School Days - Second Battery

[ronnietucker]

Saturday (28th Oct '17) was the day for installing the second battery. It'll probably never get used just now, with it getting into winter time, but I'd rather get it wired up and ready for early next year.

This locker is where the current single battery is housed. I've moved the current battery to the far right to make space for the second battery.

The little plastic box at the top is the fuse box. Yes, I have a tiny boat. The two bolts at the bottom are the inside of the isolation switch.

I'm going to use a Durite Voltage Sensitive Relay (VSR) to connect the two batteries.

The idea being that the first battery (only for starting the engine), when full, will automatically pass the charge across to the second battery (only for lights) using the VSR. In other words: the first battery always gets charging priority.

First, I had to drill a 25mm hole for the isolation switch to poke through. Then, take the wire from the fuse box and put that on the second battery isolation switch. The isolation switch then goes to the battery itself. The Durite goes between the two battery positive terminals.

I was relieved when I flicked the lights on and they worked, and that the engine started. Confirmation that the two batteries are working as they should.

I forgot to take a photo of the end result, but it's probably for the best, as it's a bit of a dog's dinner. I don't want to properly plumb in the second battery as I know I'll need to take both of them out for charging at home over the winter.

I do still need to tie both batteries down.

Later in the afternoon, I decided to go for a wander down to the Dug Cafe for a coffee. Just managed to make it before it closed. On the way back I decided to make a detour and see what was up a dirt ramp at the side. Turns out it's a nature path that takes you between the canal and the River Clyde. I even spotted two deer!

As a prize for reading this far, here's a photo of an orange ladybird I saw on my hood ceiling. I had no idea such a thing existed!

And, way off in the distance, this is me.

[ronnietucker]

This weekend I managed to remember to take a photo/two of the second battery install.

This is battery one in place:

I haven't decided where to put the VSR yet. Not sure if I'll keep the battery in the plastic box.

Battery two (obviously, not in place yet!):

Battery two should fit in that space nicely.

The new, battery two, isolation switch is the red one on the right. Sneaking in at the top right of the photo is the solar controller. At the moment it's only a piddle little solar panel that's probably doing next to nothing. Maybe Feb '18 I'll buy a nice 100W solar panel which will connect to battery one.

Currently, I have both batteries at home charging up fully. Once the cold weather has lifted a bit, and the boat becomes habitable again I'll strap them down and start planning some short practice runs. Then some day trips here and there. It's a bit more limited with Scottish Canals as we aren't allowed to operate the locks. They need to do it and require 24hrs notice.

Before leaving for the weekend I fixed the legs on the bed. Really, this should have been done since day one when I was regularly staying overnight on the weekends. It means the seating area can slide out and form a single bed (right-hand side of the above photo). Previously it was like sleeping on a sofa (left-hand side of the above photo). It can slide out another bit to put all the cushions flat, but that means blocking the bathroom door closed. Can't have that!

I still have one pesky little (not so serious) drip getting in from somewhere above the bed area. I'm probably the only person who hopes it chucks it down on a Saturday morning so I can find where the little pinhole is. I'll probably have to end up hosing down the roof to try and find it. I suspect the rain is getting in through the screws in the handrails.

Anyway, my sleepovers are done. No more until the cold weather lifts a bit as the boat has no heating on it. Take it from me. Sleeping in a little GRP cruiser with no heating when the temperature drops to 4C is NOT comfy! I've done it a couple of times. Much tea was made those days...

[Canal321]

I'd have read this earlier but I never usually look in "cruise diaries", don't know why I'm here now and why I clicked this one but I did and I enjoyed reading. Thanks.

[ronnietucker]

10 hours ago, Canal321 said:

I'd have read this earlier but I never usually look in "cruise diaries", don't know why I'm here now and why I clicked this one but I did and I enjoyed reading. Thanks.

Thanks for reading. I have a couple of other posts prior to this post about my little boat.

More to come once I get the chance to get out to the boat again. Maybe tomorrow.

[Tony Brooks]

Just read this because I noticed the title and being in Cruise Diaries it intrigued me.

In general feeding the charging current to the start battery is likely to case the VSR to carry more current than needed. Indeed may of the failures of split charge relays are basically caused by this so they burn their contacts. Remember the start battery only delivers a few amp hours at the most when starting an engine in reasonable condition so its always more or less fully charged where as the domestic battery is typically well discharged each night so for optimum reliability feed the charge to the domestic bank and use the relay to charge the start battery.

The above holds good for inboard boats but if this boat has an outboard with only a small battery charging output I would not bother with split banks at all and just make sure it pull starts easily.

 

 

[ronnietucker]

Hi Tony,

Thanks for the input.

Yes, it's a small outboard engine with a key start.

Maybe next month I plan on getting a 100W solar panel which I was going to link to the starter battery to pass charge across to the leisure battery. My batteries are only about 90Ah each, and I use maybe, at most, 10Ah.

Would you recommend going the other way around then? So have the engine (and panel) charge the leisure battery which would then pass any excess to the starter battery?

Having said that, I only see one pair of wires to/from the engine. So I'm not sure if that same pair is used to start the engine then pass the charge back to the battery from the engine?

 

[Tony Brooks]

The charging currents are so small I don't think in your particular case it matters which way you wire it.