Re: Multiple lead-acid charging

This is getting far too complicated ......find yourself a forklift company 
with an old single or 2 stage charger for sale 12volts @[EMAIL PROTECTED]
 125amp with a 
simple gas timer. because of the paralell strings this will prove much 
better than the modern chargers with fault detection and back up timers
and 
will be a fraction of the price it will also accomodate equalising which
you 
will need because no matter how fancy the charger it will only see the
best 
voltage not the batteries that are lagging.

pat


"Palindrome" <me9@[EMAIL PROTECTED]
> wrote in message 
news:ZHJ6k.80874$tY4.69509@[EMAIL PROTECTED]
> Peter Bennett wrote:
>> On Thu, 19 Jun 2008 20:58:11 GMT, Palindrome <me9@[EMAIL PROTECTED]
> wrote:
>>
>> <much snippage>
>>
>>> A typical charger for *big* batteries will be a 3 stage charger.
>>>
>>> Here follows a typical explanation:
>>>
>>>
>>>
>>> Stage 1. (Bulk Charge)
>>> A soft start delay is activated on connection to the battery to
prevent 
>>> sparking, after which a controlled constant current of 0.6 Amps is fed

>>> into the battery to rapidly raise the terminal voltage to 2.41 volts
per 
>>> cell. The length of time taken to complete stage 1 will depend on 
>>> capacity of the battery and depth of discharge.
>>
>> Where do you get that 0.6 amps? - the charger will never get anywhere
>> at that rate.
>
> as in:
>
> "Note that this is from the description of a charger intended for 
> relatively small batteries. The 0.6A in stage 1 would take a very, very 
> long time to charge a big battery. For many intelligent chargers, this 
> very, very long time would be flagged as a fault condition - hence it is

> im****tant to get a charger rated for the AH of the batteries that are 
> being charged."
>
>
> Which you snipped from the very same post.
>
>>
>>
>> According to the Xantrex Trucharge 20/40 charger manual, in the "Bulk"
>> mode, the charger will deliver its rated current (20 or 40 amps for
>> these chargers) until the batteries reach 14.4 volts. The bulk mode
>> should get the battery to about 75% of full charge.  At this point,
>> the charger will switch to "Absorption mode", where the voltage is
>> held constant near the gassing voltage, and the charging current will
>> reduce as the battery approaches full charge.  Eventually the charger
>> enters "Float Charge mode", and reduces the voltage to 13.5 volts.
>> (all voltages are for a nominal 12 volt system)
>>
>
> Where did you get a 20/40 amp charger? - many of these will never charge

> the OP's battery array as his total AH is > than this size charger's 
> specification. The charger will sense that the bulk phase is taking too 
> long, will flag a fault and stop charging. It may easily not be able to 
> supply the current needed when equalisation mode is initiated..
>
> The im****tant thing is that the charger is matched to the OP's battery 
> array - which will determine whether a 0.6A, a 20 A or whatever, charger

> is needed.
>
> --
> Sue
>
>
>
>