'Multi Stage' chargers- wot's it mean??

Submitted: Thursday, Jun 17, 2010 at 10:53
ThreadID: 79421 Views:2651 Replies:4 FollowUps:0
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In laymans terms- what does 'Multi Stage' charging mean- in relation to battery chargers..
Our inbuilt charger (for charging the house batterys from shore power) is a 3-stage Leab 6A.
And the home charger is an EIGHT stage Ctek 15A.
Is this just another case of the 'numbers game'- as in the more numbers the better??
Thanks in advance

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Reply By: Mandrake's Solar Power- Thursday, Jun 17, 2010 at 11:22

Thursday, Jun 17, 2010 at 11:22
Signman ,

In the main you have the following stages -

BULK or BOOST to rapidly charge the battery to about 80-90% capacity .

FLOAT stage is next which lowers the Amps and takes the battery slowly upto 100% capacity .

Then there's ABSORPTION phase which flickers high Amp pulses to maintain the full battery ..

Some go to the next stage of being able to rapidly pulse high amps to help de-sulphate the battery .. ( a BIT LIKE THE ABSORPTION PHASE ! )

What happens in 5,6,7 and 8 stages - I know not !!


AnswerID: 421171

Reply By: Member - res.q.guy (Vic.) - Thursday, Jun 17, 2010 at 11:29

Thursday, Jun 17, 2010 at 11:29
Hi Signman
These may help explain:
CTEK 8 Stage
3 Stage Chargers
AnswerID: 421172

Reply By: Member - Andrew (QLD) - Thursday, Jun 17, 2010 at 11:36

Thursday, Jun 17, 2010 at 11:36
CTEK's 8 stage charging process:

In many ways just a numbers game as most are quite quick and/or never used.

Whether it is "noticably" better is subjective, though some of the information makes sense :)


AnswerID: 421173

Reply By: Battery Value Pty Ltd - Thursday, Jun 17, 2010 at 11:45

Thursday, Jun 17, 2010 at 11:45
Hello Signman,

multi stage means there is more than one charging voltage involved.

3 stage is the original (and still valid) charging algorithm for all VRLA batteries.

Stage one: bulk charging with maximum current and slowly rising voltage
Stage two: as soon as the terminal voltage has reached the (boost) charge voltage level, the charger then keeps this voltage constant until the current has tapered off to around 10% of max.
Stage three: charger reduces the terminal voltage to the float level.

Many intelligent chargers test the integrity of the battery before applying the maximum current.
This can involve pulsing and is often being (intentionally) misrepresented as 'desulphation' or similar.

For flooded batteries, there is also a fourth stage which is called equalisation.
This is done by overcharging the battery in a controlled fashion.

There you have it.
And yes, I agree they're certainly in the numbers game 'more of everything can only be better'...

Best regards, Peter

AnswerID: 421175

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