[RE-wrenches] bad battery = system overvoltage = dead inverter

[Ryan]

Dan
Not all MPPT controllers do this. We took great pains to stop this in 
the Classic. But even then there could be a wind turbine or something 
hooked direct that could cause this so I could see a possible need for it.

Ryan
-- 
Ryan Stankevitz
Technical Support Manager
MidNite Solar Inc.
ryan at midnitesolar.com
360-403-7207 XT 151
Skype ID ryan.midnite

On 3/15/2013 11:05 PM, Dan Fink wrote:
> This has been happening all too frequently here. We live in a big area
> of off grid homes, dozens of systems.
> Lost a customers Trace 2624 this morning; One L-16 in older 24v bank
> opened internally. PV array/MPPT control zorched inverter as soon as
> the sun came up. First indication of problems last nite when customer
> hit microwave to warm up dinner and inverter went crazy. This morning
> the bad battery showed 3.2v (yes, I would expect 2 or 4 also) the rest
> the usual 6+v. Turned on PV array, bad battery immediately up to 11v
> (yes, 6v L16).
>
> Somebody needs to build a "battery condom" with big stacked diodes on
> a big heat sink or some such solution. A voltage brick wall for system
> charging inputs. MPPT PV controllers do NOT protect a inverter from
> input overvoltage if all or part of the battery bank disappears! And
> last year we saw a nice battery box fire and zorched inverters due to
> similar -- dual 48v L16 strings, one cell failed and opened, other
> string dumped everything into the bad one, smoke and flames. Parallel
> fusing would have stopped that......but not stopped the loss of dual
> stacked XW inverters from PV overvoltage.
>
> Or am I missing something here?
>
> Dan Fink,
> Executive Director;
> Otherpower
> Buckville Energy Consulting
> Buckville Publications LLC
> NABCEP / IREC accredited Continuing Education Providers
> 970.672.4342
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