Battery location question

[Pub911]

I'd like to add a 3rd and 4th battery to my existing setup. I now have 2 house batts and one starting battery, all Optima deep cycles, with a Heart Interface smart switch between them. But I tend to run the house down after just a day sail due to fridge and subwoofer primarily (yup, subwoofer). I'm considering the upgrade to extend time between engine running (and I have a good 90amp Balmar with one of their programmable regulator units). I'd also like the head room to be able to add a windlass soon too. My problem is I have little room in my NorthStar (aka Hughes) 38. As it is, I'm pushing the limits of the cable run lengths with some pretty hefty cables at that. I have room under the vbirth, but that's about 15 feet away. I can do the math, and spend the $ to meet the specs and reqs, but is this advisable. Might there even be an advantage in doing this given my plans to add a windlass?

Design ideas and no-no's appreciated.

Thank you.

[mitiempo]

Hi
Is there not a way to install the batteries aft somewhere? I have a 27' boat and could fit 4 batteries aft. I'd work to do this if possible. Ideally all 4 (connected as 1 bank) will be together.
As far as the windlass goes, the best most economical way is to put a starting type battery forward near the windlass with short heavy cables to the windlass (1/0 as an example) and charge the battery from an Echocharge or Blue Seas ACR from aft with a smaller gauge wire (10 gauge). This saves a long run of expensive wire and doesn't draw down the house or start with the windlass.
After 30 years in the audio business I understand - gotta have some bass!

[dacap06]

I am a EE by training and am pretty conservative when it comes to electrical design because over the decades I have seen so many low probability events happen and make things go very wrong that could have been avoided with more thoughtful design. In that light, I offer the following:

I have always been leery of putting lead/acid batteries inside enclosed spaces where there is spark and flame (e.g. a stove and switches) unless they are sealed. All lead/acid batteries generate hydrogen when they charge, and setting off hydrogen trapped by the overhead of your cabin is something to think about. While it is a very low probability event, it is easy to avoid. Alternatively, you could simply ensure that your current batteries and all future batteries bought by you and future owners are of the sealed variety (good luck with that, future owners). On a shelf in the lazarette where no electrical or electronic items are located, the hydrogen merely escapes out the lid, which is never air tight. Using similar thinking, I would also advise that your charger and switch not be located above the battery level in the same compartment, and especially not directly above them.

In any event, I recommend you review what ABYC code says about battery installation. Sorry, I don't know it myself or I would quote it. Maybe someone else will add it here for you.

[mitiempo]

Here are 2 exerpts from the ABYC regarding battery location and ventilation.

[wind_magic]

If you are going to be sailing in rough conditions you might want to make sure the batteries are tied down well. Pretty heavy things to have flying around. One of the people attempting circumnavigation a year or two ago, Ken Barnes, ran into that problem when some of his batteries went flying when his boat was knocked down, didn't sound like very much fun.

Another consideration is that keeping the heavy stuff as near to the center and bottom of the boat as possible will probably help performance (sailing, not electrical).

Cam won me over with his battery arguments, so I won't be using unsealed lead acid batteries on a boat.

[mitiempo]

wind_magic
I agree - as a matter of fact other than faster charge ability I think non-spilling is the biggest advantage on AGM batteries. If the budget allows.

[Pub911]

All the great responses above are very much appreciated. I really like the idea of locating a 'dedicated' windlass battery near the windlass and use an auxiliary charger to keep it topped off, avoiding long, expensive runs of heavy guage wire.

On the idea of 'can't you locate the extra house batteries somewhere aft...' or thereabouts...
I probably could, but would end up running an extra length of battery cable to connect them to the current house bank - making one, multi-battery/multi-location 'logical' battery bank comprised of 4 physical batteries in 2 locations roughly 8 feet apart.

With the current house batteries at 4 feet from the Heart Interface charger/inverter, will this additional extention of the house bank violate the 'length of run' requirements from batteries to charger/inverter that Heart prescribes?

[mitiempo]

While I haven't read Heart's wiring requirements, I can't think of many that can't be solved with a heavier wire gauge.

[Paul_L]

Originally Posted by mitiempo

wind_magic
I agree - as a matter of fact other than faster charge ability I think non-spilling is the biggest advantage on AGM batteries. If the budget allows.

Another advantage of AGMs in a case like this is that they can be mounted on their side and without easy access. If you are having trouble finding room for wet-cells, then this opens up a number of spots on a boat that were previously not available.

Paul L

[mitiempo]

True, but from what I have read you might lose some capacity by laying them on their sides.