Basic battery charging question

Can I charge 2 or more batteries simultaneously, connected in parallel?

(Assuming all batteries are the same type and approximately the same
age.)

-ted/2NO

Hi Ted,

I don't recommend it. I am not an expert, but it is my understanding that
slight differences in the batteries will cause one to get much more of the
current than the other.

Good Soaring,

Paul Remde

wrote in message
oups.com...
Can I charge 2 or more batteries simultaneously, connected in parallel?

(Assuming all batteries are the same type and approximately the same
age.)

-ted/2NO

How well it work will depend on the characteristics of the charger.
For a simple current limited, fixed voltage, charger they will both
reach full charge but probably not at the same time. If the charger
autoswitches to trickle mode when the first battery reaches the switch
over voltage it may take quite a bit longer, if ever, for the second
battery to get a full charge.

I think you'd be better off with separate chargers.

Andy

On the DG800 there are 4 batteries that are charged
all at once in place. They are not designed to be removed
for spearate charging.

At 15:06 07 October 2005,
wrote:
Can I charge 2 or more batteries simultaneously, connected
in parallel?

(Assuming all batteries are the same type and approximately
the same
age.)

-ted/2NO

Ted,



If they are SLA (sealed lead acid) batteries like the typical ones we
use (12v 7AH) the answer is yes. Parallel batteries tend to charge and
discharge based on their individual capacities. Some of the battery
charger people even show this as a "standard" configuration when they
could easily insist on separate chargers for each battery.



A quick Google search will reveal a fair bit of 'wisdom' on this matter.



CAVEAT: Do not charge NiMH or other chemistry batteries in parallel.



Larry





" wrote in message
oups.com:

Can I charge 2 or more batteries simultaneously, connected in parallel?

(Assuming all batteries are the same type and approximately the same
age.)

-ted/2NO

no......not with a common "smart charger" we would typically use for glider
batteries......
First off, the charger should be matched to the battery (within reason) to
achieve a good charge.too small a charger outputs will not bring the battery
fully up to capacity, too large a charger will charge too quickly and
overcharge the battery which is also bad (or worse)
the Typical "smart" charger made for these "re-chargeable" batteries is
different than your standard motorcycle/auto battery charger and will
"sense" the condition of the battery and then charge in 2 or 3
modes....typically bulk, fill and maintenance (float).....if you have 2
batteries, the charger will sense the condition of one.or both.and charge
one.....or both as if it were the better.or worse..of the two since it will
be reading an overall condition......or the better.or the worse of the
two...maybe over-simplified....but I think this should give you some idea
tim
Wings & Wheels
www.wingsandwheels.com


wrote in message
oups.com...
Can I charge 2 or more batteries simultaneously, connected in parallel?

(Assuming all batteries are the same type and approximately the same
age.)

-ted/2NO

Resist the temptation to try this in spite of the responses which indicate it's
ok IF you want to have batteries you can count on every time you soar.

Some of the manufacturers do make tail batteries or other onboard battery packs
which are 2-6 individual cells wired up in parallel. Although it may work, it's
an example of poor electrical engineering.




wrote:

Can I charge 2 or more batteries simultaneously, connected in parallel?

(Assuming all batteries are the same type and approximately the same
age.)

-ted/2NO

Not sure what you mean by a 6 volt cell so assume you mean a 6 volt
battery. The 2 individual 6 volt batteries are probably wired in
series which is perfectly good engineering. In fact that configuration
has a significant advantage over a single 12 volt battery. That is
that the batteries can be linked by a fuse that is, in effect, internal
to the battery and protects it from terminal shorts. I used that
configuration for years.

2 6 volt batteries in series will behave like one 12 volt battery as
far as charging is concerned. Only the packaging is different.

If you really meant parallel perhaps you could describe the
configuration in a bit more detail.

Andy

wrote:

Can I charge 2 or more batteries simultaneously, connected in parallel?

(Assuming all batteries are the same type and approximately the same
age.)

What situation prompted you to ask this question? A better answer can be
provided with that knowlege.


--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Eric:

My glider uses three 12V 7 amp/hr batteries. At least two, and usually
all three, have to be recharged after every flight. (One of the three
operates the transponder alone.) I often don't have the time to charge
each battery one at a time between flights on consecutive days. (And at
contests I will have 6, if not 9, batteries!) I wanted to find out if I
can charge them three at a time before I invested in two more chargers.

-ted/2NO