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Battery Charger with Generator


SWharton

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We are unhappy with how long it takes to charge our batteries when boondocking. We have a Magnum MS2000 and an Onan Gold 5000w generator. When we run the generator can I add an additional battery charger to speed up the charging? Any special charger needed?

 

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What youre saying is the converter doesnt charge fast enough correct ? What you need is a smart charger that will charge fast and then taper off as it gets full. By throwing another charger to it your converter will most likely shut itself off thinking the batteries are charged. Make sure your batteries dont get hot,warm is fine and keep an eye on the water levels. Im sure you know distilled water only.

 

Jim Spence

2000 Dodge 3500 1 ton QC 4x4 dually 5.9 diesel LB

BD exhaust brake, 6 spd manual trans

34CKTS Cedar Creek 5er, Trail-Air hitch

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3 hours ago, SWharton said:

We are unhappy with how long it takes to charge our batteries when boondocking. We have a Magnum MS2000 and an Onan Gold 5000w generator. When we run the generator can I add an additional battery charger to speed up the charging? Any special charger needed?

 

The Magnum MS2000 IS a 3 stage (actually 4 stage if you count the equalize stage) charger.  The charger is also rated at 100amps.  If memory serves me correctly you have about 400AH of battery.   Also you have AGM batteries.  You don't want to charge the batteries at more than a 100amp rate. So you don't want a second charger, unless it is solar.

About the charging time.  Some actual numbers from your process would give us something to work with.

I have a MS2000 inverter, although the vast majority of my charging comes from 650 watts of solar.

In general, these are some rough numbers from memory (all assuming 400AH of battery):

--  If you have discharged 25% you are down about 100AH

--  At that amount of discharge level the inverter will probably start charging at around 50-70amps.  After about 10-15 minutes of charging the amps will drop 10 or more amps.

--  At the end of an hour the charging amps will be quite a bit lower, maybe 20amps

--  At the end of 1.5 to 2 hours you will probably be at somewhere around 90% full, give or take 4-6%. and your charge amps will be down to less than 10, probably 6 ams.

--  To get to 100% full you will need to run the generator for 4-8 hours.

It would really help if you replicated my above description and provided your actual numbers taken from your battery monitor.  Be sure to start at batteries 100% full and the monitor AH reading at "zero".  Then let the batteries discharge 25-30% (70-75% full)

Once you start charging be sure to record from the battery monitor about every 10 minutes, the  % charged, battery voltage, AH's, amps going into the batteries.  Also, very important, before you start charging record the battery voltage.  When you record the voltage be sure to check the amps on the monitor to be sure you are discharging less than 2-4 amps.

I have more details to add later.  I have an appointment to go to. 
 

Al & Sharon
2006 Winnebago Journey 36G 
2020 Chevy Colorado Toad
San Antonio, TX

http://downtheroadaroundthebend.blogspot.com/

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Thanks all. We will be in winter quarters tomorrow but will experiment next week and get back.

FYI-or whoever-I am not getting any notifications of replies on several of my threads thought I have "notify me" checked.

Other threads are coming through but it seems the quantity is down........................Anyone else having problems..........

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Follow up on my reply to your other post.....

I suspect your batteries are never getting below 80-90% level and your Magnum is simply topping them off for you.  As Al indicated, the final charging stages are relatively low amps and it takes hours to "finish" a battery.   My Heart will do the same thing so I only bring them up to the 90-93 percent with the generator and then let solar finish them.  Even without the solar (trees, clouds, etc.) I only bring them up to the low 90% level and leave them be.

I think you would be doing yourself a great favor if you (one time only) disconnect the batteries in the morning and let them sit for thirty minutes and then put a multi-meter on them to see where they REALLY dropped to.

Lenp

Voltage Charge Remaining
12.66 100%
12.61 95%
12.57 90%
12.53 85%
12.49 80%
12.45 75%
12.41 70%
12.37 65%
12.33 60%
12.29 55%
12.25 50%
12.21 45%
12.17 40%
12.13 35%
12.09 30%
12.05 25%
12.02 20%
11.99 15%
11.96 10%
11.93 5%
11.9 0%

USN Retired
2002 Winnebago Ultimate Freedom

2012 F150 4x4

2018 Lincoln MKX

2019 HD Ultra Limited

 

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You mention getting a second charger to get a higher charge current.

I have seen comments that AGM will take a higher charging current than flooded cell batteries.  Personally I have never researched this info to understand just how much higher current the AGM will take.  I doubt that AGM would take a 50% or 100% higher charge rate w/o damage to the battery. 

The general rule I have gone by is charging at about 25% of the total battery capacity for flooded cell.  With about 200AH that would be about 50amps charging current.  The problem with trying to go to a charging current of 75amps or even 100amps is the heat.  In flooded cell that tends to boil off the water in the electrolyte.   In a sealed battery I'm not sure what affect the higher current will do.  I don't think the heat would be good for the battery. 

Al & Sharon
2006 Winnebago Journey 36G 
2020 Chevy Colorado Toad
San Antonio, TX

http://downtheroadaroundthebend.blogspot.com/

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