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Battery Replacement - Small Solar System

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Hi All 

I've been running a small solar system for about 2 years now - mostly to learn and have lights and Internet when loadshedding hits. 

But my battery was the wrong battery to start off with- I was reccomended a Royal DC31 12v ups battery. Luckily I've used it lightly - but the end is in sight. It's no longer holding charge. 

I've got the following setup: 

290 watt panel 

Victron SmartSolar MPPT 100/20 (total overkill but thinking about the future)

Royal DC31 105Ah battery  

I've got a 12v led light system that is managed by a Sonoff Sv and comes on for 3hrs in the evening and 2 hrs in the early morning. 

I also have a wifi router and a Vuma fibre OTP on it. (16w on boot and thereafter about 11w) 

I'm using about max 18 amp hours over night. 

I want to slowly build up my 12v side and expand lights etc 

Long term I will go off grid - but that is a 5 year project. (Put in solar geysers etc)

Are there any recommendations in regards batteries? 

I don't have a huge budget and based on what I'm using not a huge need at this stage to be honest. 

I'm based in Randburg 

Many Thanks in Advance


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I 'm not sure what to recommend here, but it really worries me that your 100Ah 12V "deep cycle" battery is already seeming to go down the drain, after all at 18Ah overnight, you're using not 20% of its capacity, you should get many more years out of it, I'd imagine, but I suppose these low or maintenance free batteries are short lifers and you really want something that requires checking of water levels and topping up instead, that may actually do better, long term. The other alternative would, of course be Lithium based, but not sure how well that would play with your current setup. (Either way, unless your panel is doing other things during the day, the battery should be charged back up, within an hour or so, of the sun hitting the panel properly, so maybe the Victron is doing something to the battery that it shouldn't?)

12V for going off grid, is not really an option, unless your complete consumption will never get beyond, lets say 1kW peak consumption, that would require, lets say app. 100A, which also implies batteries with at least 500Ah capacity, ideally more. So for going off grid, assuming your energy needs will peak more like 3 to 4kW, you should really be looking at a 48V setup and yup, 4kW at 48V is also creeping up on the 100A mark.


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