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fellpower asked

Switching a 75/15 PV Charger off when 2 x 12V in Series Batteries drifting - NodeRed

Hey

System:

- 75/15 PV Charger

- 2 x 12V LifePo4 100Ah in series (24V)

- Smartshunt 500A

- Victron Battery Balancer

- RasPi 4 as "Cerbo GX" with Venus OS

- Node-Red


I build my own adapters to get that VE.Direct Messages to the Pi. I can see all Data of them in Node-Red. All is fine.


But Sometimes (over time), my Batteries get out of synch, so one of them is drifting, and i get an error of my Smartshunt. But the charger wont see that - and the overvoltage batterie shuts down at 15V. Im using the Battery Balancer, but sometimes, it wont kick in, so one of my packs start raising the voltage - over the limits. because of the nature of the charger, it wont see that, so i tried to build my own "safety" with Node-Red.


But ive some trouble to do that.


As i know, i can send a "1" to swith on the charger - and a "4" to get it offline.


nodered4.png


But i struggle, to "Or" with both batteries, because, if ONE of them has a higher voltage, as i want, the "4" should be send - and a "1", if all is okay.


In the switch note, i have the min and max voltages defined - and if im above a certain voltage, i want a "4" triggered.


I know, i can read the status of the difference, with the shunt, but i want to be flexible, and use my own voltages.


Can someone help me a bit, im very new to Node-Red, bus i cant understand, why this is not working....


Chris


Node-RED
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2 Answers
Michelle Konzack avatar image
Michelle Konzack answered ·

Maybe you should check the batteries first individually,

because if ONE Lithium battery get 15V and the other MUCH lesser,

then the lesser one is probably broken.


And for Lithium Batteries you do not need the Victron BatteryBalancer

which is only used for Lead-Acid batteries and similar

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kevgermany avatar image kevgermany ♦♦ commented ·
I used to think the balancer was for lead systems only, but it's not true, and that came from high up in Victron...
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fellpower avatar image
fellpower answered ·

Nah, it isnt broken, there drifting over time, thats normal. and thats not the topic. i need help with Node-Red ;)


And Victron stated, u can use the balancer for LiFePo4 batteries. and i WANT a balancer, because u need one. What i dont like is, that its wasting energy, instead of transfering it, but...nevermind. it works.


i want only be informed, if my batteries drift - and need a switch, so the charger will stop. not more, or less ;)


Chris



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