[RE-wrenches] Magnum Battery Charger Question

[Jason Lerner]

Hello Darryl,

Yes the battery charger is going to absorb for a full cycle then to  
float,  but the problem is the battery charger is set to 14.4, but the  
battery bank only gets to 13.8 for the absorb cycle then goes to  
float.  I unplugged the BTS thinking that was bringing the Voltage  
down,  but that did not change anything.  I tried changing the absorb  
voltage using the custom setting to 15.2 Volts to try to trick a  
higher voltage absorb but that did not help.  Specific Gravity shows  
appropriate for each cell.

I connected an external battery charger to the same battery bank and  
it charges just fine,  so my question is about the Magnum battery  
charger.
Thanks for your help,
Jason
On Sep 27, 2009, at 6:47 AM, Darryl Thayer wrote:

> I am a little confused, is it the batteries or the charger that is  
> giving you problems.  Perform a charge cycle and measure the charge  
> current and charge voltage.  Check the specific gravity, resting  
> voltage before starting, perhaps the charger is going to absorb  
> volts and droping to float?
> Just a thought
> Darryl
>
> --- On Sat, 9/26/09, robert ellison <reellison at gmail.com> wrote:
>
>> From: robert ellison <reellison at gmail.com>
>> Subject: Re: [RE-wrenches] Magnum Battery Charger Question
>> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
>> Date: Saturday, September 26, 2009, 10:11 PM
>> Have you deep cycled the batteries?
>> Normally you would be way below 12.7 when you had to use a
>> generator to charge,12.7 is fully charged for a 12 volt
>> pack.
>> .
>> Cycle them down to 10.5 to 11 volts or so a few times
>> and charge them back up.
>> See if it charges better when cycled.
>> What brand of batteries are these?
>>
>> The magnum chargers are great, and if shorted it goes
>> to 14.4 volts the charger is fine.
>>
>> Any chance you have bad connection somewhere? If you
>> have one try using a infared pyrometer to look for a warm
>> connection somewhere. But it has to be after you charge for
>> a while, give it time to heat up.
>>
>> Bob
>>
>>
>> On Sat, Sep 26, 2009 at 12:04 PM,
>> Jason Lerner <wapalco at rockisland.com>
>> wrote:
>>
>> Hello
>> All,
>>
>> Have a question on a Magnum 1212MM-AE.  The battery
>> charger will not get above 13.8 Volts.  The system worked
>> fine for the first three weeks with Voltage rising to 14.4
>> volts for the absorb cycle,  but now it will not.  The
>> battery size and type setting are correct,  and using the
>> "custom" charging profile set to 15 Volts does not
>> work.
>>
>>
>> We have tried unplugging the BTS,  while also making sure
>> the battery Voltage is below 12.7 when starting the
>> generator.  The remote control is attached and there is 35
>> amps going into the battery with a 2KW honda.  It will sit
>> at 13.8 Volts and do an absorb cycle for 2 hours and then go
>> into float.  There are 4 golf cart batteries in the system
>> and all cells check out good, no dead cells,  and
>> connection are all bright and tight. Turning the main DC
>> disconnect off while the gen is running shows 14.8 Volts at
>> the battery terminals of the inverter,  but the batteries
>> will not rise above 13.8.  Magnum says the battery charger
>> is fine since it goes up to 14.8 when the batteries are
>> disconnected, but that doesn't make for a very efficient
>> charger if it is not connected to the batteries......
>>
>>
>> I am not familiar with these chargers,  did I miss
>> something,  any ideas?
>> Thanks,
>>
>> Jason Lerner
>> Waldron Power and Light Co.
>> (888) 927-2526
>>
>>
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