How many amp hours can I fit?

[labatt]

Alright, as people have noticed, I'm focusing on batteries right now. The 490AH we have right now just isn't enough - 2 kids, 2 laptops, fridge, lots of other energy draining items, and we're not going to change our usage (much). We currently have a battery area that measures 24" x 21.5" x 11" (LxWxH). Any thoughts on the best battery configuration giving me the most amp hours? I just thought I'd post this brain teaser out there for people looking for a late night boat puzzle

Chris

[chucklesR]

Chris, IIRC there are only 3 actual battery makers - all the various products out there are essentially just re branding operations.
at 24 x 21.5 x 11 you can stack 6 of the trojan 6v 125's, wiring them in pairs for 12v. Each is 10 3/8 x 7 1/8 x 10 11/16.
Trojan Battery Company
If my math hasn't failed me that's 750ah worth.

Wiring is going to be a bit of squeeze but should be doable.

They have a 145ah 6v, but it's too tall.

[xort]

There are several options available with Trojans.

I found some 12 V Trojans that will fit my tray, with a little mod. so take some time to look over all their different configs.

[Whitebear]

Hi

Consider Lithium Ion batteries. 2 x the charge for 1/2 the weight and size.

[Valiente]

Labatt, have you thought of breaking up your battery banks a bit? Echo-charge a starter battery in the engine bay and echo-charge a windlass battery in the anchor locker. Would this affect your "amp count"?

Conversely, you could consider the 200 Ah AGM 8D that are only 5" wide (used in UPS batteries in phone exchanges and server farms). These could be lying on their sides under the floorboards in many boats.

BTW, I agree with your math. I have one kid and likely fewer calls on electricity than on your boat and I am planning for a four 8D or equivalent house bank of circa 840 Ah. My goal is longevity: I want to run the boat on the hook for a week or on passage even if the wind is light or the skies are cloudy. I only want alternator amps as a byproduct of actual motoring, which we would likely do to pump the holding tank once a week out beyond the reef, so to speak.

[chuck711]

I cruised on my 1988 Cal 33 down the Island chain for a couple of years and anchored out everynight. In order to increase my Amp hours I had 1 Large
battery box built from Polyproplene ( welded) to fit my battery area. I found I could fit 5 batteries into the box. They all used the same Battery Box.
Any Plastic Fabricator can do the welding. For the mat'l and welding about $100. It worked Great! Seperate Battery Boxes take up a lot of room.

clcjr54@hotmail.com

[sailingdog]

Bad idea... not ready for prime time as the charging system LiIon batteries require are considerably more sophisticated than what's currently available. Also, the batteries are very, very expensive.

Originally Posted by Whitebear

Hi

Consider Lithium Ion batteries. 2 x the charge for 1/2 the weight and size.

As for using one large battery box, the major concern with doing that is holding down all the batteries properly. With individual boxes, it is relatively easy to do. With a single large box, it is much more difficult.

As for Labatt's original question, I'd go with the Trojans suggested, unless you've got cash to spare, since you could probably get a modular Surrette-Rolls setup with the individual 2 VDC cells that would provide more power in the same space.

[Vasco]

Originally Posted by chucklesR

at 24 x 21.5 x 11 you can stack 6 of the trojan 6v 125's, wiring them in pairs for 12v. Each is 10 3/8 x 7 1/8 x 10 11/16.
Trojan Battery Company
If my math hasn't failed me that's 750ah worth.
.

Am i missing something, 6 trojan 6v 125's is only 375 amp hours @12v

[Valiente]

No, that sounds right. The 6v to 12v calculation strikes again.

Anyone else using the Surrette "modular" system? It has some upsides in terms of not killing yourself getting the batteries out, but it creates more failure points, I think.

[svsirius]

Originally Posted by Valiente

Anyone else using the Surrette "modular" system? It has some upsides in terms of not killing yourself getting the batteries out, but it creates more failure points, I think.

Yes using the Surrette/Rolls 2v cells. System works as advertised.

It does not have additional failure points as every battery has those same connections but internal to the case instead of external.

The only downside to this system is you pay a premium for the batteries but they do offer extended life when compared to most. Also make sure you get the 'hydrocaps' they really reduce water consumption.

You can also get them without the outer case which frees up room for more cells if that buiys you anything.