killick
Well-Known Member
The altenator on my boat is charging at 14.9 volt.Is it to high? Thanks.
Battery charging voltage
- Thread starter killick
- Start date
pvb
Well-Known Member
Is that the voltage at the battery terminals? What sort of batteries?
killick
Well-Known Member
Battery charging
It is measured at the terminals of two fifty amp hour wet cell batteries.After charging the voltage went down to 13.2. After using a fan and radio for about an hour it went down to 12.6
It is measured at the terminals of two fifty amp hour wet cell batteries.After charging the voltage went down to 13.2. After using a fan and radio for about an hour it went down to 12.6
Gumpy
Well-Known Member
Provided the batteries are unsealed lead acids then its fine.
You will have to keep an eye on electrolyte levels especially if you are motoring for a long time.
The goodside is that you should get quick recharge times.
Richard10002
Well-Known Member
I charge my open lead acid at 15.1V. Since March I've checked the electrolyte monthly, and they've hardly needed any topping up. Bi-monthly would probably have been fine.
boatmike
Well-Known Member
It's often not considered that the condition of the batteries is a function of what voltage is seen at the terminals when charging but I believe it does have an effect. 14.9 is a bit high perhaps but not entirely exessive assuming lead acid batteries I would suggest. A key question is perhaps, "do the batteries hold a charge for a long period when off charge?" How old are they? I have often found fitting new batteries brings the charge rate down to expected limits compared with older "tired" batteries. Perhaps other more electrically educated forumites would suggest why?
Amulet
Well-Known Member
Probably not if the batteries are low and capable of taking "bulk" charge. Yes if they are nearly full. Nigel Calder's book explains it all in simple terms. It's all about the regulator, and how clever it is. It should ideally be sensitive to battery charge state and be worrying about the current it is stuffing in rather than the voltage until they are nearly charged. Once they are fully charged I'd be happy to see a float voltage of about 13.4.
Plevier
Well-Known Member
Float voltage is not much of a consideration for a sailing boat engine alternator as you will rarely run the engine for long enough.
You want a voltage that will give decent recharge rates without being high enough to be damaging if you do have an all day engine run.
14.2-14.4V is common (as on cars).
14.9 is high if getting to the battery (you haven't measured it before a diode splitter have you?) but unlikely to do real harm to the battery unless you motor for a very long time.
Can't guarantee all your electronics will be happy with it though.
You want a voltage that will give decent recharge rates without being high enough to be damaging if you do have an all day engine run.
14.2-14.4V is common (as on cars).
14.9 is high if getting to the battery (you haven't measured it before a diode splitter have you?) but unlikely to do real harm to the battery unless you motor for a very long time.
Can't guarantee all your electronics will be happy with it though.
pvb
Well-Known Member
Alternator regulators are generally incapable of dropping to a float voltage.
VicS
Well-Known Member
and from what I understand the fancy gizmos like Sterling's Digital advanced regulators drop to the internal regulator's setting as a "float"
pvb
Well-Known Member
Yes, they do.
sailinglegend420
Well-Known Member
I asked one of his retailers at the Boat Show for information of Sterling charging/float voltages on shorepower chargers and regulators, and they said they couldn't get the info out of Charles Sterling. Has anybody got anything in writing that shows charge/curve voltage for different stages - especially for sealed AGM batteries?
I was also told at the show that they had a problem with the regulators going back to Bulk voltage when a load was put on. I have downloaded a 2009 copy of their products brochure which clearly shows a new “Power pack” mode where current is available for domestic supplies - at float voltage. Was this a newish feature which would appear to solve the suggested problem of going back to bulk. If so what date was this introduced? If its an improvement why are they not promoting this feature now
I have emailed them today and am waiting for a reply.
Plevier
Well-Known Member
You can download instruction books that have curves and numbers in but they my be indicative rather than precise.
Georgio
Well-Known Member
I think the “Power pack” mode is only on the shorepower chargers, my Stirling smart charger does this. My Stirling alternator regulator does not appear to do this and will drop the volts down to a float charge of 13.somthing once the batts are mostly full - this only happends if the engine is running for some time or the batts were allready well charged on shorepower.
pvb
Well-Known Member
In that case, your alternator must be set to "13.somthing", as the Sterling alternator regulator can only increase the alternator voltage, not reduce it.
Richard10002
Well-Known Member
My Sterling inverter charger has 8 settings for Absorbtion Voltages and Float Voltage combinations, for a variety of battery types.
I use the setting for Open Lead Acid Calcium batteries, where Absorbtion is at 15.1V, and float at 13.6V.
Bulk charging raises the voltage to the above 15.1V at a constant 80A.
I think their latest chargers have a Custom setting where you can set your own values for Absorbtion and Float Voltages.
I use the setting for Open Lead Acid Calcium batteries, where Absorbtion is at 15.1V, and float at 13.6V.
Bulk charging raises the voltage to the above 15.1V at a constant 80A.
I think their latest chargers have a Custom setting where you can set your own values for Absorbtion and Float Voltages.
