|
|
23-10-2024, 02:48
|
#1
|
Registered User
Join Date: Dec 2009
Location: Australia
Boat: BUILT!!! Roberts Mauritius 43ft
Posts: 4,100
|
12V Battery voltages
I tried to start the Perkins 4 108 motor just a few hours ago. All I could hear was a whirring sound. I assume therefore the solenoid hadn't worked to engage the flywheel. I suspect low battery voltage would cause that?
I am using X2 12V batteries in series. When I checked the voltages of the batteries the aft battery read 16.1V and the other battery it read 12V. Initially I thought the high reading was because the solar panels were still connected but when I switched them off the readings remained the same.
I started reading other threads and I have concluded this is not an uncommon problem but there were various differing reasons.
The history of the two batteries is a bit vague but they have been OK for the last two years.
I am going back to the yacht tomorrow morning so I would appreciate any advice you may have.
PS I do have a battery tester on board but I have no idea how to use it. However my son has offered to help but that won't be until the w/e
|
|
|
23-10-2024, 03:49
|
#2
|
Registered User
Join Date: Dec 2009
Location: Australia
Boat: BUILT!!! Roberts Mauritius 43ft
Posts: 4,100
|
Re: 12V Battery voltages
If the connection between the two batteries was "dirty" could the 24V alternator (or 24 solar charge) boost the voltage of one battery around 16V and leave the second battery with just a 12V charge.
|
|
|
23-10-2024, 05:21
|
#3
|
Registered User
Join Date: Jan 2020
Location: EC
Boat: Cruising Catamaran
Posts: 1,320
|
Re: 12V Battery voltages
When charging is one battery hotter than the other, use a temp gun or the back of your hand.
Disconnect/isolate the batteries and read the voltage after 5 minutes. What volts do you get?
|
|
|
23-10-2024, 06:31
|
#4
|
Marine Service Provider
Join Date: Jun 2015
Location: Croatia
Boat: neptunus 56 fly
Posts: 1,436
|
Re: 12V Battery voltages
Quote:
Originally Posted by coopec43
I tried to start the Perkins 4 108 motor just a few hours ago. All I could hear was a whirring sound. I assume therefore the solenoid hadn't worked to engage the flywheel. I suspect low battery voltage would cause that?
I am using X2 12V batteries in series. When I checked the voltages of the batteries the aft battery read 16.1V and the other battery it read 12V. Initially I thought the high reading was because the solar panels were still connected but when I switched them off the readings remained the same.
I started reading other threads and I have concluded this is not an uncommon problem but there were various differing reasons.
The history of the two batteries is a bit vague but they have been OK for the last two years.
I am going back to the yacht tomorrow morning so I would appreciate any advice you may have.
PS I do have a battery tester on board but I have no idea how to use it. However my son has offered to help but that won't be until the w/e
|
order this https://www.aliexpress.com/item/1005...238118024trg4d
|
|
|
23-10-2024, 06:58
|
#5
|
Registered User
Join Date: Sep 2019
Posts: 561
|
Re: 12V Battery voltages
I saw some threads on other forums where unusually high voltage readings were due to low batteries in the multimeter itself. Perhaps try with fresh batteries or a second meter?
|
|
|
23-10-2024, 08:51
|
#6
|
Registered User
Join Date: Jan 2014
Posts: 2,031
|
Re: 12V Battery voltages
Quote:
Originally Posted by coopec43
I tried to start the Perkins 4 108 motor just a few hours ago. All I could hear was a whirring sound. I assume therefore the solenoid hadn't worked to engage the flywheel. I suspect low battery voltage would cause that?
I am using X2 12V batteries in series. When I checked the voltages of the batteries the aft battery read 16.1V and the other battery it read 12V. ...
|
If the batteries are connected in series should the battery voltage be over 24 volts? I have two batteries connected in parallel and they will read around 12.5ish volts.
Sounds like either the batteries are dead/dying or there is a connection issue between the batteries.
|
|
|
24-10-2024, 00:45
|
#7
|
Registered User
Join Date: Dec 2009
Location: Australia
Boat: BUILT!!! Roberts Mauritius 43ft
Posts: 4,100
|
Re: 12V Battery voltages
Quote:
Originally Posted by Tin Tin
When charging is one battery hotter than the other, use a temp gun or the back of your hand.
Disconnect/isolate the batteries and read the voltage after 5 minutes. What volts do you get?
|
They both seem to be cool while charging.
I have the batteries at home now. I have had the stern battery on charge and it now reads 12.7V
The other battery is now on charge and currently reading 11.7V
Instructions from my Son is to keep charging and he will load test both tomorrow (Having read the instructions I realize now that I could easily use the load tester myself)
I think I'm up for one new 700cca battery
|
|
|
24-10-2024, 00:52
|
#8
|
Registered User
Join Date: Jan 2020
Location: EC
Boat: Cruising Catamaran
Posts: 1,320
|
Re: 12V Battery voltages
Quote:
Originally Posted by coopec43
They both seem to be cool while charging.
I have the batteries at home now. I have had the stern battery on charge and it now reads 12.7V
The other battery is now on charge and currently reading 11.7V
Instructions from my Son is to keep charging and he will load test both tomorrow (Having read the instructions I realize now that I could easily use the load tester myself)
I think I'm up for one new 700cca battery
|
Won't you need two - is it not a 24V system? - mxing old and new batteries in series is not recommended
|
|
|
24-10-2024, 01:52
|
#9
|
Registered User
Join Date: May 2010
Location: Sydney Australia
Boat: Fisher pilothouse sloop 32'
Posts: 3,462
|
Re: 12V Battery voltages
Quote:
Originally Posted by Tin Tin
Won't you need two - is it not a 24V system? - mxing old and new batteries in series is not recommended
|
Exactly.
__________________
Rob aka Uncle Bob Sydney Australia.
Life is 10% the cards you are dealt, 90% how you play em
|
|
|
24-10-2024, 04:00
|
#10
|
Registered User
Join Date: Dec 2009
Location: Australia
Boat: BUILT!!! Roberts Mauritius 43ft
Posts: 4,100
|
Re: 12V Battery voltages
Quote:
Originally Posted by Tin Tin
Won't you need two - is it not a 24V system? - mxing old and new batteries in series is not recommended
|
I thought someone would raise that point. I can understand it if the batteries were being run in parallel but I am running them in series. I did a google and came up with this.
Can you connect different brand batteries in series?
To ensure optimal performance and safety, it is best to use batteries of the same type and rating when you can. This means not using batteries of different brands together. But if you really must, make sure to check and compare so that the type and ratings are similar or as close as possible.24 Aug 2023
The present system has been in use for several years and the batteries were secondhand when I installed them
They are starting batteries so don't get used a lot. (The starter motor is 12V but I have installed a 24V solenoid)
|
|
|
24-10-2024, 05:08
|
#11
|
Registered User
Join Date: Jan 2020
Location: EC
Boat: Cruising Catamaran
Posts: 1,320
|
Re: 12V Battery voltages
WHilst googling check out this site and read the section on different aged batteries in series. https://batteryguy.com/kb/knowledge-...ies-in-series/
|
|
|
24-10-2024, 06:20
|
#12
|
Registered User
Join Date: Dec 2009
Location: Australia
Boat: BUILT!!! Roberts Mauritius 43ft
Posts: 4,100
|
Re: 12V Battery voltages
Quote:
Originally Posted by Tin Tin
|
I have one good battery which has charged to 12.6V quite easily. Tomorrow I will load test it.
The other battery is obviously stuffed as I have been charging it for 5 hours and it is only registering 11.8V
Just looking at prices of batteries (and keeping in mind the bank balance) I can buy
X2 SCA 550CCA @ $135 ..............$270
OR X1 Supercheap 700CCA........... $216
I think I'll go for the two SCA batteries. (I hope to goodness I never need to use 550CCA)
I just had a look at the battery I took out of the yacht and it is
"LEAD ACID Sealed Maintenance Free"
|
|
|
28-10-2024, 07:59
|
#13
|
Registered User
Join Date: Aug 2007
Posts: 85
|
Re: 12V Battery voltages
In spite of the battery issues, I would look at the starter. Hard to debug "whirring", but it might be that the solenoid is frozen. This has happened to me. If there is enough juice to run the starter the bendix gear should engage. I would tap it with a mallet or remove it and clean any corrosion. It's generally possible to remove the solenoid without taking off the starter.
|
|
|
28-10-2024, 15:15
|
#14
|
Registered User
Join Date: Sep 2007
Location: Queensland, Australia
Boat: None at present--between vessels. Ex Piver Loadstar 12.5 metres
Posts: 1,476
|
Re: 12V Battery voltages
I suspect that the starter motor is spinning but the Bendix drive remains disengaged. It slides along a thread against a spring, and the thread needs to be lubricated. If it has not been lubricated for some time, this may be the cause.
You will need to remove the starter motor to do it, and while you have it out, you might as well check the motor brushes as well and replace them if worn.
If your batteries are two years old, they may be alright, but there is a chance that they are faulty and that is why they are simply not spinning the starter motor at sufficient speed to operate the Bendix drive. Terminal voltage is not the same as terminal voltage under load.
I replaced mine every two years anyway. An engine that will not start in an emergency is a potential loser of your vessel, and perhaps your life and that of any others aboard at the time.
|
|
|
28-10-2024, 22:22
|
#15
|
Registered User
Join Date: Dec 2009
Location: Australia
Boat: BUILT!!! Roberts Mauritius 43ft
Posts: 4,100
|
Re: 12V Battery voltages
Quote:
Originally Posted by Mike Banks
I suspect that the starter motor is spinning but the Bendix drive remains disengaged. It slides along a thread against a spring, and the thread needs to be lubricated. If it has not been lubricated for some time, this may be the cause.
You will need to remove the starter motor to do it, and while you have it out, you might as well check the motor brushes as well and replace them if worn.
If your batteries are two years old, they may be alright, but there is a chance that they are faulty and that is why they are simply not spinning the starter motor at sufficient speed to operate the Bendix drive. Terminal voltage is not the same as terminal voltage under load.
I replaced mine every two years anyway. An engine that will not start in an emergency is a potential loser of your vessel, and perhaps your life and that of any others aboard at the time.
|
Thanks for that.
I took both batteries home and tested them under load: one battery is excellent but the other is knackered.
Under instruction from my two diesel mechanics (Son and friend) I bought another battery with similar CCA and they are going to fit them tomorrow. AND my Son has said he will pull the starter motor off and lubricate it.
Thanks for you help.
|
|
|
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Rate This Thread |
Linear Mode
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Advertise Here
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
Vendor Spotlight |
|
|
|
|
|