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Multi Stage Battery Charging Odd Application

cornbinder89

Registered
Ok bare with me here.
I have deep cycle battery banks on my semi's, and find the need to use multi stage charging to get the most out of the cells and to make them last.
At 1st blush, it would seam one of the multi-stage regulators from Balmar or Sterling might fit the ticket. But some info I am getting say not so, I guess these regulators are designed to work and charge a battery bank that is not in use, that is to say, there are no loads on the system while charging is taking place so the processors can determine what charge rate (Bulk, absorption, or float) is needed. With a load on the system, it seams it may remain in bulk with its higher voltage setting, defeating the whole purpose of the multi stage system.
Right now I am using the stock automotive style voltage regulator, and if set to a point that does the best in cold weather, overcharges is warm, if set for warm, under charges and take too long to charge in cold weather.
For a while I was running different hot and cold weather setting on the voltage reg, but this is neither practical nor effective as weather can change from day to day.
Does anyone have any experience with these multi stage regulators?
Sterling suggested I isolate the batteries and charge separate from the running load which is neither practical, nor seam like a good idea to have an automotive alternator without a battery to stabilize the output.
None of the trucks have starting batteries they are either air start or use a supercapacitor for cranking.
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
Re: Multi stage battery chargeing odd application

I assume that the proposed voltage regulator employs a shunt in order to enable it to monitor battery charge current?

If so, connect the loads between the generator and the shunt. That way the regulator will only monitor battery charge current, regardless of system load.

It is not strictly necessary to monitor battery current in order to achieve a full charge. The absorption stage can merely be set to an adequate length of time. Of course this is not as ideal.

I would not consider any regulator that does not employ a battery temperature sensor.
 

cornbinder89

Registered
Re: Multi stage battery chargeing odd application

Neither of these employ a shunt on the main feed, I believe they may use field current to reach a set voltage as a substitute. Both have battery temp monitor optional or included but not required.
The std automotive regulator uses neither and just hold to a set voltage.
The problem I see is any DC load will throw off any calculations, and separating the batteries and charging separately is not a viable option.
http://www.sterling-power-usa.com/ProReg-BW-waterproofalternatorregulator.aspx
http://www.balmar.net/multi-stage-regulators/
http://www.sterling-power-usa.com/SterlingPower12volt130ampalternatortobatterycharger.aspx
Links to the regulators and one to the alt to battery charger
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
Re: Multi stage Battery Chargeing Odd Application

Hmm, if they do not employ a means of determining charging current, then they would be tailoring the charge profile based on time and voltage alone. Load in addition to that of battery charging should not materially effect proper charging, only the required duration to reach full charge. The exciting current is going to vary over a wide range as generator speed varies, and so would not be a viable method of determining output current. Indeed I have a really nice inverter charger that does not pay attention to battery charging current as regards the charging profile. If I had DC loads on the system, it would simply take longer to reach the absorption stage. No harm otherwise.
 

cornbinder89

Registered
But with a continuous DC load, wouldn't it quickly pull the voltage down once it hit absorption and then go back to bulk? Result is it never really gets an absorption or float charge and oscillates between bulk and absorption?

Humm, thinking more about it, the charger may just "see" a larger battery bank so might work, like you say taking longer to reach float, and needing more current when it is in float. Since the alternator has the capacity to handle both (it is doing it now with a fixed voltage setting) it should have no problem maintaining whatever the voltage settings is in the charge profile.
I may have been over thinking or looking at it wrong, the alternator can provide 75 amps of current regardless if the reg is set for 14.6 (bulk) or 13.2 (float). So it comes down to what the reg uses to set the profile. I have a good ammeter on the truck (100-0-100) that has a 270 deg sweep, so can see down to 1.5 amps with reliability.
I guess it may come down to trying it and seeing how it responds.
May have to add the companion 270 deg sweep voltmeter until I know how the system works, the std voltmeter in the trucks are all but useless.
 
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Newoldstock

Registered
That make some marine regulators that charge and float to prevent overcharge.
That might be an option.

A battery isolator ( big diode or two ) that drops the voltage to a float level from the deep cycle batteries might work too.
It sounds like you have plenty of time to charge but no way to drop to a float.
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
These multi stage regulators that are intended to be used with automotive *alternators* are actually much simpler than they appear. They depend upon the inherent current limiting design of the *alternator* (which is also the reason alternators put out low current at low speed)

So they are essentially a dual voltage regulator with a timer and a batter temperature sensor.

They start out at the high voltage setting. If the battery is low and / or the load is otherwise high, the generator (alternator) cannot generate enough current to reach the voltage set point. The regulator is simply applying full field current. This is the Bulk stage.

When the current taken by the battery and the loads diminishes sufficiently that the higher voltage setting can be reached, you have now entered the Absorption stage. The regulator maintains this voltage and the timer starts running.

When the time runs out (usually user adjustable) the regulator switches to the lower voltage Float stage. It will remain there presumably until the engine is stopped and restarted.

Although they may have a number of user adjustable parameters, they're basic operation is nowhere near as complicated as it seems! :wave:
 

cornbinder89

Registered
That make some marine regulators that charge and float to prevent overcharge.
That might be an option.
Marine regs are what we are discussing here

---------- Post added at 01:44:35 PM ---------- Previous post was at 01:35:06 PM ----------

These multi stage regulators that are intended to be used with automotive *alternators* are actually much simpler than they appear. They depend upon the inherent current limiting design of the *alternator* (which is also the reason alternators put out low current at low speed)

So they are essentially a dual voltage regulator with a timer and a batter temperature sensor.

:
Yeah, I think I was "over thinking it" comparing it to Ferro-resonate and SCR controlled chargers I have dealt with before.
I think it is time to pay my money and see what happens. I have 3 trucks to do, so give one a good try before outfitting the rest.

The thing that threw me, was unlike most applications that use these, they are not being recharged when they are not being used, but they are permanently involved with the rest of the trucks systems.
I choose the Delco 25SI for chargeing because it is brushless, low output and can handle near 100% duty cycle.
I've tried others, and they all can't handle the duty cycle long term.
The 25 SI will give 55 amps or so at idle and reaches its 75 amp limit a few hundred RPM above that.
I'd rather a long slow charge than to have 160 or 180 amp unit try and recharge quicker.
I had a 160 amp Prestolite on it for awhile, and the reg would over heat and shut off at sustained high output.
The Delcos have given good service with few if any failures. The don't call them the "Gray Ghost" for nothing, they outlast the engine overhauls.

Thanks to all for their input
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
I would agree that longer and slower with heavy duty, conservatively rated equipment is generally going to be better, so long as the running time is sufficient to do the job.

You've got me curious about the type service these trucks are in. I am perpetually curious about these sorts of things. :brows:
 

gnucklehead

Subscriber
Last Subscription Date
07/13/2019
Any regulator with on-battery voltage and temperature monitoring should be an improvement.. Multistage regulators are great, but better suited for very long runs. Any real regulator/alternator pair should have no problem charging a battery while supporting a load :shrug: Personally, I like Balmar. I don't know big rig trucks, but I do know marine systems.
 
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cornbinder89

Registered
They are OTR semi tractors, I run between Iowa and north west, SLC, Montana etc.
Because of where I run, I don't often need air conditioning at night, so don't have a APU. I did build one years ago when I did heavy haul all over the US.
SO I have an Ammonia cycle "fridge" that will operate off 110, 12 volts or LP.
During the cooler weather I run it off LP at night and plugged into an inverter during the day, in warmer weather I run it exclusively off the inverter. I keep the 12 volt as a back up, as it doesn't have a thermostat on the 12 volt heater.
In cool weather I have an Espar (diesel fired coolant heater) that circulates thru the heater core and back to the block. I get 1st crack at the heat, and whats left goes to keep the engine warm. The Espar draw around 4 amps and another 5 amps for the (trucks) heater blower motor.
Most nights in the summer, up in Montana, I can get by with screens in the windows and a small "table" fan run off the inverter.
All these loads run between 10-12 hrs with the engine off, and then get a full 11-12 hrs of recharge time.
The truck with the biggest battery box has a 620 amp/hr pack.
The next one down has 540 amp/hr
Both these trucks have air start, so there is no need for any other battery other than the deep cycle bank
The last truck doesn't have room for an air start tank, or would have to have a custom one made, so for it I bought the Maxwell super capacitor I detailed elsewhere on the "stak". It has 465 amp/hr pack.

To be sure I have over spec'd the battery packs, I have run the Espar and heater continuously overnight ( most times I have to cycle the blower on and off to keep from getting to hot) in -19 deg weather and not run out of charge, and this was on the truck with the smallest pack.
What started me down the path of the multi staged regulators, was the battery pack would not return to full charge over the week. it would come close if I returned on Friday, had no loads on it over the weekend, and charged it all day Monday before loading it again Monday night.
I initially kept the voltage on the low side 13.8 volts, than tried 14.2, 14.4 and finely reaching 14.6 as the needed setting for them to fully recover.
From all I've read, 14.6-14.8 is acceptable for flooded lead acid for bulk charge, but needs to taper back for absorption, and further for float.
In the cold weather, 14.6 does fine for a single set regulator, but in warmer weather I notice the current taper to about 5 amps and after awhile start to climb back toward 7-10 amps and water consumption increases. All telling me that the voltage is too high for the temps.
That is what has lead me to look into these multi-staged regulators.
Aren't you sorry you asked?

---------- Post added at 03:10:35 PM ---------- Previous post was at 03:00:49 PM ----------

Any regulator with on-battery voltage and temperature monitoring should be an improvement.. Multistage regulators are great, but better suited for very long runs. Any real regulator/alternator pair should have no problem charging a battery while supporting a load :shrug: Personally, I like Balmar. I don't know big rig trucks, but I do know marine systems.
Balmar and Sterling (from the UK) seam to be it in terms of regulators.
I think I'll go with the Sterling as it can either control the positive or the negative to the field. The Delco's are set up to control the negative, and while not a big deal to change, why?
Interestingly Sterling claims you can leave the stock reg in place, set it to "float voltage" and parallel the Sterling reg with the OEM. It is why they make their unit function on either system. One of the advantages is if one of the regs fails, the other will keep it operating to some deg until repairs can be made.
I don't know, I've never tried to parallel reg before, I would think they would "fight" each other but the Tech rep say no?
 

gnucklehead

Subscriber
Last Subscription Date
07/13/2019
I think you are correct on the pos/neg field (type A vs type B circuit).. Combined internal and external regulator is possible. Balmar alternators have an internal regulator that somehow works with the external, but they are matched pair.. Maybe not so friendly to other equipment, so chalk one up for Sterling.

A good battery monitor might help keep track of your state of charge/discharge or take measurements after you turn off the engine, and just before starting her up. I still use 6V golf cart lead-acids on a home backup system so I have long periods to charge/float, but if you need to get more energy into a battery in a shorter period of time, true AGM batteries are the way to go. If you are charging at C/10, then it'll take roughly +/- 8 hours @ 50 Amps to charge your +/- 500Ah battery when down to 20% charge state... You don't want to let it discharge to less than 11.5 Volts.

I haven't been thinking DC systems in awhile, so thanks for stirring up the mush :crazy:
 

cornbinder89

Registered
From all I've read and know you really want to try and keep the discharge level to no more than 50% to get the best life out of stuff.
I'm either old school or cheap (which ever way you want to look at it) and am sticking with flooded cells, I think they are more forgiving of abuse/ mis applcation than other types.
I worked on Manlifts and forklifts that were battery powered, but all that stuff was charged after the work day had finished and used SCR controlled chargers with a "board" to control the rate/voltage.
I think I have enough time in for "proof of concept" on it, and with the single stage reg set at 14.6 it recharges in 1/2 a days running. Most nights don't deplete the bank anywhere near the 50% level, so run time is not so much an issue.
 

cornbinder89

Registered
naw, I have no capacity problem in the bank or the charging system, solar wouldn't be worth the trouble.
I know the military does that with their equipment, but not worth my trouble.
 

cornbinder89

Registered
Re: Multi stage Battery Chargeing Odd Application

Hmm, if they do not employ a means of determining charging current, then they would be tailoring the charge profile based on time and voltage alone. Load in addition to that of battery charging should not materially effect proper charging, only the required duration to reach full charge. The exciting current is going to vary over a wide range as generator speed varies, and so would not be a viable method of determining output current. Indeed I have a really nice inverter charger that does not pay attention to battery charging current as regards the charging profile. If I had DC loads on the system, it would simply take longer to reach the absorption stage. No harm otherwise.
Ok I read thru the paperwork that came with the reg. It uses an algorithm to set the time based on how long the battery take to go from start up of the engine to .3 volt below bulk charge voltage, the amount of time that takes determines how long the units timer runs for Bulk charge and how long on absorption before it goes to float. The longer it takes to get to that .3 volts less than reg setting, the longer the unit holds it at bulk charge voltage and the longer the absorption voltage before for going to float.
Given that, it sound as long as the truck loads are on in the start-up phase, they will be taken into account for the timer.
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
That is interesting. More sophisticated than my Trace Engineering inverter charger, which just has a user adjustable timer for absorption. I think it comes set for three hours. I suppose it doesn't really matter if it's longer than necessary, as long as it is long enough.

It would appear that other loads on your truck will lengthen the time spent at the higher voltage, but I don't see that that is really going to hurt anything. Might help to equalize the cells a bit.
 

cornbinder89

Registered
It will be a week or so before I get it installed and can report. I am using Delco 25SI's (gray ghost) that are semi-sealed, while not "explosion proof" all the diodes and regulator are in a sealed compartment, the cooling air runs over the compartment before going over the field and stator windings. I intend to keep it sealed, so need to fit some "feed thru's" in the case.
I will set the internal voltage regulator at float voltage 13.6 voltage and that will be the fail safe setting, the Sterling will set the bulk at 14.8 and absorption at 13.8-14.2.
 

cornbinder89

Registered
Did I say a week, more like a month or so.
Got it installed today and run long enough to hit the "timer" on the high charge voltage. So far so good, in a week or so should have it out on the road for a real test. I'll report back.
 
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