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Post by Deleted on Oct 13, 2019 14:42:03 GMT
There's a lot of opinion on the best setup when it comes to batteries...I came across this comment on an old thread and I wonder how accurate it is:
"Two 110Ah better than one 220Ah.
Batteries last longer and have more capacity if the speed of discharge, i.e. discharge current is less.
With one battery, if you withdraw say 4 amps, with two batteries in parallel you're only withdrawing 2A from each. So ultimately you'll get more capacity, and they'll last longer."
Any thoughts?
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Post by Gone on Oct 13, 2019 15:02:01 GMT
I can fit 4 x 110Ah batteries in my tray, but I doubt it would take 2 x 220Ah batteries so for me 4 x 110Ah is best. Doesn’t answer your question though.
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Post by phil70 on Oct 13, 2019 15:10:45 GMT
On the face of it, it would seem to be the case, however I'm no expert so would not offer any advice but merely point out the 110s are more easily maneuvered and generally they fit better without involving any mechanics to fit. Phil
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Post by bodger on Oct 13, 2019 15:10:51 GMT
if one cell goes bad you only have to buy 110Ah, not 220Ah.
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Post by Deleted on Oct 13, 2019 15:20:07 GMT
Ok so a 110ah is smaller and lighter, and by having multiple batteries you have fewer eggs in one basket in case of bad cells. Good stuff, but what about the more arcane question of current discharge versus longevity of the battery itself?
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Post by Clinton Cool on Oct 13, 2019 15:55:43 GMT
I'm no expert but isn't how much you discharge batteries and perhaps more importantly how long you leave them at that level of discharge the pertinent point when it comes to battery longevity? If so, there's no difference between one 220ah and two 110's.
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Batteries
Oct 13, 2019 15:59:36 GMT
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Post by Jim on Oct 13, 2019 15:59:36 GMT
What I know is, it's better to have all your batteries connected, spreading the load across all, than using up one at a time, you get more hampers to pack your voles in, or something. When I had the cabin cruiser and no major charging source I used to charge the batteries at home and take them, full, to the boat.
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Post by peterboat on Oct 13, 2019 16:40:47 GMT
Ok so a 110ah is smaller and lighter, and by having multiple batteries you have fewer eggs in one basket in case of bad cells. Good stuff, but what about the more arcane question of current discharge versus longevity of the battery itself? LAs are something that has to changed every 1 to 2 years depending on your charging routine, Trojans if looked after will last longer and Tractions longer still. JohnV and I have LifePo4s looked after I am sure they will be the last batteries we ever buy and they are light, it all depends on what you want to pay
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Post by JohnV on Oct 13, 2019 16:56:27 GMT
the length of life of a battery at different discharge rates has more to do with the internal construction of the battery than anything else.
Lead acid batteries can be designed to do different jobs.
A standard automotive battery is designed to give very high current for a comparatively short time.
Traction batteries are designed to give a smaller amount of current for a longer time.
Some standby batteries are designed to give a very small amount of current for a very long time.
The efficiency of a type of battery (as regards the percentage of the total amount of power that can be drawn in a single discharge) will depend on it's internal construction.
This is why it is false economy to buy a traction battery (or even a leisure battery) if it is only going to be used to start the engine and nothing else. For that job you might as well use a standard automotive battery with the correct CCA for the engine concerned .... it's what it is designed to do
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Post by Deleted on Oct 13, 2019 17:07:00 GMT
Ok so a 110ah is smaller and lighter, and by having multiple batteries you have fewer eggs in one basket in case of bad cells. Good stuff, but what about the more arcane question of current discharge versus longevity of the battery itself? LAs are something that has to changed every 1 to 2 years depending on your charging routine, Trojans if looked after will last longer and Tractions longer still. JohnV and I have LifePo4s looked after I am sure they will be the last batteries we ever buy and they are light, it all depends on what you want to pay
Thanks for the advice, and I have a feeling that it might well be all you need to know on a practical basis. The question originally posed asserted that (in ideal conditions) two 110ah batteries would last longer (i.e continue to function as expected before replacement is needed) than one 220ah item because the draw of current has less load over each item (or some such). Personally I didn't interpret th e point as relating to the duration of useful output per cycle. It seems that such a point is perhaps quite theoretical. I've found a few sources for further reading
Peter, here's a question I expect you have contemplated: how many amps can you safely pump into a battery when charging? I realise the question is a bit nebulous but any comments appreciated. Also, whats the theoretical maximum output of you solar array and how much ah capacity do you have? Thanks.
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Post by Telemachus on Oct 13, 2019 19:08:46 GMT
There's a lot of opinion on the best setup when it comes to batteries...I came across this comment on an old thread and I wonder how accurate it is: "Two 110Ah better than one 220Ah. Batteries last longer and have more capacity if the speed of discharge, i.e. discharge current is less. With one battery, if you withdraw say 4 amps, with two batteries in parallel you're only withdrawing 2A from each. So ultimately you'll get more capacity, and they'll last longer." Any thoughts? One should consider discharge rates as a proportion of the battery capacity. So taking 10A from a 110Ah battery is nominally the same as taking 20A from a 220Ah. So no effect on longevity. Disadvantages of fewer, higher capacity batteries is that they are heavier (difficult to manhandle) and a single early failure is more expensive to remedy. Advantages are fewer interconnects.
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Post by Deleted on Oct 13, 2019 19:18:50 GMT
There's a lot of opinion on the best setup when it comes to batteries...I came across this comment on an old thread and I wonder how accurate it is: "Two 110Ah better than one 220Ah. Batteries last longer and have more capacity if the speed of discharge, i.e. discharge current is less. With one battery, if you withdraw say 4 amps, with two batteries in parallel you're only withdrawing 2A from each. So ultimately you'll get more capacity, and they'll last longer." Any thoughts? One should consider discharge rates as a proportion of the battery capacity. So taking 10A from a 110Ah battery is nominally the same as taking 20A from a 220Ah. So no effect on longevity. Thanks. And 'Trojan' is a brand name. So that's two things today. Cor blimey.
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Post by ianali on Oct 14, 2019 7:40:39 GMT
Ok so a 110ah is smaller and lighter, and by having multiple batteries you have fewer eggs in one basket in case of bad cells. Good stuff, but what about the more arcane question of current discharge versus longevity of the battery itself? LAs are something that has to changed every 1 to 2 years depending on your charging routine, Trojans if looked after will last longer and Tractions longer still. JohnV and I have LifePo4s looked after I am sure they will be the last batteries we ever buy and they are light, it all depends on what you want to pay
LA need changing every 1 or 2 years? That’s far from my experience and not what most other boaters tell me. I’d say more like 4 to 8 years.
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Post by Deleted on Oct 14, 2019 8:07:37 GMT
Have to agree ianali . My current service batteries were fitted in 2012, but I'll be replacing them in January. The fridge batteries (2x110's) only last two years, but we know the drain the fridge puts on them. Rog
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Batteries
Oct 14, 2019 8:28:04 GMT
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Post by lollygagger on Oct 14, 2019 8:28:04 GMT
Fridges are the killer, I'm half on the look out for a big gas one. Other than the fridge I think one 110ah would do us.
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