BATTERIES SEALED LEAD ACID OR VENTED LEAD ACID CHARGING VOLTAGE

[sailingrbg]

I have just bought a sealed lead acid battery and was wondering if the charging voltage for a sealed L.A. is the same as a vented L.A. battery. I currently have two 75AH batteries one for engine start and one for the house battery, I have now added a further 110 AH lead acid primarily for a new a anchor windlass / additional back up to the house battery. I have a Sterling (20A) smart battery charger with three outputs but there is a toggle switch to determine whether all batteries are of the sealed or vented type any one any thoughts on the above .

 

[VicS]

Some good reading for you:
http://www.batteryfaq.org/
http://batteryuniversity.com/
http://www.mpoweruk.com/

Should answer all the questions you may have

 

[simonfraser]

p.s. using caps suggests you are SHOUTING ! not needed, this is a v. polite forum /forums/images/graemlins/laugh.gif

 

[VicS]

[ QUOTE ]
using caps suggests you are SHOUTING

[/ QUOTE ] Sorry. Signature in profile now changed to all lower case.

 

[sailingrbg]

think it was me that started the capitals very sorry if offended you, might have been better if you were able to give some valuable advice as well!

 

[FAITIRA]

[ QUOTE ]
think it was me that started the capitals very sorry if offended you, might have been better if you were able to give some valuable advice as well!

[/ QUOTE ]

WELL SAID,,,HERE, HERE!!! BTW, I would be interested in "ANSWERS" to your query too. This hang up about CAPS IS SO INFANTILE. Bill.

 

[VicS]

[ QUOTE ]
might have been better if you were able to give some valuable advice as well!

[/ QUOTE ] Sorry i thought the three links would have given all the info you could have wished for. /forums/images/graemlins/wink.gif


I think you will find that sealed batteries should be charged at a lower rate than vented ones, at least if by sealed you mean sealed glass mat batteries which contain a much smaller volume of electrolyte.

 

[roly_voya]

To answer the question very simply you need a second battery charger. If you charge all three together setting the charger level for the vented cells (14.7v) will quickly dry out and reck the sealed battery. The alternative of setting the level for the sealed cell (14.2v) is marinally safer but will mean that the vented cells tend not to be fully charged and will die from sulphation. My suggestion would be to fit the sealed battery farward close to the windlass and fit a remote charger. Overall it will probaly cost less for the charger than it would for length of cable capable adequatly of feeding the windlass from a battery sited aft. If you need to upgarade the house bank you should ideally fit a set of identical batteries of the same age otherwise you will find that only the newer one charges properly (charge acceptance drops of with age as internal battery resistance goes up)

 

[sailingrbg]

Many thanks for all who replied I found the info useful. I have now found that the sealed lead acid should be charged at 14.4v but the vented lead acids should be charged at 14.8v. I have a toggle switch on my battery charger that can either charge vented or sealed L.A. Advised to charge all at the lower voltage but this can also lead to problems with sulphation,
Wonder if it is possible to put a resistor in series with the supply to the sealed L.A. and this would hopefully reduce the voltage to it but allow the vented L.A. batteries to receive full voltage at 14.8v
Any one done this or is a too simplistic answer

Many to all again

 

[ethanhunt3055]

Last night I forgot to take out my battery for charging and this morning it was totally discharge and when I tried to charge then it gave me a minor shock of current. I don’t know how the current leads to flow in the battery because it was totally discharge. Does the discharge battery too have some leading power for some run ups?

lead answer @ leading way

 

[Plevier]

Many thanks for all who replied I found the info useful. I have now found that the sealed lead acid should be charged at 14.4v but the vented lead acids should be charged at 14.8v. I have a toggle switch on my battery charger that can either charge vented or sealed L.A. Advised to charge all at the lower voltage but this can also lead to problems with sulphation,
Wonder if it is possible to put a resistor in series with the supply to the sealed L.A. and this would hopefully reduce the voltage to it but allow the vented L.A. batteries to receive full voltage at 14.8v
Any one done this or is a too simplistic answer

Many to all again

First of all RTFI for the battery i.e. see what instructions the battery manufacturer supplies and follow them. They know better than the charger manufacturers.
Different batteries have different requirements depending on the lead alloy used, the electrolyte specific gravity etc. You cannot generalise with accuracy if you see what I mean.

Having said that the most common situation is that a true sealed (i.e. AGM, VRLA, SLA, AGR and possibly other acronyms) battery will be damaged by the sort of voltage that a multi stage charger will apply to flooded batteries. Most sealed batteries will lose electrolyte if you go above 14.2V for any length of time. 14.4V that you mention will be for a limited time recharge; don't leave it on that for days, just hours.

However if you are using a single voltage charger (float charger) AGM batteries will in general need a slightly higher voltage then open batteries because the recombination reaction can cope and stop electrolyte loss up to 13.8V or in some cases 14V. Because sealed batteries in general have higher specific gravity than open batteries, most will not recharge satisfactorily below 13.8V however long you give them.

If you mean "sealed maintenance free" as opposed to SLA then these are just normal batteries with the vents covered. Treat them like open batteries but find out how to top them up, very often you just peel off a label and the vent cover is below.

No you can't use a resistor as you suggest because fully charged the SLA battery will take very little floating current and so the voltage drop in the resistor will be negligible. You could use a diode, that is reasonably successful and some commercial chargers do that to lower one output. It might work quite well with the figures you give.

BTW 14.8V is fairly fierce even for open batteries, particularly if they are lead antimony as most European ones are, and will lead to more water loss. 14.5V is a more common recommendation. 14.8V is more for lead calcium which is an alloy used more commonly in US batteries.

You will find quite widely varying ideas from different charger manufacturers. It is much safer to go by what the battery manufacturer says.

 

[VicS]

This is a 3 year old thread you are replying to!

 

[Plevier]

Oops! Bumped up by ethanhunt's new post!

 

[Pye_End]

BTW 14.8V is fairly fierce even for open batteries, particularly if they are lead antimony as most European ones are, and will lead to more water loss. 14.5V is a more common recommendation. 14.8V is more for lead calcium which is an alloy used more commonly in US batteries.

Mr Sterling suggest 14.8v boost for open lead acid, and a 15.1v boost for lead calcium.

 

[Plevier]

Mr Sterling suggest 14.8v boost for open lead acid, and a 15.1v boost for lead calcium.

So are you assuming "open" means "antimony"? And what about sealed? Very unclear.

My charger (CRISTEC, standard fitting on a Jeanneau) says 14.5V boost for antimony, 15.4V boost for calcium. (Presumably flooded not sealed - doesn't say.)

Can't both be right. Maybe neither is. Maybe each is right sometime.

Take your pick - or listen to the battery manufacturer.

Of course lots of people don't know if they have got antimony or calcium. No easy way to tell. A very few batteries have neither. Also the antimony content can vary from ca 1% to as much as 8%, I don't think you see more than that these days, and that makes quite a difference. High antimony gasses more at a lower voltage. Other alloying elements such as tin and silver also have an effect.

There is no one right answer.

 

[DaveS]

Last night I forgot to take out my battery for charging and this morning it was totally discharge and when I tried to charge then it gave me a minor shock of current. I don’t know how the current leads to flow in the battery because it was totally discharge. Does the discharge battery too have some leading power for some run ups?

lead answer @ leading way

You are replying to an old thread (2008) with what appears to be an unrelated query.

I cannot understand your post. I initially thought that English is maybe not your first language, but your signature link implies that you are in, or at least connected with, the USA, so meaningful communication should be possible. If you could re-phrase your query so that it is understandable, preferably as a new thread, then I am sure you will get help.

 

[Barry Jones]

or spam intended to draw you to the link at the bottom ??

 

[Pye_End]

So are you assuming "open" means "antimony"? And what about sealed? Very unclear.

14.4 for sealed.

Float charge also different for each type.

 

[DaveS]

or spam intended to draw you to the link at the bottom ??

I did consider that, but decided to, at least provisionally, give him / her the benefit of the doubt. His / her only other post is equally carelessly written, but just might be genuine. I also admit to being intrigued by a post that started off sounding like a genuine question before deteriorating to apparent nonsense!

The link is to a marketing outfit offering data handling services, so it's not obvious how spam posts to a sailing site would help them.

OTOH if there's no sensible response to my reply and he/she posts more garbled rubbish then I will certainly report it to the mods as suspected spam.

 

[vyv_cox]

Plenty of people in USA don't have English as their first language.

I suspect the poster didn't actually receive an electric shock at all, 12 volts is considered to be perfectly safe. Maybe some sort of nerve activity. Unless this is a gasoline engine and he touched the live coil or spark plug lead, in which case even a discharged battery might hold enough charge to give a shock.