Canal Boat – July 2018

canalboat.co.uk Canal Boat July 2018 75

BACKCABIN

Q

I read with interest the

issue with the inverter

bypassing the isolators in April’s

issue. I have the same issue. My

question relates to batteries. I

currently have six leisure

batteries which seems a lot. The

230v equipment on board runs

to a fridge, compact washing

machine, TV and DVD plus the

immersion. The inverter/

charger is a Victron 3Kw. Do you

think I need six or will fewer do.

Also the main cables appear to

be taken from the end battery.

WINCHY

A

TONY REPLIES: The easy

part of your question is

that it is far from ideal to have

both the positive and negative

take-offs at the same end of the

battery bank. If at all possible

change one to the opposite end

(as perdiagram above). At

present you are working those

batteries closest to the

connections harder than those

at the other end. This may have

a battery life implication.

As far as the need for six

batteries is concerned I can not

answer your question. You give

no battery capacity and no

power audit or indication of

when and how you charge and

when you use those mains

appliances. On the face of things

it looks to me as if you are well

on route to perpetually

renewing batteries at short

intervals but I can not be sure. If

you are running the immersion

from the inverter then you

probably are but if not and you

only run the washing machine

when under way or on shore-

power then maybe not. I

submitted another question for

possible publication in the June

issue that covers much of this. If

you send me an email address I

will then send you that question

and answer. You can the see

what I need to know so I can give

proper advice. Email Tony@

tb-training.co.uk

PART 2

Q

The batteries are all 110AH

and we are based in a

marina with hook-up. The

immersion is only used when

hooked up and the washing

machine when hooked up or

moving. My main concern was

the batteries not getting fully

charged due to the number of

them. Finally, am I right in

assuming from the reply to

Kevin Blick’s question that the

batteries are not being charged

when I’m away from the boat

with both isolators removed?

A

TONY REPLIES: If your

inverter/charger are wired

like Kevin’s appeared to be then

with the master switch off no

charge could get to the batteries

but remember I have not seen

and tested your system. The

easiest way to fix this so you

can turn off virtually all the

domestic electrics yet keep

charging is by fitting an extra

master switch so one isolates

the engine, one the domestics

and one just for the inverter-

charger. It is vital that you set

the inverter/charger so it can

not charge from the inverter

output when there is no

shoreline or generator

connected. As far as not

charging the batteries I am

afraid the number of batteries

matters little, its how much you

have taken out of them that

dictates how much you need to

put back in. That is the purpose

of the power audit. Once that is

done and we know the

alternator output and how long

you run for after each discharge

period we can work out if it is

possible to put back in what you

have taken out.

Power audit needed

Best way to black the hull

Q

Which is the best roller to

use for Intertuff 16

GWYNEDD

A

TONY REPLIES: The

answer might be “use a

brush” because it depends

upon how pitted the hull is and

which coat you are putting on.

For the first coat at least you

may need a brush to really

scrub the blacking into any pits

in the hull. I also note that the

Intertuff 16 data sheet does

not mention using a roller in the

application instructions but

does, almost as a foot note, at

the end of the sheet.

The roller to use will be one

that is not attacked by the

thinners in the product but the

data sheet does not say what

International Thinners Number

One actually is. I suspect it is

closely related to white spirit

and if so a roller sold for use with

oil based gloss paint should do.

These are usually foam. The

hairy ones that are sold for

water based paints can

disintegrate when used with oil

based products.

Ballast

Q

I am having a

new boat

built and wish to

raise the concrete

bricks used for

ballast of the

baseplate for

better ventilation.

What would you

say is the best

way to do this

PUNYAMINI1

A

TONY

REPLIES:

There are a

number of options

but whatever you

decide must be

more or less

waterproof and

not be a potential

cause of galvanic

corrosion so that

rules out wood

and many metals.

Zinc or aluminium

strips would be

OK but they would

probably eat

themselves away

over the years.

That leaves some

form of plastic so

think about uPVC

strips that

window fitters

use to disguise

damaged plaster,

plastic floor tile

spacers (they are

larger than wall

tile spacers so

provide a greater

air gap) or lengths

of scrap electrical

cable but try to

ensure no copper

conductor is

projecting from

the cut ends. Fit

any long lengths

running fore and

aft so they allow

water to find its

way to the back of

the bilge