#140764  by MiriamNZ
 Sat May 19, 2018 3:33 pm
Neddy wrote:
Sat May 19, 2018 9:36 am
The device should be set to the Float voltage recommended by the battery manufacturer.

This is quite likely to be 27.4 volts.
My truck batteries are ALCO calcium batteries. MF90D26R
2 batteries to give 24v.

12V 75Ah(20hr)
130Min(RC) 630A(CCA)

Cant find ALCO online. Found a business in Auckland selling them, their website lists all sorts, but not a float voltage.

I googled calcium batteries: found a stray comment that they require a higher charge voltage.

Trying to work out what voltage the step-up device should be set to to keep 24v battery bank charged.
 #140767  by MiriamNZ
 Sat May 19, 2018 3:59 pm
MiriamNZ wrote:
Sat May 19, 2018 3:33 pm
Cant find ALCO online. Found a business in Auckland selling them, their website lists all sorts, but not a float voltage.
Looks like Alco has morphed into Energi.
Found the product number on their website and an Alco dealer in Auckland whose website goes to enirgi

The product with same serial number does not say it is calcium. Does not list a float charge.
Their help page says their flooded or vrla batteries both have a float charge of 26.4.r

So should I guess that the correct setting for my step up device is 26.4v?
Any votes?
 #140770  by Neddy
 Sat May 19, 2018 4:28 pm
Manufacturers of most calcium batteries around the capacity of yours specify a Float voltage of 26.4v - 27.0v, though I did find one that quoted 27.0v - 27.6v.
On that basis, I would plump for 27.0v but even a Float voltage of 26.4v is way better than no Float at all.

Neville.
 #140775  by rawill
 Sat May 19, 2018 5:30 pm
Often on the side of the battery the float voltage, (and other voltages) are mentioned.
So for 24v system just double, it will probably be around 27.4v.
I don't imagine a point or two here or there is going to make a huge difference.
 #140948  by Doit
 Thu May 24, 2018 12:00 pm
IMG_20180524_115245.jpg
My setup has an engine cutoff switch between the two starter batteries. As far as I can see, I will only be able to charge these when the switch is closed. I suspect my last DC/DC converter blew up because it had no load on it's output. Can anyone suggest a simpler solution than the drawing on the right?
 #140953  by Doit
 Thu May 24, 2018 4:06 pm
I looked at that but it wouldn't be easy due to switch position and existing cable lengths.
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