question

mpmattman avatar image

Help with switching simple 12v marine system from PWM to MPPT. Which compnents needed?


Hi Everyone,

I am new to the community.

I have a simple to moderate 12v solar system on my 26ft. sailboat. Because of weight, I want to switch from PWM and lead acid to MPPT and lithium. While money isn’t really and issue, I would still rather not have overkill with components that I might not need, so was looking for some advice as to the exact components that I need.

Current specs:

· 720ah wet batt. bank (lead acid)

· 40A 12v PWM controller (Steca Solarix 4040)

· 350W solar (all in parallel - different sizes because of the shape of the boat):

o 2x 16.7 V Max. (each) / 5.99 A Max. (each) (100Wp) ETFE Mono-Flex

o 3x 17.2 V Max. (each) / 2.92 A Max. (each) (50Wp) ETFE Mono-Flex

· All loads (except motor) connected with terminal bar and then to PWM load terminal (including 2 small 300w inverters for port and starboard), everything with on/off switches and fuses (max combined current @ 35 amps)

· External max 60A 12v trolling motor connected directly to battery, also with fuse and switch.

First of all, am I correct in assuming that I cannot connect different wattage (amperage) panels in series for an mppt system (as the lowest amperage would be taken), and would therefore have to keep everything in parallel?

After the research, this is what I envisioned (using all Victron parts, except for batteries):

· 4x 120ah lithium batts…total 480ah

· Victron smart controller mppt 100/30 (https://www.victronenergy.com/solar-charge-controllers/smartsolar-100-30-100-50)

· The above 350w solar panels in parallel. I know mppt would work better with higher voltages, but I am assuming if I put them in series, it would take the lowest amperage and therefore lose 50% efficiency?

· Cerbo GX ( https://www.victronenergy.com/panel-systems-remote-monitoring/cerbo-gx) I know this seems like overkill, but I need to be able to remoter monitor charge and temp, plus connect a few devices….

· All loads, including motor directly connected to batt through 100A battery protector (https://www.victronenergy.com/battery_protect/battery-protect) whereas the protector would be connected to the Cerbo (is that possible?)

· Mppt control display connected to cerbo?? (https://www.victronenergy.com/panel-systems-remote-monitoring/mppt-control)

· Temp sensor connected to cerbo? (https://www.victronenergy.com/accessories/temperature-sensor-qua-pmp-venus-gx)

The reason I want to switch to a Victron mppt system, is because the batteries are so expensive, that I want to ensure maximum life. So am I missing anything above, component wise? Should I be using a BMV instead of the mppt control display or a BMS in stead of/or in conjunction with the battery protector? Do I need a smart shunt, relay switch or any other components to make this system work efficiently and hassle free?

My goal is to get advice on the exact components to buy. Any and all advice or information is greatly appreciated!

Cheers,

Matt


MPPT - Solar Charge ControllerLithium Batteryparalleldc system
2 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

0 Answers