multiple battery banks / one hub

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Fritz
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multiple battery banks / one hub

Post by Fritz »

Old system, ancient but workable bank0, misc. panels & micro hydro,
New system, new bank1, misc. panels on 4 mx + hub10 + mate2 (+fx)

At times bank0 is struggling and I am wanting to divert the output of one of the mx controllers from bank1.
Will the COMM system object?
one mx being powered from different battery bank?
will it blow the hub?
(disconnect the COMM before switching?)
I don't care if the summary data for bank1 is wrong for the duration but are there electrical gotchas?
Thanks
Fritz
raysun
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My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
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Re: multiple battery banks / one hub

Post by raysun »

In general it would be ill-advised to swap battery banks in a system of sufficient complexity to require a communications hub.

The solar charge controllers are MX series? The charge controllers operate autonomously, so its possible the controller could be safely disconnected from the PV array, then disconnected from the main battery at its Bat +/- terminals, then connected to the old battery and PV reconnected . If the two batteries are of the same chemistry, structure and voltage, then the charger might not need reprogramming. The controller being used to charge the old battery can also be unplugged from the hub to eliminate any possible interaction.

NEVER make any connections that combine the battery banks in any way.
Fritz
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Re: multiple battery banks / one hub

Post by Fritz »

complexity?!
(digression:) I bought a new battery cause the old ones' capacity wouldn't pull my lifestyle anymore. It edall the AC loads.
But there is enough capacity in the old battery to pull the dedicated DC wired loads, SunFrost and some emergency lights. (/digression)
Yes the controller in question is an MX. I have disconnected it from battery A and then connected to battery B with impunity (without PV disconnecting) but that was without any COM at all. Now that the MX is on the COM network i just want to make sure the two battery banks won't try to send hundreds of Amps through the hub ;-)
raysun
Forum Emperor
Posts: 4540
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: multiple battery banks / one hub

Post by raysun »

Fritz wrote: Tue Mar 02, 2021 10:00 am complexity?!
(digression:) I bought a new battery cause the old ones' capacity wouldn't pull my lifestyle anymore. It edall the AC loads.
But there is enough capacity in the old battery to pull the dedicated DC wired loads, SunFrost and some emergency lights. (/digression)
Yes the controller in question is an MX. I have disconnected it from battery A and then connected to battery B with impunity (without PV disconnecting) but that was without any COM at all. Now that the MX is on the COM network i just want to make sure the two battery banks won't try to send hundreds of Amps through the hub ;-)
The Hub is a communications device. It doesn't carry primary battery current.

Disconnecting the MX from the battery without disconnecting from PV first can cause damage to the unit. Obviously not in all circumstances, but the risk is definitely there.
Fritz
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Posts: 34
Joined: Sun Mar 09, 2003 11:01 pm
Location: Redway CA

Re: multiple battery banks / one hub

Post by Fritz »

actually I was worried more about COMM pileup or worse because of ground level mismatch.
Thank you kindly
raysun
Forum Emperor
Posts: 4540
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: multiple battery banks / one hub

Post by raysun »

Fritz wrote: Tue Mar 02, 2021 11:49 am actually I was worried more about COMM pileup or worse because of ground level mismatch.
Thank you kindly
The easiest way to avoid that is simply unplug the MX from the hub when connected to the old battery.
Fritz
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Posts: 34
Joined: Sun Mar 09, 2003 11:01 pm
Location: Redway CA

Re: multiple battery banks / one hub

Post by Fritz »

Indeed. Thank you. I apologize for being a smartass.
raysun
Forum Emperor
Posts: 4540
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: multiple battery banks / one hub

Post by raysun »

It takes one to know one.

YW.
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