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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: 06 Bill on May 19, 2011, 07:28:43 AM

Title: Battery Chargers
Post by: 06 Bill on May 19, 2011, 07:28:43 AM
I have 2 dumb 25 amp chargers that run fine on shore power. When I try to run them on the gen. they will
charge for a few minutes and then cut out, cool off, and come back on. This sequence continues as long as  they are
on the gen. One charger on each bank (coach & chassis). Gen. voltage 115- 120 under load.  Thanks in adv. 06 Bill

Title: Re: Battery Chargers
Post by: thomasinnv on May 19, 2011, 07:48:34 AM
what kind of genny? you might check the hertz output. should be 60 cycles.

Title: Re: Battery Chargers
Post by: zimtok on May 19, 2011, 07:54:47 AM
Might be a bad ground, or reverse polarity.

With a volt meter;
1. check the hot to neutral - should be 110-120vac
2. check the hot to ground - should be 110-120vac
3. check the neutral to ground - should be 0 vac

Are you trying to charge the same battery whether connected to the generator or shore power?
I had a bad battery that would cycle the overload of the battery charger.

Every battery charger I have works well plugged into the generator. I have a battery charger that keeps the generator battery charged anytime the generator is running or if I'm connected to shore power.


Title: Re: Battery Chargers
Post by: boogiethecat on May 19, 2011, 08:05:17 AM
What's your generator make and model, and KW rating, and what make and model are your chargers?
Depending on the technologies involved, they may simply not be compatible. I've seen this before...

For example, if your chargers are old ferroresonant units (VERY common for "dumb" chargers), and your generator is not frequency stabilized electronically, the combination could do exactly what you are experiencing.
  Ferroresonant chargers are exactly what their name implies... made of iron and tuned to be resonant to the power line.  They rely on receiving exactly 60hz to do their job properly, and if the frequency is even slightly off, their regulation capability effectively disappears.

There are other combinations that can also end in disaster, but this is my first guess.  The only fix would be to get a non-ferroresonant charger, or a new generator that has an electronic governor that nails 60hz exactly regardless the load.

Title: Re: Battery Chargers
Post by: 06 Bill on May 19, 2011, 08:13:36 AM
The chargers are connected to the same batts. whether on shore or gen. Voltage is 115-120 underload. According
to my meter it is at 59-60 cycles. Gen is Honda 2500 watts. Does the same thing with one or both chargers on.
Voltage is within 1-2 volts of shore power. 06 Bill

Title: Re: Battery Chargers
Post by: bs4104 on May 19, 2011, 08:30:11 AM
What if you use only one of the chargers at a time?? Does it also cycle?  Bruce

Title: Re: Battery Chargers
Post by: boogiethecat on May 19, 2011, 09:03:26 AM
If your honda generator is an EU style (inverter) then there's something else going on because EU gene's are electronically governed to exactly 60hz.
  But if it's a standard mechanically governed honda gen (and most are) I'd bet that's the problem.  "59-60"  isn't anywhere near close enough, it has to be 60.0 hz exactly for a ferroresonant to work properly.  If it's even slightly off, the resonant part of the charger that is tuned for exactly 60 hz cannot regulate as it's deisgned to do, and overheating/overcurrent at the output is not surprising.   The line voltage coming in makes absolutely no difference.

Measure the actual charging current while the chargers are on line and on gene- if this is the problem you'll see a big difference.