flex max 80 setting . what are end amps?

offgridcabin2015

i have 12 rolls  445ah in paralell , that's  13335ah. with the flexmax 80 charge conroller. It has setting called end amps
i assume i tell it to stop charging once it reaching a set number?

i'm uncetain as to what i set this number to be at. 

I think i recall 100ah is a 2 setting , i dont' want to mess this up.

Can someone explain the setting and it's importance to me . (lost with this part)

Thankyou experts

mike95490

offgridcabin2015 said:

i have 12 rolls  445ah in paralell ,.....

I'm sorry.   That's a VERY difficult configuration to get working properly.  2 or 3 cells in parallel are workable.  12 in parallel
nearly impossible, without using heavy buss bars and measured cables

The battery end amps setting, if I recall, might be about 10% of the C rating of the battery bank. 
That amperage is far beyond the capacity of your small 80ah charger.

A 13335ah would NEED to have a 150A charger as a minimum to keep the battery healthy.

I think a design review is in order before you buy anything more.

offgridcabin2015

i have made a mistake on the numbers . 445x3 is 1335. 

Vic

Hi ogc..,

OK, so assume that you have three strings of 6 v batteries, in parallel in a 24 V system?

These are Flooded Lead Acid (FLA) batteries ?

For the FLAs here, the EA setting is about 1.2 % of actual 20 hour Capacity.

You might try beginning with about 20 Amps for EA.

Unless your system uses a separate Shunt in the battery negative lead, with the FNDC accessory, the FM80 will not be able to use actual battery charging current  --  the FM80 will be using its internal shunt, which is the sum of the battery charge current, plus the current that the loads on the inverter rerpresent at your battery voltage.

Without the shunt and FNDC,  trying to use EA, might not work well for you, unless the loads on the system are fairly repeatable, and consistent, at the time that the Absorb stage would generally need to end.

Also, on the systems here with FLAs, the external shunt measurement of battery charge current varies quite a bit, at the proper point of Absorb end,  depending on the Depth Of Discharge that the battery experienced, in its previous discharge.  If this DOD, is also fairly consistent,  this apparent variation in the needed EA should not be too large of an issue.

A good way to try to find a good starting point for the EA setting, is to set a  L O  N   G  Absorb time, and watch the battery charge current diminish, during Absorb.  When this current stops descending, this current is a good EA setting to begin with.

Later, just IMO,  Vic