battery frame. After extensive dialog with vapah.inc and bench tests of all seven 4800 to 5200 mA, I am convinced that I found in the US a very viable source. No commercial or any other interest, now my only problem is how to get rid of the other junk.
> 
> 
> Bert Kehren
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