[Amel Yacht Owners] Re: Batteries


Hi Mark & Tom,
Thanks for your thoughts.
To answer your questions:

I have battery voltage monitors on my solar panels as well as having checked with my multimeter, the voltages appear correct. I am measuring under load of refrigeration and know I will get slightly lower readings.
I’ve tested them individually with my electronic tester and they all appear to be ok.

I just heard back from Crown Battery’s tech department.  He was very interested in the issue and asked a million questions about my systems and charging regimen.  He corrected me and said these batteries are actually 130AHr capacity.  So I have a 520AHr house bank
I used the charging recommendations I got from the same tech department  when I got the batteries...28v abs, 26.4v float, 29.4v equalize.  This engineer says I should be using 29v Abs, 27v float, and 31v equalize, and that I should equalize for 3 hours at least once a month.

It’s hard to know what’s right when I get two regimens from the same department, but I think this latest recommendation will probably solve the problem.

My solar panel regulators ( one for each of three pairs) have an equalization cycle that happens automatically, so I set it at 29v to avoid damaging equipment rated for 24-30v.  I will have to turn off all equipment when I equalize with the Victron Skylla charger set at 31v for 3 hours.

I’ll try this and report back what happens.

Kent & Iris
S/V Kristy
SM 243

On Jan 24, 2019, at 10:45 AM, 'Mark Erdos' mcerdos@... [amelyachtowners] <amelyachtowners@...> wrote:




Your math is correct and you should be reading slightly higher voltage reads than you are getting.


A couple of thoughts:


Are you depending solely on the meter in the panel to monitor the batteries? If so, the meter may be out of adjustment of failing. Did you adjust the Peukert exponent when installing the new battery bank?


The best way to check the voltage of the bank is to disconnect the bank for a while by turning off the red handle switches, check the voltage with a good quality meter from the main studs in the battery well.

Do you have any load on the batteries when checking the voltage. A load such as a refrigerator running will cause lower voltage reads.


Have you load tested each battery to determine if you were sold a faulty or defective battery?


Hope this helps.



With best regards,





Sailing Vessel - Cream Puff - SM2K - #275

Currently cruising - Santa Marta, Colombia



From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, January 24, 2019 11:50 AM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Re: Batteries in Caribbean



I have a battery issue too, that I’d like opinions about.

I just bought 8 new series 31 120 AHr deep cycle marine batteries in August (while in Maryland). They were kept fully charged with solar before we headed S in late Dec. After only a month, they are not acting like 120 AHr batteries.. They stay charged fully during the day with solar (900watts) but at night they discharge to ~24.7V and the monitor says I’ve only used ~45AHrs. I reset the monitor at dusk when the solar is no longer charging. 24.7V should be about 70% of capacity. That is where I’d like to set my minimum voltage before recharging, in the interest of battery life. But my 480 AHr battery bank shouldn’t get there until I’ve used 30% of capacity, which would be about 160 AHrs.

Am I thinking correctly about that?

I checked the batteries which consistently showed low specific gravity of 1..225 to 1.250 (in the”Fair” range). This didn’t change appreciably after running two equalization cycles with my Victron Skylla charger. It does seem that the batteries are a bit better in that they are now at about 24.8 V just before sunrise.

What do you think is going on here? Should I just keep running equalization cycles until the SG gets back to normal?

Thanks for any advice, thoughts, etc in advance.

Kent & Iris
SM 243
Still in Ft Lauderdale (We’re calling it Hotel California...you can check out but you can never leave.)

Alan Leslie

Hi Kent

The first voltages you mentioned .... 28v abs, 26.4v float, 29.4v equalize.  
sound pretty much the norm to me for standard flooded deep cycle batteries
29v Abs, 27v float, and 31v equalize
seems a bit extreme ....that's more than what most AGM manufacturers recommend for batteries that have a higher acceptance rate than yours.

Are you sure your battery monitor is reading / setup correctly for these batteries? As Mark said..Peukert constant set correctly?

My understanding is that lead acid batteries only need to be "equalised" in the case of sulphation caused by repeated deep discharges followed by incomplete charging.

It sounds like you are charging your batteries fully and limiting discharge, you shouldn't have a problem....maybe it's the meter that has the problem..?

Elyse SM437
Opua, New Zealand...for now