Where to put the battery charger

[P A Baddeley]

I have recently bought a narrowboat with a semi trad stern where the engine lives under deck boards at the stern. The boat had a battery charger fitted in the cabin that led back to the battery bank in the engine hole via a length of wire that had been cut and joined in several places and as a result was about 8 feet long and then crocodile clips to attach it to the batteries as needed. 

 

Having had to use the charger ashore it transpired that it was dead and I have invested in a very snazzy thing with the intention of having it permanently connected as it says it was suitable for this. Reading the instructions it says that if doing this you need to remove the crocodile clips and replace them with rings. No problem with that. It also says you should not extend the wires as the voltage drop would make the unit ineffective - I also understand (I think) why that would be.

 

The charging wires are about 3ft long and wont reach from the cabin to the battery bank. So I am thinking of locating a 240v socket in the engine hole and connecting the charger there. Only thing is do I then run into problems if gas is given off in charging and the presence of diesel etc?

 

In an ideal world I would put the charger in the cabin and then I can see what it is doing without disappearing in the the engine hole.

 

Anyone else had this problem and what solution did you come up with?

 

Thanks

 

 

[Tony Brooks]

I doubt the gas will cause any problems whatsoever but unless its a central engine room damp & condensation may well do.

[ditchcrawler]

Can you replace the cables with thicker ones to reduce volt drop

[P A Baddeley]

Thanks for the replies.

 

Yes its a stern engine hole so damp etc may be an issue.

 

I could put thicker cables onto the charger but I am reluctant to open it up to do so as that will invalidate the warranty, do you think adding thicker cable to the end of the existing ones would make any difference?

 

Andy 

 

 

[WotEver]

9 minutes ago, ditchcrawler said:

Can you replace the cables with thicker ones to reduce volt drop

Or if you don’t want to open up the box, simply extend the cables (using crimps) with some decent sized cable. What power is the snazzy charger? Tell us that and we can advise the cable size. 

Just now, P A Baddeley said:

do you think adding thicker cable to the end of the existing ones would make any difference?

I’m unsure what you mean by ‘difference’ but extending the cables with fatter cable would be the way to go, particularly if you shorten the existing. 

[P A Baddeley]

It’s a PACO 7 stage 20,000mA 12 volt charger for battery banks of between 134 and 400 Ah. When I say snazzy it is a comparative term to the ones I have had in the past.

 

Andy

[WotEver]

So a 20A charger. You’ll be fine extending the cables with 6mm². 

[P A Baddeley]

Thanks that’s great as I have to put a fuse in the wire to the battery bank if leaving it permanently connected so a length of 6mm2 it is then.

 

Andy

[WotEver]

1 minute ago, P A Baddeley said:

Thanks that’s great as I have to put a fuse in the wire to the battery bank if leaving it permanently connected so a length of 6mm2 it is then.

 

Andy

The fuse needs to be as close to the battery as possible but outside of the battery box

[P A Baddeley]

Thanks

 

Andy

[ditchcrawler]

I would shorten the existing wires as far as possible and replace the remainder all the way to the batteries with thicker cables. The charger will probably be looking at voltage to decide what stage of charge to run at. I would also put a 30 Amp fuse at the battery end of the cable

[Ray T]

Our battery charger is permanently wired in. It is housed in a cupboard as shown.

 

It is well away from moisture, heat etc. Our boat is a "trad" stern however.

Edited November 20, 2019 by Ray T

[Mad Harold]

I had a problem with too long electric wires.

I fitted a Chinese diesel heater to my boat which worked perfectly well when I tried it out at home in my garage,but when installed in the boat it would go through about half of it's start up cycle and cut out with the low voltage symbol showing on the LCD panel.

The wiring went from the battery to the master switch,to a junction box in the toilet,and from there to the stern,under the outboard well (the boat is a GRP cruiser) then back along the other side to the cabin.Didn't measure it,but I guess there must have been at least twenty foot of wire between the battery and the heater.

The fix was to wire the heater direct to the battery with it's own isolating switch,thereby giving the heater it's own cicuit.Now works fine.

While I am on the subject,may I ask cleverer people than me a question that has been nagging me?

The heater uses about 12amps for five minutes for start up,and about 10amps for five minutes for shut down.On continuous running it uses about 1.4amps.

My question is; does the heater use more total leccy starting up,In the evening,running for a couple of hours and shutting down.Then in the morning starting up,running for a couple of hours,then shutting down.Or would it use less total leccy starting it up ,leaving it running overnight (say eight hours)then shutting down.?? I get a different answer every time I try to work it out.

 

[Tacet]

On your figures (someone will be along to say they are wrong, of course) the break even point for electrical consumption is about an hour and a half. 

[Sea Dog]

1 hour ago, P A Baddeley said:

It’s a PACO 7 stage 20,000mA 12 volt charger for battery banks of between 134 and 400 Ah. When I say snazzy it is a comparative term to the ones I have had in the past.

 

Andy

Similar clever chargers by the likes of Ctek for example are IP rated such that they'd be fine in the engine 'ole, so I wondered whether you could mount it closer to the batteries.  I checked the specs for yours on Paco's website, where it appears to be marked "For Indoor Use Only" on a label on the underside. So indoors it is then, but try to find a site to keep the 12v run as short as possible.

[WotEver]

27 minutes ago, Mad Harold said:

I guess there must have been at least twenty foot of wire between the battery and the heater.

The fix was to wire the heater direct to the battery with it's own isolating switch,thereby giving the heater it's own cicuit

An alternative fix would have been to use a decent size of cable. However the shorter the run the better of course. 

[WotEver]

29 minutes ago, Mad Harold said:

The heater uses about 12amps for five minutes for start up,and about 10amps for five minutes for shut down.On continuous running it uses about 1.4amps.

12A + 10A for 5 mins = 22 x 5/60 = 1.83Ah. 
 

1.4A = 1.4Ah per hour. 
 

1.83/1.4 = 1.29 hours. 
 

So running it for an hour and a quarter is the break-even point. 

Unless I’ve confused myself wiv my maffs

17 minutes ago, Tacet said:

On your figures (someone will be along to say they are wrong, of course) the break even point for electrical consumption is about an hour and a half. 

Yeah, an hour and 17 minutes by my calcs. 

[Tacet]

 

2 minutes ago, WotEver said:

12A + 10A for 5 mins = 22 x 5/60 = 1.83Ah. 
 

1.4A = 1.4Ah per hour. 
 

1.83/1.4 = 1.29 hours. 
 

So running it for an hour and a quarter is the break-even point. 

Unless I’ve confused myself wiv my maffs

Yeah, an hour and 17 minutes by my calcs. 

Or five minutes is 1/12 of an hour.  So 12A for 5 mins is 1AH.  10A isn't much less than 12A, so for another five minutes, call it 2AH.

 

Which is about an hour and a half at 1.4A

[Jen-in-Wellies]

2 hours ago, P A Baddeley said:

The charging wires are about 3ft long and wont reach from the cabin to the battery bank. So I am thinking of locating a 240v socket in the engine hole and connecting the charger there. Only thing is do I then run into problems if gas is given off in charging and the presence of diesel etc?

Are there any thick, large cross section cables already running between the batteries and the inside of the boat cabin? Perhaps to a set of bus bars, for distribution to various circuits in the boat? If so, then mount the battery charger close to the bus bars, shorten the wires to the charger and connect it to the bus bars, with a fuse to protect the smaller size wires to the charger. This would save you having to install new large diameter cable, but give you the same effect and reduce the voltage drop to levels that the charger is expecting.

 

Jen

Edited November 20, 2019 by Jen-in-Wellies

[Detling]

24 minutes ago, Jen-in-Wellies said:

Are there any thick, large cross section cables already running between the batteries and the inside of the boat cabin? Perhaps to a set of bus bars, for distribution to various circuits in the boat? If so, then mount the battery charger close to the bus bars, shorten the wires to the charger and connect it to the bus bars, with a fuse to protect the smaller size wires to the charger. This would save you having to install new large diameter cable, but give you the same effect and reduce the voltage drop to levels that the charger is expecting.

 

Jen

But those wires probably go via the isolator so you would have to keep the boat live if you wanted to go away whilst plugged into shore power.

 

[Jen-in-Wellies]

30 minutes ago, Detling said:

But those wires probably go via the isolator so you would have to keep the boat live if you wanted to go away whilst plugged into shore power.

 

Correct. Depends how you want to shut down power when not onboard. Some people just throw the big switch and have things like bilge pump and charger permanently connected, bypassing the main isolator. Others, like me, turn off individual switches at the main panel for everything that isn't needed. My suggestion works in the later case, but not the former.

Jen

[blackrose]

I would do as some others suggest and extend using thicker cables. If you're using the charger from shore power rather than from a generator then the charger has an infinite amount of time to charge so the voltage drop becomes less relevant. 

 

What max voltage does it charge at (14.4v, 14.8v, etc) and what sort of batteries do you have (sealed, wet lead/acid) and does it have settings for different battery types? Also does the charger have a single or multiple 12v outputs?

Edited November 21, 2019 by blackrose

[blackrose]

9 hours ago, Jen-in-Wellies said:

Correct. Depends how you want to shut down power when not onboard. Some people just throw the big switch and have things like bilge pump and charger permanently connected, bypassing the main isolator. Others, like me, turn off individual switches at the main panel for everything that isn't needed. My suggestion works in the later case, but not the former.

Jen

 

The only 12v consumers I switch off from the panel when I leave the boat are the water pump and the toilet as they're operated by pressure switches. Everything else is off anyway. Would it be safer to switch everything off at the panel? How would that protect the cables between the batteries and the panel? My 12v battery isolators are under deck boards so switching them off when leaving the boat is never going to happen. I've just been switching off the toilet and water pump for 15 years without doing anything else and no ill effects so I'll probably just carry on.

Edited November 21, 2019 by blackrose

[Jen-in-Wellies]

3 hours ago, blackrose said:

 

The only 12v consumers I switch off from the panel when I leave the boat are the water pump and the toilet as they're operated by pressure switches. Everything else is off anyway. Would it be safer to switch everything off at the panel? How would that protect the cables between the batteries and the panel? My 12v battery isolators are under deck boards so switching them off when leaving the boat is never going to happen. I've just been switching off the toilet and water pump for 15 years without doing anything else and no ill effects so I'll probably just carry on.

That is pretty much what I do too. Fuses should be present and sized to protect every cable, so I don't think switching off the master switch when leaving the boat is necessary, although a lot of people do. If the electrics on board are so ropey that random short circuits can happen when someone is away, then perhaps that should be looked at!

 

Jen

[Mad Harold]

11 hours ago, WotEver said:

12A + 10A for 5 mins = 22 x 5/60 = 1.83Ah. 
 

1.4A = 1.4Ah per hour. 
 

1.83/1.4 = 1.29 hours. 
 

So running it for an hour and a quarter is the break-even point. 

Unless I’ve confused myself wiv my maffs

Yeah, an hour and 17 minutes by my calcs. 

Many thanks for the replies.

Electrics are a bit of a mystery to me,and the leccy consumption of my heater is clearer now.