Hi all,

As part of my electrical system upgrade, I intend replacing my existing 50A alternator with one that can maintain 100 - 150A continuously. The reason for this is to recharge my new 360AH AGM battery bank in a reasonable time (depending on depth of discharge of course, but say within an hour or so). Alternators from Balmar and others meet this criteria.

My problem though, is finding a truly 'smart' alternator regulator - that is, one that monitors the actual battery current and terminal voltage during the charging process.

There are plenty of so called fancy 'smart' regulators around but if they don't monitor the actual battery current and terminal voltage during the charging process, they are dumb - they are just guessing, or the software is being super conservative so as not to cause any damage to the battery.

So, does anyone know of a truly 'smart' regulator, one that charges batteries the way they should be charged?

regards to all,
allan

Useless answer: the Xantrex Link 2000-R, from p. 4 of the user manual:

"How the Link 2000-R charges:
...
Acceptance Cycle:
...
When the batteries have reached the acceptance voltage and the current is below 2%, the Acceptance Hold Cycle begins."

This is a useless answer though, as the Xantrex Link 2000-R was obsoleted by Xantrex and I do not know of any replacement of all the smart regulator and battery monitoring functions in one unit by any manufacturer.

I do not know of any other smart regulator that monitors charge current (the Xantrex Link 2000-R includes a shunt so that it can measure the charge current, up to 230 amps) and voltage (the Xantrex Link 2000-R also monitors alternator temperature).

The Balmar Max Charge MC-614 does not monitor the charging current (so another useless answer, maybe I should just give in and admit I'm stumped). It can monitor temperature, its fully programmable (it can charge a LPO battery), it can limit the alternator charging current (which is sometimes used to avoid burning out the alternator).

someday said..
Useless answer: the Xantrex Link 2000-R, from p. 4 of the user manual:

"How the Link 2000-R charges:
...
Acceptance Cycle:
...
When the batteries have reached the acceptance voltage and the current is below 2%, the Acceptance Hold Cycle begins."

This is a useless answer though, as the Xantrex Link 2000-R was obsoleted by Xantrex and I do not know of any replacement of all the smart regulator and battery monitoring functions in one unit by any manufacturer.

I do not know of any other smart regulator that monitors charge current (the Xantrex Link 2000-R includes a shunt so that it can measure the charge current, up to 230 amps) and voltage (the Xantrex Link 2000-R also monitors alternator temperature).

The Balmar Max Charge MC-614 does not monitor the charging current (so another useless answer, maybe I should just give in and admit I'm stumped). It can monitor temperature, its fully programmable (it can charge a LPO battery), it can limit the alternator charging current (which is sometimes used to avoid burning out the alternator).

Sorry to disappoint you with my answer Someday. I was really only telling Datawiz what I have on my boat and how I improved the output of the alternator to reduce charge time.

i suppose this is another useless answer.

someday said..
Useless answer: the Xantrex Link 2000-R, from p. 4 of the user manual:

"How the Link 2000-R charges:
...
Acceptance Cycle:
...
When the batteries have reached the acceptance voltage and the current is below 2%, the Acceptance Hold Cycle begins."

This is a useless answer though, as the Xantrex Link 2000-R was obsoleted by Xantrex and I do not know of any replacement of all the smart regulator and battery monitoring functions in one unit by any manufacturer.

I do not know of any other smart regulator that monitors charge current (the Xantrex Link 2000-R includes a shunt so that it can measure the charge current, up to 230 amps) and voltage (the Xantrex Link 2000-R also monitors alternator temperature).

The Balmar Max Charge MC-614 does not monitor the charging current (so another useless answer, maybe I should just give in and admit I'm stumped). It can monitor temperature, its fully programmable (it can charge a LPO battery), it can limit the alternator charging current (which is sometimes used to avoid burning out the alternator).

Hi someday,
Thanks for this post, you help substantiate what I found so far.
It seems that there's a lot of marketing hype out there, but inadequate adressing of the ideal requirements of battery charging and management.

Charging batteries is not rocket science, but to do it properly you need to know the net current into the battery (ie total input current less load current), true terminal voltage and internal temperature, but that means installing a current shunt, cabling for sensing terminal voltage and temperature sensor.
- seems too messy to deal with for alternator regulator manufacturers....

regards,
allan

Datawiz said..
Charging batteries is not rocket science, but to do it properly you need to know the net current into the battery (ie total input current less load current), true terminal voltage and internal temperature, but that means installing a current shunt, cabling for sensing terminal voltage and temperature sensor.
- seems too messy to deal with for alternator regulator manufacturers....

regards,
allan

whilst on first blush it seems like it should be straightforward to measure the state of charge of a battery, it's actually a very tricky business:

batteryuniversity.com/index.php/learn/article/how_to_measure_state_of_charge

for optimum charging, doesn't the charger need to be able to continuously work out the state of charge of the batteries?

All the charging systems I've heard about are based purely on voltage, and as far as I'm aware they do a pretty good job. All variations of:
* Bulk phase: Constant current at a rate determined by the battery capacity/chemistry, (typically in our situation though, as much current as the system can supply) until the Absorption Voltage is reached
* Absorption phase: Constant voltage (Vabs) for a predetermined interval. Although ideally the termination of this phase is based on the acceptance current dropping to a threshold value, it's usually based on how long it took to reach Vabs.
* Float phase: Drop back to a lower float voltage for indefinite maintenance.

Pretty sure I've seen systems where there is a second Absorption phase at a lower voltage.

I'm sure you'll find that most "smart" alternator regulators have facility for temperature monitoring, as thermal runaway is a dangerous condition. And most regulators will have dedicated sensing inputs that are meant to be connected directly to the battery terminals, to avoid the effect of voltage drop due to charging current.

I don't think it's possible to fully charge lead-acid chemistry in the sort of time you're talking about. The bulk phase gets you to something like 70% charged, but after that it's a slow process that can't be accelerated without damaging the battery. A corollary of this is that 150A alternator will only be outputting its full rate for a relatively short time.

If you want 100% charge in an hour or two, you need LiFePO4.

QLDCruiser said..
All the charging systems I've heard about are based purely on voltage, and as far as I'm aware they do a pretty good job. All variations of:
* Bulk phase: Constant current at a rate determined by the battery capacity/chemistry, (typically in our situation though, as much current as the system can supply) until the Absorption Voltage is reached
* Absorption phase: Constant voltage (Vabs) for a predetermined interval. Although ideally the termination of this phase is based on the acceptance current dropping to a threshold value, it's usually based on how long it took to reach Vabs.
* Float phase: Drop back to a lower float voltage for indefinite maintenance.

Pretty sure I've seen systems where there is a second Absorption phase at a lower voltage.

I'm sure you'll find that most "smart" alternator regulators have facility for temperature monitoring, as thermal runaway is a dangerous condition. And most regulators will have dedicated sensing inputs that are meant to be connected directly to the battery terminals, to avoid the effect of voltage drop due to charging current.

I don't think it's possible to fully charge lead-acid chemistry in the sort of time you're talking about. The bulk phase gets you to something like 70% charged, but after that it's a slow process that can't be accelerated without damaging the battery. A corollary of this is that 150A alternator will only be outputting its full rate for a relatively short time.

If you want 100% charge in an hour or two, you need LiFePO4.

Excellent input QLDcruiser...you put it better than my discarded attempts...

deepcyclebatterystore.com/how-to-maintain-batteries/

Can you please summarised ...
I do not quite follow.
-Led-acid batteries are for charging and discharging always
control by voltage. Monitoring current is meaningless.
Under discharge - voltage is proportion to capacity left.
When charging , the same thing.
-Nealy all alternators have build in smart charger controller ,
and you like to instal external controller to blast your
house bank with 100 amp. plus.

Any combination of sources is quite OK.
Each charging device has cut off voltage.
Current is simply added and there is no conflict
between sources.
Its tru that different charges might have different
cut off voltage but in real life who cares, because
as was mentioned last 10 % charge takes hours
becase the current is reduced to bare minimum.
Solar can take care of that bit of charge, if you really
won it, but check solar controller cut off or simply by- pass
and monitor voltage.
Sadly lot of articles are salesman b., create more confusion
into primitive led-acid bat.

Charriot said..
Can you please summarised ...
I do not quite follow.
-Led-acid batteries are for charging and discharging always
control by voltage. Monitoring current is meaningless.
Under discharge - voltage is proportion to capacity left.
When charging , the same thing.
-Nealy all alternators have build in smart charger controller ,
and you like to instal external controller to blast your
house bank with 100 amp. plus.

This is my understanding too. Modern alternators have a voltage sensing input and reduce charging current as the voltage approaches the (configured) maximum voltage or vice versa.

In the PV world, you can get high-end charge controllers that literally count Coloumbs of charge, but most commodity charge controllers just measure voltage, and reduce/increase charge rate accordingly.

Trek said..
Batteries are chemical reactions that need to be babied.

Each kind of battery is similar in that if you feed electrons into them you can get them out later. But they are different in how to get the most electrons into a battery in a given time without hurting them and how to tell how many are in one at any given time.

How many electrons are available in a lead acid or sealed lead acid battery can be estimated by the terminal voltage under or not under load and knowing the batteries temperature.The red yellow green gauge we all have seen.

Lithium batteries terminal voltage changes hardly at all between well charged and not, so you cant tell whats available from its voltage. The red yellow green gauge no work. Once its flat you need to count how many electrons you put into it (coulomb counting) to know how many you can take out like a bank balance.

So a smart alternator/charger that's any good must know what kind of battery is connected, what capacity it is, how many electrons are in already and what the ambient temperature is. If its lithium it needs a coulomb counter and counting start point. Fully flat is a good time to start counting coulombs in. Then the charger can put the right amount in for the exact moment. If it doesn't then it will be overcharging a charged battery or not charging a flat one enough. If its lead acid it needs to know so it wont boil a battery dry with overcharge or let one go dead by not charging enough.

Good to see an objective, knowledgeable analysis based on electronic principles - thanks Trek.

scruzin said..

Charriot said..
Can you please summarised ...
I do not quite follow.
-Led-acid batteries are for charging and discharging always
control by voltage. Monitoring current is meaningless.
Under discharge - voltage is proportion to capacity left.
When charging , the same thing.
-Nealy all alternators have build in smart charger controller ,
and you like to instal external controller to blast your
house bank with 100 amp. plus.

This is my understanding too. Modern alternators have a voltage sensing input and reduce charging current as the voltage approaches the (configured) maximum voltage or vice versa.

In the PV world, you can get high-end charge controllers that literally count Coloumbs of charge, but most commodity charge controllers just measure voltage, and reduce/increase charge rate accordingly.

And I should have clarified that I was referring to batteries with lead-acid chemistry, where voltage is proportional to state of charge.