Battery bank under the stairs

[dmr]

Ive had a look at those links., interesting. The Triskel system is complicated and only really good for a certain type of boating, cruising days and huge leccy consumption over night (air con, leccy cooking etc), its really just saying "load the engine with an alternator when there is spare torque available".

 

The parallel lead-acid Lithium concept is I think what Dr Bob has done. Its half way there but doing it with DC-DC converters (B t B chargers?) is much better. DC-DC discharging gives the option of properly charging (14.8v) and equalising the lead acids. Charging the lithiums is the difficult bit as priority has to go to the lead acids. Ideal is to use the Triskel concept and to take suitable current from the alternator once the lead-acids go into absorption charge. Assuming there is no off the shelf system then it means making something. If a DC-DC or BTB could be controlled over a bus then that's half way there, then its another Arduino project.

 

................Dave

[peterboat]

4 hours ago, magnetman said:

The way to transfer power from the 48v bank to the domestic 12v bank is to use a MPPT controller. Victron smartsolar 75/15 would be ideal. 

 

The 48v is the equivalent to the solar input and the output, up to 15a, goes to the 12v system. That particular one is a little under £100 and the current limit can be set via smartphone, as can the charging voltages and you can also set an equalisation manually or auto. 

 

I reckon done right the lead acid domestics could end up being very pampered batteries and last a bit longer than they usually would. 

 

 

ETA this is an interesting read. 

 

https://www.mby.com/gear/new-gear-triskel-marine-launches-automatic-electrical-generator-integrel-system-100495

 

And this 

 

https://www.zwerfcat.nl/en/lithium-hybrid.html

Or use a cheap golf cart 48 volt to 12 volt charger I have a couple on my electric vehicles work well and cheap as chips. It's also a tried and tested solution that is very simple and robust, why reinvent the wheel?

Edited October 31, 2020 by peterboat

[magnetman]

I quite like the controllability of the Victron gear. You can choose how much power you want to go to the 12v at the tap of a screen, adjust charging time, voltages, current etc. 

 

This seems to be more functionality than a 48v-12v charger. 

 

Obvious example if you wanted all the available power for the main 48v system you can just turn off the Victron output without needing to interact with the device. So placement of device is more flexible, and less switches. 

 

 

It seems to make sense to me but have not tried it to be fair. 

 

How "cheap" are these 48-12v golf chargers ? And how controllable? Do they have multi stage charging and are they less than £90 for up to 15a output? 

Edited October 31, 2020 by magnetman

[peterboat]

1 minute ago, magnetman said:

I quite like the controllability of the Victron gear. You can choose how much power you want to go to the 12v at the tap of a screen, adjust charging time, voltages, current etc. 

 

This seems to be more functionality than a 48v-12v charger. 

Why bother? With high tech comes high unreliability! I have 3 of these chargers in use, a 24 to 12 volt on the boat and two on the car and van  they work and work well  and are cheap and reliable perfik 

[magnetman]

Have you got a link to where they are for sale ? 

 

I know what you mean about reliability but I think modern good quality electronic stuff is ok these days. 

Edited October 31, 2020 by magnetman

[peterboat]

6 minutes ago, magnetman said:

Have you got a link to where they are for sale ? 

 

I know what you mean about reliability but I think modern good quality electronic stuff is ok these days. 

Ebay mate it's where I bought all of them. The problem is I have had two quality converters catch fire so I don't believe the hype anymore 

Edited October 31, 2020 by peterboat

[IanD]

3 minutes ago, peterboat said:

Ebay mate it's where I bought all of them

So do they have proper bulk/absorption/float with tempco charging or do they just under/overcharge the batteries? If the second, that's why they're cheap as chips...

[peterboat]

4 minutes ago, IanD said:

So do they have proper bulk/absorption/float with tempco charging or do they just under/overcharge the batteries? If the second, that's why they're cheap as chips...

Batteries still ok after 3 years so they must work ok, if your 12 volt usage is small under 30 amps it doesn't even need a battery to run the 12 volt stuff 

Edited October 31, 2020 by peterboat

[magnetman]

1 hour ago, peterboat said:

Batteries still ok after 3 years so they must work ok, if your 12 volt usage is small under 30 amps it doesn't even need a battery to run the 12 volt stuff 

I was referring to maintenance of an existing lead acid set of batteries which would include the engine starting batteries. As a way of extending the life of the batteries. 

 

Not just a technique to provide 12v from 48v. 

 

 

[magnetman]

1 hour ago, peterboat said:

Ebay mate it's where I bought all of them. The problem is I have had two quality converters catch fire so I don't believe the hype anymore 

Would be interested to know which brands these were. 

 

Fire risk is quite a serious trust issue with electronic gear. You don't usually want the boat burning down. 

 

 

[Dr Bob]

15 hours ago, dmr said:

Not convinced about this, comparing like for like,proper lithiums with proper lead acids (Trojans etc) its only 2:1 or maybe just 3:1, and I also don't believe you only need half the amp-hours with lithium. But, lithium are very attractive and when the price falls just a bit they will win hands down.

 

Not into all this RCD stuff but suspect its easier to meet with Lithiums if EuroRules are your thing?

 

...................Dave

Li's allow you to charge at full power - all the time - if you are charging between 20 and 90% SoC

This means that in the winter you can start your engine and put 90Ahr of power into  the batteries in one hour if you alternator can put out 90A. We use circa 160Ahr per 24 hrs and we put the engine on for an hour in the morning and an hour in the afternoon when we are out and about this time of year. We are usually around 75% full each time we turn the engine off each afternoon. We estimate we would be running the engine for 4 hours a day to keep LA's full each day. Our Li's have not changed in capacity/performance in nearly 2 years.

 

 

3 hours ago, dmr said:

 

 

The parallel lead-acid Lithium concept is I think what Dr Bob has done. Its half way there but doing it with DC-DC converters (B t B chargers?) is much better.

 

................Dave

I had them in parallel on our old boat but had control over the alternator output so could easily control charging. On the new boat, I have a 240A alternator but cannot control it. I am therefore using 2 Sterling 60A BtoB's. I am not impressed with the BtoB's and dont use them for winter charging when moored. The problem is that even with a custom programme, you cant get a setting that works perfectly as one always goes into float too soon so the voltage drops so then you are charging at half the speed with the other one. No problem if long cruises each day. Still far better than LAs but controlling the alternator like Nick is doing is a better solution.

For the OP, your choice is to buy a proper commercial  solution like what Victron offer (and pay a fortune) or go for 2nd hand car batteries and sort out your own BMS. Drop in lithiums are not a good idea - as per Ian D's note above - with comments from the 'marine how to site'. Commercial systems will not drop in price by a half in the next few years - 2nd hand car ones might as more and more become available.

[dmr]

3 minutes ago, Dr Bob said:

Li's allow you to charge at full power - all the time - if you are charging between 20 and 90% SoC

This means that in the winter you can start your engine and put 90Ahr of power into  the batteries in one hour if you alternator can put out 90A. We use circa 160Ahr per 24 hrs and we put the engine on for an hour in the morning and an hour in the afternoon when we are out and about this time of year. We are usually around 75% full each time we turn the engine off each afternoon. We estimate we would be running the engine for 4 hours a day to keep LA's full each day. Our Li's have not changed in capacity/performance in nearly 2 years.

 

 

I had them in parallel on our old boat but had control over the alternator output so could easily control charging. On the new boat, I have a 240A alternator but cannot control it. I am therefore using 2 Sterling 60A BtoB's. I am not impressed with the BtoB's and dont use them for winter charging when moored. The problem is that even with a custom programme, you cant get a setting that works perfectly as one always goes into float too soon so the voltage drops so then you are charging at half the speed with the other one. No problem if long cruises each day. Still far better than LAs but controlling the alternator like Nick is doing is a better solution.

For the OP, your choice is to buy a proper commercial  solution like what Victron offer (and pay a fortune) or go for 2nd hand car batteries and sort out your own BMS. Drop in lithiums are not a good idea - as per Ian D's note above - with comments from the 'marine how to site'. Commercial systems will not drop in price by a half in the next few years - 2nd hand car ones might as more and more become available.

An hour morning and an hour in the evening was the tradition but that's hard on the engine. Its said that most engine wear occurs at startup from cold so you would be much better just doing one two hour run each day, that halves the engine wear, and also makes sure the engine gets proper up to temperature. In fact I suspect that if you factor engine wear as well as diesel into your costings its possible that one four run each day (for lead-acids ?) is more cost effective than your two one hour runs.

 

I want enough battery to only run the engine once every second or even third day in winter. This was ok last month, could just do three days, but we are just on the edge of running every day.

 

I am currently charging from two alternator in parallel (100+70), a 30 amp Victron charger off the TravelPower and a little bit from a Victron solar controller (if the sun ever shines) and you are correct, no matter what I do with the settings something is always going into float when it shouldn't.

 

I am thinking more and more that at present a lead acid bank backed up with a bit of Lithiium is the way to go, with the Lithiums used to "cure" the long absorption time of the lead-acids, and to take all of the "load" in the summer when cruising. This should ideally up the life of the Trojans to lots of years, though they already manage about 5. Lithium needs to get cheaper before it really becomes the best choice, but in cases like the OP where location is a bit tricky the extra cost of lithium could be justified.

 

.............Dave

[Dr Bob]

27 minutes ago, dmr said:

 

I am thinking more and more that at present a lead acid bank backed up with a bit of Lithiium is the way to go, with the Lithiums used to "cure" the long absorption time of the lead-acids, and to take all of the "load" in the summer when cruising. This should ideally up the life of the Trojans to lots of years, though they already manage about 5. Lithium needs to get cheaper before it really becomes the best choice, but in cases like the OP where location is a bit tricky the extra cost of lithium could be justified.

 

.............Dave

I agree.

Our new boat came with 4*120Ahr tubular gels so having 300Ahr of Li's in parallel is very similar.

The big benefit is that when charging the LA's will take full power until the tail current starts taking effect at which point the Li's take full power. The big bonus is at the top end of the LA charge, with a typical set up, solar cant charge at the full rate due to the tail current so often you are resticted to 10A going in from solar. With Li's you can get a full 30A from 500W of panels all the time.

One issue to watch though is that if you discharge your LA's to 40 or 50% and then charge, the Li's are unlikely to get far charging the last 10% as the voltage is only 13.2V ish. I do not know over time if 13.2V is high enough to convert the sulphate deep in the pores of the LA. With our system on the old and new boat, I always have given the LAs a charge at 14.2V+ if they have been significantly been discharged. Discharing only to 90% ish and the Li's have no problem in keeping the LAs in good condition.

 

On running the engine twice per day - we like hot water in the morning and pm. The engine is still hot in the afternoon.

[IanD]

The simple fact is that unlike LA DIY LiFePO4 is not a sensible -- and possibly not safe -- option for your Joe Average boater (not Richard or Peter or Dr Bob or me or...) who doesn't really understand much about electrics in general and the peculiarities of lithium cells in particular. If they can't deal with keeping a simple LA system in reasonable shape (which many can't), they're certainly not safe to let loose with installing and using lithiums, no matter how many vloggers say how easy it is.

 

Of course LAs and lithiums are completely different and need completely different mindsets and approaches, but many people don't even get the basics about how to wire up and configure boat electrics, never mind home-brew a lithium-based system. LA has the advantage that a completely basic system will work, so will a typical one (second alternator, split charging relay, inverter, maybe some solar) with very little user intervention or control -- yes the batteries might only last a couple of years but at least they're cheap, and lots of people know how boat electrics like this work.

 

Lithiums have been enthusiastically marketed to the yachting and RV markets for far longer than narrowboats, many more inexperienced people (thousands) have installed them (DIY or drop-in), and lots of these have had holes burned in either their pockets or their boats/RVs as a consequence. Anyone considering them for a narrowboat should really sit down and read through the extensive information on the marinehowto site first (from somebody with years of experience in a large number of installations) before jumping in with both feet just because people on this forum or youtube say it's dead easy and works for them.

 

If after doing all this you conclude you have enough understanding to do a cheap DIY lithium installation based on second-hand or cheap ebay cells then go ahead, it'll probably be fine for you just like the lithium enthusiasts/fanboys. Just remember that they're probably not aware of all the people who also thought they knew what they were doing until it all went horribly wrong (see all the yacht/RV stories), they tend to only see the good side of lithiums and their own personal (successful) point of view.

 

Which is exactly what the marinehowto site said -- lithiums are great when done properly (which many aren't) but they're not ready for general (Joe Public) DIY use yet, even commercial systems are not always good but certainly are always expensive (far too much for most narrowboaters). If you're going to DIY to make lithiums affordable then do plenty of research, including from sources that point out the problems and realities as well as the advantages, and make sure you understand what you're building and what could go wrong with it.

 

Do all this and you should be another happy lithium success story. Take too many quick/easy/cheap short cuts and you could well be another unhappy lithium disaster story.

 

And if you conclude that it's all too difficult and complex for you to design/build/run, either cough up a fortune for a properly designed commercial system (bearing in mind that cost is no guarantee of quality) or stick with lead-acids, which even with all their problems have the merits of being simple, widely understood, and cheap ?

Edited October 31, 2020 by IanD

[peterboat]

1 hour ago, magnetman said:

I was referring to maintenance of an existing lead acid set of batteries which would include the engine starting batteries. As a way of extending the life of the batteries. 

 

Not just a technique to provide 12v from 48v. 

 

 

 

1 hour ago, magnetman said:

Would be interested to know which brands these were. 

 

Fire risk is quite a serious trust issue with electronic gear. You don't usually want the boat burning down. 

 

 

I have had them 3 years! I can't remember who they came from, but they are keeping the batteries ok and haven't burst into flames yet, unlike the 2 expensive vetus inverters. 

Its like the batteries you are thinking of purchasing very expensive with little storage which to me is pointless, especially as you can visit James and see his large battery bank in operation 

[Detling]

17 hours ago, dmr said:

Not into all this RCD stuff but suspect its easier to meet with Lithiums if EuroRules are your thing?

 

...................Dave

They are UK law unfortunately, including the lifetime liability, if things go wrong and the fitout was not to RCD standard.  How do you fancy a compensation claim from a bereaved spouse.?

[magnetman]

1 hour ago, peterboat said:

 

I have had them 3 years! I can't remember who they came from, but they are keeping the batteries ok and haven't burst into flames yet, unlike the 2 expensive vetus inverters. 

Its like the batteries you are thinking of purchasing very expensive with little storage which to me is pointless, especially as you can visit James and see his large battery bank in operation 

They actually aren't particularly expensive if you factor in the existence of a BMS and the packaging of the product. And I think that is a real warranty which I doubt would be available with second hand cells. 

 

I do know that it's worth having a warranty on batteries as I bought £600 of Rolls FLA batteries once which failed quite quickly and yes they did replace them under warranty. This was despite the fact that it was probably my own management of the batteries (generator charging) which killed them..

 

 

Of course with these new LFP things the charging history is embedded into the microprocessor so if you did kill them by inappropriate charging then it would be quite easy to prove. 

 

They do say 90% DOD and there is a specified charge rate so I have a feeling it might be ok. 

 

I'm a practical type of person but not at all interested in DIY or second hand LFP batteries. 

 

 

 

 

Edited October 31, 2020 by magnetman

[dmr]

5 hours ago, Dr Bob said:

I agree.

Our new boat came with 4*120Ahr tubular gels so having 300Ahr of Li's in parallel is very similar.

The big benefit is that when charging the LA's will take full power until the tail current starts taking effect at which point the Li's take full power. The big bonus is at the top end of the LA charge, with a typical set up, solar cant charge at the full rate due to the tail current so often you are resticted to 10A going in from solar. With Li's you can get a full 30A from 500W of panels all the time.

One issue to watch though is that if you discharge your LA's to 40 or 50% and then charge, the Li's are unlikely to get far charging the last 10% as the voltage is only 13.2V ish. I do not know over time if 13.2V is high enough to convert the sulphate deep in the pores of the LA. With our system on the old and new boat, I always have given the LAs a charge at 14.2V+ if they have been significantly been discharged. Discharing only to 90% ish and the Li's have no problem in keeping the LAs in good condition.

 

On running the engine twice per day - we like hot water in the morning and pm. The engine is still hot in the afternoon.

Sounds like you need a bigger calorifier but that's likely not easy to do. We have good hot water the day we run the engine and maybe the next morning. Later its just about ok for a shower. Third day its cold so boil a kettle for washing up and  don't even think about showers.

 

Interesting that you say charging priority implicitly goes to the lead acids, I need to learn more or talk to you more. I believe lead acids, or at least Trojans, really do need 14.8 volts (minimum) to get them charged so would still need a dc-dc type thing to finish charge the LAs from the lithiums.

 

.............Dave

[Dr Bob]

15 hours ago, magnetman said:

I'm a practical type of person but not at all interested in DIY or second hand LFP batteries

In that case then buying a decent commercial system is your only option and that will cost £3-5K or more. 12V 'drop ins' will not work.

[LadyG]

Companionway or 'steps'

Edited November 1, 2020 by LadyG

[peterboat]

7 minutes ago, LadyG said:

Companionway or 'steps'

Back stairs

[cuthound]

On 31/10/2020 at 16:06, Dr Bob said:

 

Our new boat came with 4*120Ahr tubular gels

 

You didn't get them off Mike Oldfield then? ??

[Dr Bob]

5 hours ago, cuthound said:

 

You didn't get them off Mike Oldfield then? ??

.......bass guitar.