Battery Ah size v Solar panel watts output

[TrevandJenny]

Will a pair of 120Ah AGM batteries be sufficiently charged by a 120 watt solar panel whilst off grid??

 

[wildebus]

general rule of thumb is 1W of solar for 1Ah of Battery.
Other aspect is how much you can expect to get from a panel - a 120W panel in the UK will bring in a lot less than a 120W panel in Greece, for example, so WHEN and WHERE you are makes a big difference.
Long story short ... If you actually need a pair of 120Ah batteries, a single 120W panel is very likely not enough.

 

[compost]

ive got 1025 of solar and 2xlead acid 135ah

 

[TrevandJenny]

general rule of thumb is 1W of solar for 1Ah of Battery.
Other aspect is how much you can expect to get from a panel - a 120W panel in the UK will bring in a lot less than a 120W panel in Greece, for example, so WHEN and WHERE you are makes a big difference.
Long story short ... If you actually need a pair of 120Ah batteries, a single 120W panel is very likely not enough.

As it appears my 2 x 100Ah Platinum AGM batteries have died, I find I can buy 2 x 120Ah for around the same price as the 100s,.
.
I thought maybe the panel could cope, hence with 40Ah excess over the 100s when fully charged could reduce reduction in overall battery power available.

 

[wildebus]

As it appears my 2 x 100Ah Platinum AGM batteries have died, I find I can buy 2 x 120Ah for around the same price as the 100s,.
.
I thought maybe the panel could cope, hence with 40Ah excess over the 100s when fully charged could reduce reduction in overall battery power available.

It won't cause a problem, it just is not the optimum. No reason to not get better/bigger batteries if you have the chance.

The only real 'issue' with solar mismatching is if you have a really big solar array with a small battery bank in comparision - in that situation you could end up up just wasting money as your batteries would be recharged and you would have loads of excess capacity wasted.

 

[DACS]

Will a pair of 120Ah AGM batteries be sufficiently charged by a 120 watt solar panel whilst off grid??

It all depends on how much power you use each day.

 

[Exwindsurfer]

I would rather have to much than to little.You can't take it with you David lolol

 

[wildebus]

I would rather have to much than to little.You can't take it with you David lolol

Well, when it comes to solar, if you are going to put one panel on the roof, you may as well fit two - or three - or whatever sensibily fits whilst you are at it, as better to much than to little, as mr windy says

 

[marchie]

I would rather have to much than to little.You can't take it with you David lolol

Sign at the side of our Church Collection Plate:

'You can't take it with you; but you can send it on ahead ... The Vicar'

Steve