Maximum capacity for my battery box

AntarcticPilot

AntarcticPilot

Well-Known Member
Joined
4 May 2007
Messages
11,117
Location
Cambridge, UK
www.cooperandyau.co.uk
My domestic battery has given up the ghost, and I wish to replace it with the highest capacity that I can. I have moulded in battery boxes, so the space available is tightly constrained. However, I currently have a 110 Ah battery which fits easily, so I would hope to get rather more than that.

The battery box is 14" (355 mm) long, 7.5" (190 mm) wide and 9.5" (240 mm) deep. The battery voltage is 12V.

I've had a quick search on the internet, and so far the highest capacity I can find that will fit is 120Ah; these are standard deep cycle batteries and are reasonably priced (about £100). However, these still leave some space in the battery box - not much, but enough to make me suspect that it should be possible to get 150Ah in there, if I can find a battery with the right dimensions!

Any suggestions?
 
AntarcticPilot said:
My domestic battery has given up the ghost, and I wish to replace it with the highest capacity that I can. I have moulded in battery boxes, so the space available is tightly constrained. However, I currently have a 110 Ah battery which fits easily, so I would hope to get rather more than that.

The battery box is 14" (355 mm) long, 7.5" (190 mm) wide and 9.5" (240 mm) deep. The battery voltage is 12V.

I've had a quick search on the internet, and so far the highest capacity I can find that will fit is 120Ah; these are standard deep cycle batteries and are reasonably priced (about £100). However, these still leave some space in the battery box - not much, but enough to make me suspect that it should be possible to get 150Ah in there, if I can find a battery with the right dimensions!

Any suggestions?
Click to expand...

Hi AP,
For what it's worth have you considered looking at 6v batteries and wiring them in series to get your 12v (or is that parallel....never remember the terms!)?
I've been browsing for batteries and on the surface of things they may be easier to configure to maximise your usable space.
Good luck!
Martin
 
martinteeluck said:
Hi AP,
For what it's worth have you considered looking at 6v batteries and wiring them in series to get your 12v (or is that parallel....never remember the terms!)?
I've been browsing for batteries and on the surface of things they may be easier to configure to maximise your usable space.
Good luck!
Martin
Click to expand...

Thanks for the suggestion; that would certainly work. Snag is, to get 12 volts, you have to have an even number of 6 volt batteries, and that may be a more severe constraint than appears at first sight. It may be that golf-cart or mobility scooter batteries could be packed more closely, though.
 
Don't think you will get much more than 120 in there. A big jump up to 150 which are typically around 500mm long.
 
I bought some 142AH Exides from Furneaux Riddall which are 349 x 175 x 290 if you can accommodate the extra height, their ref ER 650. Around £150 each.
 
Hadenough said:
I bought some 142AH Exides from Furneaux Riddall which are 349 x 175 x 290 if you can accommodate the extra height, their ref ER 650. Around £150 each.
Click to expand...

Sadly, the bottom of the box is (almost) the bottom of the boat, and the top is the base of the bunk - and there's none too much air-space above the bunk already! 2 inches extra height is not possible, I'm afraid.
 
Paul - I have two 110ah service batteries wired together in the battery boxes under the bunk. I have a 76Ah starter battery under the fill-in in the aft cabin. I needed to buy a longer positive battery cable to get all the way to the 1-both-2 switch. The proper starter battery works very well and I can run the fridge and instruments for at least 2 days without having to plug the charger in. I did wire the fridge so that it can only run off the service batteries (I never use the 'both' position on the switch).
 
AntarcticPilot said:
My domestic battery has given up the ghost, and I wish to replace it with the highest capacity that I can. I have moulded in battery boxes, so the space available is tightly constrained. However, I currently have a 110 Ah battery which fits easily, so I would hope to get rather more than that.

The battery box is 14" (355 mm) long, 7.5" (190 mm) wide and 9.5" (240 mm) deep. The battery voltage is 12V.

I've had a quick search on the internet, and so far the highest capacity I can find that will fit is 120Ah; these are standard deep cycle batteries and are reasonably priced (about £100). However, these still leave some space in the battery box - not much, but enough to make me suspect that it should be possible to get 150Ah in there, if I can find a battery with the right dimensions!

Any suggestions?
Click to expand...

Dims available here
http://www.batterymegastore.co.uk/p...ies+by+Application|Application|Boat|A+Layer|/
 
Thinking outside the box (sorry)
If you can find an under-used locker somewhere (plus some thick-ish and well-supported cables); there is no law that says all the batteries must be in the same box. Presumably sealed batteries might be advisable
 
I have seen it recommended that you keep all the batteries together with equal size/length interconnections, in order to ensure that the load on all the batteries is equal - even in a bank of batteries kept together there can be a significant difference in the load on each battery depending on how you connect them up. That said, there may be no alternative to having separate battery banks and I guess if you swapped the batteries occasionally during their life it shouldn't make too much difference.

Neil
 
sam_uk said:
I can raise you 5amps on the 120 you have found so far:

http://www.elecsolbatteries.com/products/Leisure-Batteries/Elecsol-125.html

Supposed to be tolerant of discharge: http://www.elecsolbatteries.com/faqs/#07

Although some difference of opinion as to how easy it is to claim on the 5yr guarantee: http://www.ybw.com/forums/archive/index.php/t-273579.html

I'm happy with mine so far (3yrs fair bit of abuse)
Click to expand...

Well, £40 for an extra 5 Ah (plus the better warranty, of course) seems like a lot to pay. I've had over 5 years out of a pretty ordinary battery so far.
 
MoodySabre said:
Paul - I have two 110ah service batteries wired together in the battery boxes under the bunk. I have a 76Ah starter battery under the fill-in in the aft cabin. I needed to buy a longer positive battery cable to get all the way to the 1-both-2 switch. The proper starter battery works very well and I can run the fridge and instruments for at least 2 days without having to plug the charger in. I did wire the fridge so that it can only run off the service batteries (I never use the 'both' position on the switch).
Click to expand...

I was thinking along those lines; I don't really need that great a capacity at present, but of course, power use expands to use the capacity available!

I didn't measure the locker on the starboard side under the bunk, but I wonder if a starter type battery would fit there? Of course, ideally I would put the battey in a box as the locker is open to the bilge.
 
The locker under the bunk has a steep sloping floor and is not open to the bilge. My starter battery is not vented but I don't leave it on extended charging.

Red Flash batteries are small but very expensive. I have read of starter batteries being put in the bottom of the nav seat.
 
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