Battery wisdom

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Gwylan

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We have 2 x 110Ah batteries for the house system. Totally separate circuits for engine starting and the fridge.

The 110 batteries are basic leisure batteries replaced in 2010 for that season.
Now one of them is not holding its charge.
We use the boat a lot and having energy on tap is important to my co owner. It is not life threatening if the battery fails, just have to short it out and bang on with only one battery for a while.

The choice is to replace them both with sexy high tech batteries at twice the price? Are they really worth it?
Or just replace the faulty one with cheapest leisure batteries andif it turns out to not be too bad, flog it on Gumtree or similar?
Or just get a pair of cheap leisure batteries and expect to replace them in 4 years?
 
I'd suggest replacing both with a pair of 6v 225AH Trojan deep cycle batteries - gives you the same capacity at 12v, and aren't nearly as expensive as the fancy ones (AGM Gel etc) but last around 15 years if charged properly and looked after and can be happily discharged to below 50%..
About £110 each on eBay etc including normally free delivery.
 
The question to ask seems to be - why did the current one fail in a relatively short time? Keeping the voltage above about 12.4 volts will ensure a reasonable life. If the batteries are frequently discharged to 12.0 V or less it doesn't matter how sexy the replacements are, they will also only last 3 years.
 
Thanks for that lateral thought. Shame I built a beautiful battery box for my 2x110 batteries. Certain to be able to use the space for storing stuff.

Off to scour internet for best deal on Trojans
 
Gwylan said:
Thanks for that lateral thought. Shame I built a beautiful battery box for my 2x110 batteries. Certain to be able to use the space for storing stuff.

Off to scour internet for best deal on Trojans
Click to expand...

I think Trojans have to be kept in a wooden horse, not a box.:)
 
They did get rather hammered on an extended trip to France when things were left running when we left the boat for a week. The crew assured me they switched everything off and were confident that we were connected to the mins on the pontoon. So I am only surprised that they did not fail sooner.
Have now correctly wired the low voltage protection on the circuit. All learning has a price.
 
Gwylan said:
They did get rather hammered on an extended trip to France when things were left running when we left the boat for a week. The crew assured me they switched everything off and were confident that we were connected to the mins on the pontoon. So I am only surprised that they did not fail sooner.
Have now correctly wired the low voltage protection on the circuit. All learning has a price.
Click to expand...
Trojans are expensive & will fail under those same conditions
http://www.batterymegastore.co.uk/product/J250G/

i have 3 of these for domestics & another for the engine
http://www.batterymegastore.co.uk/product/DC31/
 
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sailorman said:
Trojans are expensive & will fail under those same conditions
http://www.batterymegastore.co.uk/product/J250G/

i have 3 of these for domestics & another for the engine
http://www.batterymegastore.co.uk/product/DC31/
Click to expand...

I'd much rather spend £112.50 on a Trojan T105 than £94.50 on the DC31 in your link above. Not really a huge price difference and T105s are heavier batteries at 28kgs vs. 23.4kgs for DC31. Another reason for my preference is that I was able to get technical details with estd. cycles vs. depth of discharge from Trojan. It seems to be harder to get this information from many other battery manufacturers. It might be worth asking Alphline support to compare.
http://www.batterymegastore.co.uk/product/T105/
 
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Mistroma said:
I'd much rather spend £112.50 on a Trojan T105 than £94.50 on the DC31 in your link above. Not really a huge price difference and T105s are heavier batteries at 28kgs vs. 23.4kgs for DC31.

http://www.batterymegastore.co.uk/product/T105/
Click to expand...

Only problem is you need 2 x T105 to make up 125Ah @ 12v , OK if space is available to do it?

I would love to have T105 but don' have the room for them so have to manage with normal 110Ah Leisure Batteries
 
xeitosaphil said:
Only problem is you need 2 x T105 to make up 125Ah @ 12v , OK if space is available to do it?

I would love to have T105 but don' have the room for them so have to manage with normal 110Ah Leisure Batteries
Click to expand...

Pretty obvious he'd buy 2, so I didn't mention it as OP said he already had 2 x 110Ah.
2 x 110 Ah 12V gives 220Ah @ 12V
2 x 225 Ah 6V gives 225Ah @ 12V

So it's reasonable to compare the 12V & 6V. The main problem fitting T105s is that they are taller. No redundancy with only 2x6V, you can always remove 1 dud 12V and use the other. Less of a problem for me as I have a bank of 4.

........Len.xWidth.xHt.
DC31 330x172x242mm
T105 264x181x284mm

It was a close squeeze with my battery box but 4xT105s just fitted into space for original 4x110Ah 12V batteries. I did decide to widen the box and lower the base in order to give room for ventilation via fan. I remember that they were not as tall as I expected and would have just about squeezed into the existing box. It had a small unused area under a metal beam and T105s would slide underneath with zero risk of a short.

I bought my T105s from Tanya as they gave a small additional discount and were marginally cheaper than BatterMegaStore.
 
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