Buying Batteries

[Tony Brooks]

1 hour ago, smileypete said:

Multicell almost certainly get their AGMs made by another manufacturer, and are just passing on their charging requirements.

If the charging equipment can't generate the voltages needed,  there's many other brands of AGMs, and other types of lead acid batt.

Maybe buying AGMs from the likes of Trojan and US Battery would get you access to a better source of technical help if they make them in house.

My gut feel is that a correct charge voltage is best for getting the batts out of deep discharge, and that the belief that any old lower voltage will do, is probably mistaken It did come about in the Gibbo era :). IMHO it MIGHT work OK-ish for shallow discharges but take that as information only.

I would expect that in order to get the supplier/manufacturer to stand behind their product, you need to follow their charging requirements.

Pete, I think the highest charging voltage the batteries can accept will be best for taking batteries out of a very deep discharge but I doubt 14.5 or 14.8 applied for long enough would make a major difference.

Multicell have admitted they are not a manufacturer (but we can all guess that anyway) but they have never stated that it is their manufacturer that demand that voltage. They say it is them and "they are battery experts".

I guess the vast majority of boats are not fitted with 14.8 volt alternators so on that score Multicell AGMs are not fit for purpose so should not be advertised as for marine use

[smileypete]

10 minutes ago, cuthound said:

Not sure that stratification is the problem it is often made out to be.

Many telecommunications plant are permanently on float, at 2.2v per cell, so not enough to gas them,  and they never move off the battery racks, yet I never encountered stratification. 

Yep, there's your reason right there. Bit hard to cause stratification if the SG of the acid never changes!

Edited August 3, 2017 by smileypete

[peterboat]

I am going to use GTP batteries on the bathtub, fortunately for me my charging will be by solar [controller can be set at what I want], and the 24 volt Whispergen which can be adjusted to suit as well. It does seem to be a minefield out there at the moment with poor advice being the norm

Edited August 3, 2017 by peterboat

[smileypete]

11 minutes ago, Tony Brooks said:

Pete, I think the highest charging voltage the batteries can accept will be best for taking batteries out of a very deep discharge but I doubt 14.5 or 14.8 applied for long enough would make a major difference.

Multicell have admitted they are not a manufacturer (but we can all guess that anyway) but they have never stated that it is their manufacturer that demand that voltage. They say it is them and "they are battery experts".

I guess the vast majority of boats are not fitted with 14.8 volt alternators so on that score Multicell AGMs are not fit for purpose so should not be advertised as for marine use

If their manufacturer requires a certain charge voltage, they'd be stupid not to pass that requirement on the their customers. At least they're being honest about this requirement, I'd bet they'd love to allow lower charge voltages as that would only increase sales.

I don't see that as making them 'not fit for purpose' for marine use as such. From a quick web search it looks like Mastervolt AGMs call for 14.25V and Vetus AGMs call for 14.4V then 14.8V in two current limited stages!

Anyway it seems most narrowboaters are best off with bog standard leisures, AGMs are more suited to the off shore lumpy water brigade who are a lot more dedicated about their kit - with good reason!

Nevertheless a few boaters buy the Trojan/US Battery type batts which need up to 15.5V, maybe they do that with programmable solar controllers or batt chargers instead of alternators.

 

[bizzard]

Go back to dynamos and control boxes. The old control boxes were fully adjustable for charge rate voltage, and could be set where you wanted, early RB Lucas boxes adjusted by screwdriver for voltage reg and the cut out.  Later ones with a key, which I still have somewhere.

[Tony Brooks]

Yes - a chuck key from an old B&D/Wolf  electric drill. Actaully I used to have a proper one but have not seen t-it for yaars.

[WotEver]

1 hour ago, Tony Brooks said:

I think the highest charging voltage the batteries can accept will be best for taking batteries out of a very deep discharge but I doubt 14.5 or 14.8 applied for long enough would make a major difference.

Agreed 100% unless the manufacturer can supply a chemical reason for the assertion. 

[Tony Brooks]

2 minutes ago, WotEver said:

Agreed 100% unless the manufacturer can supply a chemical reason for the assertion. 

Which rather than doing seems to think its more productive to threaten legal action.

[WotEver]

1 hour ago, smileypete said:

Yep, there's your reason right there. Bit hard to cause stratification if the SG of the acid never changes!

Eh? An unused battery is quite likely to suffer stratification due to the heavier acid gradually settling to the bottom of the battery. It's not just poor charging to less than 100% that causes it.

[matty40s]

41 minutes ago, WotEver said:

Eh? An unused battery is quite likely to suffer stratification due to the heavier acid gradually settling to the bottom of the battery. It's not just poor charging to less than 100% that causes it.

Not if you have one of Bizzards patent Battery Wobbleezer

Edited August 3, 2017 by matty40s

[smileypete]

26 minutes ago, WotEver said:

Eh? An unused battery is quite likely to suffer stratification due to the heavier acid gradually settling to the bottom of the battery. It's not just poor charging to less than 100% that causes it.

I was responding to a post regarding stationary standby batts, which were never discharged from new and so never got stratified.

If you're not discharging and recharging, how is some acid going to get heavier than the remaining acid?

Edited August 3, 2017 by smileypete

[WotEver]

13 minutes ago, smileypete said:

If you're not discharging and recharging, how is some acid going to get heavier than the remaining acid?

By settling out. Any diluted acid will gradually become stronger at the bottom of the container than the top, that's simple physics

[smileypete]

43 minutes ago, WotEver said:

By settling out. Any diluted acid will gradually become stronger at the bottom of the container than the top, that's simple physics

You have just GOT be winding me up, sulphuric acid does NOT just 'settle out' on it's own. Talk to a chemist, or Mr Google for some research papers on diffusion.

Why not just point people to something like The Battery FAQ, there's good info there and I can't fault it really.

1 hour ago, WotEver said:

Agreed 100% unless the manufacturer can supply a chemical reason for the assertion. 

If a car mfr says to use certain grades of oil in their engine, do they have to qualify that with a full explanation of the tribology behind it, accessible to the layman?

Since Multicell are more budget orientated I don't think it reasonable to expect similar, maybe Trojan etc can supply more info for their batts.

With my engineering hat on I just accept that a batt mfr is going to know what's best for their product, and to stick to that.

 

[WotEver]

14 minutes ago, smileypete said:

If a car mfr says to use certain grades of oil in their engine, do they have to qualify that with a full explanation of the tribology behind it, accessible to the layman?

A full explanation of tribology? Nope. However car manufacturers do nevertheless usually give a good explanation as to why they recommend a particular oil. It may be because of the detergent properties, viscosity range or whatever. What they don't do is attempt to blind you with science and threaten legal action if you ask them the very simple question "Why?"

Trojan have some pretty specific charging requirements for T105s and are very happy to discuss and explain their reasons via email without threatening legal action for daring to ask the simple question "Why?"  In fact they appear to quite welcome questions about charge voltages, performance, temperature range, length of time from new to full capacity etc etc. 

Multicell by contrast say "Because we say so" and if you dare to query that they threaten legal action.

As for the effectiveness of diffusion, if it worked so well then stratification couldn't exist. The problem with diffusion is that it's very very slow. 

[nicknorman]

4 hours ago, smileypete said:

Nevertheless a few boaters buy the Trojan/US Battery type batts which need up to 15.5V, maybe they do that with programmable solar controllers or batt chargers instead of alternators.

 

We just charge our Trojans from the standard Iskra alternator (which gives 14.5v or so at the end). I have on rare occasions used the Combi to give them an equalise at 15.5v but probably only once or twice a year. Keeping them fully charged by long days cruising or being on float charge when in the marina seems to keep them happy. Which correlates with what Tony B suggests regarding the combination of charge voltage and time. Currently the Smartgauge SoC is always higher than the AH counter SoC (set to original battery capacity) after 3 years use, so they are pretty healthy.

[smileypete]

46 minutes ago, nicknorman said:

We just charge our Trojans from the standard Iskra alternator (which gives 14.5v or so at the end). I have on rare occasions used the Combi to give them an equalise at 15.5v but probably only once or twice a year. Keeping them fully charged by long days cruising or being on float charge when in the marina seems to keep them happy. Which correlates with what Tony B suggests regarding the combination of charge voltage and time. Currently the Smartgauge SoC is always higher than the AH counter SoC (set to original battery capacity) after 3 years use, so they are pretty healthy.

Sounds like shallow discharges and relatively light use on the whole, which is probably going to help.

ISTR there's at least couple of CCers on here with the same batt type who seem to be fighting some capacity loss in the winter months, I suspect that's partly due to the charge voltage not being high enough for winter temperatures.

Edited August 3, 2017 by smileypete

[Tony Brooks]

A further thought occurred to me over night.

I think a charging voltage of 14.8 is getting very close to a typical gassing voltage of a calcium battery. Further more I understand the gassing voltage is not a fixed point and tends to vary according to temperature, state of charge, current flowing etc. If my thoughts are correct then The MDs statement that they recommend the use of an A to B starts to make some sense if you accept that 14.8 volt charge is mandatory. A to Bs seem to have a float phase built into its charging maps and this will prevent excess gassing after several hours of charging at 14.8V into "fully" charged batteries. Open cells will cope as long as you top them up but if that gassing exceeds the AGM batteries recombination performance damage must occur from loss of water and all that follows from that.

I do not have any gassing voltage data from Multicell so do not know if my suspicions are likely to come to pass or not but if they are then the website should also explain that their batteries require additional charging equipment costing in excess of £250 plus fitting.

If I am correct then simply fitting a 14.8 volt regulator may well result in battery damage. I am also trying to understand what simple "adjustment" to charging voltage is provided on the majority of alternators in use today so another questionable statement.

[WotEver]

8 hours ago, smileypete said:

I suspect that's partly due to the charge voltage not being high enough for winter temperatures.

I suspect it has as much to do with insufficient charge time. Despite Trojan stating something like 14.8V finishing voltage (at 25C, so much higher in the winter) the experience of Nick and others shows that long enough charge times with a lower voltage will fully charge the battery. Heck, 13.6V will fully charge a battery given enough time. What a low charge voltage won't do though is eliminate all sulphation (should it exist), so the occasional higher charge voltage will be required to convert it all. A high voltage charge might be the most efficient but I've yet to see any evidence that it's 'required' 

[cuthound]

3 minutes ago, WotEver said:

I suspect it has as much to do with insufficient charge time. Despite Trojan stating something like 14.8V finishing voltage (at 25C, so much higher in the winter) the experience of Nick and others shows that long enough charge times with a lower voltage will fully charge the battery. Heck, 13.6V will fully charge a battery given enough time. What a low charge voltage won't do though is eliminate all sulphation (should it exist), so the occasional higher charge voltage will be required to convert it all. A high voltage charge might be the most efficient but I've yet to see any evidence that it's 'required' 

I'd  agree with this. I've worked with batteries of various types all my working life and they all behave the same, except for slight differences in chsrging voltages to allow for the levels of calcium sometimes used in the plates. 

Providing the voltage is suffieicient to prevent self discharge and maintain a slight charge (float voltage) then the batteries will fully charge given enough time. 

However to remove sulphation a much higher voltage is required periodically. 

[WotEver]

1 minute ago, cuthound said:

Providing the voltage is suffieicient to prevent self discharge and maintain a slight charge (float voltage) then the batteries will fully charge given enough time

Absolutely. This describes it in a nutshell. 

[WotEver]

30 minutes ago, Tony Brooks said:

The MDs statement that they recommend the use of an A to B starts to make some sense if you accept that 14.8 volt charge is mandatory.

I don't accept that without some kind of explanation. 

32 minutes ago, Tony Brooks said:

If I am correct then simply fitting a 14.8 volt regulator may well result in battery damage.

Unfortunately, their current stance means that we'll never know if you're correct. 

[nicknorman]

8 hours ago, smileypete said:

Sounds like shallow discharges and relatively light use on the whole, which is probably going to help.

ISTR there's at least couple of CCers on here with the same batt type who seem to be fighting some capacity loss in the winter months, I suspect that's partly due to the charge voltage not being high enough for winter temperatures.

No we tend to be fairly hard on our batteries, we often used the electric kettle, coffee machine, toaster for breakfast so that by the time we start the engine, especially in the winter, the SoC is down in the 60s. But we do cruise relatively long days. The folk on here who have had problems with these battery types are those who want to keep their boat in one place for 14 days or whatever, and thus want to minimise the frequency and duration of engine running.

[smileypete]

11 hours ago, nicknorman said:

No we tend to be fairly hard on our batteries, we often used the electric kettle, coffee machine, toaster for breakfast so that by the time we start the engine, especially in the winter, the SoC is down in the 60s. But we do cruise relatively long days. The folk on here who have had problems with these battery types are those who want to keep their boat in one place for 14 days or whatever, and thus want to minimise the frequency and duration of engine running.

Sounds like you start the day with SoC 78-80, take a bit out then charge it straight away. Still what I'd call relatively light use.

[MtB]

3 minutes ago, smileypete said:

Sounds like you start the day with SoC 78-80, take a bit out then charge it straight away. Still what I'd call relatively light use.

 

Yes. Try draining them down to 50% over say a week, and then fully recharging them. I predict disaster!

 

[smileypete]

9 minutes ago, Mike the Boilerman said:

Yes. Try draining them down to 50% over say a week, and then fully recharging them. I predict disaster!

I predict that at least part of the problem is that the correct charge voltage isn't used, especially in winter temperatures - maybe as much as 16V for some batts.

Have you done some EQ every week or so over summer on yours, if so how are the SGs recovering?

I guess that some who buy these type batts have been somwhat persuaded that they're a panacea, where have I heard that before? hmmmm...

Edited August 4, 2017 by smileypete