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diy solar

System compatability and size input

Dsldsl1980

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Joined
Jun 30, 2021
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I'm in the early stages of building an off grid setup for a casita but would like to be able to use the batteries in my rv when we take a trip.

What feedback do you have on this system design?

Lv6548 mpp hybrid inverter/charger $1400 https://store.santansolar.com/product/mpp-lv6548-hybrid-inverter-120v-48v-ul/

24 250w solar panels for 6k watts $1320 https://store.santansolar.com/product/santan-solar-t-series-250w-silver-frame-solar-panel/

4 100 ah 12v ampere time batteries in series $2000 https://www.amazon.com/dp/B092R4JS3W/ref=cm_sw_r_cp_apa_glt_fabc_C1KB1RXZJ0CG6FCN1YTN

Total system cost $4720 for 6000w of solar and 4800Wh of battery.

Does that seem reasonable for a small casita or large rv? The Casita has a 240v 13kw on demand water heater so I think I would need 2 lv6558s to power that right?
 
Not much battery amp-hour capacity, can you replace water heater with a tankless propane something like CAMPLUX CM264 ?
 
I'm in the early stages of building an off grid setup for a casita but would like to be able to use the batteries in my rv when we take a trip.

What feedback do you have on this system design?

Lv6548 mpp hybrid inverter/charger $1400 https://store.santansolar.com/product/mpp-lv6548-hybrid-inverter-120v-48v-ul/

24 250w solar panels for 6k watts $1320 https://store.santansolar.com/product/santan-solar-t-series-250w-silver-frame-solar-panel/

4 100 ah 12v ampere time batteries in series $2000 https://www.amazon.com/dp/B092R4JS3W/ref=cm_sw_r_cp_apa_glt_fabc_C1KB1RXZJ0CG6FCN1YTN

Total system cost $4720 for 6000w of solar and 4800Wh of battery.

Does that seem reasonable for a small casita or large rv? The Casita has a 240v 13kw on demand water heater so I think I would need 2 lv6558s to power that right?

No.

Systems should be sized based on consumption. Link #1 in my signature for an energy audit.

6000W on 4800Wh of 48V (technically 5120 since LFP has 12.8V nominal vs. 12V), means you have the potential to charge your batteries at greater than 1C, which will damage them if their BMS tolerate it at all.

2X LV6558S will consume about 150W just by being on, i.e., they will eat 24h * 150W = 3600Wh or 70% of your battery capacity JUST BY BEING POWERED ON AND RUNNING NO LOADS.
 
No.

Systems should be sized based on consumption. Link #1 in my signature for an energy audit.

6000W on 4800Wh of 48V (technically 5120 since LFP has 12.8V nominal vs. 12V), means you have the potential to charge your batteries at greater than 1C, which will damage them if their BMS tolerate it at all.

2X LV6558S will consume about 150W just by being on, i.e., they will eat 24h * 150W = 3600Wh or 70% of your battery capacity JUST BY BEING POWERED ON AND RUNNING NO LOADS.
Is there a reason you say 2 lv6558s? I believe 1 will support that solar array right?

I see I for sure need more batteries or less solar if I will be completely off grid. I do already have power to plug the lv6558 into though.

Would Changing the batteries to 200ah ones be an ok start or still likely too small?

 
I see I for sure need more batteries or less solar if I will be completely off grid. I do already have power to plug the lv6558 into though. The load will fluctuate a ton bases a many factors and I'm not sure I want to build it to support 100% off grid to start.

Would Changing the batteries to 200ah ones be an ok start or still likely too small?

 
You referenced 2X inverters in your original message.

System should be sized based on an energy audit.

If you plan to build/upgrade a system over time, it is VERY important to design the FINAL system and figure out how to piecemeal it together. Otherwise, you'll be wasting money on things that need to be replaced.
 
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