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Keeping batteries fully charged


Kalapattar

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2 hours ago, RufusR said:

Solar can be enough in winter if you have enough , but you need lots , we can charge to 100 percent most days but have 1630 watts , you have to think big if you want it to work , I am with Tony a back up generator is also a good idea for those odd ultra low light days but we only run it on average once every 2-3 weeks  dec jan and never other times , Wind seems fun and attracts me as s project one day but just for a hobbie rather than any expectation of it have a worth the money effect . 

 

Running engine Ines with alternator rarely gets batteries to a proper full state unless you are running it for ever , so alternate methods are preferable if living aboard . IMO most people don’t think big enough regard solar arrays on narrow boats hence disappointment when it does deliver in winter months . Solar panels are pretty cheap these days .  Roof space is an issue but can be overcome if creative thinking on a lot of boats 

Ok, thanks for your reply! After reading replies and advice I’m having to accept that there’s no magic solution unless my mooring becomes like ‘Silicon Valley’ lol!

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1 hour ago, Tony Brooks said:

 

In my opinion also but doubt you could get enough on a narrrowboat for periods of winter if you still have a land based mind set and expect a floating cottage. This is why a power audit is vital so you know how to reduce your demand when you need to. Simply turning the fridge off during winter will save between 30 adn50 Ah per day, that is roughly equivalent to one typical battery. If you don't want to keep fresh food outside in winter cut a hole in the floor under a cupboard and keep the milk sitting on the base plate.

 

I find it rather disppoinmting that the OP says "I have no idea how to audit power. AVO,  calculations goes over my head. All I need is a cost saving easier way of preserving batteries, keeping them topped up rather than having to change them every couple of years". It is tantamount to saying "I can't be bothered to do any research so expect you lot to do it all for me even when I don't give you the information you would need to do so". Its not as if there are no examples of power/energy audits on the internet.

 

Basically the answer can only ever be:

 

A. reduce your consumption to the level at which you can fully recharge by whatever method.

B. increase your ability to recharge by some way that is practical and likely to work.

C. a combination of these.

 

Learning to use a simple ammeter and an accurate digital voltmeter to infer state of charge is probably the cheapest way of battery monitoring but that involves effort on the part of the user. Even with the majority of  all singing and dancing battery monitors will involve the user in a  good deal of study and learning if they want the best out of them.

 

For a start Mr @Kalapattar go onto my website and study the electrical course notes and also the   power/energy audit part of the maintenance notes. They will explain Amps, Volts and Ohms in terms you may better understand and also explain why you need so much apparent excess battery capacity and charging.

 

Totally agree with this , what I didn’t say as thought was as read , we don’t have a huge power usage and ration even that in winter , we have 12 volt fridge but that is biggest draw , we added 12 volt sockets everywhere when we moved off grid so as not to use inverter except for the odd thing like oven ( needs fan to operate ) and even then ration use , we don’t watch TV instead stream to iPads which recharge for dc sockets , lights are all LED and we only use those sparingly , etc etc . It is simply not possible to live like a houser off grid on a boat in winter . Give this is not an option give up and buy a house or move to marina / mooring with electric hook up . To echo Tony , Detailed power audit and constant accurate monitoring are crucial if you want to have prolonged battery life past a year or two or even less . I know from experience and a wrecked battery bank within 3 months of moving off grid . 

Another winter trick is using power blocks to recharge phones , pads etc and recharging them at work if you have an understanding boss ?

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12 minutes ago, LadyG said:

I don't think it is related to solar, it's doing it when it is raining and in 6/8 cloud, 

I'll have a look at the alternator and check it's data sheet, keeps me busy, or motivated, or something, anyway if it is an intentional function, it has to be a positive, my alternator is quite small, I think 70amps,  but 'if it ain't broke' .        

Do these battery monitors need to be on each domestic battery bank, do they need me to do 'wiring'?

I am planning to replace my two (unknown type) batteries next year, easiest to replace similar footprint and orientation than with one monster, they are fairly difficult to access

You just need a shunt , you may need one on each bank if they are operating Independently. Look at victron smart shunt no screen you can install remotely and read from mobile phone app via Bluetooth 

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1 hour ago, blackrose said:

Then learn how do do it. It's really not that difficult. You're either interested in learning about this stuff or you're not.

 

https://notefromaboat.com/2018/12/15/how-to-do-a-power-audit/

 

That's quite a good description. Apart from the continuous references to "Amps per hour".:banghead:

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1 minute ago, Kalapattar said:

Ok, thanks for all your replies! I like the idea of 12v sockets! I use a cigarette lighter type socket to recharge my iPhone etc! Biggest draw is my 3 way fridge but I use gas option! 

NEVER use the 12v option on your 3-way fridge. They do not have a thermostat, they are running continously  and will flatten your batteries in a small number of hours.

They were designed for use in caravans, the idea being :

 

Whilst packing your caravan at home, plug it into the mains overnight at home and let it get down to temperature.

Switch onto 12v whilst towing and the engine is running

Switch over to gas immediately you arrive at the camp-site.

 

In the owneres manual there was actually a warning stating that if you stopped at 'services' for lunch etc then switch off the fridge as you would not be able to restart your car.

 

They are very thirsty !!

 

 

One version of the manual :

Screenshot (44).png

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18 minutes ago, Kalapattar said:

Ok, thanks for all your replies! I like the idea of 12v sockets! I use a cigarette lighter type socket to recharge my iPhone etc! Biggest draw is my 3 way fridge but I use gas option! 

The fact its  a gas fridge is the best bit of news for you. As long as your heating is by stove and gravity circulation to any rads then sensible things like changing to all LED lamp bulbs and not running cottage type domestic equipment from an inverter should allow the panel to provide for much, but not all of the year. Just a voltmeter - even a plug into a cigarette light socket cheap Ebay one will allow you to guestiomate the state of battery charge once you learn when to take readings and how to infer state of charge from rested voltage. That is voltage after something has been drawing current for a awhile or an hour or so after charging has stopped. An ammeter makes it far easier to know when its OK to stop charging.

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48 minutes ago, RufusR said:

You just need a shunt , you may need one on each bank if they are operating Independently. Look at victron smart shunt no screen you can install remotely and read from mobile phone app via Bluetooth 

Oh, out of my comfort zone, I'l wait a few years and see if my batteries are still working satisfactorily.

I may succumb to a bluetooth keyboard, but I'm going to ask for it as a christmas pressy, so donor will get it up snd running, I usually get things to work, but not first time around.

 

 

 

 

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5 hours ago, LadyG said:

 Do these battery monitors need to be on each domestic battery bank, do they need me to do 'wiring'?

 

How many domestic banks do you have? Most people just have one plus a start battery.

 

I installed my battery monitors about 12 years ago so no bluetooth features. I've got a Smartgauge which are the easiest to fit and accurately give battery state of charge as a % and voltage of up to two banks (I think?) and I've also got a shunt type monitor which gives voltage and state of charge (less accurately) of two banks and also gives me amps in/out of the domestic bank. It only has one shunt so only shows amps in/out of one bank, but it's a really useful thing to have. It's a bit more involved to install the shunt type as all battery negatives have to be on one side of the shunt.

 

How you know when to start or stop charging if you're CCing and moored somewhere for several days without a battery monitor? The simplest way if you don't already have one would just be to install a good voltmeter and use it in conjunction with one of the tables Alan of Enfield posted earlier for your battery type, example below. Always try to charge to 100% and never let the bank fall below 50%. Ideally for accuracy you'd only take voltage readings after 24 hours with no charge or discharge but that's impractical for liveaboards. Remember that voltage readings taken immediately after charging will be measuring the surface charge on the plates so they'll be giving you a falsely high reading. Also for "off charge" voltage readings make sure everything is switched off.

image.png.3e22776b68668e72327c54fa21f00fc7.png

 

Edited by blackrose
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2 minutes ago, RufusR said:

Short of running big gennie all day not sure what that is ? Interested in the solution as always looking for ways to generate more power on dark days , 

 

 

Fit 2nd hand Lithium batteries of course. When out and about, we run our engine for 2 hours a day to replenish the 160Ahrs we take out each day.

It is only a solution for those who understand batteries and charging however.

The quote I always remember is from @Tom and Bex when they said that fitting Lithiums was far better than fitting solar for their 24/7 liveaboard style during winter. I agree. We have no solar now.

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16 minutes ago, Dr Bob said:

Fit 2nd hand Lithium batteries of course. When out and about, we run our engine for 2 hours a day to replenish the 160Ahrs we take out each day.

It is only a solution for those who understand batteries and charging however.

The quote I always remember is from @Tom and Bex when they said that fitting Lithiums was far better than fitting solar for their 24/7 liveaboard style during winter. I agree. We have no solar now.

160Ah/12V is less than 2kWh, which is a fair bit but nowhere near what's needed to "live like a houser" with fridge/freezer, washer/drier, dishwasher, toaster, microwave, TV, laptop(s), which is what many people seem to want to do nowadays.

 

All of which *is* possible with a *lot* of solar, a *big* battery bank (~10kWh LiFePO4 or bigger LA), a way of charging *fast* from the engine (with hours extra for equalising LA), and a big inverter/charger. Like a Rolls-Royce, if you want to know how much all this costs (especially if you can't roll your own LiFePO4 solution), you probably can't afford it ?

 

(go and look at some yachting sites/forums where setups like this are common and pockets are much deeper, not narrowboat ones where they aren't)

Edited by IanD
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Ah yes you are right , I really should have saved harder and had lithium’s this time around instead of AGM’s ( which are much better that fl lead acid btw) but yes lithium’s would be the icing , next time will def put them in maybe sooner . What bms do you have or it is integrated ? 

 

Cost at is what puts most off but I am beginning think worth saving for the more I research it . I think I will always have solar as like making free leccy from photons and don’t like burning hydrocarbons to get leccy . 

Edited by RufusR
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4 minutes ago, RufusR said:

Ah yes you are right , I really should have saved harder and had lithium’s this time around instead of AGM’s ( which are much better that fl lead acid btw) but yes lithium’s would be the icing , next time will def put them in maybe sooner . What you have or it is integrated ? 

 

Cost at is what puts most off but I am beginning think worth saving for the more I research it . I think I will always have solar as like making free leccy from photons and don’t like burning hydrocarbons to get leccy . 

450Ahrs/12V of 2nd hand thundersky Lifepo4 cells with a DIY BMS. Total cost around £1200. Payback circa 5 years or less. Only useful for someone willing to understand how to manage batteries properly.

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Just now, Dr Bob said:

450Ahrs/12V of 2nd hand thundersky Lifepo4 cells with a DIY BMS. Total cost around £1200. Payback circa 5 years or less. Only useful for someone willing to understand how to manage batteries properly.

Ok so DIY solution! Not for most I imagine , I would not want to do that , I do understand how to manage and charge lithium’s however so will prob build a solution around Victron smart lithium’s and BMS cost currently be around 3k for 300 Ah which would be plenty for us if lithium’s . It’s a lot but will pay back over life span probably twice . 

 

Saving now lol

Just now, RufusR said:

Ok so DIY solution! Not for most I imagine , I would not want to do that , I do understand how to manage and charge lithium’s however so will prob build a solution around Victron smart lithium’s and BMS cost currently be around 3k for 300 Ah which would be plenty for us if lithium’s . It’s a lot but will pay back over life span probably twice . 

 

Saving now lol

 

Ps if I have lithium will have lots more solar available to divert to heat water for longer during the year , have cool diversion circuit but runs out of grunt in Oct when charging current 550 Ah bank 

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For me part of living on a boat is not to live exactly like I'm in a house. When I'm away that means reducing my electrical power consumption. I have a gas fridge, led lighting, a smaller 12v tv that only draws 2 amps and a 35w/channel car stereo that draws 1amp. I have 450 amp/hours of trojan lead/acid batteries and can go 4 or 5 days without recharging them. I don't even have any solar panels although I've been planning to install some for a few years. 

 

If you must live like you're in a house then you'll need an expensive electrical setup including perhaps lithium batteries, but for me the solution is much simpler.

Edited by blackrose
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It also depends on what is meant by living like in a house.

 

I have everything I need/want that I have in the house. Not an issue to do toast under the grill, and wash up a few pots. If we didn't have a house, I'd probably enjoy the trip to the laundrette, and would still give some money to the ironing shop.

 

Lithiums haven't made any of this more accessible,  but they have made it much easier to maintain a level of power.

 

On looking after lithiums, and apart from the money at stake, its just a different mindset:

 

Don't charge them longer than enough to get them to 100% - they don't actually need to be charged to 100%, so stop charging at 90% or find a way to automate that.

 

Don't discharge them too low. 15% to 20% is fine, so not much different to LA.

 

Don't charge them if the temperature is less than 5C.

 

Consider the balance of the cells, (bit like equalising with LAs).

 

None of it is rocket science. Some of it isn't new, albeit different, and it can all be automated relatively simply.

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Lithiums definitely the best money we've spent on the boat. Trouble is we're now using noticeably more power than when planning our system, due to ease of charging and maintenance! We were using around 90-100ah per day, now seem to be using 120-130ah per day or more!

 

Seriously considering increasing our 320ah of 2nd hand lithiums now, trouble is, to take full advantage of any increased capacity, I'd need to look at increasing our alternator to keep within 1-2hrs a day engine running. And that would require a poly vee belt, so new engine pulley needed, and so it goes on!

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20 hours ago, Tom and Bex said:

Lithiums definitely the best money we've spent on the boat. Trouble is we're now using noticeably more power than when planning our system, due to ease of charging and maintenance! We were using around 90-100ah per day, now seem to be using 120-130ah per day or more!

 

Seriously considering increasing our 320ah of 2nd hand lithiums now, trouble is, to take full advantage of any increased capacity, I'd need to look at increasing our alternator to keep within 1-2hrs a day engine running. And that would require a poly vee belt, so new engine pulley needed, and so it goes on!

 

Surely running 3 hours a day should give you enough for 150Ah if 2 hours is enough for 100Ah?

 

So add half again to the bank, and spend the alternator upgrade money on fuel in winter.  Use solar the rest of the year and the diesel costs average out.

 

Have you only got one alternator?  If not, can you upgrade the little one keeping the same drive pulley?

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3 minutes ago, TheBiscuits said:

 

Surely running 3 hours a day should give you enough for 150Ah if 2 hours is enough for 100Ah?

 

So add half again to the bank, and spend the alternator upgrade money on fuel in winter.  Use solar the rest of the year and the diesel costs average out.

 

Have you only got one alternator?  If not, can you upgrade the little one keeping the same drive pulley?

Don't encourage him to be profligate with energy - lithium batteries are supposed to help us to use it more efficiently, not help us to get efficient at using more of it! Tut! ;)

 

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4 minutes ago, Sea Dog said:

Don't encourage him to be profligate with energy - lithium batteries are supposed to help us to use it more efficiently, not help us to get efficient at using more of it! Tut! ;)

 

 

It's the little people's fault. 

 

I know for sure that BobBiscuits is using a lot more power than he did when he just lay in a basket gurgling quietly.  Tom and Bex have a slightly bigger version onboard, so if they are only up 20% of planned they are doing well ...

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21 hours ago, Tom and Bex said:

Lithiums definitely the best money we've spent on the boat. Trouble is we're now using noticeably more power than when planning our system, due to ease of charging and maintenance! We were using around 90-100ah per day, now seem to be using 120-130ah per day or more!

 

Seriously considering increasing our 320ah of 2nd hand lithiums now, trouble is, to take full advantage of any increased capacity, I'd need to look at increasing our alternator to keep within 1-2hrs a day engine running. And that would require a poly vee belt, so new engine pulley needed, and so it goes on!

Solar is your green non polluting friend .

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7 hours ago, TheBiscuits said:

 

Surely running 3 hours a day should give you enough for 150Ah if 2 hours is enough for 100Ah?

 

So add half again to the bank, and spend the alternator upgrade money on fuel in winter.  Use solar the rest of the year and the diesel costs average out.

But we've got used to only 2hrs a day!

 

7 hours ago, TheBiscuits said:

 

Have you only got one alternator?  If not, can you upgrade the little one keeping the same drive pulley?

Twin alternators that are both A127, but start battery one runs on a smaller pulley. Also only have the one regulator (should have bought 2 before they went commercial!) We were seeing around 100A when starting charging, but have had to dial back the settings to around 70A to avoid killing alternator too quickly!

 

6 hours ago, TheBiscuits said:

 

It's the little people's fault. 

 

I know for sure that BobBiscuits is using a lot more power than he did when he just lay in a basket gurgling quietly.  Tom and Bex have a slightly bigger version onboard, so if they are only up 20% of planned they are doing well ...

Fully agree! Along with increased water usage, toilet emptying etc! No concept of saving power and water despite our best efforts. 

 

6 hours ago, RufusR said:

Solar is your green non polluting friend .

Have solar, and surprised how much better it works with lithium batteries. Trouble is we get nothing October to February, and have shading til midday on our mooring in summer due to trees. 

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