I have 1,000 AH of Toyama hybrid gel batteries
in my house bank (5 x 200AH), but during a night passage
, I'm only getting about 10 hours of discharge before I hit 10.5 volts and the alarms start going off causing me to run the genset. This typically happens about 4am on a night passage
This unhappy state has brought to light several issues:
1. Assuming I have 50% of available capacity, then in order to use 50% of the capacity of the bank in 10 hours I would be drawing an average of 50 amps. The ammeter built into the Matervolt charger
is nowhere close to this, so either a) the ammeter is incorrect and I'm drawing 5 times more than I think I am. Or b) My battery
bank is toast.
2. These batteries
were (supposedly) installed new in 2009, so they should still be operating per design.
3. I am installing a new ammeter to verify, and assuming my true amperage readings are less than 50A (average), I must have degraded capacity in the house bank. So I will need to test each battery
to see if it needs to be replaced. This raises the issue of how to best verify the state of the batteries.
I have scoured the Internet
and can't find any charge, vs. voltage data for my Toyama hybrid Gel batteries (certainly won't be buying
them again), so I'm going to have to improvise.
I figure if I test each battery in turn by connecting it to a DC battery monitor
that is connected to a 20amp load, which is controlled by a voltage switch that will shut the load off when the voltage drops below 10.8 volts, I can then read the Amp Hours consumed during the test.
This raises some questions, that I am hoping you can help me answer:
1. Is this a valid approach for testing deep cycle batteries?
2. What % of rated AH capacity is acceptable for the test?
3. What is the result threshold for replacing the battery(ies)
This is making my head
hurt, so I'm hoping someone who has dealt with this before can help!