Another beginner battery question

[Phoebeg543]

Hi all,

 

I think this has probably been covered before but I've had a good scroll and gotten into a muddle.

I've currently got these batteries that came with the boat which should be isolated by this   . With someone telling me to turn it to 1 to start the boat and then onto both when things are running and down to off at the bottom for turning them off. But when I put it on off the lights and stuff (e.g. bilge/water pumps) can still be used, which seems incorrect? Also are these compatible if I got something to tell me the level of charge I have, as well as an invertor (currently only got 12v) and maybe a solar panel? Currently I'm just taking that red wire off the light grey terminal when I leave which doesn't feel entirely safe (not sure if it's even necessary but I don't want to come back to a flat battery). 

 

There's also two random plugs that I don't know what they're for, one for I think a water heater I don't understand and some switches that don't seem to do anything. Am I best trying to trace the wiring to figure it all out or do I rip it all out/get some new batteries and just start again, and how easy is that all to do?

 

Thanks so much!

 

[nicknorman]

Always difficult to work out how someone else has wired a boat.

There is a placard next to the switch which says "emergency battery switch under". So perhaps the switch you are looking at is not the battery isolator, that might be elsewhere "under" the placard area. The switch you are looking at might be a charge selector - connecting the alternator to the starter battery, the leisure battery, both, or neither. In which case be careful not to select it to "off" when the engine is running. And do not leave it on "both" when the engine is not running as it will possibly flatten the starter battery.

 

The easiest way to tell the level of charge  - in terms of installation - is probably a Smartgauge. These are pretty good for state of charge during discharge, not so good during charge but probably OK for your purposes. There are just 2 wires to be connected directly to the leisure battery terminals (via a fuse).

 

As to inverters and solar, this is a complex subject and I would say that if there is only one leisure battery, that is probably not enough for anything but the smallest inverter. And with an inverter comes dangerous mains voltages, the need for a consumer unit with RCD protection etc etc. Not a trivial thing to do properly. And a solar installation needs a controller between the panels and the batteries, again I suggest that with your current level of electrical expertise perhaps not a DIY job.

Edited August 23, 2023 by nicknorman

[robtheplod]

Where are you? maybe a member can spare an hour to have a look??

[Skeg]

1 hour ago, Phoebeg543 said:

Hi all,

 

I think this has probably been covered before but I've had a good scroll and gotten into a muddle.

I've currently got these batteries that came with the boat which should be isolated by this   . With someone telling me to turn it to 1 to start the boat and then onto both when things are running and down to off at the bottom for turning them off. But when I put it on off the lights and stuff (e.g. bilge/water pumps) can still be used, which seems incorrect? Also are these compatible if I got something to tell me the level of charge I have, as well as an invertor (currently only got 12v) and maybe a solar panel? Currently I'm just taking that red wire off the light grey terminal when I leave which doesn't feel entirely safe (not sure if it's even necessary but I don't want to come back to a flat battery). 

 

There's also two random plugs that I don't know what they're for, one for I think a water heater I don't understand and some switches that don't seem to do anything. Am I best trying to trace the wiring to figure it all out or do I rip it all out/get some new batteries and just start again, and how easy is that all to do?

 

Thanks so much!

Hi, all of that is dodgy. The battery switch is of a type that is prone to get faults and work incorrectly, especially one that old. The installation of the batteries in plastic crates is plain stupid, they don’t have a protective cover on the top so you could easily drop a spanner across the terminals and cause problems, shirt circuits etc. I see the right hand one is prevented from moving by a lump of wood. I can’t understand how they would pass a Boat Safety Inspection. If your battery master switch was working correctly there would be no need to disconnect a wire when you leave the boat. Rather than try to do something yourself I think you need to get a marine electrician to sort out a new safe system and get more batteries on board and something that will monitor them for you.

 

[Jen-in-Wellies]

It's a fairly normal arrangement. One battery, probably the small black one, is just for the engine. The other battery, probably the big grey one, is for domestic use. When starting the engine, you connect just the engine battery (selecting 1, or 2, depending on how it is wired). When the engine is running, you select 1&2, so the now hopefully working alternator is charging both up. After stopping the engine, you connect only the domestic battery (2, or 1, depending), so the domestic battery is being discharged for your lights, pumps etc, but the engine battery is isolated, so it is always fully charged and able to start your engine. Turn to off to disable (almost) everything. It is important not to let the switch turn to off, or pass through off with the engine running, as the alternator may be damaged.

As @Skeg says, the switches of this type are of dubious reliability, though there are notoriously less reliable ones commonly out there that have red plastic handles. Are the crates fixed down? They are there I suspect as a way of passing various boat safety scheme requirements for the batteries to not move, even in the event of the boat seriously tilting. Does it have a recent BSS pass? Certain circuits are allowed to bypass the isolation switch, and connect direct to the domestic battery, via suitably rated fuses. This is often done with bilge pumps, solar controllers, but not normally with lights. It really needs all the wires followed and mapped out.

If you want to learn more about narrowboat electrics, look at @Tony Brooks www.TB-Training.co.uk site. A good self learning set of training notes.

Jen

[Phoebeg543]

23 hours ago, nicknorman said:

Always difficult to work out how someone else has wired a boat.

There is a placard next to the switch which says "emergency battery switch under". So perhaps the switch you are looking at is not the battery isolator, that might be elsewhere "under" the placard area. The switch you are looking at might be a charge selector - connecting the alternator to the starter battery, the leisure battery, both, or neither. In which case be careful not to select it to "off" when the engine is running. And do not leave it on "both" when the engine is not running as it will possibly flatten the starter battery.

 

The easiest way to tell the level of charge  - in terms of installation - is probably a Smartgauge. These are pretty good for state of charge during discharge, not so good during charge but probably OK for your purposes. There are just 2 wires to be connected directly to the leisure battery terminals (via a fuse).

 

As to inverters and solar, this is a complex subject and I would say that if there is only one leisure battery, that is probably not enough for anything but the smallest inverter. And with an inverter comes dangerous mains voltages, the need for a consumer unit with RCD protection etc etc. Not a trivial thing to do properly. And a solar installation needs a controller between the panels and the batteries, again I suggest that with your current level of electrical expertise perhaps not a DIY job.

Ahhh okay, that's good to know, thanks! I'll have a rummage about and see if I can find the battery isolator. Would you recommend getting a smartguage and then assessing my battery usage/figure out what I approximate it to be in the future and then get another battery or two and scale up the invertor requirement accordingly?

23 hours ago, robtheplod said:

Where are you? maybe a member can spare an hour to have a look??

Near Glascote currently, slowly moving towards Macclesfield

22 hours ago, Jen-in-Wellies said:

It's a fairly normal arrangement. One battery, probably the small black one, is just for the engine. The other battery, probably the big grey one, is for domestic use. When starting the engine, you connect just the engine battery (selecting 1, or 2, depending on how it is wired). When the engine is running, you select 1&2, so the now hopefully working alternator is charging both up. After stopping the engine, you connect only the domestic battery (2, or 1, depending), so the domestic battery is being discharged for your lights, pumps etc, but the engine battery is isolated, so it is always fully charged and able to start your engine. Turn to off to disable (almost) everything. It is important not to let the switch turn to off, or pass through off with the engine running, as the alternator may be damaged.

As @Skeg says, the switches of this type are of dubious reliability, though there are notoriously less reliable ones commonly out there that have red plastic handles. Are the crates fixed down? They are there I suspect as a way of passing various boat safety scheme requirements for the batteries to not move, even in the event of the boat seriously tilting. Does it have a recent BSS pass? Certain circuits are allowed to bypass the isolation switch, and connect direct to the domestic battery, via suitably rated fuses. This is often done with bilge pumps, solar controllers, but not normally with lights. It really needs all the wires followed and mapped out.

If you want to learn more about narrowboat electrics, look at @Tony Brooks www.TB-Training.co.uk site. A good self learning set of training notes.

Jen

Yeah fairly recent BSS (September 2022). I'll try and track the wires and see where they go and do some reading up

[nicknorman]

1 hour ago, Phoebeg543 said:

Ahhh okay, that's good to know, thanks! I'll have a rummage about and see if I can find the battery isolator. Would you recommend getting a smartguage and then assessing my battery usage/figure out what I approximate it to be in the future and then get another battery or two and scale up the invertor requirement accordingly?

 

Yes the thing with the Smartgauge is that it tells you the actual state of charge based on the actual capacity (not the capacity when it was new). The general thing with lead acid is to avoid going below about 50% overnight, so if you find that you are doing so, you need to add more battery capacity.

 

Regarding an inverter it depends on what you want to use it for / how big it will be. If it is just for charging devices like phones and laptops then you will just need quite a small one without large battery capacity. But if you want to run short term power hungry devices like electric kettle, hair dryer etc then you need sufficient battery size so that they can supply the heavy current reasonably easily. I suggest you should think in the region of 100Ah per 500w of consumption as a minimum.

[Tony Brooks]

15 minutes ago, nicknorman said:

The general thing with lead acid is to avoid going below about 50% overnight, so if you find that you are doing so, you need to add more battery capacity.

 

That is absolutely true if you started the evening with (say) 85% plus fully charged. If not you have to look at increasing your charging procedure so you do. 

 

Any battery, but lead acids in particular, needs to be considered for its capacity to service your needs AND your ability to regularly fully recharge them.

 

LiFePo4 lithiums are easier to get fully charged, but are much more demanding in respect of charging and voltage control.

[blackrose]

29 minutes ago, nicknorman said:

 The general thing with lead acid is to avoid going below about 50% overnight, so if you find that you are doing so, you need to add more battery capacity.

 

Or find ways to reduce battery discharge/Ah consumption.

Edited August 24, 2023 by blackrose

[IanD]

22 minutes ago, Tony Brooks said:

 

That is absolutely true if you started the evening with (say) 85% plus fully charged. If not you have to look at increasing your charging procedure so you do. 

 

Any battery, but lead acids in particular, needs to be considered for its capacity to service your needs AND your ability to regularly fully recharge them.

 

LiFePo4 lithiums are easier to get fully charged, but are much more demanding in respect of charging and voltage control.

 

Also don't forget that LA capacity drops rapidly as you increase the discharge rate, typically they lose half the capacity at 1C (1-hour discharge rate).

 

So if you start with a 100Ah battery and draw 1kW from the inverter with a heavy load, this will typically take about 100A out of the battery (1C rate) by the time voltage drop and inverter losses are considered -- but at this rate the capacity (100% SoC to 0% SoC) will only be 50Ah. And if you only want to go down to 50% SoC to maximise lifetime, only 25Ah is usable. So you might think the load would run for an hour, but actually it only runs for 15m. This is why LA battery banks need to be considerably bigger than you might think... 😞

 

LFP don't have this problem -- loss of capacity at high discharge rates, or only going down to 50% SoC -- and they don't need long periods of engine running to get to 100% SoC to avoid sulphation. But they are expensive to buy, and do need a proper charging control system, especially from an alternator.

[ditchcrawler]

2 hours ago, Phoebeg543 said:

 

Near Glascote currently, slowly moving towards Macclesfield

 

Pity I didn't know sooner, came through yesterday

[Stroudwater1]

We don’t know what you have bought the boat for, is it static use,  holidays or livaboard?

 

Before you start getting gizmos lithium batteries etc many boaters happily exist on 12v. without such things. Apart from a hairdryer for the Mrs we are fine like that but we do still have three 110a domestic batteries. We have 2 car style push in Phone and computer/ iPad chargers, fridge freezer etc. 

 

it’s always tempting to pull everything out stamp your mark on things you’ve just bought  but if I were you it maybe best to travel up to Macclesfield and see how you get on before incurring significant cost. It looks like an older boat so presumably the previous owners were fine with that set up for some time. Did they explain what the switch’s that don’t seem to work were for and the random plug or can you get hold of them to ask?

 

To me it looks OK, and you’ve already heard stuff that’s not quite correct , it’s all an opinion after all. The key is the setting on that switch which Nicknorman has covered, and it seems you were advised correctly in your first post. We have one of those unreliable switches which I’m sure will one day go wrong but it’s been OK with pretty hefty use for 15 years though not 360 days a year. 

Everyone seems to want an inverter nowadays but  thats extra things to go wrong. 

 

However we don’t livaboard. If you do then it looks like there’s a lot of electoral work to do, but maybe it isn’t quite the right boat to livaboard on either without incurring much cost? 

Edited August 25, 2023 by Stroudwater1

[Quattrodave]

5 hours ago, Stroudwater1 said:

Everyone seems to want an inverter nowadays but  thats extra things to go wrong.

 

Agreed.  Personally I don't have an inverter, everything on the boat (lighting, radios, TV, fridge etc) are all natively 12v.  Phones, tablets & laptops all charge from a decent quality USB C 12v charger that really want much money (Anker PowerDrive III Duo if you're interested). I find it much more efficient (power, cost & simplicity) this way.

 

Solar panels are in my opinion defiantly worth it.  Mine are currently charging at 8.46 amps, I recon batts should be fully charged by 11am

Edited August 25, 2023 by Quattrodave

[Alan de Enfield]

2 hours ago, Stroudwater1 said:

........... If you do then it looks like there’s a lot of electoral work to do,

 

Maybe they don't want to register to vote ?

[Tony Brooks]

55 minutes ago, Quattrodave said:

 

Agreed.  Personally I don't have an inverter, everything on the boat (lighting, radios, TV etc) are all natively 12v.  Phones, tablets & laptops all charge from a decent quality USB C 12v charger that really want much money (Anker PowerDrive III Duo if you're interested). I find it much more efficient (power, cost & simplicity) this way.

 

Solar panels are in my opinion defiantly worth it.  Mine are currently charging at 8.46 amps, I recon batts should be fully charged by 11am

 

I also agree. We had our boat or about 20 years and although not full time live-aboards we went away for months during the summer and never felt deprived. I can see that a washing machine would be useful for a live-aboard, but there are 12V twin tub types and by repute they spin the cloths dryer than may automatics.

 

We did have a small, cheap 200 watt inverter for charging my power tools and a hand held vacuum cleaner. It was also useful when guests brought a phone but not a car charging lead.  Note - being modified sine wave, it might have destroyed electric hair tools or electric toothbrushes. The inverter was never on unless in use, so for probably 98% of the time absolutely no current drain.

 

However, if a boater must have a floating version of a country cottage then a decent quality inverter is needed, but so is a means of recharging the batteries, in my view that is the more difficult part.

[manxmike]

Our daughters and us used our boat for about the equivalent of ten to twelve weeks of the year, plus numerous weekends, all on 12 volts. We never felt the need to seriously upgrade our leisure batteries so we could run 240 volts, since everything we wanted ran on 12 volts it wouldn't have been worthwhile.

If you get the correct leads and sockets that's all you need. Don't bother with a 12 volt hairdryer by the way - they are about as much use as a chocolate fireguard, you'd be better blowing on her head to dry her hair.

[Phoebeg543]

On 25/08/2023 at 09:06, Quattrodave said:

 

Agreed.  Personally I don't have an inverter, everything on the boat (lighting, radios, TV, fridge etc) are all natively 12v.  Phones, tablets & laptops all charge from a decent quality USB C 12v charger that really want much money (Anker PowerDrive III Duo if you're interested). I find it much more efficient (power, cost & simplicity) this way.

 

Solar panels are in my opinion defiantly worth it.  Mine are currently charging at 8.46 amps, I recon batts should be fully charged by 11am

Ohh yes this seems much easier! I'll be livingaboard but laptop/phone charging/lights are the main power requirements so I'll stop over complicating things and save the money for a solar panel

[Quattrodave]

5 hours ago, Phoebeg543 said:

Ohh yes this seems much easier! I'll be livingaboard but laptop/phone charging/lights are the main power requirements so I'll stop over complicating things and save the money for a solar panel

 

Make sure all lights are LED and the 'colour' you want.  Personally 'warm white' for me. Get as much solar as you can fit/afford.  It might be over spec'd in the summer but it'll be under spec'd in the winter...

If in doubt over spec the solar controller so you can add panels at a later date.