Dedicated starting battery

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
(I have an update on this after one year, and I'm posting this to keep the thread alive, i.e., not locked, until I get a chance to write it up. I'm not sure of the thread-locking algorithm).

After one year, but not many cycles on the new batteries, I got results that I did not anticipate, and that are disappointing. I'd like your analysis of this.

I connected all four batteries individually using essentially the same length wires, home-runned to plus and minus battery bus bars. The plus feed to the panel, engine alternator, and shore power charge terminal are connected the the plus bus, too. A second negative bus is connected to the first via the shunt for the Vectron BMV-600 monitor. The second negative bus also has the panel ground, engine ground, and shore charger ground.

The batteries started out at 531, 509, 496, 501 CCA (Argus AA400). After one year, less than a dozen cycles, no charging over the winter, and on solar daily since early June: 491, 478, 448, 437.

These are Duracell part number 24DCC, 20 amp hour rate:75, BCI Group Size:24, CCA at 0 degrees F:500, all purchased at the same time, fresh, and apparently from the same manufacturing lot.

First test all were close to full charge: 98%, 96%, 100%, 100%. Second test all were at 100%.

All electrolyte levels checked, correct level for all.

Should I cry, or is this close to expected? My cause for concern was that the AA400 reports low BL (Battery Life) values for these for the second test: 92%, 82%, 58% 49%; but I don't know how this measure applies to deep cycle batteries.

Thanks!

jv
 
Feb 6, 1998
11,665
Canadian Sailcraft 36T Casco Bay, ME
(I have an update on this after one year, and I'm posting this to keep the thread alive, i.e., not locked, until I get a chance to write it up. I'm not sure of the thread-locking algorithm).

After one year, but not many cycles on the new batteries, I got results that I did not anticipate, and that are disappointing. I'd like your analysis of this.

I connected all four batteries individually using essentially the same length wires, home-runned to plus and minus battery bus bars. The plus feed to the panel, engine alternator, and shore power charge terminal are connected the the plus bus, too. A second negative bus is connected to the first via the shunt for the Vectron BMV-600 monitor. The second negative bus also has the panel ground, engine ground, and shore charger ground.

The batteries started out at 531, 509, 496, 501 CCA (Argus AA400). After one year, less than a dozen cycles, no charging over the winter, and on solar daily since early June: 491, 478, 448, 437.

These are Duracell part number 24DCC, 20 amp hour rate:75, BCI Group Size:24, CCA at 0 degrees F:500, all purchased at the same time, fresh, and apparently from the same manufacturing lot.

First test all were close to full charge: 98%, 96%, 100%, 100%. Second test all were at 100%.

All electrolyte levels checked, correct level for all.

Should I cry, or is this close to expected? My cause for concern was that the AA400 reports low BL (Battery Life) values for these for the second test: 92%, 82%, 58% 49%; but I don't know how this measure applies to deep cycle batteries.

Thanks!

jv
Some thoughts..

#1 Your batteries are not yet even broken in. Do a number of deep cycles to 50% with recharges to full.

#2 Push and equalization voltage for a couple of hours and see what happens.

#3 With the Argus the only values that really matter are from your baseline. I always pre-charge and push new batts to 15V + before commissioning and take a read with my Midtronics or Argus after doing so. This is my baseline (it can be slightly misleading as they are not yet broken in). As long as I am using the same settings and same meter these baselines are good.

#4 Test each battery three times re-clamping the probes each time and getting a good bite on the lead. Take the average. You'll notice very slight variations.

#5 Draw the batteries down and put them under charge with at least 40 - 60A flowing from the alt.. Now measure for voltage drop in each of the star configuration wires. Place the pos of the DVM on one end of the wire and the neg on the other end. You should have a reading of 0.000V. If you have an accurate clamp meter, that is good with very low current resolution, you can clamp each wire and be sure each battery is taking similar current.

I suspect once broken in and equalized you will see the CCA values start to come closer together... Be sure you are isolating each battery before testing.

This was my three group 31 Wal*Mart batteries at the end of year six. They were wired end to end..

 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Thanks, MS,

The only thing I've done is #4, and also made sure the are isolated. It's easy to isolate without taking the house down with the wiring scheme I've implemented, I just have to disconnect one battery lead from a battery and it's isolated. I also clamped the tester leads onto the large, lead terminals and pressed them, rocked them to make sure I had firm connection.

BTW, I have a question about the AA500 - can you print a report with the internal resistance, too, or only the print outs you show?

Thanks,

jv
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
So, five years later...the "new" house batteries are shot. Yes, they were abused a bit, but were useable until this week, when they just fell of a cliff.

I have two, new 100AH AGM deep cycle batts that I will use in place of the four flooded 75AH ones.

More later....
 
Feb 6, 1998
11,665
Canadian Sailcraft 36T Casco Bay, ME
Five years on Group 24 flooded "deep cycle" batteries is about what is to be expected and longer than most get from them.. If you want longer life actual deep cycle batteries, not just a "sticker", can get you 5-12 + years. Some AGM & GEL batteries can also give long life such as Lifeline, Firefly, Odyssey, Northstar and the East Penn or Sonnenschein made GEL batteries.
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Thanks Maine. I'm thinking there may be something else going on, as my 17 year old Xantrex InCharge smart regulator is acting up. It gets into a mode where it turns on and off, on its own, and I can reset it by dropping power to it with the key switch, and its OK for a while. I think it's probably not worth trying to get it fixed, at this point. But, when I charge, from apparently low batteries, it almost immediately gets up to near acceptance voltage of 14.5V or so. Seems weird.
 
Nov 16, 2012
1,037
Catalina 310, 2000, #31 31 Santa Cruz
Maine Sail: quick question (I hope). I'm planning on rewiring our Catalina 310 and using this dedicated start battery wiring scheme. Would it be a bad idea if the On/Off switch was next to the battery, and not easily accessible? Or should it be in plain view, and turned off when not on the boat? Logistically the former is easier.
 
Feb 6, 1998
11,665
Canadian Sailcraft 36T Casco Bay, ME
Maine Sail: quick question (I hope). I'm planning on rewiring our Catalina 310 and using this dedicated start battery wiring scheme. Would it be a bad idea if the On/Off switch was next to the battery, and not easily accessible? Or should it be in plain view, and turned off when not on the boat? Logistically the former is easier.
A switch could easily be flush/back mounted on the front or side of the settee where the batteries are located. Battery switches should always be easily accessible for emergency use.
 
Nov 16, 2012
1,037
Catalina 310, 2000, #31 31 Santa Cruz
A switch could easily be flush/back mounted on the front or side of the settee where the batteries are located. Battery switches should always be easily accessible for emergency use.
Got it. Thanks!