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Newbie: Solar Charge Contoller Advice Please


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Hi to all the members here

 

I was hoping to ask for some advice please (before spending a lump sum of money).

 

I am trying to decide whether it’s worth spending a small fortune on a Victron SmartSolar MPPT 100/50 charge controller or just buy a cheaper solar charge controller. As a man who knows nothing about this, I noted that they work faster, prolong battery life for people who are novices like myself, will function more efficiently when there is less sunshine, and this is important to me when my battery bank is very small.

 

But I noted if I buy the Victron 100/50, then with a 12 volt battery bank, I am limited to 700 Watts in total of solar panels. If I move up to 24 volts, then I am limited to 1400 Watts (with this specific Victron model). It does not go beyond 24 Volts (this model, which is already quite an expensive device).

 

My question is, if I start off with a 12 volt battery bank, with this Victron 100/50 and 700 Watts solar panels, which I connect (not me personally) to the main grid of the house, but later decide I want to add another 1000 watts of solar panels, then is it possible to have 1700 watts connected to the main grid of the house, and just alone the 700 watt portion to the batteries (this Victron model will only go up to 700 watts)? Is it complex to do it like this at a later stage?

 

I have read that it is entirely possible to have no batteries and just connect the solar panels to the main grid of the house, therefore I thought a small battery bank would be fine for now to use for a few hours at night or when there is a power outage (which is freqent).

 

I also thought of buying light weight solar panels of 2kg each of perhaps 100 Watts each and then connect them together. If they are light, then I can easily take them away from the house when going camping. I am just not sure how water resistant these ones are (I saw some are slightly flexible/bendable up to a point).

 

I have also read that it is possible to directly connect solar panels to an inverter. Does anyone perhaps know if the Victron 100/50 will allow this? Or must there be a battery connected? Do you think the inverter will get dammaged if connecting the solar panels directly to the inverter? Does anyone know if this Victron is rain proof?

 

Finally, may I ask a last question please? My idea of multiple small light weight 2kg solar panels connected to each other, and placed in the sun in the garden (a bit like camping) versus massive, heavy visible solar panels on the roof makes me think that there are no government registration requirements. Am I thinking correctly?

 

Many thanks to everyone for taking the time to read this and provide advice.

Thank you

Best regards

James


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Hi Vassen

 

Thank you kindly for this, and thank you for the welcome

 

The inverter I have is 3000 watts, DC in and AC out with a plug socket and 2 xUSB sockets and LCD screen.  So now you have taught me that I need a different type of inverter if I wanted to connect the solar system to the house (to save a few rands; you also kindly taught me that this will not function during load shedding). Thank you for this.

I think from what you are saying its best just to keep this totally separate from the house as a back up, and insert an extension lead/cable from the inverter to the rest of the house to use more than one appliance. So if I but this Victron 100/50, then it seems 700 Watts of Solar panels will be the maximum, and then used to charge 2 x 120 AH batteries (I have a third battery, but a torally different model, therefore I believe it cant be connected with these 2, but perhaps as a single back up battery).

 

Vassen I think you have helped me greatly by pointing me in the more practical direction of having an entirely separate off grid back up system.

 

May I ask you or anyone else if 700 watts solar panels can charge a bicycle electric battery of 48 volts directly with a solar charge controller connected. I presume that Two 12 volt batteries of 120AH each will not be able to charge this 48 volt electric bicycle battery?

 

This link shows a 150 watt solar panel that weighs 830grams when you scroll down the page:

https://www.bidorbuy.co.za/item/488603609/150W_18V_Mono_Solar_Panel_USB_12V_5V_DC_Monocrystalline_Flexible_Solar_Charger_For_Car_RV_Boat_Batte.html

 

And there is another link of a 150 Watt solar panel that weighs 1830 grams below:

 

https://www.wish.com/product/5da96c1823c2510f335521e7?hide_login_modal=true&from_ad=goog_shopping&_display_country_code=ZA&_force_currency_code=ZAR&pid=googleadwords_int&c={campaignId}&ad_cid=5da96c1823c2510f335521e7&ad_cc=ZA&ad_curr=ZAR&ad_price=1833.00&campaign_id=9527731563&exclude_install=true&gclid=EAIaIQobChMIm9nCwpbL7gIVjt_tCh2mfQ9PEAQYCyABEgLZ1fD_BwE&share=web

 

I am just not sure if these panels can withstand rain. Does anyone perhaps know?

 

So, based on what you have taught me, I now know that I must forget about connecting to the house, and just keep things totally separate.

 

Thank you for your words of wisdom Vassen. I highly appreciate it.

 

Best wishes

 

James

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@NewbieNewbie like @Vassen said it's important to know if it's a Pure sinewave or modified sine 12v/24v or 48v, also what you'll be running of the system as modified sinewave sometimes creates interference with electronics.

On something like that it would be a waste of money to try and integrate it into a house the electrician would cost you 3x what the system dit because he'll have to split the loads. Rather run it as a UPS.

If your inverter is 12v the mppt and batteries also needs to be 12v.

 

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Hi Vassen and Chloe

 

Thank you kindly for all this excellent advice.

 

It sounds like a good option re using the solar panels to feed into the grid of the house.Then use the batteries when there is a load shedding.

 

This inverter is supposed to  be a pure sine wave inverter. I am not sure if you are familiar with it. It is called Lai Run, 12 volt and 3000 Watts, but am I correct in assuming that this inverter is different to a grid tied inverter. This inverter that I have, I can plug an appliance into it and then connect a battery to the other side via its terminals.

 

Is my assumption correct that a grid tied inverter is totally different?

 

To be honest the electrician is someone I know, who will help at a reasonable cost, and has to travel a vast distance to reach here (when he comes for his holiday LOL).

 

I don’t think he has your experience Vassen and Chloe.

 

How many watts do you think this grid tied inverter should be for an average family with one and a half kids considering I must start with 700 watts solar panels and maybe increase at a later stage?

 

Finally I read somewhere that unlike lithium ion batteries, these two sealed batteries 120 AH that I have must be constantly charged. Is this true? You were saying its not worth charging them and rather use the solar energy to run into the house with a grid tied inverter? (I also have a trickle charger).

 

Thank you again for all your excellent advice Vassen and Chloe

Best wishes

James

 

 

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Sorry Vassen, can I please confirm with you that you said this 48 Volt battery of the electric bike can be charged by connecting a 12 volt 120 AH battery to the 12 volt 3000 Watt inverter and then the charger of the 48 Volt battery connected to the inverter?

Thank you again

Best wishes

James

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16 minutes ago, NewbieNewbie said:

Sorry Vassen, can I please confirm with you that you said this 48 Volt battery of the electric bike can be charged by connecting a 12 volt 120 AH battery to the 12 volt 3000 Watt inverter and then the charger of the 48 Volt battery connected to the inverter?

Thank you again

Best wishes

James

The 12V interter will convert the power to 240V AC, and then the battery charger will take the 240V AC to charge the battery. You will lose quite a lot of power in the conversions, but it will work.

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