Originally Posted by cal40john
I agree with what is in the link.
I don't see how your link applies to what I stated. I was only talking about the case where the bulk phase voltage trip point is set higher than the acceptance voltage set point.
Can we say that the voltage is primarily set by the SOC and charge acceptance of the house bank to start with? Can we say the start battery is essentially charged after a short time? As long as the voltage doesn't exceed approx. the normal 14.4 volt typically set for acceptance I agree there is no problem. As the voltage rises you are applying that same voltage to the start battery. Since you are applying say 14.8- 15.0 volts to the start battery its charge acceptance increases. If it is fully charged doesn't it just outgas and heat up, presumably causing damage?
As far as I can tell Maine Sail's article only discusses paralleling batteries where the voltage set point does not rise above a nominal 14.4 volts. I completely believe what he has found there. What I would like to find out is what is wrong with my statement of applying high voltages to charged batteries causing problems?
I wouldn't be surprised at all if on a practical level the amount of time spent at the higher voltages is small enough that it has no noticeable affect on the longevity of the start battery. Does Maine Sail have experience this?
It does not harm the batteries as the house bank and start bank are at the same voltage for the same exact duration. Both banks will be gassing and getting a good for them
high absorption voltage for a short period
Heck my "yard battery" that I use to power my heat gun etc. in boat yards, or on moorings, where running an extension cord is difficult, is always charged to 14.8V. I quite often forget to use the timer and it stays at 14.8V for a few days. The battery is 8 years old and was retired from deep cycle use. It still puts up about 90% of its rated capacity and drives my heat gun for as many times per day as I need it. 14.8V only seems to have helped this battery survive.
We really need to forget about using the term "bulk" as a voltage limited stage of charging. The hair stands up on my neck every time I hear that..
has tried to re-define
what bulk is and they are simply wrong, and do this only for marketing
purposes.. Sadly other companies have now jumped on this marketing
I have tried like hell to get Balmar
to do the right thing and relabel them as they should be; Absorption #1 and Absorption #2. Bulk is NOT voltage limited charging is is constant current
. Rick J. just laughs because it sells stuff........
Voltage limited charging is absorption or float or equalizing etc.. If you have any more voltage limited stages they should be named appropriately but calling one of the voltage limited stages bulk I guess helps sell more regulators to the naive....
That said the vast majority of Balmar regs I see, not installed by me, have NEVER been properly programmed for the bank. Better than half of them are still on UFP which is a 14.1V Absorption #1 setting........ Most boats suffer from chronic under charging rather than over charging...
I have plenty of boats out there with Trojan's or US Battery banks, with combiners, and the regs set to 14.7V - 14.8V for Absorption #1 and the start batteries out live the house banks... I have a number of Full River and Odyssey batts that also charge at high voltages and the start batteries out live the house banks. I don't just install ACR's or combienrs thougha nd I do have many boats with Duo's, Sterling B2B's and Echo's...
I can't think of a single
combiner boat where the start batteries "cooked" and failed before the house banks. Batteries need & like a good gassing voltage to keep the plates less sulfated. Still, this should be a short duration of the charge cycle then drop back to a slightly lower absorption voltage.
I have one customer with a Defever trawler
who does lots of engine hours per year and his start battery bank is now about 9 years old. He's had a combiner for at lest 7 of those years and Balmar reg set to 14.8V Absorption #1 & 14.6V Absorption #2....