Replacing my outdated battery charger. One starter bank, an one house bank. What amp size are you currently using??
battery charger amp size
- Thread starter b crites
- Start date
What size are each of the banks, in terms of amp hour capacity, and what type are they (flooded,gel, or AGM)?
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,818
BC... Interestng question but not sure it will give you much information.
It is like saying, I have a car and it has 4 wheels, What size truck do you have?
Are you just surveying battery chargers? You will need to share more info to get a responsive answer.
How do you use the boat? How big are the batteries (amp hours)? What type of batteries? Just to start.
It is like saying, I have a car and it has 4 wheels, What size truck do you have?
Are you just surveying battery chargers? You will need to share more info to get a responsive answer.
How do you use the boat? How big are the batteries (amp hours)? What type of batteries? Just to start.
I would go with at LEAST the rated capacity being 20% of the house bank total.
Depending on the charger and place of installation (ventilation), the actual amps you'll see will automatically be derated because of internal unit heat. Our 130 Amp Xantex only put-out 60-65 Amps on a "great day"; and our current 200 Amp Mastervolt only puts-out a bit less than 140 Amps.
We have space for the inverter which doesn't give it as you might -- but it's the same story: DON'T BELIEVE THE LABEL on Amps. (It the same as stereo equipment's "Watts" of output.)
If you have AGM's or Gel Cels -- then i) you have the ability to recharge more quickly; and, ii) with AGM's, especially, you have the need to have a more sophisticated contorls and robust charging capacity to get the most out of the batteries.
As others have said, to answer the question, you need to better describe what, where, and how the rest of "your package" is about. Other than knowing you (may) have a Hunter 34, we know little about your needs, uses, or or equipment.
It's kind of like saying, how much horsepower is best?
Depending on the charger and place of installation (ventilation), the actual amps you'll see will automatically be derated because of internal unit heat. Our 130 Amp Xantex only put-out 60-65 Amps on a "great day"; and our current 200 Amp Mastervolt only puts-out a bit less than 140 Amps.
We have space for the inverter which doesn't give it as you might -- but it's the same story: DON'T BELIEVE THE LABEL on Amps. (It the same as stereo equipment's "Watts" of output.)
If you have AGM's or Gel Cels -- then i) you have the ability to recharge more quickly; and, ii) with AGM's, especially, you have the need to have a more sophisticated contorls and robust charging capacity to get the most out of the batteries.
As others have said, to answer the question, you need to better describe what, where, and how the rest of "your package" is about. Other than knowing you (may) have a Hunter 34, we know little about your needs, uses, or or equipment.
It's kind of like saying, how much horsepower is best?
A couple of links for you:
A previous thread on the topic -
https://forums.sailboatowners.com/index.php?threads/battery-charger-sizing.149329/
And Maine Sail's how to on charger selection and installation -
https://marinehowto.com/installing-a-marine-battery-charger/
A previous thread on the topic -
https://forums.sailboatowners.com/index.php?threads/battery-charger-sizing.149329/
And Maine Sail's how to on charger selection and installation -
https://marinehowto.com/installing-a-marine-battery-charger/
Purchased the following unit in 2003. Supports a 500 amp house and separate 80amp starter bank:
Electrical Specifications - Inverter
Output power (continuous) 2500 W
Surge power (AC amps) 62.5 A
Output frequency regulation 60 Hz, quartz regulated
Inverter voltage regulation 120 V +/-5% true RMS
Output wave form Modified sine wave
Efficiency (full load) 87%
Peak efficiency 93%
No load current draw (idle mode) 0.12 A
AC transfer switch 30 A
Electrical Specifications - Charger
Charge rate 130 A DC
AC input voltage range 90 − 130 VAC
Battery voltage (nominal) 12 VDC
Battery voltage range 10.0 − 15.5 VDC
Low battery cut-out 10.0 VDC
AC input (max. charge mode) 26 A AC
Bulk charge voltage 14.4 VDC
Float charge voltage 13.5 VDC
Equalize charge voltage 16.3 VDC
Battery charge outputs 3
Charge control 3-stage
Battery type settings Wet/Gel 1/Gel 2/AGM
Equalization Yes
Temperature sensitive charging Yes
General Specifications
Optimal operating temp. range 32°F − 104°F (0°C − 40°C)
*derated below 0°C and above 40°C
Optional remotes Freedom Basic Remote or Link instrumentation
Dimensions (H x W x L) 7.9 x 11.5 x 13.2” (201 x 292 x 335 mm)
I faced the same dilemma about 5 years ago. I have a 800 plus hour house banks and separate engine start batteries. My Heart Freedom unit (1998 vintage) wasn't putting out in real time, more than 60 amps (on a good day). I was told that Mastervolt could put-out 200AMP real output. Alas that isn't really so. NO one really puts out an inverter/charger that in the real world puts out its rated output.
Let me first say -- I really like the Mastervolt system. I'd buy it again. It has a number of elements (shunts, remote control, Combi unit, etc.) It's a true-sine unit. I believe you'd not likely be able to get 100 Amp charge in -- but I doubt you have a reasonable option for the 200 Amp charger (which I don't think you need, anyway).
IF your old Freedom unit works, I wouldn't replace it unless your charger doesn't provide a quick-enough charge-up for you. The modified sine wave inverter uses a lott less power on standby. If it hasn't caused you an difficulties with your use of the inverter, The Heart isn't quite as "smart" as the Mastervolt -- but it really seemed to work fine with our AGM batteries. I am careful not to recharge the batteries, not let them get too low if possible.
Let me first say -- I really like the Mastervolt system. I'd buy it again. It has a number of elements (shunts, remote control, Combi unit, etc.) It's a true-sine unit. I believe you'd not likely be able to get 100 Amp charge in -- but I doubt you have a reasonable option for the 200 Amp charger (which I don't think you need, anyway).
IF your old Freedom unit works, I wouldn't replace it unless your charger doesn't provide a quick-enough charge-up for you. The modified sine wave inverter uses a lott less power on standby. If it hasn't caused you an difficulties with your use of the inverter, The Heart isn't quite as "smart" as the Mastervolt -- but it really seemed to work fine with our AGM batteries. I am careful not to recharge the batteries, not let them get too low if possible.
This is not a dilemma. It is a choice.
These include sizing recommendations:
Wiring a new charger From Maine Sail:
http://forums.sailboatowners.com/in...ation-tips-considerations.136765/#post-880275 and
http://www.pbase.com/mainecruising/installing_a_marine_battery_charger
Sorry, just noted that David had previously posted one of these. Good stuff...
These include sizing recommendations:
Wiring a new charger From Maine Sail:
http://forums.sailboatowners.com/in...ation-tips-considerations.136765/#post-880275 and
http://www.pbase.com/mainecruising/installing_a_marine_battery_charger
Sorry, just noted that David had previously posted one of these. Good stuff...
Just cut and paste, you know. Had trouble finding our particular unit...Freedom 2512. Well, the rest, easy peasy Japaneasy.
The question is "what are you using?". When our 30A OEM charger took a dive we went to a 20A smart charger which now charges our batteries around 20% faster. Obviously no charger description would be complete without the specs of the bank(s) it serves. We have two group27 wet cell batteries for a total of 210 a/h for house and starter duties. We complement the small bank with a generator and it serves all of our coastal cruising needs.
+1 to DL. The West book says flooded batteries can use 25% of the battery rating if you must charge ASAP, but normally, 10% is the guideline. My B323 came with 2 batteries and a 20 amp Xantrex charger. I found a good buy at Bacons on an almost new 40 amp Xantrex when I went to a 3X31 battery system. I overlooked changing the 25 amp charger-to-battery fuses, and all three were blown when I got to my destination's shore power. Lucky there was a West in Rock Hall, so got the bigger (50?) fuses TO HANDLE THE 40 AMP CHARGER and all has been okay..
Depends on your battery chemistry. AGM's (and lithium) batts can take massive current and you might like getting your batteries back up to full capacity fast especially if you have a big batt bank. In my case I went big (100A) because there are times when I charge off my genset, my bank can accept way more than 100A and who wants to listen to that thing all night?
The load that the batteries will see are whatever the charger is putting out -- less then the current draw from your onboard systems.
I'd be interested to hear what you're getting out of your inverter/charger. i.e., what is rated at in the catalog (60, 100, 130, 200 or whatever) and what's actually getting to a discharged set of batteries actually -- that's after the unit has settled-down and heated-up to operating temps. It's my experience that larger, built-in charger/inverterts initially start at their "listed" capacity, but then (as they heat-up) the internally tune-down to a much lower real world output.
I wouldn't worry about having too much power for a smart inverter/charger if you have space and money for it.
I'd be interested to hear what you're getting out of your inverter/charger. i.e., what is rated at in the catalog (60, 100, 130, 200 or whatever) and what's actually getting to a discharged set of batteries actually -- that's after the unit has settled-down and heated-up to operating temps. It's my experience that larger, built-in charger/inverterts initially start at their "listed" capacity, but then (as they heat-up) the internally tune-down to a much lower real world output.
I wouldn't worry about having too much power for a smart inverter/charger if you have space and money for it.
This occurs because as a battery becomes more fully charged the internal resistance increases and the battery can accept less current. Excess current is converted to heat energy, which reduces the ability of the battery to accept a high charge current. Smart temperature compensated charges account for this and reduce the current and voltage accordingly. Its all based on Ohm's law. See some of the earlier referenced posts by Maine Sail for a more detailed explanation.
The 10% recommendation made earlier is for flooded lead acid batteries. Other battery chemistries may require or accept different charge rates. I use a 50 amp Promariner charger for the 460 amphour bank on my boat.
This occurs because as a battery becomes more fully charged the internal resistance increases and the battery can accept less current. Excess current is converted to heat energy, which reduces the ability of the battery to accept a high charge current. Smart temperature compensated charges account for this and reduce the current and voltage accordingly. Its all based on Ohm's law.
That's true at some point, but it's not material in the case where the battery bank will take the amperage, but the charger just can't put it out. In those cases you would like to have more charging capacity.
I'm speaking from experience with and over 800 AH main bank. I have had temperature sensors on the banks for 30 years on our last two boats.
The issue isn't the ability of the batteries to accept charge when you need the juice -- it is later in the charge cycles (when you might prefer to be charging at higher voltages, but that's a different story). The acceptance limits ramp down as the batteries move up closer to full capacity (depending on sulfatation, which might reduce their capacity to accept charge).
An example -- If you're charging in "bulk mode" at 14.4 Volts, your batteries might only accept 3 amps if they are 97% full. But at 80%, they would accept (in my case 120 amps of total real charge into the house bank. Same temperature for the batteries. (Right now in Maine, my batteries are at 63 degrees F -- if I'm filling them with juice, they might cycle to 69 degrees, and them come back down as they get through their bulk phase.
That's true at some point, but it's not material in the case where the battery bank will take the amperage, but the charger just can't put it out. In those cases you would like to have more charging capacity.
I'm speaking from experience with and over 800 AH main bank. I have had temperature sensors on the banks for 30 years on our last two boats.
The issue isn't the ability of the batteries to accept charge when you need the juice -- it is later in the charge cycles (when you might prefer to be charging at higher voltages, but that's a different story). The acceptance limits ramp down as the batteries move up closer to full capacity (depending on sulfatation, which might reduce their capacity to accept charge).
An example -- If you're charging in "bulk mode" at 14.4 Volts, your batteries might only accept 3 amps if they are 97% full. But at 80%, they would accept (in my case 120 amps of total real charge into the house bank. Same temperature for the batteries. (Right now in Maine, my batteries are at 63 degrees F -- if I'm filling them with juice, they might cycle to 69 degrees, and them come back down as they get through their bulk phase.
I installed a 30 amp Sterling Pro Charge Ultra (same build as Promariner ProNautic) for my 200 ah lead acid house bank (2 grp 27's) and separate start batt (auxiliary). So far, so good. I considered the 20 A model to be suitable but they are the same case and size. For a few extra dollars, I think the upgrade made sense.