Category Archives: battery

Bouncy battery box

When I bought Tammy Norie in 2013 she had no battery. There was a wooden frame for a motorbike-sized battery in the cockpit locker.

IMGA0759 - Version 2

I really wanted a larger battery — at least 70Ah — and Dad and I first put it here, in the engine locker.


It didn’t take much sailing to reveal what a bad idea this was. The engine locker is wet, and in heavy weather I noticed how much salt water was splashing around.  I particularly remember accidentally pouring water that had accumulated in the locker lid on to the battery during my first time out in rough water (see Against the Weather). It wasn’t long after that I realized there was a very snug location for the battery inside the boat: under the cockpit.


It didn’t take long to fix this up, and Tammy’s battery has been snug and dry every since. However, if you study this photo you’ll see that things are definitely not ideal, especially if Tammy were knocked down or rolled over.


The battery box, although snug, was essentially just sitting in the locker, on a slight slope, held in place by a block resting on the cockpit drain seacocks. It became one of those things that you must sort out “later”. I’m ashamed to say I’ve only really fixed the problem this year!

What mostly held me back was the idea that I’d need to build some sort of enclosing frame for the battery. For example, here’s the battery mounting (again, in the cockpit locker) from Sinobee:


Chris Boxer’s Emmelène also has a fine battery frame below the companionway. I’m sure I’ve taken photographs of it too, and will link them here if I find them! The thought of wood- and glasswork in the small space beneath the cockpit definitely held me back.

Over time I’ve become more and more interested in solving problems with “soft” solutions: more lashings and ropes and less rigid stuff. I realized earlier this year that I could just lash the battery in place. So I went to the chandler and bought a couple of small dinghy cleats, and and a length of shock cord and made this:


And yes, the battery is standing on rubber doorstops. I happened to have a few of these because I hoped that they might work as mast wedges, but unfortunately they’re much too weedy and hollow. I was very pleased to find a use for them.

This isn’t the end of the story though.

Firstly, for the curious, here’s what else goes in the volume under the cockpit in Tammy Norie. Forward of the battery go parts and spares. These live in watertight containers that I’ve (mostly) labelled clearly using masking tape and a big marker pen. It helps me find them in tricky circumstances. With this “system” you can swiftly yank out one box and the others tend to fall down surprisingly tidily.


Forward of the parts and spares go the tools, in water-resistant bags. Tammy Norie is a floating workshop and I have a lot of tools. One day I’ll write a very long and boring post about them all.


And then finally, forward of the tools goes the removable door with the companionway step.


Now, as part of the unsinkability plan I’m lining the boat with closed-cell foam. Here’s a sample 1m×1m×30mm of foam that I ordered from Lux Distribution.


It was quite a simple matter to mount the battery in a foam compartment. Here’s the place before I started.


I have to say at this point that these pictures look bright because my camera has an efficient flash. In reality, the area under the cockpit has no light, and most of this work was done with a head torch. Also, this space is 30cm wide and 25cm tall!  I have to get to it by shuffling forwards on my belly like a worm, with my arms above my head like Superman. There isn’t enough space to bend your arms once you’re in!

Anyway, the job was remarkably easy. Having measured the areas, I laid them out on the paper backing of the foam and cut it with scissors.  I cut a bit out of the aft foam for the bilge pump pipe (like Superman, remember). I did not, at this stage, peel off the backing and stick the foam to the boat, and I may never do so for this job: the foam isn’t going anywhere and I want to get to the bulkhead for inspection and maintenance.

Here’s how it turned out.


It was then a simple matter to put the battery in the foam. I say simple, but in fact it involves wiggling into the area like a worm, arms forward like Superman, while lifting a 20kg block of lead and acid over the seacocks. And then you discover that the nice slippery plastic surface of the battery actually has very high friction with the foam, and you have to shoehorn it into place using an HDPE chopping board.


Once that was done I could withdraw the board and tidy things up. Here’s the battery finally in place and reconnected.


This is a very “soft” solution.  The battery wobbles like a stiff jelly if you poke it. It’s being hugged in a gentle but firm manner by the foam and the shock cord.  I’m very confident that it will stay put and working even if the sea picks up Tammy and gives her a good shake!

This was also a great opportunity to experiment with the foam. This foam is going to make up the bulk of the floatation I’m planning for unsinkability. I’m hoping to get most of that done this winter. Watch this space!


Filed under battery, Repairs and Modifications

Maximum power

I’ve been having some difficulty with my battery slowly running down over time, in spite of installing a second solar panel. I’d been advised to install a maximum power point tracking (MPPT) charge controller.

Solar panels don’t produce consistent power at all voltages. If you connect them directly to your battery their voltage is pulled down to around 12V, but many produce more power at around 20V. In fact, the ideal voltage varies with the light conditions.

An MPPT controller has a voltage converter to allow the panels to stay at a higher voltage, and it has a processor that adjusts that voltage to track the maximum power point.

But beware, many Chinese suppliers are sticking the letters MPPT on everything to get sales. Some controllers have even changed from being MPPT to not because manufacturers have economized on components. This is all fraudulent, of course, but hard to police.

YouTubers to the rescue. Amateur enthusiasts on YouTube like to review gadgets, and these helpful videos by Adam Welch reviewed a low cost controller.

I now have one of these installed on Tammy Norie and it appears to be doing the job nicely. I’ve been able to connect my two panels in series rather than parallel so that they’re producing over 12V even in quite low light. The controller seems to hold the combined voltage at about 48V in sunlight, suggesting that my NASA panels have a maximum power point around 24V.


I haven’t been able to get an accurate current measurement. My meter seems to upset the controller, which may indicate that it’s doing something quite delicate. Time will tell if this scheme works well and I will report back.

In the meantime, this is the eBay listing I used. Worth a try for £25 I thought.

Update 2017-09-19: So far this is not working very well and I don’t suggest buying this until until I’ve had a chance to do more experiments.

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Filed under battery, electrics

Wiring diagram

I’ve made this diagram (which is also on the “About” menu of this blog) in case anyone’s interested.

wiring diagram

wiring diagram

I’ll try to keep it up to date if anything changes. The only addition I’m expecting this year is a fixed VHF radio, probably a Standard Horizon GX2200 because it has built-in GPS and AIS, and so can provide me with a ship proximity alarm without any further equipment.

Here’s a slightly out-of-date picture of where the switch panel and most of the connections are located, under the bridge deck. The main difference now is that I have an integrated digital volt/ammeter that is much more responsive.



Filed under battery, compass, Equipment, instruments

The solar panel

I’ve just written a reply to a thread asking about solar panels on the YBW forums, and I thought it’d be worth reproducing here for anyone interested.

I have a Nasa 20W through a CMP12 solar regulator to my Platinum SD685L 75Ah leisure battery, from which the main drain is the tiller pilot. I use the tiller pilot a lot as I’m usually solo, and the panel keeps up with the drain on a sunny day, and generally has no difficulty keeping up with the instruments and lights. My VHF is handheld and charged from the main battery occasionally.

I haven’t hooked up a sensitive ammeter and done the calculations yet. However, I do have one of these volt/ammeters with the ammeter in line with the battery and can highly recommend it. (I know then the solar panel is keeping up because the ammeter reads zero drain.) I filled the back of the meter with silicone electronic potting compound to keep the electronics from getting damp.

The solar panel was held down by duct tape on the aft locker for a lot of last year, but now it’s stuck down with a generous bead of Sikaflex. Nasa recommend this as a method. It suits me as it’s removable and doesn’t involve making holes in the boat, and especially not putting screws in the deck core, which you should never do.

Here’s a picture of the solar panel in its new position.  This spot is almost never in shadow.


I just have to trim those Sikaflex blobs and clean off the old duct tape glue.

The wiring isn’t final either. I’ve looked at a few deck glands but there’s a fairly large connector on the other end of the wire, and I’d like to avoid cutting it off or making a hole in the boat. The wire actually squeezes nicely down the hinge side of the locker, so I might just fix it down (more Sikaflex) more or less where you see it, reinforce where it might chafe in the hinge, and then use some self-adhesive cable fixings inside to connect it forward.


Filed under battery, Equipment, Repairs and Modifications

First tour of Tammy Norie

On the way from Shotley to West Mersea I recorded this little tour of Tammy Norie. Things mentioned:

  • boat layout
  • autopilot
  • solar panel
  • sheeting system
  • deck fittings
  • deck locker contents
  • sail trim
  • mysteriously long burgee halyard
  • oars
  • cockpit drains
  • Coromandel versus Corribee topsides and cabin layout
  • headlining
  • Plastazote® insulation and buoyancy foam
  • mystery flies

There’s plenty more to show for another time.  Let me know if you have anything you particularly want to see or know about.


2014-08-13 · 07:53