Did you mean to say LFP? It depends on who made the battery. LFP batteries can 
be charged using CC/CV. Some, like the Elite PS/GBS battery packages can accept 
a simple CV power supply of 3.65 Vpc.

The inverter is always on and isolated from the grid so it’s not affected by 
poor power quality unless you allow ripple or spikes to the battery system. 
That should be protected at the AC input of your charger/PS and PS filtering. 

What is the daily power consumption? If the battery and PS are sized to meet 
your loads, then it won’t matter when the grid is available. Grid Outages 
longer than you design for can be backed up with a generator. 

Larry Crutcher
Starlight Solar Power Systems



On Mar 13, 2020, at 6:09 PM, Jeff Clearwater <[email protected]> 
wrote:

Thanks All,

Mick and Tump - I'll look into the Victron - good suggestion - Thanks!

Chris - I'm not sure a transformer will buffer the spikes and frequency but 
just pass them on - others?

Larry and Jerry - If I were to go with the separate battery charger/PS approach 
- what specific  48 V  LFeP battery Charger/PS might you recommend and how to 
protect it with what sort of surge and LV equipment?  If either the inverter or 
PS/Charger is protected within too narrow a range then it might defeat the 
purpose - wanting to maximize pulling in as much opportunity charging as we can 
get.

Seems to me like there might be a market for a highly tolerant battery charger 
between 160-260 VAC and frequency tolerant as well - something bulletproof we 
could put on these systems - perhaps that is the Victron - but I'd rather have 
it in a separate beefy battery charger then risk the inverters - especially if 
we are going to buffer the customer from the grid with the battery/inverter 
system.

For instance we have a hospital that can only use the available grid for the 
office but they can't risk it for their hospital equipment.  But If I could 
pull the grid into batteries safely and always power their loads with the high 
reliability battery/inverter system - now we are talking.

So specific 48V battery chargers that can take it? Any equipment out there 
anyone is aware of?

Thanks!

Jeff

Tump wrote on 3/13/20 2:47 PM:
> Check out the Victron line of Chargers as well as the inverter charger units. 
> AC in 187-265 45-65 Hz. for the inverters 230V/50Hz, inverter.
> Please feel free to e mail me 4 additional info. Great BT support / internet 
> access. well thought out product.
>> On Mar 13, 2020, at 5:11 PM, Jerry Shafer <[email protected] 
>> <mailto:[email protected]>> wrote:
>> 
>> Jeff
>> I have been there too in most cases we have programmed in the VAC max/mins 
>> with tighter setting so as the grid starts to go we just disconnect. I did 
>> just do a charger instead of the inverter because the grid was generally low 
>> on frequency but the charger just charged and l see it on optics when that 
>> happens
>> Jerry
>> 
>> On Fri, Mar 13, 2020, 12:03 PM Jeff Clearwater <[email protected] 
>> <mailto:[email protected]>> wrote:
>> Good Day Esteemed Wrenchers,
>> 
>> So we are doing more work in developing countries where the grid is super 
>> unreliable but on for some hours almost daily.
>> 
>> So let's say we have a grid that's on 9 AM - 11 AM and 4 PM - 7 PM each day 
>> but often browns-out during those hours and comes on and off during those 
>> hours. 230 VAC voltage can drop to 160-180 periodically or go above 260 in 
>> spikes.
>> 
>> The present practice in many of these situations is for battery based system 
>> designers/installers is to set up an off-grid system in parallel to the 
>> mains but not relying on them - so the grid AC IN is not connected.  They 
>> just install a transfer switch and manually switch or they wire a critical 
>> loads panel to the solar.
>> 
>> This avoids constant switching and nuisance shut-downs from the battery 
>> inverter and protects it from burning out trying to handle the grid.
>> 
>> MY QUESTION:
>> 
>> I'm wondering what we can do to use the grid when it is up for opportunity 
>> charging of the batteries while at the same time not subjecting our nice new 
>> battery inverters to constant brown-out tripping and possibly long term 
>> damage.
>> 
>> So question #1 - Is anyone using existing battery inverters but succesfully 
>> navigating such a grid variablity settings such that you are able to take 
>> advantage of the grid even if browning out often?
>> 
>> or question #2 - Can we add some sort of high Voltage and Frequency tolerant 
>> battery charger to the system - keep the battery inverter/charger off grid - 
>> but charge the batteries from something able to handle the wonky grid 
>> without constantly nuisance charging or burning itself up?
>> 
>> Your thoughts and wisdom I await!!!
>> 
>> Best,
>> 
>> Jeff
>> 
>> 
>> -- 
>> ~~~~~~~~~~~
>> Jeff Clearwater
>> Village Power Design
>> linkedin <https://www.linkedin.com/in/jeff-clearwater-0622a312/> 
>> www.villagepowerdesign.com <http://www.villagepowerdesign.com/>
>> cell - 413-559-9763
>> ~~~~~~~~~~~~~~~~~~~~~~~

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