First post. Lets hope I don't embarrass myself.
So I'm thinking of putting a solar system on my RV (on a budget). Its a 26 foot fiberglass travel trailer (/w 15/30a shore power), with a fair bit of stuff on the roof, so I think I will only be able to manage 1100w of solar panels (potential to add some ground solar and combiner box). My plan is for 2x server rack batteries (48v, 100Ah each). A Growatt or EG4 3000w inverter charger, and a converter to provide my 12v.
In my question today I want to focus on the inverter charger. As I understand solar so far (mainly thanks to Will's videos - Thanks Will!), I need enough solar DC voltage hitting the charge controller to activate charging. The inverter chargers seem to want a minimum of 120VDC to start charging. If I can only fit 3x 365W panels (that have an operating voltage just shy of 40V), my 1095w array will not meet the minimum voltage requirement. I took a look at the Victron MPPT 150/35, and it says it starts up at Vbat +5v so about 53-60V DC depending on battery SOC. This is half the DC voltage required by the inverter chargers. Did I understand that right? I really wanted to take advantage of the great price/performance the cheaper inverter chargers offer. Yes I know Victron makes the EasySolar-II 3kVA MPPT 250/70 GX, but it cost twice as much (It also has a startup of Vbat +5v, so should work fine with my small array). The goal here is best bang for buck and simplicity.
Could someone in the know let me know if my assumptions are correct? Or did I miss understand something. Thanks for any constructive feedback.
So I'm thinking of putting a solar system on my RV (on a budget). Its a 26 foot fiberglass travel trailer (/w 15/30a shore power), with a fair bit of stuff on the roof, so I think I will only be able to manage 1100w of solar panels (potential to add some ground solar and combiner box). My plan is for 2x server rack batteries (48v, 100Ah each). A Growatt or EG4 3000w inverter charger, and a converter to provide my 12v.
In my question today I want to focus on the inverter charger. As I understand solar so far (mainly thanks to Will's videos - Thanks Will!), I need enough solar DC voltage hitting the charge controller to activate charging. The inverter chargers seem to want a minimum of 120VDC to start charging. If I can only fit 3x 365W panels (that have an operating voltage just shy of 40V), my 1095w array will not meet the minimum voltage requirement. I took a look at the Victron MPPT 150/35, and it says it starts up at Vbat +5v so about 53-60V DC depending on battery SOC. This is half the DC voltage required by the inverter chargers. Did I understand that right? I really wanted to take advantage of the great price/performance the cheaper inverter chargers offer. Yes I know Victron makes the EasySolar-II 3kVA MPPT 250/70 GX, but it cost twice as much (It also has a startup of Vbat +5v, so should work fine with my small array). The goal here is best bang for buck and simplicity.
Could someone in the know let me know if my assumptions are correct? Or did I miss understand something. Thanks for any constructive feedback.
