Battery

[MtB]

On 26/04/2017 at 08:57, nicknorman said:

For monitoring, the Victron BMV is fine as an AH counter but the addition of a Smartgauge will allow you keep an eye on your batteries' capacity (recent issues with calibration not withstanding).

 

Point of order M'lud.

Keeping an eye on your batteries' capacity is the one thing a Smartgauge cannot help you with. It re-calibrates itself as capacity reduces with age. Nick probably meant state of charge. The BMV will be more help in keeping an eye on capacity.

[Sea Dog]

15 minutes ago, Tony Brooks said:

I all depends how you end up using your boat

Exactly - and which might be quite different to how you currently think you might use it. A set of decent sealed lead acid batteries will allow you to learn what you want or can get from your electrical system without having made a really expensive mistake. Neither will it preclude you from 'upgrading' to something which suits your needs and your charging abilities better once you've established what they are, although I'd be surprised if they turn out to be far off about right.

[peterboat]

I would buy flexible solar panels and stick them down if possible running the cables into the boat about 500 watts should do it. I would fit a better quality solar controller MPPT type which can do equalistion charges if it senses the need [my Midnite did this on Monday]. I would if you have the room put full traction batteries in with a watering system, and all things being equal you should be ok for five years plus. Solar is worth its weight in gold for looking after batteries.

[Chewbacka]

11 minutes ago, rusty69 said:

What inverter please? Standby sounds good. 

It's a Studer which also came with a 5 year warranty.  People that love fiddling with settings would hate this inverter as it is a box with a tiny on/off button and a tiny potentiometer used to set the inverter on trigger load.  It is designed to turn on and forget.

If you want more info, have a look here - https://www.advanceyacht.co.uk/downloads-inverters

Note - the falling pound seems to have pushed the prices up a fair bit.  

Edited April 26, 2017 by Chewbacka

[rusty69]

5 minutes ago, Chewbacka said:

It's a Studer which also came with a 5 year warranty.  People that love fiddling with settings would hate this inverter as it is a box with a tiny on/off button and a tiny potentiometer used to set the inverter on trigger load.  It is designed to turn on and forget.

Thanks. Looks like a good price. 

Edited April 26, 2017 by rusty69

[rusty69]

26 minutes ago, Mike the Boilerman said:

 

Point of order M'lud.

Keeping an eye on your batteries' capacity is the one thing a Smartgauge cannot help you with. It re-calibrates itself as capacity reduces with age. Nick probably meant state of charge. The BMV will be more help in keeping an eye on capacity.

I would have thought a Smartgauge in addition to a bmv could be used to estimate the battery capacity. 

[WotEver]

9 minutes ago, rusty69 said:

I would have thought a Smartgauge in addition to a bmv could be used to estimate the battery capacity. 

Yes that is the easy way to do it. In fact you won't be estimating, you'll be accurately measuring. 

[nicknorman]

50 minutes ago, Mike the Boilerman said:

 

Point of order M'lud.

Keeping an eye on your batteries' capacity is the one thing a Smartgauge cannot help you with. It re-calibrates itself as capacity reduces with age. Nick probably meant state of charge. The BMV will be more help in keeping an eye on capacity.

No I meant what I said (for once!). A Smartgauge in conjunction with an AH counter like a BMV allows one to know the actual capacity of the batteries, pretty effortlessly, by comparing the Smartgauge's actual SoC with the BMV's theoretical SoC. there is no easy other way.

[Tony Brooks]

1 hour ago, Mike the Boilerman said:

 

Point of order M'lud.

Keeping an eye on your batteries' capacity is the one thing a Smartgauge cannot help you with. It re-calibrates itself as capacity reduces with age. Nick probably meant state of charge. The BMV will be more help in keeping an eye on capacity.

To amplify what Nick said above.

With partially discharged batteries take the Smartguage reading and note the AH in from the BVM.

Charge until the ammeter on the BVM shows around 1 to 2% of battery capacity or until the amps stops falling over half an hour or so.

Subtract the amp hours in from BVM From the original BVM Ah in reading OR if the BVM was zeroed at the start of charging simply read the Ah in.

You now have the number of Ah that was required to as near as dam it fully charge the batteries. You know the % of discharge this represents. So for example if the Ah in said 60Ah and the original Smartguage reading said 70% you know 60Ah = 30% (100-70) of actual battery capacity. Thus 60/30 x 100 = 200 Ah of usable battery capacity - whatever the battery lable may claim.

 

[rusty69]

13 minutes ago, Tony Brooks said:

Thus 60/30 x 100 = 200 Ah of usable battery capacity - whatever the battery lable may claim.

Would you not  have 100Ah of useable capacity depending on battery type? 

[Tony Brooks]

10 minutes ago, rusty69 said:

Would you not  have 100Ah of useable capacity depending on battery type? 

Ah - I see what you mean after applying the 50% rule. I added usable battery capacity to try to differentiate between the capacity on the label and  the actual capacity. You could use the full 200Ah or close to it but probably at the expense of battery life.

[rusty69]

3 minutes ago, Tony Brooks said:

Ah - I see what you mean after applying the 50% rule. I added usable battery capacity to try to differentiate between the capacity on the label and  the actual capacity. You could use the full 200Ah or close to it but probably at the expense of battery life.

Sorry Tony. I didnt mean to confuse things. 

[nicknorman]

1 hour ago, Tony Brooks said:

To amplify what Nick said above.

With partially discharged batteries take the Smartguage reading and note the AH in from the BVM.

Charge until the ammeter on the BVM shows around 1 to 2% of battery capacity or until the amps stops falling over half an hour or so.

Subtract the amp hours in from BVM From the original BVM Ah in reading OR if the BVM was zeroed at the start of charging simply read the Ah in.

You now have the number of Ah that was required to as near as dam it fully charge the batteries. You know the % of discharge this represents. So for example if the Ah in said 60Ah and the original Smartguage reading said 70% you know 60Ah = 30% (100-70) of actual battery capacity. Thus 60/30 x 100 = 200 Ah of usable battery capacity - whatever the battery lable may claim.

 

That is a way of doing it, but it seems a little complicated and doesn't take account of CEF. Surely it is simpler to start with fully charged batteries (fully charged as you describe), BMV and Smartgauge both showing 100% SoC, then discharge normally, to a reasonable state of discharge but the more the merrier within reason, say down to 50% SoC on the Smartgauge. If the BMV is also showing 50% then you have batteries at their rated capacity, but presuming the BMV shows a higher SoC you have lost capacity in the proportion of DoD (not SoC) indicated by the BMV to DoD (not SoC) indicated by the SG. So let's say you had 50% SoC = 50% DoD on the SG, and 75% SoC = 25% DoD on the BMV, the actual capacity compared to the rated capacity set in the BMV is 25/50 = 50% of rated capacity.

[rusty69]

18 minutes ago, nicknorman said:

That is a way of doing it, but it seems a little complicated and doesn't take account of CEF. Surely it is simpler to start with fully charged batteries (fully charged as you describe), BMV and Smartgauge both showing 100% SoC, then discharge normally, to a reasonable state of discharge but the more the merrier within reason, say down to 50% SoC on the Smartgauge.

Wouldn't it be easier to do as you suggest above and then just use the Ah reading? 

[nicknorman]

2 minutes ago, rusty69 said:

Wouldn't it be easier to do as you suggest above and then just use the Ah reading? 

Yes you could do that too, but I don't think it's any easier. You would note the SG DoD (100%-SoC), multiply it by the nominal AH capacity, and compare to the Ah acutally taken out according to the BMV. So if you had 440AH nominal capacity, taken down to 50% on the SG, that should be 220AH. But if the BMV only showed 110AH taken out, you would have 110/220 ie 50% of nominal capacity.

[WotEver]

1 hour ago, rusty69 said:

Wouldn't it be easier to do as you suggest above and then just use the Ah reading? 

I think that's much easier. It also completely ignores any mis-setting of the capacity on the BMV. 

Sorry Nick

Take 'em down to 50%, double the Ah taken to get you there - there's the capacity. 

[nicknorman]

22 minutes ago, WotEver said:

I think that's much easier. It also completely ignores any mis-setting of the capacity on the BMV. 

Sorry Nick

Take 'em down to 50%, double the Ah taken to get you there - there's the capacity. 

Yes if you are going to take it down to 50% SoC then all the above discharging methods require the same amount of calculation. If you don't want to go to 50% you have to "do it properly" as I described! Although the point about the capacity setting on the BMV is accepted and I suppose you might want to adjust that to reflect the current capacity.

[WotEver]

6 minutes ago, nicknorman said:

Yes if you are going to take it down to 50% SoC then all the above discharging methods require the same amount of calculation. If you don't want to go to 50% you have to "do it properly" as I described!

Take 'em down to 75% and multiply by 4, down to 67% and multiply by 3... it ain't rocket science.

[peterboat]

I really cant see the issue? its a toy boat going out for holidays and long weekends 500 watt of solar will keep the batteries in good condition and charged when not used and when cruising the alternator will do it with solar topping up as needed. Put in full tractions with watering system, or some Trojans with watering system and bobs your aunty cos you arnt ever going to take em down far enough for it to be an issue

[rusty69]

3 minutes ago, peterboat said:

its a toy boat going out for holidays and long weekends

AA batteries should be fine then. I was under the impression it was a full scale boat. 

[peterboat]

2 minutes ago, rusty69 said:

AA batteries should be fine then. I was under the impression it was a full scale boat. 

LOL but you know what I mean it all gets technical for no good reason just build in the charging capability at the beginning and the rest is easy

[rusty69]

4 minutes ago, peterboat said:

LOL but you know what I mean it all gets technical for no good reason just build in the charging capability at the beginning and the rest is easy

I agree,these threads do tend to drift. I am guilty of contributing to this.

A lot of these electrical threads will depend on budget. The more stuff you got the more money you will need to service it.

Anyone remember the simple days of boating? 

Edited April 26, 2017 by rusty69

[peterboat]

1 minute ago, rusty69 said:

I agree, but a lot will depend on budget. 

True but but solar is cheaper than some of the fancy battery chargers and £600 buys full traction batteries is it worth putting crap leisure batteries in? On my old boat I did what I said to do, 6 years later with only the gauge on the MPPT controller I fitted those batteries onto my new boat, never had flat batteries or problems so it works. So now 6 years on those batteries are still working on  this boat along with another bank and all is still well and working ok. 

[mrsmelly]

59 minutes ago, rusty69 said:

 

Anyone remember the simple days of boating? 

Yes. Our first liveaboard boat had a hand start only engine, a foot operated water pump and only one 12volt domestic battery and hot water was heated on the stove as it was the only way. We luvved it and lived on it nearly five years cruisng around and updating. We now have all the usual crap that we all think we need today but in reality ninety percent of it is nonsense. We live on a boat not a poxy house so why do we fit household stuff that costs a bomb to maintain and power up? Yes I am a dinosaur but the more basic the boat the better it is in reality.

[nicknorman]

18 minutes ago, mrsmelly said:

Yes. Our first liveaboard boat had a hand start only engine, a foot operated water pump and only one 12volt domestic battery and hot water was heated on the stove as it was the only way. We luvved it and lived on it nearly five years cruisng around and updating.

 But bearing in mind you previously lived in a paper bag in the middle of the road, it was a major step up.