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Author Topic: Charger Charge Rate Settings  (Read 326 times)

bill dean

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Charger Charge Rate Settings
« on: November 04, 2017, 06:11:05 PM »
Those of you that are using an inverter/charger like a Magnum MMS1012 with 2 Trojan t-105 batteries what Charge Rate setting do you use? The above charger is a 50 amp charger. When dry camping with a generator I would think you would want to set the charge rate as high as you can so you can charge your batteries back without running your generator for 3 or 4 hours or more. I see Trojan recommends 10 to 13% of the 20hr Capacity, which would be 25 to 30 amps at the Bulk stage. Just wondering what everyone else does and how its working for you?

Larry N.

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Re: Charger Charge Rate Settings
« Reply #1 on: November 04, 2017, 08:50:00 PM »
I've never added or changed one out, so I've always left them set as they came when I bought the rig -- seems to work for me.

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so you can charge your batteries back without running your generator for 3 or 4 hours or more.

Careful that you don't set it higher than the batteries can handle. Those Trojans ( and most other RV batteries) are not Quick Charge-type units.
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John From Detroit

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Re: Charger Charge Rate Settings
« Reply #2 on: November 05, 2017, 07:19:13 AM »
Trojan recommends a fairly slow charge, around 25 amps for those batteries. However the maximum safe charge rate per other experts is between 60 and 70.

The slower charge rate means the batteries should last a bit longer (In years) but I do not know that the difference is prounced enough to matter.

Other battery makers, save for Lifeline AGM. and Xantrex all recommend 30% C/20 as the max charge rate. for those batteries that's about 66 amps.  But Trojan recommnds the slower charge

(Lifeline and ONLY lifeline, recommends a much faster charge for their AGM's but my chargers can't do it).
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Gary RV_Wizard

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Re: Charger Charge Rate Settings
« Reply #3 on: November 05, 2017, 08:07:50 AM »
Per the Magnum manual:

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Charge Rate:
This setting can be used to turn off the charger, or
limit the amount of current that the charger can use (leaving more
current available to power loads); or, to ensure small battery banks
are not overheated because of a charge rate that is too high.

Charge rate is expressed as a percentage of the total available charger amps, so the default 100% setting allows the charger to manage the actual amp rate up to the limits of its charging algorithm. That's where you should leave the rate setting unless you have some specific reason to limit the available amps. As you say, when charging from a genset, you want to let the charger do the max it can safely manage.

You should alter the Battery Amp Hrs setting to reflect your actual battery bank. Two 6v GC2 batteries will be in the 205-230 AH range, so set a value in that range or as close to it as allowed. If there is no setting in that range, choose the next highest value. The Magnum default setting is 400 AH and the RV manufacturer probably did not alter that.
« Last Edit: November 05, 2017, 08:09:22 AM by Gary RV_Wizard »
Gary
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Paul & Ann

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Re: Charger Charge Rate Settings
« Reply #4 on: November 05, 2017, 08:38:24 AM »
Trojan recommends a fairly slow charge, around 25 amps for those batteries. However the maximum safe charge rate per other experts is between 60 and 70.

The slower charge rate means the batteries should last a bit longer (In years) but I do not know that the difference is prounced enough to matter.

Other battery makers, save for Lifeline AGM. and Xantrex all recommend 30% C/20 as the max charge rate. for those batteries that's about 66 amps.  But Trojan recommnds the slower charge

(Lifeline and ONLY lifeline, recommends a much faster charge for their AGM's but my chargers can't do it).

Here is what Trojan says about charging its' batteries.

There are many types of chargers available today. They are usually rated by their start rate, the rate in amperes that the charger will supply at the beginning of the charge cycle. When selecting a charger, the charge rate should be between 10% and 13% of the battery’s 20-hour AH capacity. For example, a battery with a 20-hour capacity rating of 225 AH will use a charger rated between approximately 23 and 30 amps (for multiple battery charging use the AH rating of the entire bank)

Paul & Ann  Iowa
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http://stoughrvadventure.blogspot.com/

bill dean

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Re: Charger Charge Rate Settings
« Reply #5 on: November 05, 2017, 09:12:13 AM »
Per the Magnum manual:

Charge rate is expressed as a percentage of the total available charger amps, so the default 100% setting allows the charger to manage the actual amp rate up to the limits of its charging algorithm. That's where you should leave the rate setting unless you have some specific reason to limit the available amps. As you say, when charging from a genset, you want to let the charger do the max it can safely manage.

You should alter the Battery Amp Hrs setting to reflect your actual battery bank. Two 6v GC2 batteries will be in the 205-230 AH range, so set a value in that range or as close to it as allowed. If there is no setting in that range, choose the next highest value. The Magnum default setting is 400 AH and the RV manufacturer probably did not alter that.

This is true for the charger only, when you add in the Magnum Energy ME-RC50 Remote Control the charge rate is reduced to 80% by default which is still 40 amps. Of course with that remote you can change it to what ever you like. I have tried the 100% default valve of the magnum charger and see no over heating issue when putting 50 amps to the batteries. Of course its 30* degrees here and may be different when it warms back up. The charger is temperature compensated from the probe you attach to the battery. That in itself increase the voltage 3 or 4 volts

Gary RV_Wizard

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Re: Charger Charge Rate Settings
« Reply #6 on: November 05, 2017, 09:31:14 AM »
Note that the Charge Rate setting merely controls how many amps are available to the charging function. The charger's multi-stage, smart-charging algorithm still determines the actual amount to be applied.  The only reason for setting less than 100% is to prohibit the charger from using all the available power. 

You need have no concern about the MS-1012 overcharging your dual-6v batteries if the battery bank size parameter (in amp-hours) is reasonably close to reality. Probably not even if the AH setting is high, but closer is better.  With a 200 AH battery bank, the algorithm should never be using all the 50A max available anyway, even in bulk mode.
Gary
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bill dean

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Re: Charger Charge Rate Settings
« Reply #7 on: November 05, 2017, 10:22:57 AM »
Note that the Charge Rate setting merely controls how many amps are available to the charging function. The charger's multi-stage, smart-charging algorithm still determines the actual amount to be applied.  The only reason for setting less than 100% is to prohibit the charger from using all the available power. 

You need have no concern about the MS-1012 overcharging your dual-6v batteries if the battery bank size parameter (in amp-hours) is reasonably close to reality. Probably not even if the AH setting is high, but closer is better.  With a 200 AH battery bank, the algorithm should never be using all the 50A max available anyway, even in bulk mode.

Thanks Gary...I always questioned whether my setting are correct. The only one I had some concerns about was the charge rate, as Trojan seems to say or at least the way I interpreted it, you should charge between 25 and 30 amp on the t-105. This is how I have it set up now, the Absorb time 60 minutes (based on battery Amphrs Capacity 225), Absorption Voltage 14.8, Float Voltage 13.5, Equalization Voltage 15.5, Charge Rate is 60% but I think I will be putting this back to 100%.

Paul & Ann

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Re: Charger Charge Rate Settings
« Reply #8 on: November 05, 2017, 10:46:00 AM »
Thanks Gary...I always questioned whether my setting are correct. The only one I had some concerns about was the charge rate, as Trojan seems to say or at least the way I interpreted it, you should charge between 25 and 30 amp on the t-105. This is how I have it set up now, the Absorb time 60 minutes (based on battery Amphrs Capacity 225), Absorption Voltage 14.8, Float Voltage 13.5, Equalization Voltage 15.5, Charge Rate is 60% but I think I will be putting this back to 100%.

Here is an important line from my quote from Trojan.

"for multiple battery charging use the AH rating of the entire bank"

I read that to mean that if you have four Trojan T-105s in series parallel, you can charge then at twice the rate you could if you only had two T-105s in series.
Paul & Ann  Iowa
2005 Winnebago Voyage 38J
http://stoughrvadventure.blogspot.com/

John From Detroit

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Re: Charger Charge Rate Settings
« Reply #9 on: November 05, 2017, 05:39:54 PM »
Here is what Trojan says about charging its' batteries.

There are many types of chargers available today. They are usually rated by their start rate, the rate in amperes that the charger will supply at the beginning of the charge cycle. When selecting a charger, the charge rate should be between 10% and 13% of the battery’s 20-hour AH capacity. For example, a battery with a 20-hour capacity rating of 225 AH will use a charger rated between approximately 23 and 30 amps (for multiple battery charging use the AH rating of the entire bank)

Thanks paul. as I said around 25 amps ( I did know it was 10% but was rounding a bit to make the math easier) .... Like you, I have read the Trojan manual :) (Even if I don't have 'em)

Also read the Xantrex manual (I do have one of those. don't work, but I have one)
Nothing adds excitement like something that is none of your business
My Home is where I park it.

QZ

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Re: Charger Charge Rate Settings
« Reply #10 on: November 05, 2017, 06:10:30 PM »
I was charging four GC2 at up to 70 amps with a combination of converter and power supply when I ran on generator only.

bill dean

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Re: Charger Charge Rate Settings
« Reply #11 on: November 05, 2017, 09:47:39 PM »
Here is an important line from my quote from Trojan.

"for multiple battery charging use the AH rating of the entire bank"

I read that to mean that if you have four Trojan T-105s in series parallel, you can charge then at twice the rate you could if you only had two T-105s in series.

That would be my understanding also. 2 t-105's =25 to 30 amps and 4 would equal 50 to 60 amps

Paul & Ann

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Re: Charger Charge Rate Settings
« Reply #12 on: November 05, 2017, 09:54:19 PM »
 :))
Paul & Ann  Iowa
2005 Winnebago Voyage 38J
http://stoughrvadventure.blogspot.com/

Gary RV_Wizard

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Re: Charger Charge Rate Settings
« Reply #13 on: November 06, 2017, 05:23:59 AM »
The Trojan advice (which is pretty much the same as all battery manufacturers) doesn't take into account how smart the charger is, simply because they have no idea what charger you may be using.  Most any decent quality multi-stage smart charger will monitor the battery voltage and amp acceptance and adjust the charge amps accordingly, so no need for concern about amp rate or over-charging. Single stage chargers, though, begin at some initial high amp rate and then let it taper off.

The Charge Rate parameter on the Magnum (and Xantrex too) is poorly named and not the same "rate" that Trojan is talking about. It is actually the Charge Proportion, i.e. the part of the total power that is available for use by the charging function.  That's why it is expressed as a percentage rather than an amp limit. It is used with converter/chargers, where the total power available is applied to two functions:
1. Power direct to the 12v distribution bus
2. Power to the battery charger

The Charge Rate determines how much of the total is available for use by the charger. The rest is reserved for direct power to the bus. Limiting it to, say, 60% restricts how much charging can be done, but is not necessary in the vast majority of situations.  The Magnum's charge algorithm is smart enough to understand and implement the C/10 optimum charge recommendation and will avoid excessive amp rates.

Using a rate of 100% allows the charger to automatically adjust. In  Bill's case,a Charge Rate parameter of 60% still allows the charger up to 30A, so still [barely] enough to use for charging of a 225 AH battery bank.  A higher percentage gives the charger more flexibility and may allow a higher amp rate  for the first several minutes of charge when the battery bank is very low. However, the charger will quickly reduce the amp rate as the battery charge begins to build up.  That's the whole idea behind 3-stage charging.
« Last Edit: November 06, 2017, 05:32:42 AM by Gary RV_Wizard »
Gary
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Summers: Black Mountain, NC
Home: Ocala National Forest, FL

bill dean

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Re: Charger Charge Rate Settings
« Reply #14 on: November 06, 2017, 06:45:15 PM »
The Trojan advice (which is pretty much the same as all battery manufacturers) doesn't take into account how smart the charger is, simply because they have no idea what charger you may be using.  Most any decent quality multi-stage smart charger will monitor the battery voltage and amp acceptance and adjust the charge amps accordingly, so no need for concern about amp rate or over-charging. Single stage chargers, though, begin at some initial high amp rate and then let it taper off.

The Charge Rate parameter on the Magnum (and Xantrex too) is poorly named and not the same "rate" that Trojan is talking about. It is actually the Charge Proportion, i.e. the part of the total power that is available for use by the charging function.  That's why it is expressed as a percentage rather than an amp limit. It is used with converter/chargers, where the total power available is applied to two functions:
1. Power direct to the 12v distribution bus
2. Power to the battery charger

The Charge Rate determines how much of the total is available for use by the charger. The rest is reserved for direct power to the bus. Limiting it to, say, 60% restricts how much charging can be done, but is not necessary in the vast majority of situations.  The Magnum's charge algorithm is smart enough to understand and implement the C/10 optimum charge recommendation and will avoid excessive amp rates.

Using a rate of 100% allows the charger to automatically adjust. In  Bill's case,a Charge Rate parameter of 60% still allows the charger up to 30A, so still [barely] enough to use for charging of a 225 AH battery bank.  A higher percentage gives the charger more flexibility and may allow a higher amp rate  for the first several minutes of charge when the battery bank is very low. However, the charger will quickly reduce the amp rate as the battery charge begins to build up.  That's the whole idea behind 3-stage charging.

What I see happening with my Magnum charger durning the Bulk stage which last about 1 hour at a charge rate of 100% is this:
1. The voltage starts out low depending on how far the battery is discharged
2. The amps gradually ramp up, close to 48 amps after 5 or 10 minutes.
3. The amps stay high until the voltage reaches 14.8 to 15.2 volts (45min to a hour) then it goes into absorb mode and the amps start tapering back and the voltage stays constant at 15 to 15.2 volts for another hour. At this point the battery is 96 to 98% full. Next it goes into float mode.

At 60% Charge rate it does the same as above, but the bulk and absorb stage limits the amps to 27 and it takes about 3 1/2 hours to get the batteries up to 96%

 

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