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Charge Controllers and Clippers => The "Classic" charge controller => Topic started by: Narrowboat boy on June 24, 2020, 03:59:44 AM

Title: End Amps
Post by: Narrowboat boy on June 24, 2020, 03:59:44 AM
Hi All

I am setting up my system . I plan to use whizzbang jr end amps feature . The good folks at Victron have told me they use 4% for end amps for their 110 Ah deep cycle AGM which is 5.5A per battery I have 5 in parallel so that is an end amps of 22A correct ? This seems high to me can any one else verify ? What makes me think this is that victron uses 4 stage charging on their inverters etc where the absorb cycle seems to always end quite early and into what they call float but actually charging carries on until it drops into a 4 th resting cycle when the batteries are considered full . When I run my generator through the victron multiplus it seems to go to “float “ at about 11A and then to rest at about 5-6 amps this would tie in with 4% of a single battery rather than the whole bank .

Any thoughts ? Should end amps be 22A I which case given I am quite a light cycler we probably we never get an absorb cycle to speak of or 11A as observed or 5.5 A when it appears under victrons 4 stage charging the batteries are full

I am confused as you can tell

Simon
Title: Re: End Amps
Post by: boB on June 24, 2020, 12:53:05 PM

Simon, I would first, just install the WB Jr. and watch the amps you get after a couple of hours of Absorb stage charging and see what it turns out to be.

That will give you an idea if those figures were correct.  You will have time to change the ending-amps values.

So, to do that test, just don't use ending-amps to start with and just watch the amps from the WB Jr. over the next few hours.

Maybe mark down the battery voltage, WB Jr. amps readout versus time so you can make a quick graph of current and time for the Absorb cycle.
The Absorb time will want to be longer than expected to keep it in Absorb and from going to float charge just to make this measurement. 

Maybe set for 3 or 4 hours ?

Others here will chime in with their input I hope.
Title: Re: End Amps
Post by: mike90045 on June 24, 2020, 06:40:49 PM
5 AGM in parallel is a tough thing to keep balanced
Follow the ideas from this site:
http://www.smartgauge.co.uk/batt_con.html
  Good Luck
Title: Re: End Amps
Post by: Narrowboat boy on June 28, 2020, 05:38:24 AM
Thanks all ,

Bob will do just that thanks .

Mike , already done , unfortunately space restrictions on narrowboats mean most have multiple smaller Ah batteries but they are connected as article suggests to help balancing.

Regards
Simon
Title: Re: End Amps
Post by: australsolarier on June 30, 2020, 08:25:01 PM
mike,
victron have special devices for paralleling batteries. plus, i imagine each of the victron batteries has their own built in BMS. so there shouldn't be a problem in any case

besides paralleling lifepo4 batteries is heaps easier than lead acid.