Author Topic: Midnite Solar (KiD) vs SLA Battery terms - unsure how to set up the KiD  (Read 75 times)

pobox88

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Hi,

I have a 48V 464A US Battery bank. US Battery specifies bulk charge, absorb charge, float charge and equalize charge.

The KiD has setup parameters for absorb charge, float charge and equalize charge.

I am not 100% sure how I should set the KiD to charge my batteries. I have my system setup and all seems OK, but I'd like to confirm that I have
setup the KiD properly. My concern is the batteries make a distinction between bulk and absorb (and have different charge specs), while the KiD
only has absorb available.

Thanks all.
2 x KiD, 12 x REC 235W Ser./Par.
(installed as 2 identical systems)
Victron Multi 5000, 1 x Whizzbang, 1 x BMV702
US Battery (x16) Flooded 48V 464A bank

Westbranch

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In both the KID and the Classics BULK and ABSORB are the same value....  as you can only enter a value for ABSORB...

When the charge Controller starts to charge, the Volts will ramp up to the value ( for ABSORB) that you have set and then that is the max voltage for that stage of the charge... which goes until either the Absorb timer runs out or the End Amps value is met... then the FLOAT phase is entered...
To use End Amps you need a WhizBang jr ...
During the ABSORB phase the voltage is held steady and the amps drop. 
In Float phase the amps and voltage are held at a very low value (trickle charge)
CL647 asleep
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CL 29032 FW V.2126-NW2097-GP2133 175A E-Panel WBjr, 3Px4s 140W > 24V 900Ah AGM,
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pobox88

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Thanks heaps, I think I've got my head around my PV system.

I might tweak the charge voltage/amps values to get a more consistent charge from BOTH KiDs. And set the WBjr to use END-AMPS.

With the current values, the MASTER KiD is resting most of the day and only starts charging mid-afternoon, the SLAVE appears to be charging all day. My gut feeling
is that it might be related to the bulk/absorb 58.8V required by the battery specs, and the KiDs, under load, are pulling the PV voltage down below 58.8V.

2 x KiD, 12 x REC 235W Ser./Par.
(installed as 2 identical systems)
Victron Multi 5000, 1 x Whizzbang, 1 x BMV702
US Battery (x16) Flooded 48V 464A bank

tecnodave

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Pobox88,

I'm thinking that you do not have a high enough p.v. Input volts. If you are using 2 60 cell panels in series that might be your problem. I would be using series strings around 90 volts for a 48 volt battery system. That would be 3 panels in series for each string for 60 cell panels. My own systems use 72 cell panels and one panel in each string will produce about 35 volts which is to not enough to charge my Rolls Surette L-16's, which charge at 30.0 volts on absorb. Two in series produce about 70 volts at MPP , voltage should be 10-20 volts above charge voltage.

Balancing controllers (getting them to share load)  in parallel can be tricky, try going to "tweaks" in the menu and offsetting the battery voltage on the "lazy" kid that is not doing its share. Increase or decrease the voltage offset .1 volt at time to achieve a better load sharing between the controllers

David
#1 Classic 150 12 x Sharp NE-170, 2S6P, 24volt L-16 Rolls-Surette S-530, MS4024 & Cotek ,  C-40 dirv.cont. for hot water
#2 Classic 150 12 x Sharp NE-170, 2S6P, 24 volt L-16 Interstate,Brutus Inv.
#3 Kid/WBjr 2 Suntech 280 24v AGM 105 a.h. Exeltech Inv.
#4 Kid/WBjr 2 Suntech 280 12v AGM 105 a.h.