Solar batteries question

[goblin00]

Hi there. My current set up is as follows:

1 x 200w panel + 1 x 100w panel (12v both monos)

MPPT converter

3 x 85ah lead acid leisure batteries - https://www.tayna.co.uk/leisure-batteries/powerline/679/

The batteries have unfortunately come to the end of their life after roughly 6 years, they wont hold a charge for more than 12h (first few years, never had any issues with the batteries running flat unless we had 3/4 days of bad weather)

Im looking to replace the batteries but wondering if getting like for like 3x85ah batteries are the most efficient way? Would 2 x 110/105ah lead acid batteries work just the same with these 300w panels?

I have the batteries feeding:

Dometic CRX50 12v campervan fridge - Energy Consumption (DC@5/25°C) 0.26784 kWh/24h
6 LED spot lights and 2 x led strip lights.
Small water pump
12v USB inputs for charging phones/laptops/occasional camera batteries

So its a pretty modest set up but looking to you Solar gurus before I pull the trigger on battery replacements.

Much appreciated for your time and feedback

 

[VXman]

Two batteries would work as well as three ask long as they fit, and it would be a bit tidier.

You'd have slightly less AH but your solar would probably fill them a little quicker so I reckon it might work just as well.

Alternatively a lithium battery might be an option. More useable AH from a smaller capacity . With lead acid you can only use 50 % of capacity whereas with Lithium you can pretty much use it all. So instead of 240 AH in lead you could just get 120 Lithium.

You need to make sure the charger can do Lithium and they are a bit more expensive.

 

[Guigsy]

Two batteries would work as well as three ask long as they fit, and it would be a bit tidier.

You'd have slightly less AH but your solar would probably fill them a little quicker so I reckon it might work just as well.

Alternatively a lithium battery might be an option. More useable AH from a smaller capacity . With lead acid you can only use 50 % of capacity whereas with Lithium you can pretty much use it all. So instead of 240 AH in lead you could just get 120 Lithium.

You need to make sure the charger can do Lithium and they are a bit more expensive.

Lithium can also charges a bit more efficiently, so you'll get back more of every Ah you put into the battery. And it charges at maximum current until it's nearly full. Both means you'll get more from your existing solar setup... But as VXman said, the chargers (mains, solar and the DC charge from your alternator) should (ideally) be able to support the lithium battery charge profile.

 

[Jev88]

Think of your AH number. It doesn't matter if you get to that by using one, two or more batteries in parallel. Maximise the AH in the space available, unless you go Lithium where they are always more AH per square footprint.

 

[goblin00]

Appreciate the info guys ... I would love lithium but think its a little out of my current budget unfortunately!

Im looking on Tayna now for batteries and the cheapest 110ah I can find is this at £114:

EXV115 Enduroline Calcium Leisure Battery 12V

EXV115 Enduroline WET Lead Acid Calcium Leisure Battery <i>Enduring Power for Every Cycle</i> The Enduroline brand name is the flagship battery of Tayna Batteries. With the highest quality, power and performance. With much care and attention to detail lavished on every model. We are extremely...

www.tayna.co.uk

However on ebay I can pick this 110ah up for £72:

12V 110AH LEISURE BATTERY HEAVY DUTY LOW HEIGHT (110 AH AMP) 110 AMP DUAL PURP | eBay

110AH LEISURE DEEP CYCLE/DUAL PURPOSE/SOLAR. Capacity (C100) 110AH. This will ensure that the battery you are purchasing is the correct battery for your vehicle. Suitable for DUAL POWER use: LEISURE/DEEP CYCLE/SOLAR/STARTING.

www.ebay.co.uk

Would you say there is that much or any difference between them both?

thanks

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[goblin00]

Think of your AH number. It doesn't matter if you get to that by using one, two or more batteries in parallel. Maximise the AH in the space available, unless you go Lithium where they are always more AH per square footprint.

Thanks, however im not sure my 300w panels are doing my 3x85ah set batteries any good if they aren't always fully charging them up. That was the main reason I asked if 300w panels would be just as efficient in giving me a similar experience with 2x110ah batteries

 

[Guigsy]

Thanks, however im not sure my 300w panels are doing my 3x85ah set batteries any good if they aren't always fully charging them up. That was the main reason I asked if 300w panels would be just as efficient in giving me a similar experience with 2x110ah batteries

I don't think lead acid is too concerned about charge level... as long as you don't flatten it. You could argue that having less capacity means you're more likely to be in a situation where they get flattened.

 

[goblin00]

I don't think lead acid is too concerned about charge level... as long as you don't flatten it. You could argue that having less capacity means you're more likely to be in a situation where they get flattened.

hmm OK, maybe I should just replace with the same 3x85ah batteries as previously then to be on the safe side. I don't want to lose out by going 2x110ah

 

[oldiesontour]

If you existing chargers are able to do lithium it would workout about the same price.You can get 200amp lithium £380. =160ah useable. 3 x 85ah =255ah =127.5ah useable.
Lithium less than 1/2the weight and size,10yr min life Vs probably four to 6yrs lead acid .
Lithium can be bought for considerably less via Ali express (£1 per ah) but 6 weeks delivery

 

[goblin00]

If you existing chargers are able to do lithium it would workout about the same price.You can get 200amp lithium £380. =160ah useable. 3 x 85ah =255ah =127.5ah useable.
Lithium less than 1/2the weight and size,10yr min life Vs probably four to 6yrs lead acid .
Lithium can be bought for considerably less via Ali express (£1 per ah) but 6 weeks delivery

Thanks, 3x85ah comes in at £245. My MTTP doesn't look like it chargers lithium unfortunately.
This is what I have:

https://mo.eco-worthy.com/catalog/worthy-mppt-solar-charge-controller-12v24v-p-182.html

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[oldiesontour]

Thanks, 3x85ah comes in at £245. My MTTP doesn't look like it chargers lithium unfortunately.
This is what I have:

https://mo.eco-worthy.com/catalog/worthy-mppt-solar-charge-controller-12v24v-p-182.html

They must be bottom end batteries at that price so probably 2 years capacity likely to fall quickly likely to die young,another drawback is flooded batteries are very limited for output current so using an inverter for anything meaningful is going to shorten the life even more,so you loose the choice now and in the future.
Above lead acid vary massively in price and quality ( lifespan & how fast capacity falls )
If you buy cheap budget 3yrs and they will be down by 25/50 capacity,better (more expensive CAN last 2 to 3 times as long)
Don't be mislead by guarantee so long as they hold and deliver some power at 2 yrs old they are not faulty,just suffering from normal wear and tear

 

[autorouter]

Im looking on Tayna now for batteries and the cheapest 110ah I can find is this at £114:

EXV115 Enduroline Calcium Leisure Battery 12V

EXV115 Enduroline WET Lead Acid Calcium Leisure Battery <i>Enduring Power for Every Cycle</i> The Enduroline brand name is the flagship battery of Tayna Batteries. With the highest quality, power and performance. With much care and attention to detail lavished on every model. We are extremely...

www.tayna.co.uk

However on ebay I can pick this 110ah up for £72:

12V 110AH LEISURE BATTERY HEAVY DUTY LOW HEIGHT (110 AH AMP) 110 AMP DUAL PURP | eBay

110AH LEISURE DEEP CYCLE/DUAL PURPOSE/SOLAR. Capacity (C100) 110AH. This will ensure that the battery you are purchasing is the correct battery for your vehicle. Suitable for DUAL POWER use: LEISURE/DEEP CYCLE/SOLAR/STARTING.

www.ebay.co.uk

Read the small print carefully. The battery Ah capacity can be specified at the 20 hour rate (C20), the 100 hour rate (C100) or the 5 hour rate (C5). All lead-acid batteries have more capacity at C100 and less capacity at C5, compared to the C20 rate. Usually the headline Ah rate quoted in adverts is the C20 rate. Like the first of those batteries you linked to at Tayna Batteries, a reputable battery supplier.

However for the second link, Ebay, you will notice in the spec sheet that the '110Ah' refers to the C100 rate, and the C20 rate is 80Ah. So most ads would say it's an 80Ah battery, not 110Ah. Either the Ebay supplier doesn't know what he is doing, or even worse knows exactly what he is doing.

 

[Lenny HB]

You tend to get what you pay for with batteries, cheap leisure batteries are normally starter battery with a different label on them.
Enduraline are Tanya's own branded batteries normally a good company to deal with but I don't have a clue who makes them.

I would go for a branded battery Varta, Exide or a cheaper option that has a good rep Hankook.