Will talked me into it.

[Capt. John]

Will, you talked me into it. I bought 3 BYD’s from Big Battery, that should add 9k more to my system. I used Morningstar controllers but if the BMS turns of the battery for any reason that will burn up my controller. What controller do I need to get, also which AC to dc charger do I need so as not to hurt the setup when I have to repair or when working on some part of the system?

 

[Will Prowse]

Which solar charge controller instead of the morningstar? And the BMS shouldn't disconnect unless something bad happens. Set absorption of charge controller manually for the pack. Which in your case will be 28.2V-29V.

It is a myth that SCC will burn up when disconnected from battery. Victron can be left connected to solar array for months, no problem.

24V battery chargers are hard to come by. I would use a RV one.

 

[Capt. John]

I have a 24v charger I use on my lead battries but it will not stop charging until 31 volts. Is this safe to used? I ’m not sure about the myth I have burnt up a mppt controller. Which Victron?

 

[Dzl]

I have a 24v charger I use on my lead battries but it will not stop charging until 31 volts. Is this safe to used?

31V = 3.88V per cell which is outside of the recommended voltage range for Lifepo4 (2.5V to 3.65V is what most manufacturers recommend) and usually companies and people tighten this bandwidth (stop charging at 3.5-3.625).

I ’m not sure about the myth I have burnt up a mppt controller. Which Victron?

Victron has confirmed it is not an issue with their controllers. Can't personally speak to others, but Will has apparently tested a few others (Epever I think). But its probably still worthwhile to consult the manual for your specific controller and see if they caution against it.

See this thread