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Old 06-02-2017, 11:07 AM   #31
Senior Member

City: Casco Bay
Join Date: Feb 2016
Posts: 283
Over the years I spent many, many hours on the phone with the late Michael Frost, the engineer who designed the Balmar regulators. I was forced to do this because the folks at Balmar had a tough time answering the questions I often had. Michael was a great guy, passionate bout his designs, and he designed a very good feature packed voltage regulator that was, and by many respects still is, way ahead of its time compared to other commercially avaible voltage regulators.

If you want one that does transitions based on current or voltage, and you are an electrically minded open-source experimental type, contact Tomasonw who posted above, in this thread, or see his blog:

Arduino based Alternator Regulator

I have one of Al's regulators and unfortunately have not had enough time to begin testing and experimenting with it. Sorry Al I promise I will get to it..

A few quick points to consider...

#1 I cut open a lot of dead & murdered batteries. I have yet to see a quality AGM "dried out" by overcharging, even on trawlers that leave a dock with full batteries. What I do see however are piles and piles of chronically undercharged batteries. The undercharged batteries out number over-charged AGM's by about 99.9% to .1% in my market.

The last few percent of charging takes many hours. All the energy removed from a battery should ideally be returned, plus Coulombic efficiency losses, before transitioning to float, this is nearly impossible to time exactly with voltage only regulation. There are also numerous poorly designed shore based chargers that will pop back to a 2 hour or 4 hour "egg-timer" absorption when an on-board load kicks in. Still, I rarely see batteries die from over charging. Can it happen? Yes but it is almost always due to a non-regulation issue rather than regulated even if too high.

For example a Lifeline battery using "return amps at absorption voltage" (also often called tail-current) 100% SOC is considered 0.5% of Ah capacity at 14.4V (temp compensated). This means that until you see 0.5A on a 100Ah battery, at 14.4V, the battery is not "full"..

Manufacturers such as East Penn and Enersys/Odyssey want to see 0.3% of Ah capacity for 100% SOC using "return amps at absorption voltage".

In the marine industry we have been lulled into accepting 2% as "full" by Ah counting battery monitor makers. Unfortunately a tail current of 2% is not full and will not yield the full capacity of the battery but it is, for many cruisers, full enough so as not to waste fossil fuels pushing beyond that last 1.5% to 2% of tail current. Unfortunately regularly & repeatedly not returning this last 2% can lead to sulfation, more rapid capacity lost and PSOC walk down..

Even with lab grade equipment, in ideal conditions, meaning no premature floatulation, battery at 77F etc., when charging a slightly used Lifeline AGM (100Ah battery still delivering about 96% of capacity), it still takes about 5.5 hours at a .4C charge rate (40A for a 100Ah battery) from 50% SOC to 100% SOC. The last 4% takes the longest. If you dropped to float at 2% the time to full could easily be well in excess of 8-10+ hours depending upon where you set float voltage. Set it too low and it could take 14+ hours. As your batteries age and sulfate......

For example a 100Ah Lifeline charged from 50% SOC for 2 hours at .4C (40% of Ah capacity) can achieve approx 96% SOC in just two hours. This is tremendous! The remaining 4%, to get to 100% SOC, takes another 3.5 hours...! This is why batteries are rarely over charged because even a slight removal of capacity requires many hours to replenish.

#2 Adjusting the field transitions is, as some have discovered, tedious and time consuming and not always very accurate or reliable because your loads on the vessel are variable.

If you want to use field threshold transitions I would strongly urge a considerably higher float voltage than you use at the dock with an IC or shore charger. This will still allow your battery to remain slightly below gassing but still actually do some charging, if you're still dropping to float prematurely.

Unfortunately, with the highly litigious society we live in, most voltage regulated charge sources in the marine industry suffer from "premature floatulation". With premature floatulation the battery makers win & you lose cycle life. A float voltage somewhere in the 13.8V range to 14.2V range, for Lifeline's, is going to be a reasonable figure for an alternator regulators float setting. The lower the float voltage the longer charging will take.

I threw a used AGM battery in my wife's classic Mercedes a number of years ago. The Bosch alternator in this car pumps out 14.47V -14.49V steadily (Fluke 289 NIST Calibrated). That battery, despite being used when I threw it in there, now has over 70,000 miles on it...

Keep in mind that a marine alternators float voltage does not need to be the same as a continuous use shore chargers float setting, where it would floated indefinitely, because on an alternator it won't be floated indefinitely. Unless you are motoring across an ocean, non-stop, set your float high enough to "finish" charging the battery in a reasonable time, if you can't program your regulator to prevent premature floatulation...

#3 Balmar has a second temp sensor port on the MC-614. This can be *creatively used, with a dash switch and resistor, to simulate the batteries going over temp. I have only done this once when an owner insisted he was going to over charge his batteries. I did it, and it made him feel better. Flip the dash switch and the resistor on the battery temp sense circuit simulated an over-temp situation creating an artificial float type reduction in target voltage.

I have been bugging Balmar/CDI for a while to offer this as a piece of mind option. In my scribbled notes I think I may have used a 2.21K resistor but don't quote me on that one.. *If you don't have a good grasp of electrical work please don't try this on your own..

#4 You can also install a dash switch and interrupt the brown/ignition wire for the first 30 minutes or so from the dock (or depending upon planned motoring duration) then flip it back on and you're now well within your not exceeding your desired duration back to full from a high SOC.

#5 b1c and A1c are timers that run out the clock duration you set them for. Calculated bulk and calculated absorption can either extend these times or end after the clock for b1c or A1c run out. They work in relation to being able to maintain voltage set point for more than 2 seconds and if threshold has either been met or not.

#6 BV, AV & FV must be set 0.1V apart from one another. If you need to adjust down, such as for LFP batteries to 13.8V +/-, you need to work backwards meaning you drop FV first then AV then BV.

#7 The Balmar regulators essentially have two absorption stages. I understand why Michael called the constant voltage stage of b1C "bulk voltage" but it is not correct terminology for a constant voltage stage and he even admitted this to me. When he created these there was nothing else like it so it was named what it was. Sadly other manufactures have now followed this lead further muddying the waters. Sounds good for marketing purposes though...

Bulk charging is generally referred to as constant-current or CC. If we go by DIN definitions bulk is "I" as in IUoU charging..

I = Bulk-Constant Current-CC-Max Potential
Uo = Absorption-Constant Voltage-CV
U = Float-Constant Voltage-CV

When we apply this to alternators I tend to prefer to describe Bulk charging as a maximum potential. Unlike a charger the output of an alternator is governed by such parameters as RPM and temperature. In "bulk" an alternator regulator is producing the most it can (it's max potential) while increasing battery terminal voltage. In bulk, voltage is not held constant unless we improperly define "bulk". For an external regulator bulk just means it is driving the alt as hard as it can.

Having two absorption voltage stages or constant voltage stages; IUoUoU is actually a nice tool. For short duration run times you can set a higher short duration voltage, and pack more energy into the battery before turning off the motor or dropping down to a longer duration absorption voltage. I will sometimes program for 0.1V to 0.2V over battery makers suggested absorption voltage recommendation for 6-36 minutes +/- or so, depending upon application, battery type and how the alternator and vessel are used.

#8 Belt Manager or as it was previously called "Amp Manger" is a field reduction based on field potential. Field potential is essentially your battery voltage. Many folks assume a belt manager reduction of level 3 is an across the board 15% reduction of a 100A alternator making it an 85A alternator, but it's not. It is a 15% reduction in the maximum field output based on the available field voltage to the regulator.

Belt Manager is a great first line defense for keeping the alternator within a safe working temp range, on your boat, and not continually pushing the temp limit leading to an early demise of the alternator. Dialing this in, and setting up BM can be achieved by forcing the alt into bulk with an inverter and space heater while the running the vessel, with engine room closed, and a temp probe connected to alt, at cruise speed. Give it a good 40 minutes to 1 hour run at cruise speeds and monitor the alt temp remotely. If it pokes above the desired limit, dial it back another 5%. You then stop the boat and let the engine run at high idle, still under full load, and make sure temp does not creep up again (lower fan speeds at fast idle). If it does, dial BM back another 5%....

#9 If I recall correctly, in about 2012 Michael re-coded the regulator for improved alt temp sensing. For what it's worth there are more than 15,000 lines of code in an MC-614.. The new code allows the regulator to hone in on the maximum sweet spot the alt can work at for the environment. Every engine bay and demand is different and belt manager is really only first level protection. Alt temps sensing in conjunction with BM creates the ultimate insurance policy for long alternator life. I call this new coding Adaptive Alternator Temp Compensation or AATC. The Balmar marketing team has largely ignored this industry leading feature, but they should not.

When the optional alternator temp sensor is used the MC-614 will find the maximum output the alternator can safely run at, for the surrounding ambient temps, and the demand being placed on it. Other commercially available external regulators simply cut the alternators field by 50% or by 100%, when they are up on the temp limit. As such these regulators will ping-pong back and forth off the high temperature limit for as long as needed.

100% Output > Cut to 0% > Back to 100% > Cut to 0%, over & over


100% Output > Cut to 50% > Back to 100% > Cut to 50%, over and over

This antiquated method of temp sensing digs into an alternator performance and becomes very, very annoying. Heck Balmar's old 50% cut was annoying but the regs that drop to 0% are even worse. In contrast the MC-614's processor decreases the alternator filed in small increments (both down and up in 5% steps) until the optimum output is attained to maintain the temp at a safe level. As the alternator cools or accepted current drops off the output increases to maintain the highest output that is possible at all times. AATC means you're getting the fastest possible charging and the most out of your alternator as you can at all times. Most are completely unaware of this feature but it is a tremendous tool.

#10 The regulator B- wire or black wire in the Ford plug is the other half of the voltage sensing circuit. While the MC-614 gives you a dedicated non-current carrying positive volt sense lead it can only correct for half the drop... The Balmar manual is incorrect on the optimal location for the regulator B- wire. It needs to be connected to the battery bank negative terminal or your missing the negative side volt drop.

Alternators and Voltage Sensing

The Balmar regulators feature an "advanced programming" menu. Please do yourself a favor and use it.... The factory lawyer safe settings are just that "lawyer safe". They are far too conservative to maintain healthy batteries, and get the most cycle life out of them, in a PSOC use application.

#12 If you have a large bank and buy a 100A alternator please don't expect it to run at 100A in bulk. If you want or desire 100A as your design output in bulk, you buy a 120A to 140A alternator. This is especially true with any small case alternator. There is no small case alternator out there I have not seen cooked by continuous demand. I've also seen large frame "school bus" type alternators fried by continuous duty demand so even they benefit from belt manager.. The growth of LiFePO4 batteries has really exposed the myth of the continuous duty alternator output. The only way I know of to push an alt to full output, for long duration's, more than 45 minutes to an hour, is to remove the rectifier and rectify the alternator remotely. Bottom line if you expect 100A buy 120A+ and limit it with belt manager.. If you expect 150A buy 175A+ and limit it with belt manager. This will yield a good long service life.
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