lead acid vs lithium batteries and solar usage

[Onewheeler]

3 hours ago, Mike Hurley said:

Never understood why people get so uptight about emptying a cassette toilet, if they are that squeamish do they get someone else to wipe their arse?

Isn't that what a dog is for?

[Alan de Enfield]

1 hour ago, Onewheeler said:

Isn't that what a dog is for?

 

Aesop's fables :

Br'er Fox to Br'er Bear : "what do you use in the forest to wipe your backside ?"

 

Br'er Bear's rely : "Br'er rabbit"

 

[Mike Hurley]

1 hour ago, Onewheeler said:

Isn't that what a dog is for?

Cats are easier, more manoeuvrable and smoother.

[Onewheeler]

3 minutes ago, Alan de Enfield said:

 

Aesop's fables :

Br'er Fox to Br'er Bear : "what do you use in the forest to wipe your backside ?"

 

Br'er Bear's rely : "Br'er rabbit"

 

Dogs have bigger tongues

[Alan de Enfield]

22 minutes ago, Onewheeler said:

Dogs have bigger tongues

 

[Zen]

Bringing it back to semi-normality... I suppose using 10% of my max energy storage is a bit much for a single loo trip. Going to keep compost loo as backup assuming space allows for a small separate loo room.

 

Maybe best going back to pump out system. It seems like the normal size for black water storage is around 200lts is this right? Apparently most flushes use 6ltrs of water so that is only 33 visits not including the deposits. Again seems a bit limited. From most threads I've read the black water is normally stored under the main bed which means it could be larger? (I'm assuming the bow area is full of fresh water tank)  I know you guys said it is £20 for a pump out, is there a limit to how much is pumped?

 

Would a bidet system (like the japanese built in toilet version) be a good idea to save on paper waste? my thinking is although the liquid will probably take up more space than the paper (which would break down over time) it might overcome some of the blockage issues associated with it (before the break down). With that in mind are macerators needed in pump out loos.

 

@cheesegas and @Tony1 found the hotbins, there is a mini hotbin that's 100lt in size which could be practical if I can find somewhere to store them, would need 2, one which is being filled up and the other which is composting, 3 month rotation

 

thanks to everyone for their replies, help and humour

[cheesegas]

Just now, Zen said:

Maybe best going back to pump out system. It seems like the normal size for black water storage is around 200lts is this right? Apparently most flushes use 6ltrs of water so that is only 33 visits not including the deposits. Again seems a bit limited. From most threads I've read the black water is normally stored under the main bed which means it could be larger? (I'm assuming the bow area is full of fresh water tank)  I know you guys said it is £20 for a pump out, is there a limit to how much is pumped?

 

@cheesegas and @Tony1 found the hotbins, there is a mini hotbin that's 100lt in size which could be practical if I can find somewhere to store them, would need 2, one which is being filled up and the other which is composting, 3 month rotation

It's been a while since I used a pump out thankfully, but the price varies between £25 for a CRT pump out to £40 in a marina on the Thames, as I once paid... Generally though, marinas are £25-30. It's on a timer, I think it's around 10 minutes but a regular pump out user can correct me here! I'm not usually a CRT basher but they've switched from pump outs to contactless which is great in principle...but the contactless readers (a Nayax Onyx) have a 4G connection via two exposed, not ruggedised, fragile plastic antennas which just unscrew. Unsurprisingly, these are frequently broken off or stolen. The reader is designed for vending machines in a protected location, not an exposed, unattended machine! Bafflingly, Nayax also do a version of the Onyx with an internal antenna connection so they could have put a 4G puck antenna on top of the machine and not used the fragile stick antennas. Poor choice of subcontractor.

 

Anyway, people I've spoken to have had problems using the machines with broken antennas - some will still sort of work if one antenna remains, some don't.

 

My tank was a plastic thing partially in the bathroom and under the wardrobe, but I believe under the bed is a common place too. I know someone who had an ex Black Prince boat where the tank is steel and integral, like the fresh water tank - except it rusted through and seeped sewage under the floorboards slowly. It was so big that the boat listed when it was full!

 

I used to have a single full size hotbin perched on top the rear gas locker. I could still get up the deck boards to get to the engine but it got in the way quite a lot, hence moving to containers. 

[MtB]

6 minutes ago, Zen said:

Going to keep compost loo as backup assuming space allows for a small separate loo room.

 

Point of Order...

 

Despite its large size, a "compost loo" does not produce any compost. YOU have to do that later, and probably in an area separate from the loo room. They are 'separating loos', not 'compost loos'. All they do is separate the wee from the poo and you have to have your own strategy for disposing of each. Some people choose to compost the poo. Others chuck it over the hedge or put it in the dog poo bins. 

 

Bear in mind they also stink unless you get one with a fan to blow the stink up a pipe to outside (so passers-by can sniff it instead) and you are back to your bog depleting your batteries in winter.

 

 

 

 

[cheesegas]

4 minutes ago, MtB said:

Bear in mind they also stink unless you get one with a fan to blow the stink up a pipe to outside (so passers-by can sniff it instead) and you are back to your bog depleting your batteries in winter.

I have one with a fan. It draws 300ma which is noticeable (~7ah per 24hrs which equates to 6 mins engine runtime) but hardly a deal breaker. Doesn't smell outside at all, unless you stick your nose right up against the vent, and it smells inside less than a regular water toilet in a house.

 

My friend in a marina has one with a fan and internal carbon filter, which I thought would smell but it doesn't. After the marina's pump out boat broke for a month, making everyone walk 5 min back and forth to the marina toilets in the middle of winter, a lot of people switched to compost.

 

I'd recommend owning one for a while before making assumptions. 😉

Edited October 18, 2024 by cheesegas

[PeterF]

22 minutes ago, Zen said:

 

Maybe best going back to pump out system. It seems like the normal size for black water storage is around 200lts is this right? Apparently most flushes use 6ltrs of water so that is only 33 visits not including the deposits. Again seems a bit limited. From most threads I've read the black water is normally stored under the main bed which means it could be larger? (I'm assuming the bow area is full of fresh water tank)  I know you guys said it is £20 for a pump out, is there a limit to how much is pumped?

 

@cheesegas and @Tony1

Our ump out tank under a double bed is 330litres and it could have been a bit bigger. If you use a macerator toilet it uses 0.5-1.0 litre a flush, much less than a domestic loo. There are 2 of us on the boat and we get to 80% full after 3 weeks at which point we start thinking about a pump out as we have another 5 days left.

 

If the pump out works properly £20 will empty a 330l tank with time to spare for a bit of rinsing.

[MtB]

9 minutes ago, cheesegas said:

I'd recommend owning one for a while before making assumptions. 😉

 

You are correct, I've never owned one so I'm not posting from personal experience. 

 

But I LIKE making assumptions! And I was just trying to provoke some discussion really as I fear the OP might be imagining the bog does the composing for him. (As I did in the early days of them, before I had a good look at one.)

[cheesegas]

Just now, MtB said:

I fear the OP might be imagining the bog does the composing for him. (As I did in the early days of them, before I had a good look at one.)

Indeed. You need to allocate space and time to do the composting bit of it, but for some boat usage patterns this is much easier and more convenient than a pump out.

[IanD]

1 hour ago, Zen said:

Bringing it back to semi-normality... I suppose using 10% of my max energy storage is a bit much for a single loo trip. Going to keep compost loo as backup assuming space allows for a small separate loo room.

 

Maybe best going back to pump out system. It seems like the normal size for black water storage is around 200lts is this right? Apparently most flushes use 6ltrs of water so that is only 33 visits not including the deposits. Again seems a bit limited. From most threads I've read the black water is normally stored under the main bed which means it could be larger? (I'm assuming the bow area is full of fresh water tank)  I know you guys said it is £20 for a pump out, is there a limit to how much is pumped?

 

Would a bidet system (like the japanese built in toilet version) be a good idea to save on paper waste? my thinking is although the liquid will probably take up more space than the paper (which would break down over time) it might overcome some of the blockage issues associated with it (before the break down). With that in mind are macerators needed in pump out loos.

 

@cheesegas and @Tony1 found the hotbins, there is a mini hotbin that's 100lt in size which could be practical if I can find somewhere to store them, would need 2, one which is being filled up and the other which is composting, 3 month rotation

 

thanks to everyone for their replies, help and humour

 

200l is pretty small; we have a 350l black tank, with two of us onboard this consistently fills up at about 25l/day (there's a level gauge. see plot) so in theory could go 2 weeks between pumpouts -- but obviously going right up to 100% reading is risky, so I always fill up at least a day before it's full -- and usually more than this, to allow for things like pumpout closure. I've never had to pay more than one standard charge for emptying it even when filled right up, this varies from £15 to £25 depending on location.

6l per flush -- or use -- is too high. Mine (Vetus WCS) uses 2.2l/flush on "normal" (poo) and 1.2l/flush on "eco" (wee) -- and you can also just empty it (wee) without flushing any fresh water through. Other brands may of course be less economical... 😉 

 

Edited October 18, 2024 by IanD

[Gybe Ho]

2 hours ago, MtB said:

 

Point of Order...

 

Despite its large size, a "compost loo" does not produce any compost.

 

 

It does host a composting process, as do you.

 

2 hours ago, MtB said:

They are 'separating loos' 

 

 

I hope you are plumbed likewise.

 

2 hours ago, MtB said:

they also stink unless you get one with a fan to blow the stink up a pipe to outside (so passers-by can sniff it instead) 

 

 

The Compoost toilet has an optional carbon filter attachment that is so effective the fan fumes can be exhausted directly out into the bathroom. Pumpout toilets need an air filter inline with the tank breather, in this respect their effect on the towpath is similar.

 

An important function of the exhaust fan in a composting toilet is to create a drying airflow.

1 hour ago, IanD said:

 

200l is pretty small; we have a 350l black tank, with two of us onboard this consistently fills up at about 25l/day (there's a level gauge. see plot)

 

 

If @Zen were to read through my "tankage for a month of splendid isolation" thread he would find some useful feedback on the subject. Those with black tanks in the 350l to 400l range seemed more satisfied with their operation.

 

 

Edited October 18, 2024 by Gybe Ho

[IanD]

21 minutes ago, Gybe Ho said:

 

It does host a composting process, as do you.

 

 

I hope are plumbed likewise.

 

 

The Compoost toilet has an optional carbon filter attachment that is so effective the fan fumes can be exhausted directly out into the bathroom. Pumpout toilets need an air filter inline with the tank breather, in this respect their effect on the towpath is similar.

 

An important function of the exhaust fan in a composting toilet is to create a drying airflow.

 

If @Zen were to read through my "tankage for a month of splendid isolation" thread he would find some useful feedback on the subject. Those with black tanks in the 350l to 400l range seemed more satisfied with their operation.

 

 

It's a very long*** thread, but I note you started off assuming 5l/day and a 150l black tank... 😉

*** too long to easily find what you finally decided on

[cheesegas]

I'd also like to add that toilet emptying intervals is very very variable if there's two of you living on board but you both do a combination of working from home and from site/office.

 

Sometimes a 12 litre urine container takes over a week to fill if we're both not working from home and the hours are long, other times it's a few days if both on the boat working/eating/drinking there.

 

Likewise, the poopy bit of the toilet can go well over a month, or sometimes it's under a month.

[Gybe Ho]

3 minutes ago, IanD said:

It's a very long*** thread, but I note you started off assuming 5l/day and a 150l black tank... 😉
 

 

That was for a single person which implies fitting a tank for double that. As others pointed out later in the thread few narrowboater empty their tank at 100% full, which means extra buffer capacity is needed.

 

6 minutes ago, IanD said:

*** too long to easily find what you finally decided on

 

 

As that discussion progressed I concluded holding tank capacity would more likely limit tow path independence than the fresh water tank, particularly in view of the limited pumpout locations compared to water taps. I revised my plan to reduce the water tank and increase black tank capacities. Months later I concluded a composting toilet was the win-win choice.

[IanD]

14 minutes ago, cheesegas said:

I'd also like to add that toilet emptying intervals is very very variable if there's two of you living on board but you both do a combination of working from home and from site/office.

 

Sometimes a 12 litre urine container takes over a week to fill if we're both not working from home and the hours are long, other times it's a few days if both on the boat working/eating/drinking there.

 

Likewise, the poopy bit of the toilet can go well over a month, or sometimes it's under a month.

Indeed -- my numbers (25l/day) were for a week or so with two of us on the boat full-time.

[Zen]

@MtB I know that the composting toilet is just the container and that they are really just separating loos, wees to the front poops to the back (sometimes with a greaseproof style bag and remembering to open the hatch (depending on version)), they seem on average to hold about 20lts of deposits which seems to be anything between 20 and 40 visits. There are some composting loos that have a stirring function but that will only start the process on the oldest dried poop, the whole thing takes 9-12 months to become proper compost unless you use the hotbin which takes 3 months. 

 

The fans to reduce/eliminate odour are very low power ~0.3w = about 50WH a week, someone with 3x 110ah leisure lead acid may find this drain significant (50% usage =165ah = 1980WH) although it is only 2.5% of a full charge but with a min planned setup of 15KWH Lithium Iron Phosphate storage the loss in wire resistance is going to be a higher loss for me.

 

@PeterF That info is very useful thank you, that equates to about 44lts per human per week

 

@IanD Very different numbers from PeterF although your flush values are much larger than his, I'm assuming that plot is from a monitoring app? is is using floatation or pressure measurements? what is the app and do you recommend it?

 

@Gybe Ho I have that thread open on another tab (on one of my machines) but people here are generously fast with their replies and I dont want to seem ungrateful by not answering quick(ish), no doubt I'll have some questions for you a bit later once I've gone through the 9 pages.

 

@cheesegas I imagine time of year affects it too, summer drinking a lot more fluids, winter less active but more hearty meals

[Onewheeler]

43 minutes ago, cheesegas said:

I'd also like to add that toilet emptying intervals is very very variable if there's two of you living on board but you both do a combination of working from home and from site/office.

 

Sometimes a 12 litre urine container takes over a week to fill if we're both not working from home and the hours are long, other times it's a few days if both on the boat working/eating/drinking there.

 

Likewise, the poopy bit of the toilet can go well over a month, or sometimes it's under a month.

My missus used to be in a medical research organisation. Someone was studying piss and the staff were provided with 5 L containers to collect their micturate over 24h. She was the only one to need two containers and was thereafter known as Pisser Douglas. She can fill a portapotti very quickly.

[Gybe Ho]

11 minutes ago, Zen said:

@Gybe Ho I have that thread open on another tab (on one of my machines) but people here are generously fast with their replies and I dont want to seem ungrateful by not answering quick(ish), no doubt I'll have some questions for you a bit later once I've gone through the 9 pages.

 

 

No problem, if you do have time to review the thread please be aware that the initial diesel genset kWh calc was wrong, I got the ratio of diesel litres/ kWh completely reversed. I corrected that later in the thread which resulted in a much lower diesel consumption.

[IanD]

29 minutes ago, Zen said:

@MtB I know that the composting toilet is just the container and that they are really just separating loos, wees to the front poops to the back (sometimes with a greaseproof style bag and remembering to open the hatch (depending on version)), they seem on average to hold about 20lts of deposits which seems to be anything between 20 and 40 visits. There are some composting loos that have a stirring function but that will only start the process on the oldest dried poop, the whole thing takes 9-12 months to become proper compost unless you use the hotbin which takes 3 months. 

 

The fans to reduce/eliminate odour are very low power ~0.3w = about 50WH a week, someone with 3x 110ah leisure lead acid may find this drain significant (50% usage =165ah = 1980WH) although it is only 2.5% of a full charge but with a min planned setup of 15KWH Lithium Iron Phosphate storage the loss in wire resistance is going to be a higher loss for me.

 

@PeterF That info is very useful thank you, that equates to about 44lts per human per week

 

@IanD Very different numbers from PeterF although your flush values are much larger than his, I'm assuming that plot is from a monitoring app? is is using floatation or pressure measurements? what is the app and do you recommend it?

 

@Gybe Ho I have that thread open on another tab (on one of my machines) but people here are generously fast with their replies and I dont want to seem ungrateful by not answering quick(ish), no doubt I'll have some questions for you a bit later once I've gone through the 9 pages.

 

@cheesegas I imagine time of year affects it too, summer drinking a lot more fluids, winter less active but more hearty meals

 

Those are recorded black tank levels over a week or so -- I have similar results form other trips, and for two of us 25l/day is pretty consistent. I don't count how many time we flush the toilet using which type of flush. The tank level is measured by a 4-20mA 0.1bar pressure sensor (connected to a Tank 140, connected to the Cerbo) at the top of a dip tube, which means it's not prone to getting gummed up with cr*p but does mean the reading varies a bit with temperature as the air inside the tube heats and cools, hence the daily fluctuations you can see on the plot.

 

The data came from VRM (Victron Remote Monitoring), all the recorded data from the boat since installation is stored there, and can be read via a web browser or the VRM Portal app -- here's an example for the last couple of days, but it goes back more than a year.

 

 

[PeterF]

@Zen I gave you a figure of  getting to 80% in 3 weeks then looking for a pump out, I mis remembered, we get to about 80% after 2½ weeks and then look for a pump out and can get up to 3 weeks max. I have since looked at the most recent trip, like IanD I have Victron electrical system on my boat with all tanks connected, in this case 250 litres in 17 days, which is 15l/day for 2 or 52.5l/day/person. That has confirmed that at 330l max we would take 21 days.

 

The tank level sensor on my is from https://www.mcsboatproducts.co.uk/our-products/wastewater, it is a top down tube sealed at the top, open at the bottom, inserted into the tank from the top. There is a pressure sensor at the top and as the fluid fills it pressurises the air (questionable gas not sure it is air anymore) in the tube. In this case it outputs a 0 to 4.5V signal, again connected to a Victron GX Tank 140 and into the Cerbo GX.

 

ps, do not use fluid saving tips like using the hedgerow.

Edited October 18, 2024 by PeterF

[Gybe Ho]

23 minutes ago, IanD said:

 

The data came from VRM (Victron Remote Monitoring), all the recorded data from the boat since installation is stored there, and can be read via a web browser or the VRM Portal app -- here's an example for the last couple of days...

 

 

Great stuff.

 

I note how your PV production kicks in sharply once some threshold is exceeded. The graph of sun elevation would be smoother.

What is the Y-axis unit on the PV graph, ah think I just worked it out - watts?

I get the impression that your moored up base load is 4 amps (normalised to 12volts).

[Alan de Enfield]

43 minutes ago, PeterF said:

I have Victron electrical system on my boat with all tanks connected, in this case 250 litres in 17 days, which is 15 l/day for 2 or 52.5 l/day/person. That has confirmed that at 330l max we would take 21 days.

 

 

Is this a typo ?

Or, am I reading it incorrectly - One person uses 3x more than 2 people ?