Making system simpler

AkoAko Registered Users Posts: 179 ✭✭

Since joining this site I have posted several questions and been extremely grateful for all the valuable advice which has helped me identify the options available to improve my system . The system I have at present has served me well and been trouble free for many years but for personal reasons I have to look to making changes so that its not defendant on my intervention when the weathers not so good . I have 16 panels and they are a mixture of wattages and voltages , 12 are 12 volts and 4 are 24 volts , the 12 volts are wired into pairs to provide 24 volts then the whole array is split into 2 so that I have 2 inputs into my home . Each input cable carries the output from 8 panels so are equal in voltage/current . Once inside the home they are connected together in parallel so there 1 cable with double the Amps going into my MorningstarTS60 PWM Charge Controller which feeds 4x6 volt AGM batteries then to a bus bar and a 1500 watt pure sinewave inverter . I need to find a foolproof way to charge the batteries when the weather has been bad for a day or two . For me its not a problem because I know the voltages when the Generator needs to be started and when to terminate the the charge but although they are expensive quality battery chargers they need to be monitored as the cut off voltage is to high and if left charging would overcharge the batteries . My wife is not technically minded at all and would have no idea so I need to find a better way to charge the Batteries with our Honda Inverter Generator . I have identified 2 options , either I can buy a Victron IP43 Battery charger which has custom settings and looks like it would be fool proof together with a 24 volt MPPT Charge Controler in the hope I might squeeze a little more from my Array . The other option would be to buy a 12 volt MPPT Charge Controller and feed the 24 volt cables from the Array into it so that there is a longer charging period and make it possible to use Lithium batteries in the future , that option would mean I would need to change the Inverter also to a 12 volt Inverter/Charger which I would be prepared to do . Of course the cheapest option would be to make my 24 volt inputs into 48 and just buy a 24 volt MPPT Charge Controller with an IP43 Battery Charger but I think that could only be done by rewiring the whole 16 panels in the Array which because of the situation would be a major job which I dont want to attempt .

Each cable from the Array entering the house consists of connections from the following panels

2 x 140 watts 24 volts

4 x 75 watts 12 volts-wired as 2 x 24 volts

2 times 110 watts 12 volts-wired as 1 x 24 volts

Option 1 , change to 12 volts .

Victron 12 Volt MPPT Charge Controller

Victron 12 volt Inverter/Charger

Option 2 stay at 24 Volts-wired

Victron 24 volt MPPT Charge Controller

Victron IP43 Battery Charger

I apologize if my post is long winded or over complicated but if anyone can help I am more than happy to supply any additional information that would assist

1840 Watt Array  4 x 460 Watt Mono Panels 
Victron Smart 150-70 MPPT Charge Controller
24 volt Battery Bank 4 x 6v 400 Amp/Hr Trojan L16 AGM
Victron 1200w Multiplus Inverter/Charger


  • SaggysSaggys Solar Expert Posts: 176 ✭✭✭
    Option 2, do not go to 12 volts, may need to increase your cable size and change your inverter, too costly.
  • AkoAko Registered Users Posts: 179 ✭✭
    edited April 2022 #3
    I was thinking that if i used the existing 2 cables that came into the house and feed them into a 12 volt MPPT that batteries would start to charge sooner and continue longer in the day as i would have 24 volts coming into the MPPT and batteries would only need about 13.5-14 volts to start charging which is a consideration for later maybe with Lithium , at the moment i would louse to much charging time for Lithium waiting for the voltage to reach the point where they would accept a charge , also louse the other end of the day as the sun starts to go down .The cables from the array to the house are sufficient as nothing would change . The downside to going for 12 volt is that i have 2 x 24 volt turbines that i occasionally switch on when weather is bad and there is little sun and we have wind , they are only 400 watt high speed turbines but have saved the day more than once , changing to 12 volts would mean they could no longer be used as i dont think its possible to send there output to what would be a 12 volt battery bank .. I have seen step down converters on Amazon but not sure if they would be of any use in this situation , the turbines are not like panels where the power is relatively constant and stable , the turbines are erratic when they run and watching the Ammeter and batteries the power is constantly up and down and the voltage in the batteries constantly change , suddenly rising with a gust of wind up to 1 volt then slowly decrease then up again so i dont know what effect that would have on a step down transformer/converter , if it would cope or be suitable .
    1840 Watt Array  4 x 460 Watt Mono Panels 
    Victron Smart 150-70 MPPT Charge Controller
    24 volt Battery Bank 4 x 6v 400 Amp/Hr Trojan L16 AGM
    Victron 1200w Multiplus Inverter/Charger
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