Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 01-11-2018, 20:08   #1
Registered User

Join Date: Feb 2015
Posts: 29
Rapid voltage drop under small loads with new Trajan T-105

After 5 years of service and signs of declining capacity, I decided to replace our house batteries. We have 4 6V batteries wired in a series/parallel configuration providing 450 Amp-hr of theoretical capacity.

I bought 4 Trojan T-105 2 weeks ago. They were manufactured in March 2018 and were only ~65% charged when I got them (6.19V). After installing them on the boat, I gave each 12 V bank a long reconditioning charge with a CTEK Multi 25000 charger. But they could not seem to handle any load. As en example, an evening I recorded voltage dropping from 12.7 to ~12.2 V after 7 hours under 8 amp of load.

Suspecting an issue with the batteries, I talked to the dealer which agreed to replace them. The new batch was nearly fully charged. I installed them yesterday and am in the process of giving them a good reconditioning charge with the same CTEK charger. The bank that has not been put on charge yet (besides couple hours of engine run) is already showing the same rapid voltage drop syndrome under small load. After 12 hr, the bank on charge had not reached float charge, which is surprising since the batteries were supposedly nearly charged when I got them 2 days ago. Specific gravity measured 1 hr after disconnecting the charger was 1.26 on all cells for one battery and 1.24, 1.25 and 1.26 for the cells of the other battery.

Unless the dealer has badly neglected a whole batch of battery, what could trigger such a rapid voltage drop under even small loads?

Thanks a bunch, this is driving me crazy!!
__________________

BluJu is offline   Reply With Quote
Old 01-11-2018, 20:18   #2
Registered User
 
sparrowhawk1's Avatar

Join Date: Jan 2014
Location: Miami Beach Fl
Boat: Colombia Cc 11.8
Posts: 1,629
Re: Rapid voltage drop under small loads with new Trajan T-105

I'm not going to give any advice, I'll just tell you a story. Once upon a time I bought a starter for my van that only lasted one to two weeks. this happened three times. the "dealer" had no problem exchanging them but after the third one I went someplace else and lived happily ever after.
__________________

sparrowhawk1 is online now   Reply With Quote
Old 01-11-2018, 20:29   #3
Registered User

Join Date: Feb 2013
Location: WY / Currently in Hayes VA on the Chesapeake
Boat: Ocean Alexander, Ocean 44
Posts: 1,005
Re: Rapid voltage drop under small loads with new Trajan T-105

It is possible that they need a few cycles to get "broken in". A friend of mine had that type of issue with a set of batteries and the manufacturer said to "hammer 'em for 3 or 4 cycles and they should be better" and they were.
darylat8750 is offline   Reply With Quote
Old 01-11-2018, 20:41   #4
Registered User

Join Date: Feb 2015
Posts: 29
Re: Rapid voltage drop under small loads with new Trajan T-105

I talked to Trojan today and they suggested it might take 50 full cycles for the batteries to deliver their full capacity. They said capacity might be as low as 80% of rated capacity upon leaving the factory.

I just found another thread describing the same issue.
Trojan T-105 voltage under load

Seems like some consider my observations normal, others not. I will continue with the "breaking in" but any advice as to what may be causing this voltage drop is welcome. I have no indications of unwanted/undetected current draw but I'm wondering if that could be a factor.
BluJu is offline   Reply With Quote
Old 01-11-2018, 21:22   #5
Registered User
 
Stu Jackson's Avatar

Join Date: Jan 2011
Location: Cowichan Bay, BC (Maple Bay Marina)
Posts: 7,903
Re: Rapid voltage drop under small loads with new Trajan T-105

Breaking in New Wet Cell Batteries: "Breaking In" New Wet Cell Batteries
__________________
Stu Jackson
Catalina 34 #224 (1986) C34IA Secretary
Cowichan Bay, BC, (Maple Bay Marina) SR/FK, M25, Rocna 10 (22#) (NZ model)
Stu Jackson is offline   Reply With Quote
Old 02-11-2018, 03:50   #6
Registered User

Join Date: Jan 2017
Posts: 12,578
Re: Rapid voltage drop under small loads with new Trajan T-105

Yes, AKA "commissioning charging." The first few dozen cycles, go easy on the amps, avoid high current rate discharges and charges.

First step really **fully** charge, as in hold Absorb V to the top spec until amps taper to .005C in your case 2A or below, however long that takes. Let SG go a bit over spec, no harm occasionally.

Then manually follow Trojan's equalizing instructions, ideally on each 6V unit separately, again letting trailing current taper down to .005C or 1A at the higher V.

Next, discharge at .05C or 10A in your case, for about 20 hours. The battery voltage should then be around 5.25,

don't let it drop past that, and start recharging immediately,

at ~.15C for the rest of the break-in period, say two months if regularly cycling, trying to avoid huge draw currents as well.

Note if it takes lots less time than 20 hours for any one 6V unit to get to 5.25V from 100% Full, return it.

Where are you located?
john61ct is offline   Reply With Quote
Old 02-11-2018, 03:54   #7
Registered User

Join Date: Jan 2017
Posts: 12,578
Re: Rapid voltage drop under small loads with new Trajan T-105

You should not be allowing any other loads than the ones you control during the commissioning / testing draw-down process, and none at all during the charging side.
john61ct is offline   Reply With Quote
Old 02-11-2018, 04:14   #8
Registered User

Join Date: Jun 2009
Location: BVI
Boat: Leopard 40 (new model)
Posts: 1,340
Re: Rapid voltage drop under small loads with new Trajan T-105

Quote:
Originally Posted by john61ct View Post
Yes, AKA "commissioning charging." The first few dozen cycles, go easy on the amps, avoid high current rate discharges and charges.

First step really **fully** charge, as in hold Absorb V to the top spec until amps taper to .005C in your case 2A or below, however long that takes. Let SG go a bit over spec, no harm occasionally.

Then manually follow Trojan's equalizing instructions, ideally on each 6V unit separately, again letting trailing current taper down to .005C or 1A at the higher V.

Next, discharge at .05C or 10A in your case, for about 20 hours. The battery voltage should then be around 5.25,

don't let it drop past that, and start recharging immediately,

at ~.15C for the rest of the break-in period, say two months if regularly cycling, trying to avoid huge draw currents as well.

Note if it takes lots less time than 20 hours for any one 6V unit to get to 5.25V from 100% Full, return it.

Where are you located?
Great post, but I want to emphasize the importance of making SURE (as when using a multimeter, not any fixed instrument) that the voltage AT THE BATTERIES during absorption phase is equal to spec by the manufacturer. It its very easy to overlook the importance of voltage on the relationship between trailing amps and SOC.
svlamorocha is offline   Reply With Quote
Old 02-11-2018, 05:19   #9
Marine Service Provider
 
Maine Sail's Avatar

Join Date: Jan 2007
Location: Maine
Boat: CS-36T - Cupecoy
Posts: 3,062
Re: Rapid voltage drop under small loads with new Trajan T-105

Quote:
Originally Posted by BluJu View Post
After 5 years of service and signs of declining capacity, I decided to replace our house batteries. We have 4 6V batteries wired in a series/parallel configuration providing 450 Amp-hr of theoretical capacity.

I bought 4 Trojan T-105 2 weeks ago. They were manufactured in March 2018 and were only ~65% charged when I got them (6.19V). After installing them on the boat, I gave each 12 V bank a long reconditioning charge with a CTEK Multi 25000 charger. But they could not seem to handle any load. As en example, an evening I recorded voltage dropping from 12.7 to ~12.2 V after 7 hours under 8 amp of load.

Suspecting an issue with the batteries, I talked to the dealer which agreed to replace them. The new batch was nearly fully charged. I installed them yesterday and am in the process of giving them a good reconditioning charge with the same CTEK charger. The bank that has not been put on charge yet (besides couple hours of engine run) is already showing the same rapid voltage drop syndrome under small load. After 12 hr, the bank on charge had not reached float charge, which is surprising since the batteries were supposedly nearly charged when I got them 2 days ago. Specific gravity measured 1 hr after disconnecting the charger was 1.26 on all cells for one battery and 1.24, 1.25 and 1.26 for the cells of the other battery.

Unless the dealer has badly neglected a whole batch of battery, what could trigger such a rapid voltage drop under even small loads?

Thanks a bunch, this is driving me crazy!!

1- Your CTEK charger is not capable of charging your Trojans as the manufacturer suggests and is likely why your SG readings are what they are. It may be telling you the batteries are "full" but, they're not.

Unless something has recently changed the max absorption voltage for the CTEK is 14.4V and this is just not high enough for deeply cycled Trojans. A target of 14.8V for absorption will result in healthier batteries.

2- Your batteries need to be broken in. The fastest way to do this is deep cycling them and then recharging to 100% SOC after each discharge. Your CTEK is likely not capable of getting your batteries back to 100% SOC...

3- Where are you measuring this voltage and with what equipment. The only voltage reading that matters is one taken directly from the battery terminals with a known accurate volt meter or DVM. Taking this measurement anywhere else in the system, as most boats volt meters do, is simply a poor data to work from.

4- Lead acid batteries can exhibit a voltage drop then a rebound on discharge. This discharge graph below was a Trojan battery during a 20 hour capacity test that delivered 77% SOH based on the factory rating of 130Ah. Notice the initial dip in voltage to the far left and then the rebound. This dip, then rebound, was close to 0.1V. A voltage difference for a lead acid battery of 0.1V can actually be 10% of a lead acid batteries capacity, so going by voltage here can could certainly be a bit misleading.

I've also highlighted when this battery hit about 88% SOC based on the actual Ah's it could deliver. Your battery bank, based on the "as new" rating, was also down about 12% +/-. The voltage under the .05C load on this used battery was 12.26V.

With a 0.018C load, and that voltage, I suspect you have a charger issue, non-broken in batteries and potentially a voltage sensing location or equipment issue. If you get a good quality charger, that can charge them per Trojan's guidance, I suspect you will see your loaded voltage support do much better as they begin to break in.

__________________
Marine How To Articles
Maine Sail is offline   Reply With Quote
Old 02-11-2018, 05:33   #10
Registered User

Join Date: Jan 2017
Posts: 12,578
Re: Rapid voltage drop under small loads with new Trajan T-105

Is the mfg date also March on the new set?
john61ct is offline   Reply With Quote
Old 02-11-2018, 05:46   #11
Registered User

Join Date: Jul 2018
Posts: 166
Re: Rapid voltage drop under small loads with new Trajan T-105

Quote:
Originally Posted by BluJu View Post

I bought 4 Trojan T-105 2 weeks ago. They were manufactured in March 2018 and were only ~65% charged when I got them (6.19V). After installing them on the boat, I gave each 12 V bank a long reconditioning charge with a CTEK Multi 25000 charger. But they could not seem to handle any load. As en example, an evening I recorded voltage dropping from 12.7 to ~12.2 V after 7 hours under 8 amp of load.
Confused by your note 65% and 6.19v those are 6v batteries. If your talking about 6.19v in your series batteries then you should look at the battery that was not changed. What are the voltages of each battery.
__________________
Gary
ohgary is offline   Reply With Quote
Old 02-11-2018, 07:32   #12
Registered User

Join Date: Feb 2015
Posts: 29
Re: Rapid voltage drop under small loads with new Trajan T-105

Quote:
Originally Posted by john61ct View Post
Is the mfg date also March on the new set?
yes, same batch of batteries
BluJu is offline   Reply With Quote
Old 02-11-2018, 07:34   #13
Registered User

Join Date: Feb 2015
Posts: 29
Re: Rapid voltage drop under small loads with new Trajan T-105

We're in Halifax right now, but getting ready to leave to Bermuda in the next few days, and Caribbean after that.
BluJu is offline   Reply With Quote
Old 02-11-2018, 07:38   #14
Registered User

Join Date: Feb 2015
Posts: 29
Re: Rapid voltage drop under small loads with new Trajan T-105

"1- Your CTEK charger is not capable of charging your Trojans as the manufacturer suggests and is likely why your SG readings are what they are. It may be telling you the batteries are "full" but, they're not.

Unless something has recently changed the max absorption voltage for the CTEK is 14.4V and this is just not high enough for deeply cycled Trojans. A target of 14.8V for absorption will result in healthier batteries.

2- Your batteries need to be broken in. The fastest way to do this is deep cycling them and then recharging to 100% SOC after each discharge. Your CTEK is likely not capable of getting your batteries back to 100% SOC...

3- Where are you measuring this voltage and with what equipment. The only voltage reading that matters is one taken directly from the battery terminals with a known accurate volt meter or DVM. Taking this measurement anywhere else in the system, as most boats volt meters do, is simply a poor data to work from.

4- Lead acid batteries can exhibit a voltage drop then a rebound on discharge. This discharge graph below was a Trojan battery during a 20 hour capacity test that delivered 77% SOH based on the factory rating of 130Ah. Notice the initial dip in voltage to the far left and then the rebound. This dip, then rebound, was close to 0.1V. A voltage difference for a lead acid battery of 0.1V can actually be 10% of a lead acid batteries capacity, so going by voltage here can could certainly be a bit misleading.

I've also highlighted when this battery hit about 88% SOC based on the actual Ah's it could deliver. Your battery bank, based on the "as new" rating, was also down about 12% +/-. The voltage under the .05C load on this used battery was 12.26V.

With a 0.018C load, and that voltage, I suspect you have a charger issue, non-broken in batteries and potentially a voltage sensing location or equipment issue. If you get a good quality charger, that can charge them per Trojan's guidance, I suspect you will see your loaded voltage support do much better as they begin to break in."




Thanks for this detailed reply. I measured all voltages at the battery terminals with a conventional digital voltmeter. I realize that the CTEK charger does not deliver the required absorption voltage. I will see about sourcing one that can.
BluJu is offline   Reply With Quote
Old 02-11-2018, 08:13   #15
Registered User

Join Date: Jan 2017
Posts: 12,578
Re: Rapid voltage drop under small loads with new Trajan T-105

This thread goes into some detail on optimal care specs for those

6vdc Trojan T105 (225ah) Equalization
__________________

john61ct is offline   Reply With Quote
Reply

Tags
loa

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Trojan T-105 voltage under load Sam the Sailor Electrical: Batteries, Generators & Solar 59 21-08-2018 05:49
Voltage Drop in AGM Under Load? neelie Electrical: Batteries, Generators & Solar 103 28-08-2014 11:47
Voltage drop under load, amps read 99% ?? VVD Electrical: Batteries, Generators & Solar 25 28-06-2011 16:25
Isolate Shore Power Loads from Inverter Loads RoyHB Electrical: Batteries, Generators & Solar 4 19-04-2010 06:02

Advertise Here


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 12:09.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
×

ShowCase vBulletin Plugins by Drive Thru Online, Inc.