[RE-wrenches] Discharging a high voltage battery

[Mac Lewis]

Hi Larry,

I doubt the MPPT algorithm would be able to actually vary the voltage of
the battery bank like it can the PV string.  Also, I think that the actual
MPP of a battery bank would be much higher amperage than the inverter could
export.  It would be an interesting to see if it would just max out the
exported amperage or if something else would happen.  I'll donate some
older non-code compliant Sunny Boys if you want to try it.




On Thu, Feb 23, 2017 at 4:14 PM, Starlight Solar Power Systems <
larry at starlightsolar.com> wrote:

> Hello August,
>
> Help me understand your point. If the MPPT circuit is sweeping, it will
> see the same voltage everywhere. Would it not just continue sweeping
> because it can’t lock on? Or perhaps it times out? As long as it is
> producing power during that process, won’t it be fine?
>
> Thanks to all for the responses.
>
> Larry
>
>
>
>
> On Feb 22, 2017, at 1:04 PM, August Goers <august at luminalt.com> wrote:
>
> Larry –
>
>
> My immediate thought is that you would need a listed grid tied inverter
> designed for the purpose of connecting to this type of battery and
> inverting to the grid. A regular PV inverter won’t cut it since it is
> designed to MPT PV modules.
>
>
> The SolarEdge StorEdge product sounds like the closest thing on the market
> that might be close to working. But, once again, it needs to be setup to
> work with your particular battery. I think StorEdge is planning on working
> with Tesla and LG Chem RESU batteries in the 350 to 400 v range.
>
>
> August
>
>
> *From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
> Behalf Of *Starlight Solar Power Systems
> *Sent:* Wednesday, February 22, 2017 11:17 AM
> *To:* RE-wrenches
> *Subject:* [RE-wrenches] Discharging a high voltage battery
>
>
> Hello Wrenches,
>
>
> Someone has asked me about discharging their EV battery into the grid.
> They have an existing grit tie system. What they want to do is connect a
> 5kW grid tie inverter to their 340 volt, 32kWh EV battery bank and feed the
> grid to discharge the battery. Why was not discussed but sure bugs me.
>
>
> My uneducated guess is the inverter will be immediately damaged. My
> thought is how would it limit the input current? Or, is there such an
> inverter available that can do the job?
>
>
> Any input is appreciated.
>
> Larry Crutcher
> Starlight Solar Power Systems
>
>
>
>
>
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-- 



Mac Lewis

*"Yo solo sé que no sé nada." -Sócrates*
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