MPPT battery cut off

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question

cp111 asked Jan 17, '19

MPPT battery cut off

Hi,

I have 3 Victron MPPT’s (1 75/15 and 2 100/30) charging a LiFePO4 12v battery on my sailboat. There are occasions where I want to be able to shut the solar off completely; example, for maintenance, or during storage. I have a breaker switch between the MPPT’s and the battery, so this could happen manually. Or, if I go over current or over/under voltage, the battery could be cut off by my BMS or by my LVC or HVC’s. It’s not the “normal” case, but it could happen and it would leave a situation where the panels are still active and connected to the MPPT but there is no battery connection.

So, my question is, is this ok for the MPPT’s, i.e. you still have solar input but no battery. I’d just like to make sure that I won’t damage the devices. If it is not OK, then how would I protect the MPPT?

Thanks

Chris

MPPT Controllers battery charging

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alleletric answered · Jan 20, 2019 at 08:31 AM

I asked a similar question regarding placing a battery protect on the output of two mppt100/30 controllers to act as a hvc, hears the answer hope it helps

Johannes Boonstra (Victron Energy Staff) answered · Jan 04 at 4:12 PM · ACCEPTED ANSWER

Using the BatteryProtect to switch the charge current to the battery from a MPPT is perfectly fine. Thats how mainly lithium systems use the battery protect for this.

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wkirby answered · Jan 20, 2019 at 09:38 AM

I have done some experiments with my MPPT.

See here:

https://community.victronenergy.com/questions/5433/smartsolar-what-if-arbitrary-bms-cuts-off-battery.html?childToView=5833#answer-5833

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Answer 1 · 2019-01-18T09:07:32Z

thanar answered · Jan 18, 2019 at 09:07 AM

I am asking the same thing on another question, and have not yet got a reply. My question is focused on what would happen if, while charging, the battery built-in proprietary BMS would cut off due to a cell group going over the safe threshold.

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greenbimoon commented · Jan 24, 2019 at 03:32 PM

I am also very interested in the same thing, as I have 2 latching relays to disconnect my battery, using them to protect my battery in a High Voltage or a Low Voltage situation.

So is my MPPT going to be ok if it is disconnected from the solar while charging ???

Thanks

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wkirby ♦♦ greenbimoon commented · Jan 24, 2019 at 04:26 PM

https://community.victronenergy.com/questions/5433/smartsolar-what-if-arbitrary-bms-cuts-off-battery.html?childToView=5833#answer-5833

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Answer 2 · 2019-01-20T08:32:51Z

alleletric answered · Jan 20, 2019 at 08:32 AM

use a victron battery protect to disconnect the mppt100/30 battery output as illustrated in the diagram on the last page of the battery protects manual (Rev12 30-04-2018 fig5).

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Answer 3 · 2019-01-20T08:34:21Z

alleletric answered · Jan 20, 2019 at 08:34 AM

https://www.victronenergy.com/upload/documents/Manual-Battery-Protect-12V-24V-65-A-100-A--220-A-EN-NL-FR-SE-DE-PT-ES-IT.pdf

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