CarpForum.co.uk brand mark, a blue stylized fish with a white eye and a smooth modern look, set in the site header against a clean background CarpForum.co.uk wordmark in a bold flowing script style, reading CarpForum.co.uk, displayed in the site header
Menu
Utils
Go Premium Who's Online Members Weather Photo Gallery Articles
Account
Login Register
Testing Lead Acid Batteries (23 posts / 1,099 views)
Old-Cornishman
Posts: 688
Post #16 12 Jun 2020 08:46
0
In reply to Post #15
Without doubt the capacity of a lead acid drops significant when its cold (50% @ -18 deg C) but as far as I know no permanent damage should occur if it's fully charged. As you say bringing it inside during the winter doesn't hurt if you have the space.
However using a lead acid battery at high temperatures will reduce its life so it's advisable not to leave a boat cooking in strong sun before use.
Tinhead Tinhead
Posts: 17,089
Post #17 12 Jun 2020 08:55
0
In reply to Post #13
i would just use a multi meter across the terminals as has already been discussed.

That's really the point of creating this thread. Batteries can have a high voltage reading but as soon as they have a load put on them they can plummet.

Most people just probably recharge when the batteries are obviously dead which is fair enough but if you want to measure them then it may not be so straight forward.
Old-Cornishman
Posts: 688
Post #18 12 Jun 2020 13:21
0
In reply to Post #17
Testing under load is pretty much meaningless unless you have manufacturers data to go by.
Possibly you could take some readings with a new battery to compare the degradation but resting voltage is the best for us imo.
At home rest for 24 hr off charge, off load and ideally unmoved before taking a reading.
On the bank, if you are charging, take some power say 1 or 2% of the capacity before taking a reading, whether charging or using, its best to rest as long as possible before taking your reading.
Do not let the voltage drop below 12.4 otherwise it will be reducing its life.
Store fully charged, keep as cool as possible in summer otherwise battery life will be reduced, keep charged in winter to prevent freezing



AJM123 AJM123
Posts: 558
Post #19 12 Jun 2020 13:39
0
In reply to Post #17
I must admit i am slightly confused as to what your trying to ascertain, and if you are referring to a bait boat with used batteries or brand new batteries?
All batteries degrade over time and with repeated charges.
A leisure battery for example will usually be rated on the number of charges it will take over it's life cycle.
With respect i feel you might be trying to over complicate the issue.
With regards to a bait boat it's probably best to use an LCD voltage display meter which will numerically tell you what the state of the battery is at the time, so you know when it will need recharging.
Over time if you feel that it is not holding a charge and is depleting quicker than usual then if that is not remedied by giving it a good long charge it's time for a replacement battery.
From what i've seen batteries for bait boats are not excessively expensive so it's not something i would personally obsess over.

I hope the above doesn't come across as arsey.
It does sound a bit like it when i've re-read it.
But it's not meant to be.
Tinhead Tinhead
Posts: 17,089
Post #20 12 Jun 2020 14:59
0
In reply to Post #19
With respect i feel you might be trying to over complicate the issue. Yes probably.

It was when I noticed voltmeters being sold as battery testers it just bugged me . Yes they may give some sort of indication but it's not technically correct. Just wondered if anyone had better ways of doing it but it probably doesn't really matter that much , just me being anal
Budice Budice
Posts: 336
Post #21 12 Jun 2020 15:46
0
In reply to Post #20
If it's a 12V battery you're looking to test them something like this would be fine
Tinhead Tinhead
Posts: 17,089
Post #22 12 Jun 2020 18:55
0
Done some googling and this is what I'm trying to get at by testing batteries under load.

LINK 1

LINK 2

LINK 3 scroll down a bit

A multimeter with battery load test function built in

People have their testers or just wait for batteries to run flat and it works for them so there's no need to change but I think I have cured my own curiosity even though I don't own a bait boat

Old-Cornishman
Posts: 688
Post #23 12 Jun 2020 20:08
0
In reply to Post #22
I believe I understand what you are getting at now.
Two distinct things being discussed here, hence the confusion.
1. Testing whether the battery is serviceable, normally a high current is drawn (to replicate car starting current for instance) and a certain voltage should be maintained unless there are dead or dying cells.
2. State of charge measurement by a multimeter as discussed previously.
Are you sure?

This action cannot be undone.

Yes, continue

Loading…