Charging Curves for Hoppeker Model 8 640 5 Batteries

[Dreaming Yachtsman]

I am installing solar panels on our catamaran to power the refrigerator so the wife can make ice and to keep the batteries topped off when away from the boat. With four 130 watt Kyocera panels, we may no longer need to run the auxiliary generator except to power the air conditioning to keep the wife cool while drinking her iced beverages.

One of the features of the Outback MX 60 MPPT controller I have installed is the ability to program the ABSORB (bulk) VOLTS and FLOAT VOLTS setpoints. Default values in that device for a 12V system are 14.4V and 13.6V respectively. The installation manual strongly recommends setting it to the battery manufacturer's specifications. Unfortunately, the battery charging curves did not come with the boat.

Does anyone know how to obtain such curves (or at least the absorb and float volt values) for Hoppeker model 8 640 5, 140 Amp-Hr(C5) batteries? They are 3 years old but a recent load test showed that they are still in good shape so replacing them now is not economical.

BTW, when I do finally obtain the correct values, I plan to verify the settings in the other two charging sources: Mastervolt regulator on the stbd propulsion engine and Victron 2000 inverter/charger. Hopefully that will keep me from having the same experience CSY Man described in his recent thread, "AC charger smarter . . . ."

The brand and model number and age are not the issue, it is the type of battery that is key. If these are flooded cell batteries the default values look good, although a more typical float value would be a bit lower. The higher the voltage used in the float phase the more water you will gas out of the battery.

If they are gel or AGM batteries (which I think most Hoppeke batteries are) you'll need lower voltage settings or you'll cook them in a hurry.

At 70 degrees F the following are typical values:
Wet Cell Absorb: 14.4
Wet Cell Float : 13.5
----------
Gel Cell Absorb: 14.1
Gel Cell Float: 13.6
----------
AGM Absorb: 14.3
AGM Float: 13.3

These differences might seem trivial, but they are not if you want you batteries to last. If you run gel cells up to 14.4, especially when they are warm, they will start to gas, and blow their seals, ruining them in short order.

[Pblais]

Without knowing any more I would agree with GreatKetch. When in doubt go with the battery type to get it close. There are some other intermediate points but I think getting two right will at least not make the problem worse.

It must be nice to have that many amps. Making ice is indeed a desirable hobby! It does not sound like so much until you live on a boat! Imagine having an ice making business at an anchorage of your choice.

Clink clink!

[Dreaming Yachtsman]

GreatKetch,
Thanks for the info. These batteries are indeed flooded cell, although they are "sealed" with water tight plugs and are not supposed to need maintenance unless in very hot conditions. I will therefore use the default settings as you recommended.
+++++++++++++++++++++++++++++
Paul,
Thanks also for corroborating GreatKetch's analysis.
I hope the solar panels do indeed provide enough power to run all of our gadgets. Your idea of selling ice cubes has real potential! That sounds so much easier than embroidering tee shirts and hats to sell, which is what we are planning to do.

John