Battery Equalization-Trojans T105

[joe]

ken, can you educate us on the scale on the hydrometer. what units does it read in? what is good bad or ugly? tx joe

[Steve S.]

Thanks Ken, It makes much more sense now.  It's sort of like the old anti-freeze testers I used to ensure proper mix. 

And Joe, If I remember the Xantrex guide, it said keep equalizing until the SG hits 1.26. 

[Ken Juul]

I think the SG numbers are in one of the Ample Power links Stu posted a while back.  Or google battery specific gravity.  My hydrometer is color coded Red (bad) white and Green (good) so I haven't put any effort into remember the numbers.

[Stu Jackson]

A Google on Hydrometer battery readings finds this:  http://www.ibsa.com/www/faqs/tech_talk/maintenance/testing.htm

Their link shows: 

Specific Gravity VS. State of Charge
1.265     100%     
1.225     75%     
1.190     50%     
1.155     25%     
1.120     0%     

Also check the West Marine advisors online or in the catalog.  See: http://www.westmarine.com/webapp/wcs/stores/servlet/westadvisor/10001/-1/10001/BatteryCharging.htm

Ken's suggestion is : www.amplepower.com - download and read the Ample Power Primer.  See Reply #2 right here on this thread!!!

DON'T keep equlaizing until you reach 1.26, that's hard to do, because the ONLY valid hydrometer tests are when the batteries are at REST (24 hours, no charge or discharge).

DO equlaize to the limits indicated in the West Advisor text, which is usually 4 to 6 hours.

While you're waiting and watching on your boat, because you NEED to be there to equalize, buy and read Nigel Calder's book, or any of the printed text you've gotten from these references and others.   

You could also do a search right here on the MB for "equalize"  or "equalization"  or "equalizing" batteries.

[Kyle Ewing]

I equalized my 5 year old T105s for the first time this summer.  Specific gravity readings are affected by temperature so I paid more attention to the range than the absolute values since I didn't want to compensate for temperature.  When I checked specific gravity (fully charged battery left idle over night) I found several cells were weaker compared to the other cells.  I equalized long enough to bring up all the cells to the same specific gravity (about 2 hours), let sit overnight, then checked again.  They were closer so I ran a second equalization charge of about 2 hours. 

Now all cells maintain about the same specific gravity and overall the bank seems to hold a charge longer.  I don't have a Link monitor yet to quantify capacity but a 24 hour full charge resting voltage prior to equalization was about 12.5 volts.  Now its over 12.6 volts.  Keep in mind that all the cells in a battery work together and a weak cell can affect capacity of an entire bank.

One other point is to make sure there are no air bubbles on the float when reading the hydrometer.  Air bubbles can make the reading appear higher than it should.

Regarding radio memory, the first time I equalized I disconnected it.  I forgot to disconnect the second time with no apparent damage.

Kyle Ewing
Donnybrook #1010
Belmont Harbor, Chicago

[Stu Jackson]

Kyle

You wrote:  "the bank seems to hold a charge longer"

That's been my experience, too, which is THE reason to equalize your house bank.

[Marshall Tonner]

I have purchased 100's of "golf cart" batteries over the years and found that all manufacturers have a very competitive product, Trojan, East Penn, Interstate, Douglas, Crown, but the worst by far in my experience is Exide.
When reading your hydrometer you should place more emphasis on the difference between cell readings than on the individual readings. A difference of 10% or more between cells is not good.Also note any discoloration in the electrolyte as a dark color will indicate overcharging and damage to the cells.
                                 Marsh

[Mike and Joanne Stimmler]

Does anyone have pictures of how the 4 6volt batteries are mounted showing how the hold down clamps are set up and also is it necessary to have some sort of a cover over them like you would with battery boxes.

Mike

[Stu Jackson]

For starters: http://www.c34.org/projects/projects-electrical-system-upgrade.html

Then this one.  Doesn't seem to be room for battery boxes.  Acid spills would (could) occur with a full knockdown. 

[Bill Asbury]

The pic Stu submitted is the way my 4 Trojan golf cart battery housebank is installed, apparently in the same starboard side compartment aft of the v-berth in the dinette.  Surveyor told me the batteries have to be secured so they can't move more than one inch horizontally or vertically, but there isn't enough room for battery boxes.  PO installed webbing attached to a plywood floor under the batters to hold them down.
Hope this helps.
Bill

[Ron Hill]

Guys : If you look in the Mainsheet tech notes, you'll find an article by Hank Recla.  It shows his 4 golf cart batteries, but he made a top rectangular cage so he could tie down the 4 batteries.
I have 3 GP 31 AGM batteries in the same size compartment.  Only one is in a battery box, but all 3 are tied down!!  A thought

[Mike and Joanne Stimmler]

Thanks all fir the replies. I have seen the post Stu has highlighted and also the info Ron mentioned. I think I can figure out a way to hold them down, do you know if there are any requirements by ABYC to have them covered on top. I believe on my initial survey, the surveyor noted that the batteries should be covered (they were in battery boxes but missing the lids). I will also check back with the surveyor to get his input. I currently have 2 group 27 batteries that I believe was the original config for the C34 and am looking to upgrade to the 4 6 volt battery system if I can figure out a safe way to do it. I know many have done it, but I want to do it safely.

Mike

[Bill Asbury]

Mike, I believe it's the battery terminals that need to be covered to satisfy the surveyors, not the whole battery---at least that was my impression from the surveyor I had---so I put terminal covers on all terminals.  However, I've screwed down the compartment lid in addition to having the webbing straps securing each battery.  Again, I the 4 battery housebank setup.  My starting battery also has terminal covers and is in a battery box with a top on it.
Bill

[Braxton]

The terminals being covered satisfied the surveyor I used on my purchase.

[Mike and Joanne Stimmler]

Thanks Guys, I just confirmed with the surveyor and he said that it is ok to just have the terminals covered as lond as the battery is secured.

Mike