Battery Charging Routine Basics

[Cinimod]

In the end I bought the Lucas Batteries from Alpha Batteries (with 3 year warranty - even on a narrow boat) for £79.99 each. Delivery would have been £50, but we were passing Rochdale so picked them up...

Not too bad - 6 x 113 = 678 AH for £479.94 -> approx. 71p per AH and they are supposed to be happy to discharge to 70%

 

Now can I ask about that - what is a 70% or a 50% discharge? (Sorry for the VERY newbie question!)

 

FYI - Spotted this on eBay - 80w Solar Panel + Cable + Regulator for £208, seems to be a slightly better deal than the Maplin one.

This is a single panel, but Maplins is 4 x 15w panel I think (60w) for £200 is it better to have a single or multi panels?

 

We bought the smart gauge too - got to put it all together this weekend.

We will be heading East from Devizes if anyone is around and can offer advice!

 

Have ordered some LED bulbs for the 'lantern' type lights we have - just need to find bulbs for the ceiling lights now... not sure what bulbs are in those, have to take one apart.

May be more worthwhile dismantling the fitting and putting a different one in... looking at Blodgers post

 

FYI - Some LED bulbs - mostly car focused though (LINK)

[deletedaccount]

your batteries will read 12.2v when they're half empty.

 

Oh, and 12.2 when half full.

[John Orentas]

Short version:

How long will I have to run the engine to fully replenish a nearly depleted 600ah bank whilst also running the fridge, water pump and lights?

 

Long version

I'm not sure how long it should take to re-charge a almost completely depleted battery bank. I've read back through a bunch of alternator/charing/battery threads but they're all a bit over my head tbh.

 

 

 

Far better not to think in terms of charge and discharge of batteries, An alternator battery circuit is far better considered to be a case of balancing loads.. On average your alternator should produce more power than your boat system is using and by quite a large margin, in the region of 50% (give it a funny name if you like but I wouldn't bother)..

 

Similarly forget all this nonsense about full charge = 13 volts, flat = 11 volts, half charged = God knows what.. A static battery voltage bears very little relationship it's state of charge, it just tells you a very small amount about who made the battery.

 

A lot of this junk and pseudo science has blighted this and I am sure other forums for several years now, it is about time to have a major rethink..

 

Fix a permanent voltmeter and ammeter into your boat, buy an reasonable multimeter (not a Rolls Royce one) and perhaps a clamp meter, we will learn more about electrics in a week that we ever learnt from any self promoting characters we have come across.

[barge sara]

Fix a permanent voltmeter and ammeter into your boat, buy an reasonable multimeter (not a Rolls Royce one) and perhaps a clamp meter, we will learn more about electrics in a week that we ever learnt from any self promoting characters we have come across.

 

Can we add a battery hydrometer to the toolkit?

Probably the best indication of condition and state of charge......

[John Orentas]

Can we add a battery hydrometer to the toolkit?

Probably the best indication of condition and state of charge......

 

 

 

For some reason I have never had much luck with hydrometers, perhaps it is all that sloshing about with sulphuric acid, some people get on with them though, so why not.

[Chris Pink]

Similarly forget all this nonsense about full charge = 13 volts, flat = 11 volts, half charged = God knows what.. A static battery voltage bears very little relationship it's state of charge, it just tells you a very small amount about who made the battery.

 

Fix a permanent voltmeter and ammeter into your boat, buy an reasonable multimeter (not a Rolls Royce one) and perhaps a clamp meter, we will learn more about electrics in a week that we ever learnt from any self promoting characters we have come across.

 

You contradict yourself John.

 

Why does one need a voltmeter if the static battery voltage is not an indicator of state of charge.

[John Orentas]

You contradict yourself John.

 

Why does one need a voltmeter if the static battery voltage is not an indicator of state of charge.

 

 

 

The voltmeter is used for other purposes, you need a ammeter to measure charge current.. There is not an instrument ever invented that will tell you the state of charge of a battery, that must be done to a large extent by calculation.. Even those big garage type resistance testers (now banned I believe) won't tell you much..

 

But to repeat, think in terms what has gone in and what has come out..

 

Or you could try Sara's hydrometer.

Edited January 28, 2010 by John Orentas

[mayalld]

The voltmeter is used for other purposes, you need a ammeter to measure charge current.. There is not an instrument ever invented that will tell you the state of charge of a battery, that must be done to a large extent by calculation.. Even those big garage type resistance testers (now banned I believe) won't tell you much..

 

I assume that you mean a drop tester, which is basically a volt meter measuring the voltage under heavy discharge.

 

Banned or not, my dad has one in his tool box!

[nb Innisfree]

The voltmeter is used for other purposes, you need a ammeter to measure charge current.. There is not an instrument ever invented that will tell you the state of charge of a battery, that must be done to a large extent by calculation.. Even those big garage type resistance testers (now banned I believe) won't tell you much..

 

But to repeat, think in terms what has gone in and what has come out..

Or you could try Sara's hydrometer.

 

 

Trouble is there is no practical way of knowing what battery capacity you have, perhaps a reasonable idea when new but after that it's an increasingly inaccurate guess.

 

your batteries will read 12.2v when they're half empty.

 

Oh, and 12.2 when half full.

 

True but only first thing in the morning.

 

In the end I bought the Lucas Batteries from Alpha Batteries (with 3 year warranty - even on a narrow boat) for £79.99 each. Delivery would have been £50, but we were passing Rochdale so picked them up...

Not too bad - 6 x 113 = 678 AH for £479.94 -> approx. 71p per AH and they are supposed to be happy to discharge to 70%

 

Now can I ask about that - what is a 70% or a 50% discharge? (Sorry for the VERY newbie question!)

 

FYI - Spotted this on eBay - 80w Solar Panel + Cable + Regulator for £208, seems to be a slightly better deal than the Maplin one.

This is a single panel, but Maplins is 4 x 15w panel I think (60w) for £200 is it better to have a single or multi panels?

 

We bought the smart gauge too - got to put it all together this weekend.

We will be heading East from Devizes if anyone is around and can offer advice!

 

Have ordered some LED bulbs for the 'lantern' type lights we have - just need to find bulbs for the ceiling lights now... not sure what bulbs are in those, have to take one apart.

May be more worthwhile dismantling the fitting and putting a different one in... looking at Blodgers post

 

FYI - Some LED bulbs - mostly car focused though (LINK)

 

80% state of charge (SOC) = 20% depth of discharge (DOD) or 80% full or 20% empty. 50% SOC = 50% DOD which is half full or half empty!

Edited January 28, 2010 by nb Innisfree

[ditchcrawler]

I assume that you mean a drop tester, which is basically a volt meter measuring the voltage under heavy discharge.

 

Banned or not, my dad has one in his tool box!

Has it got a built in switch, or do you just get a big spark when you poke it on to the battery, If the latter, take care.

[bottle]

Cinimod

 

You have a Smartgauge, it will tell you all you need to know, when it says 100% your batteries are full to their available capacity.

 

Note: this does not necessarily mean you will have the amount stated on the label because as they age they cannot be raised to the same capacity.

 

Do not let the reading go below 50% on the Smartgauge.

 

You say you have a 678Ah battery bank, not completely true but that gets technical, so using your figure and to look after your batteries, by not letting them go below 50%, you have 339Ah available, again not wholly true but it gives some idea.

 

Two links for you.

 

http://www.batteryfaq.org/

 

http://www.smartgauge.co.uk/technical1.html

 

ps. when you understand can you come back and explain it all to me

[ditchcrawler]

Cinimod

 

You have a Smartgauge, it will tell you all you need to know, when it says 100% your batteries are full to their available capacity.

 

Note: this does not necessarily mean you will have the amount stated on the label because as they age they cannot be raised to the same capacity.

 

Do not let the reading go below 50% on the Smartgauge.

 

You say you have a 678Ah battery bank, not completely true but that gets technical, so using your figure and to look after your batteries, by not letting them go below 50%, you have 339Ah available, again not wholly true but it gives some idea.

 

Two links for you.

 

http://www.batteryfaq.org/

 

http://www.smartgauge.co.uk/technical1.html

 

ps. when you understand can you come back and explain it all to me

But it will take you all day, like 12 hours to fill them up again at 40 Amps

[Cinimod]

You say you have a 678Ah battery bank, not completely true but that gets technical, so using your figure and to look after your batteries, by not letting them go below 50%, you have 339Ah available, again not wholly true but it gives some idea.

 

Thank you bottle - not sure I will ever really fully understand it, but there you go.

 

I went for these 'new technology' Lucas batteries as you are supposed to be able to discharge them to 70% reliably for 500 cycles, and Alpha said in writing that they 3 year warranty was good for boat use.

 

So hopefully we should get 474Ah rather than 339Ah from each cycle...

 

Only time will tell...

[bottle]

70% reliably for 500 cycles,

 

Now again I stand to be corrected and probably will be

 

The 70% needs to be qualified, for example is that 70% soc (state of charge) or 70% dod (depth of discharge), the latter would be 30% soc

 

and

 

500 cycles that is each time you charge/discharge them but you may not fully charge them or fully discharge each time, it still counts as a cycle, so if you charge/discharge them once a day that is 500 days

[mayalld]

Has it got a built in switch, or do you just get a big spark when you poke it on to the battery, If the latter, take care.

 

Big spark naturally. It's a proper piece of kit.

 

Back before H&S was invented, and safety depended upon following instructions properly, I listened well when told to blow the gasses of before using the thing, and I've used it many times since I was eleven years old without an explosion.

[dor]

Just for information: I replaced my batteries in the summer as they seemed to have lost capacity and even after lengthy charging on the boat rarely settled down to more than 12.4V.

 

I've been looking at one at home just recently which had a voltage of 12.35; hydrometer said it was poor but automatic car-type battery thought it was charged and switched over almost immediately to float. However I left it on float for several days, and after 24 hours to settle down the voltage read 12.8. Now a week later it is still showing 12.8V.

 

Seems to me this just illustrates how difficult it is to get a proper full charge into boat batteries unless you have a landline and are able to float charge for days. It's all very well having an alternator that will put 80amps into a half-charged battery when you first start charging, and even one that has dropped to maybe 3 amps after a day's cruising, but it seems there is still capacity there to fill.

 

I also suspect my hydrometer is lying.

[Cinimod]

500 cycles that is each time you charge/discharge them but you may not fully charge them or fully discharge each time, it still counts as a cycle, so if you charge/discharge them once a day that is 500 days

 

Indeed Bottle - I think, as with anything, it is going to be a case of suck it and see... just hope that if they expire before 3 years, they WILL honour the guarantee!

 

Back before H&S was invented, and safety depended upon following instructions properly, I listened well when told to blow the gasses of before using the thing, and I've used it many times since I was eleven years old without an explosion.

 

Nice to see someone who takes responsibility for themselves - I guess as boaters, we do reasonably well at self responsibility, though it was with some dismay that I saw all the signs go up on the locks warning about staying clear of the cill... Basics 101... (though I am sure we have probably all done it at some point, hopefully not with disastrous results.)

 

May the day when someone tries to sue BW for tripping in a pothole on the tow path, or slipping on the edge of a lock in icy weather be a long way off.

 

However I left it on float for several days, and after 24 hours to settle down the voltage read 12.8. Now a week later it is still showing 12.8V.

 

This suggests that maybe my batteries may not be as dud as I think they are, but just need a good long soak charge... Maybe I should try it... any recommendations on battery chargers to use from the mains?

 

Don't think I can do anything else with the batteries, as they are sealed.

[blodger]

Just for information: I replaced my batteries in the summer as they seemed to have lost capacity and even after lengthy charging on the boat rarely settled down to more than 12.4V.

 

I've been looking at one at home just recently which had a voltage of 12.35; hydrometer said it was poor but automatic car-type battery thought it was charged and switched over almost immediately to float. However I left it on float for several days, and after 24 hours to settle down the voltage read 12.8. Now a week later it is still showing 12.8V.

 

Seems to me this just illustrates how difficult it is to get a proper full charge into boat batteries unless you have a landline and are able to float charge for days. It's all very well having an alternator that will put 80amps into a half-charged battery when you first start charging, and even one that has dropped to maybe 3 amps after a day's cruising, but it seems there is still capacity there to fill.

 

I also suspect my hydrometer is lying.

I think that's why a genny and four stage charger or 'my lawnmower generator with battery boiler' are an occasional necessity between ability to use mains to equalise and restore capacity to its potential. I second your findings that batteries you are about to discard can be rejuvenated by long periods of little charge but constant voltage plugged into the mains!

[Justme]

500 cycles that is each time you charge/discharge them but you may not fully charge them or fully discharge each time, it still counts as a cycle, so if you charge/discharge them once a day that is 500 days

 

 

Thats not my understanding at all.

 

I thought that if you had 500 cycles to 70% dod then if you reduce the dod to say 35% the cycles would go up by more than double (say 1200 ish).

 

If it was your way then a car bat that is discharged slightly & then charged again each time the car starts would soon hit its 200 odd cycles.

 

On the 3 year warranty I would assume its the same as most warranties & it which every of the conditions comes first. Like on a car its 5 years OR 70k miles. So you bat will be 3 years OR 500 cycles.

 

 

500 cycles to 50% would last us about 4 years ish.

[bottle]

Just me

 

I do hope you are right.

 

looks like you may be right but that is qualified

 

Quote;

 

Cycles vs Life

 

A battery "cycle" is one complete discharge and recharge cycle. It is usually considered to be discharging from 100% to 20%, and then back to 100%. However, there are often ratings for other depth of discharge cycles, the most common ones are 10%, 20%, and 50%. You have to be careful when looking at ratings that list how many cycles a battery is rated for unless it also states how far down it is being discharged. For example, one of the widely advertised telephone type (float service) batteries have been advertised as having a 20-year life. If you look at the fine print, it has that rating only at 5% DOD - it is much less when used in an application where they are cycled deeper on a regular basis. Those same batteries are rated at less than 5 years if cycled to 50%. For example, most golf cart batteries are rated for about 550 cycles to 50% discharge - which equates to about 2 years.

 

How depth of discharge affects cycle life on batteries. Battery life is directly related to how deep the battery is cycled each time. If a battery is discharged to 50% every day, it will last about twice as long as if it is cycled to 80% DOD. If cycled only 10% DOD, it will last about 5 times as long as one cycled to 50%. Obviously, there are some practical limitations on this - you don't usually want to have a 5 ton pile of batteries sitting there just to reduce the DOD. The most practical number to use is 50% DOD on a regular basis. This does NOT mean you cannot go to 80% once in a while. It's just that when designing a system when you have some idea of the loads, you should figure on an average DOD of around 50% for the best storage vs cost factor. Also, there is an upper limit - a battery that is continually cycled 5% or less will usually not last as long as one cycled down 10%. This happens because at very shallow cycles, the Lead Dioxide tends to build up in clumps on the the positive plates rather in an even film. The graph above shows how lifespan is affected by depth of discharge. The chart is for a Concorde Lifeline battery, but all lead-acid batteries will be similar in the shape of the curve, although the number of cycles will vary.

 

Unquote.

 

Source; http://www.windsun.com/Batteries/Battery_F...les%20vs%20Life

[lockgategirl]

Short version:

How long will I have to run the engine to fully replenish a nearly depleted 600ah bank whilst also running the fridge, water pump and lights?

 

Long version

I'm not sure how long it should take to re-charge a almost completely depleted battery bank. I've read back through a bunch of alternator/charing/battery threads but they're all a bit over my head tbh.

 

My setup is barus shire 45 with domestic alternator (not sure of size right now - guess it's the 'default' one), starter altenator and travel power. I've got a 600ah battery bank (I think) that's about 2 years old but has only been used attached to shore power until I bought it a month ago. It's got a powermaster 1500 inverter charger that manages charging from the shore power (which I don't have)

 

It all seemed fine when I was cruising down from reading. Doing 8 hours a day left my batteries fully charged at 12.8 or so. Last week I left the boat and they were reading 12.2v according to the powermaster. I left the fridge on and a week later they were 11.8 but amazingly still powering the fridge.

 

So on saturday I moved it for three hours or so and left the engine idling for another two. Yesterday I moved it for another hour and left it idling for at least 6 (albeit with the travel power on and powering my stereo). I made it all the way back up to the heady heights of 12.2 again last night only to find it drained to 11.8 again before bed. All I'd been running was the 12v fridge, 12v lights and the laptop for an hour. Is this normal? Have I damaged my batteries by letting them get so low? Do I need to stick water in the top of them or something? Should my inverter measure the voltage as > 13 when the alternator is on (it's not) and the actual voltage when off?

 

How long should I expect to charge my bank given 12v fridge, 12v lights, pump and 1 hour laptop per day. I was guessing a couple hours a day max but I may be wrong here. How do I measure my usage?

Your fridge, if it is anything like ours, will decimate your batteries if you leave them without charging for days at a time. Also we have found that the lap top can take a lot of power if you are, for instance, playing on line games. In addition to all this I think that 12.2 volts is not a fully charged battery bank to begin with.

[LJ Crew]

When we had to go to a non-mains moorings we installed a 165 watt solar panel. For two months before we moved we ran our Inlander fridge and the automatic bilge pump without any more input than the solar panel. After we moved we left the boat with only the pump in use. So far the batteries have remained charged. The panel is pointed and elevated to the optimum year round direction for the location of the moorings. Hope this helps and encourages the use of "Green Energy".