Re: Easy Service Call - Impressive Batteries

[Jim Rojas <jrojas@xxxxxxxxxxxx>]

On 8/8/2015 2:48 PM, ABLE1 wrote:
> On 8/7/2015 9:13 PM, Jim Rojas wrote:
>
>>
>> A few months back I started experimenting with Li-Mn batteries on my own
>> security system.
>>
>> At the moment I have 2 banks of four 18650 2200ma Li-Mn batteries. It is
>> roughly a 4AH setup at the moment. So far, no problems whatsoever. I did
>> have to discharge the batteries down to 3 volts each so the security
>> system would be able to charge them up to about 13.5 volts. So far, no
>> problems at all. I still need to fully test backup time though. Since I
>> am not over stressing the batteries at 3.7-4.2v, they should last a lot
>> longer, and provide roughly 10 percent less of their overall rated
>> capacity. This is something you just can't do with SLA batteries.
>>
>> I plan to add 2 more banks to give me a total of 8AH more or less. The
>> nice thing about this setup is that it allows me to replace a single bad
>> cell without tossing out the rest of the batteries. This is something I
>> always disliked about SLA batteries. Sure I can buy Li-ion or Li-Mn
>> battery for about $100 each, but then I have the same problem with them
>> being sealed.
>>
>> I wouldn't recommend doing this out in the field, but it would be nice
>> to see these type batteries used for security systems in the future at a
>> much lower cost. I can see this battery bank lasting 6-8 years without
>> any real issues.
>>
>> If all works as planned, I will encase the completed battery bank in a
>> metal or plastic enclosure to minimize the possibility of a short
>> circuit.
>>
>> Jim Rojas
>>
>
> Hi Jim, haven't see you around these here parts for a long time.  Hope
> all is well in the "sunshine (among other things) state".
>
> So now you had to put new input into my brain that forced me to Google
> some stuff.  LiMn Lithium Manganese.  From what I have read they have
> high amp short life or something like that.
>
> I assume that you are using something like these.
> http://www.smoktek.com/Efest-18650-Hybrid-IMR-Li-Mn-Battery--2200mAh-37V-button-top_p_862.html
>
>
> Assuming that you are putting 3 batteries in a bank??
> Then you have a voltage per bank of  3 = 11.1 to 12.6vdc
>
> So what happens when you pull the AC from the panel??  How long do they
> stay up before a low battery happens??
>
> Interesting stuff.
>
> Thanks,
>
> Les
>
>
>
>
>

Hi Les. No, I am using four 18650 batteries in series which comes to
around 15v. If you use 3 batteries, then you are over stressing the
batteries and it would last no longer than SLA batteries. So what I do
is drain each bank down to no less than 11 volts under a light load.
Then you can connect it to the alarm system. It works like a charm so far.

Jim Rojas

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