Re: Multiple lead-acid charging

? "Palindrome" <me9@[EMAIL PROTECTED]
> ?????? ??? ?????? 
news:I4x5k.18708$3p2.17707@[EMAIL PROTECTED]
> eromlignod wrote:
>> Hi guys:
>>
>> I'm an ME and have run across an application where I need to charge
>> multiple lead-acid batteries connected in parallel.   The batteries
>> will discharge at near their maximum continuous current rate when in
>> use, but will be used relatively infrequently.  In other words, after
>> a discharge, they may have many hours, or even days, to recharge
>> before they're used again, so I don't need an aggressive charge rate.
>> They will always be charged and discharged together, as if they were
>> one large high-capacity, high-current battery.
>>
>> What is the best way to charge multiple batteries (say 10 or so)?  It
>> would be preferable to me to use off-the-shelf items and I would like
>> to use ordinary 120V power.  Could I use several individual chargers
>> in shunt?  Do they already make chargers for such an application?  Can
>> the batteries be used while they are charging, if necessary?
>>
>> Thanks for any help you can give me.
>
> The biggest set-up I have been responsible for had arrays of 6 Trojan 
> T125s in parallel, series connected to give 24v.
>
> No problem - other than getting scared stiff whenever I went near that
lot 
> ;)
>
> I always ensured that all the batteries that were to be connected in 
> parallel were brand new, unused and the same make, model and batch
number 
> and were individually fully charged before connecting up. I never added
a 
> battery in parallel with an existing array. I never replaced a single 
> battery but always the complete array it was a member of. All cells were

> checked weekly and equalisation used as necessary.
>
> The charger must be one designed for such a system - eg it must have
have 
> an equalisation setting.
>
> Yes they do make chargers especially for such applications.
>
> Yes, the battery manufacturer (and the charger manufacturer, Victron, 
> IIRC) were very helpful. Including helping design the wiring harnesses
and 
> circuit protection.
>
> That one ran off 240v power. I expect that there are 120v equivalents - 
> try a search on "inverter charger".
>
> It isn't something to take on without expert advice - there is one heck
of 
> a lot of power waiting to blast gallons of boiling acid all over you, if

> you get it wrong.. The battery room itself needs proper design in
regards 
> to ventilation and acid containment, if something does go wrong. The 
> batteries do need regular monitoring and easy access.
Yeah, when I was studying in Kozani, we visited the North Load
Distribution 
Centre (utility) and in the battery room of the UPS, they had special 
switches to avoid dangerous arcs, and even a specially designed bidet (!)
so 
that you could wash your eyes if they were contaminated with (sulphuric) 
acid.



-- 
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr