Building a good battery box, heres how

[captainslarty]

Please note, this may (WILL) involve some cutting n shutting... /forums/images/graemlins/blush.gif

Hope the images work !
They may not be in the correct order but I am sure you can sort them out. Our Seastream 34 was butchered for 6 Trojans. 6v Batteries.. This is the house bank only, the reserve / engine is another bank.
Any questions please ask.
This is a 675 Ah bank. Good size for us.

 

[sarabande]

Neat work, Cap'n.

Just as a quick thought.... Is the stitching in the tapes acid-resistant ? We had a nasty accident at work where acidic fumes floated past a safety strap, which was itself perfectly OK. Except that the stitching just curled up and gave up, dumping a large battery bank on top of an expensive standby generator.

 

[captainslarty]

Hi Sara, yup, everything known to monkeys, resistent. also got a bolted downd lid on and the cabling duct secures them too, so no chance of moving.
Joe

 

[ianabc]

A great job, well done!

I am wondering about the excellent connectors used to link each battery.

Brand, and price please!

 

[captainslarty]

Hi
The connecttors, all the wiring, is self assembled, I invested in a good lever crimper to size 50. Cable at the batteries is 50 cm tinned marine grade, the terminals are 50-8 (standard)
The boots are also stadard, the triple runs have a simple u nothed out to suit cable size.
All available over the shelf.
Can send you some close ups if you need.
The other things on the shelf are the main shunt in the negative and a 300 Fuse in the pos, shunt is Sterling, fuese is standard 300A around 2.5 inches long in its appropriate holder.

 

[robind]

Nice looking job! have I missed Ventilation to outside?

 

[captainslarty]

Re venting.
If you look at the second pic from the bottom you will see the start of a squarish hole. This is the location for a small fan and duct to a 1" pipe. the fan is an old computer psu unit, a simple homebrew circuit checks for voltage above 14.4 and turns on the fan to duct, it really is icing on the cake and not absolutely necessary imho. But, if a jobs worth doing etc...
Anyways, the controller for the fan is very simple, just an op-amp as a comparator driving a small transistor which drives the fan, as voltage falls it shuts off, in the last pic the unit is installed but covered by the batteries. Placing the vent at the highest point is the best method but sometimes it is not practical.
Joe

 

[chasroberts]

Electric fan - hydrogen gas. Is this not a bit ,well, risky?

 

[captainslarty]

Nope, brushless fan, no wucking furries

 

[Jake]

Hi Captain.

A first class job - not just the box itself, but the way you've presented it. Nice clear photo's, although they come up sideways on my Mac.

If you do any more like this, please bear us in mind. We need good step-by-steps and other improvement projects on PBO! Better still, we pay hard currency for them, especially if you can supply hi-res images and captions for each pic, along with prices and contacts.

I have to do a similar project myself on my ferro-cement pre-liveaboard wreck ( fitting a bow thruster) and it needs a battery box in the bow, so your job gave a good steer.

Thanks for sharing it with the Forumites - but can we have first refusal next time? And that goes for any other of you fixers, fiddlers and repairers out there. There's gold in them there step-by-steps, ideas, modifications etc, so keep your camera handy!

 

[JerryHawkins]

Excellent looking installation. Just one comment, and easily fixed if you wish...

The pos and neg take-offs should be at opposite ends of the bank so that all batteries in the bank are used equally. Currently the left-most pair of batteries (looking at your photo) will be used more heavily than the pair on the right. Just re-position either the pos or neg to the other end. The difference is minimal, I know, but as you said - if a job's worth doing well...

Have a look here to see what I mean:

http://www.smartgauge.co.uk/batt_con.html

Cheers,

Jerry

 

[captainslarty]

Hi . to Jerry, heres my reply.
Re the balancing of batteries, the site you quote has good info, however, in my humble opinion far fetched, he quotes an oft´undersized installation, for example, 35cm cable,
With ref to the above,
I dont use 35 for this, way undersized, I use 50cms - the article also refers to 35 as common and many undersized installations. In my case I calculate the required cable size PRIOR to installation, this is at the design phase and depends on distance of run times 2 normally for the return path.
The article depends on the average load applied to the bank, my average load is less than 120 Ampere Hours Per day. - ie 5AH, 10 at the worst case. The calculations, if you feed them into a spreadsheet, are of no consequence. So with the greatest respect the caclulations made are meaningless in this situation. the difference is not even discernable. variations between batteries themselves make more difference here. AND I use a VERY good battery.
This is NOT a thrown together system, it is a pre calculated and considered installation which is the best for MY requirements, I can start my engine from them if I want, but unusual. So, to sum up, I respectfully ask M´Luds to consider that I also know how to calculate load and distribution, if you can offer a mathematical, definitive reason to change the layout on 50 cms cable, then I will change it, however, I am confident it will suffice and produce an acceptable balance overall with in specification discharge and charging requirements and an equal and predictable load on all apsects of the system.

 

[JerryHawkins]

Hi,

Never meant to suggest that your system was "thrown together". Clearly, from the photos, it is a quality, considered installation. I did say that the difference would be minimal and, as you say, at the low currents you are dealing with, the difference would be so small as to totally discount it. I just thought it worthwhile passing on the info I had discovered on this site some time ago - I have one of their SmartGauges as well as a Xantrex Link20 monitor to keep an eye on my system (which like yours, uses 50mm2 cable not 35 (my system is 24v).

I connected my system before I saw this article, so mine is also not connected in the best "theoretical" way, but is neat and simlple to understand for anyone (with some knowledge) looking at it for the first time. I too can start my engines from my house bank should the need arise - I have three main battery switches, house, engine and "emergency parallel".

Cheers,

Jerry /forums/images/graemlins/smile.gif

 

[captainslarty]

Jerry, no worries,
Didnt mean to get on me high horse there lol....
My switches are exactly the same as yours.... house, engine, and emergency parallel. the best and easiest imho.
Theory and practice is often not compatible.
But, if it does the job, in a sfe and sound way, fits the space you have, or can make, and provides the goodies, then great.
Nice to meet up
Joe n Jayne n Molly the one eyed cat. currently bummin´around in northern spain

 

[JerryHawkins]

Hi Joe,

Interested to know a bit more about your set-up. Which model Trojan are those - are they the T105? What are your charging arrangements - alternator size, additional charging devices - wind gen, solar panels etc? Currently my alternator needs replacing, only a 55A model; I have a DuoGen and a Honda Eu10i for occasional use (can then use shore-power mains charger); thinking about solar. I only have about 220AH capacity, but at 24v. So maintaining a 50% discharge floor I only have a bout 110AH of usable capacity. I can use 100AH in a day at anchor if I just use everything without any thought for power saving! My TFT telly is the largest consumer!!!

Cheers,

Jerry

 

[captainslarty]

Hello
As for charging etc, well... we have a towed genny for use at sea, AMpair (Aquair) 100.. around 1amp per knot... we have an Ampair wind genny, basically not worth bothering with... we have a portable generator, a 50A mains charger and a 130 A Balmar alternator with reg.

The bats are T105´s

As for power consumtion on board...
We..errrm, have a few bits. LOL
We have a dedicated Wifi AP, a server for movies and audio, an lcd projector to a 70" screen, 3 laptops, lots of non necessary instruments, Everything we need really.
Aint bothered with solar yet, too darn expensive..

 

[captainslarty]

Re: Fao Jake

Jake, I have sent you a PM

 

[Jake]

Re: Fao Jake

Hi Joe

Many thanks! Got your PM but having a lot of problems replying via that system at the mo. Could you send me an email I can use to reply, to: jake_kavanagh@ipcmedia.com

I have the info you need - and need to talk!

Best wishes