LA Batteries are not self regulating. What makes it appear that they are is charging them with a voltage regulated (or at least voltage-regulated) charging source. If you dont believe me, try charging a six cell LA Battery with a power supply set to 20V open circuit...
The datasheet which I found for the LT1083 describes it as a fixed voltage regulator.
However it does show an application where the output voltage is adjustable, but does not give detail to allow me to make calculations.
https://www.farnell.com/datasheets/1941079.pdf
And that regulated output had better not be more than 14V or the lead acid will be overcharged. Continuous float charge is even less, more like about 13.4V.Hi,
I think the only problem was that you said something like you could connect anything to the battery and it will take what it wants, which of course is not true. If you use a REGULATED voltage source then you might get away with it because as the battery charges the current comes down and so the battery does not overcharge.
And that regulated output had better not be more than 14V or the lead acid will be overcharged. Continuous float charge is even less, more like about 13.4V.
Just ask the battery makers. We designed the charging IC's that Chrysler and Ford use in their electrical systems. The current consensus is to use 14V for the system voltage for faster restore of charge. But for long term charging (float charge) it is less to reduce boil out. All you have to do is ask the battery makers, they supply exact values (per cell) for optimum charging.Hi,
I cant agree with that 14v quote because i have seen my battery in my older vehicle always undercharge at that voltage level, and that is why i had to bring it into the house periodically to charge it at a higher voltage. 14.2 was a little better though.
Just ask the battery makers. We designed the charging IC's that Chrysler and Ford use in their electrical systems. The current consensus is to use 14V for the system voltage for faster restore of charge. But for long term charging (float charge) it is less to reduce boil out. All you have to do is ask the battery makers, they supply exact values (per cell) for optimum charging.
And it definitely is not 15V for a six cell battery.
"The problem at 14v is that the internal resistance was too high so it would not draw much current at 14v, but at a higher voltage like 14.5v it would draw some current and then eventually the battery would charge and then take a better charge at the lower voltage of 14v."
Sounds like you are describing a battery which has been damaged or has sulphation or some other problem.
Maybe because they make the batteries and know how to charge them. Here are the manufacturer's specs for the lead acid batteries made by Scorpion about sustained charge:Hi,
Well this happened with two batteries, one new and one used. Once charged properly however, they both worked fine.
I dont believe the 14v spec i dont care what anybody says and wonder why they would say that anyway.
To answer your question about where the info I posted came from, one was from the web site of the Scorpion battery manufacturer and the other was from the Battery University article on charging lead acids.Hello again,
Well i am not sure what kind of battery that chart is for, or where it came from.
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So you see there is some variation and it doesnt matter what the battery manufacturer says
To answer your question about where the info I posted came from, one was from the web site of the Scorpion battery manufacturer and the other was from the Battery University article on charging lead acids.
As for:
" it doesnt matter what the battery manufacturer says "
It may not matter to you, it matters to me. I posted the info I did to keep people from screwing up their batteries by over charging them.
As for:
"Also keep in mind that battery manufacturers want to constantly sell batteries."
The one I just bought has a 96 month warranty so I doubt very seriously they are building the charging systems to intentionally kill the batteries.
"I cant help it if you dont agree with what is happening in the real world"
The real world is in my garage and the float charger I built 25 years ago to maintain the lead acid battery in my motorcycle has a voltage set point of 13.4V (exactly as stated by the battery maker) and I currently have eight years of use on the Scorpion battery I am running. That's real life. It's a sealed AGM type and if I had been stupid enough to over charge it, it would have been ruined years ago.
The info supplied by battery makers reflects testing of many thousands of batteries, not anecdotal one offs. That's why I follow their specs.
The charging information I posted are for new AGM lead acid batteries.Automotive starting battery makers started adding Calcium to their battery plates a few years ago. That increased the set-point charging voltage of the alternator voltage controller to progressively higher settings. For example, my 2015 Subaru has the ACU putting out ~14.6V, as does my 2004 GMC, while my old 1982 AMC Jeep sits at 13.95V. The tables that BH posted are likely for the older batteries with pure lead plates.
The charging information I posted are for new AGM lead acid batteries.
Here is the data for recommended continuous charging voltage from Exide who is probably the largest maker of car batteries in the USA. Note that this data is for calcium type.
**broken link removed**
This shows exactly why I said that for continuous charging, the set voltage should be 14V or less. The spec listed below is 13.5 - 13.8V. See the attached image, fourth and fifth columns. The only charge modes that use a higher set voltage are current limited/timed for short duration which means they do not apply to automotive use or continuous charging such as the OP of this thread was asking about.
Like I said: I go with the battery maker's data. You do what you want. If you think the maker publishes incorrect data, you can ignore it.
**broken link removed**View attachment 99133
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