Voltage "hitting the wall" on manual charger

smkettner wrote:
Generally at that voltage 1/2 of 1% of capacity in amps would be fully charged.
So pretty much anything below 3 amps (on 740ah) is full charge afaik.

I had gathered that from some posts BFL did a while ago but not quite an exact number it seems. I'm hoping that the hang means it's actually full. I'll check with the hydrometer tomorrow and report back. If this turns out to be the case on subsequent recharges this will reduce the amount of hydrometer use to periodic checking. I don't use it much as it is but I'd like to take some guesswork out of the maintenance.

Generally at that voltage 1/2 of 1% of capacity in amps would be fully charged.
So pretty much anything below 3 amps (on 740ah) is full charge afaik.

From the recent thread on manual vs autos
by Gale Hawkins

Posted: 11/14/13 08:47pm Link | Quote | Print | Notify Moderator

We own 4 automatics but this is my go to charger for refreshing the charge.

It is simple. It is a requirement if you own automatic chargers so you can make the automatics work on a very discharged battery.

On a 12v auto/tractor battery I can set it on 12v/6 amps over night. If it has tapered down to a 1 amp rate I have a known healthy battery. If it stops tapering at 2-3 amps I know it is a sick battery.

I forget and left one on at 6 amp rate for about a month a couple years ago. Just had it load and SG tested at Interstate Dist a couple weeks ago. He said it was built in 2006 but still load tested well with balanced SG readings. From that I gather you do not have to baby set a manual charger charging at a low rate.

Now if the battery is at the end of the life cycle and will only taper to say 3 amps a month later (days actually) it would be fried along with the charger I expect.

Automatics have their place but not as your solo charger from my experience. Now what I think is ideal is to put the automatic in Desulf Mode for three 24 hours cycles with the manual charger on 6 amps for the first day and 2 amps for the next two days.

With a 12v battery if it has not tapered to 1 amp after 24 hours or less depending on its starting SOC (starting state of charge and size) I will run it on the two amp rate for the next two days to see if I can recover some run time capacity.

Dying batteries should be replaced soon if in mission critical applications like driving across the USA.

BFL13 wrote:
I noticed my 1a manual trickle charger can only get the batts so high, but a higher amp trickle charger can get them to a higher voltage before stalling.

when using the Honda gen's DC charger, it stalled out at 16+ v when on Economy but when on full revs it got to 17+ volts on the batts

It must be another one of those power ( Watts---eeeuw) things.

When my batteries were brand new the charger could get them farther into the 15V range on 2A setting, took some time, but it would get there. Once they got broken in, then the charger would stall out right ~15V. The 10A setting will push it right up to 16V and beyond but I want the batts to take that 15+V until SG gets up to baseline. 2A does do it but I'm wondering if I should stop it when it stops.

I noticed my 1a manual trickle charger can only get the batts so high, but a higher amp trickle charger can get them to a higher voltage before stalling.

when using the Honda gen's DC charger, it stalled out at 16+ v when on Economy but when on full revs it got to 17+ volts on the batts

It must be another one of those power ( Watts---eeeuw) things.