New house batteries

[robertager1962]

Looking at the data sheets, I am not 100% sure what the rated capacity of the T105 actually is as they give a range of values. If it is 105 amps (as I am guessing) and I put 2 in series, will that give a capacity of 12 volt at 105 amp? Sorry, I mulled this over last night one of the other skippers here and am amazed at just how dense we are. Travel several 1000's miles - no problem, work out battery calculations and we are all at sea no wonder we all get ripped off by the chandleries.

 

[GHA]

Looking at the data sheets, I am not 100% sure what the rated capacity of the T105 actually is as they give a range of values. If it is 105 amps (as I am guessing) and I put 2 in series, will that give a capacity of 12 volt at 105 amp? Sorry, I mulled this over last night one of the other skippers here and am amazed at just how dense we are. Travel several 1000's miles - no problem, work out battery calculations and we are all at sea no wonder we all get ripped off by the chandleries.

T105s are 225Ah at the 20 hour rate which is the usual benchmark for boaty batts, though less than honest suppliers might occasionally quote the 100h rate to make them look bigger. So with a load of capacity/20 (=11.25A) they should run for 20 hours at 25 deg C before the voltage drops to 10.5V (for 2 in series) . Hotter will give more power, colder less.
So 1 batt gives you 6v with 225Ah, 2 in series you get 12v with 225Ah.

Have they changed the name to 'motive' recently? This came up on google >

 

[KompetentKrew]

Err..... no..

If 'condition' is capacity at 'boat type' discharge rates then the most accurate method isn't easy. A constant current load in a temperature controlled environment, usually at 25DegC. Temperature can make a significant difference to the battery capacity. >

Not sure why you're saying "err… no" and then agreeing with me?

You can achieve a constant load with a car headlamp bulb, but it's not reasonable to expect OP to test his batteries in a temperature-controlled lab - his existing observations that they're defunct were not made under these conditions.

Not sure why you refer to a CCA battery testing. I was of course referring to the discharge test that is done over several hours. This is what Plymouth battery Centre gave me:

I was very impressed by this battery store - they talked me out of buying new batteries. Anyway, along the x-axis you can see the scale in hours.

 

[Richard10002]

Not sure why you're saying "err… no" and then agreeing with me?

You can achieve a constant load with a car headlamp bulb, but it's not reasonable to expect OP to test his batteries in a temperature-controlled lab - his existing observations that they're defunct were not made under these conditions.

Not sure why you refer to a CCA battery testing. I was of course referring to the discharge test that is done over several hours. This is what Plymouth battery Centre gave me:

Pics snipped.........​

I was very impressed by this battery store - they talked me out of buying new batteries. Anyway, along the x-axis you can see the scale in hours.

Very impressive!!
Did they charge you for the test?

It would be nice to think they do it because they are good guys, and are happy to give you good advice which talks you out of buying a battery, on the basis you will spread the word, and buy from them when you need something.

I haven't come across any battery supplier, (or anywhere), who openly offers this kind of test - I wonder how we find who does it in various locations around the country?

 

[GHA]

Not sure why you're saying "err… no" and then agreeing with me?

You can achieve a constant load with a car headlamp bulb, but it's not reasonable to expect OP to test his batteries in a temperature-controlled lab - his existing observations that they're defunct were not made under these conditions.

Not sure why you refer to a CCA battery testing. I was of course referring to the discharge test that is done over several hours. This is what Plymouth battery Centre gave me:

I was very impressed by this battery store - they talked me out of buying new batteries. Anyway, along the x-axis you can see the scale in hours.

Not actually agreeing with you....

impressive from a battery shop though - did they have a constant temperature bath? Looks like the test ended before 10.5v as well, and no mention of constant current.
As it was a few hours then obviously a 20h test. So well worth it but won't be 'very accurate', you'll need more than one 20H test constant current/constant 25degC for that, though for us 'very accurate' isn't really that necessary s'pose.
'You can achieve a constant load with a car headlamp bulb' - 'fraid not, the current will decrease as the voltage goes down - some electronics is needed to keep the current constant. Still possible for the geeky boat owner but a bit involved, made one a while ago with ebay bits for testing smaller batteries -

Though end of the day if a batt shop can give what you got then at least it's something, probably plenty enough for most of us.

 

[KompetentKrew]

Very impressive!!
Did they charge you for the test?

Nope. Just cost me a taxi to get them there.

Whilst I'm praising Plymouth tradesmen, Tim Beck Marine Gas Services picked them up for me a couple of days later, as a favour on his way to MOT my stove and gas locker. ?

It would be nice to think they do it because they are good guys, and are happy to give you good advice which talks you out of buying a battery, on the basis you will spread the word, and buy from them when you need something.

I think that was it. It's clearly an owner-operated business and I assume he thrives on repeat business. He was insistent that I should give him the dimensions of my battery compartment if I needed to replace them and he'd figure out the best bang-per-buck replacements for me. He seems to like AGM batteries and was very complementary when he learned mine were Victron.

He saved me hundreds with this test, which he was also very forthright in recommending. I had planned to start a new thread at a later date to express my satisfaction with them. They also re-crimped some battery cables for me for not much money - maybe £2 each.

 

[robertager1962]

I just wanted to thank you all for helping me through this baffling subject that are deep cycle batteries. Good to hear from users rather than retailers. Funnily enough I have left my batteries off mains charge for 48 hours (just relying on solar charging) and they are behaving impeccably, never dropping below 12.5v and the battery monitor never going below 75% and this with the fridge running so I am going to see how long I can nurse them along. However I have decided that when they eventually die, I will doctor my battery box and fit 2 x Trojan 105s. Now for the Jabsco toilet leak :-(

 

[Richard10002]

I just wanted to thank you all for helping me through this baffling subject that are deep cycle batteries. Good to hear from users rather than retailers. Funnily enough I have left my batteries off mains charge for 48 hours (just relying on solar charging) and they are behaving impeccably, never dropping below 12.5v and the battery monitor never going below 75% and this with the fridge running so I am going to see how long I can nurse them along. However I have decided that when they eventually die, I will doctor my battery box and fit 2 x Trojan 105s. Now for the Jabsco toilet leak :-(

My battery box takes either 3 "normal size" 110Ah batteries, or 4 Trojan T105s. The normal batteries are a bit loose, and the Trojans a tight fit.

 

[Graham376]

I just wanted to thank you all for helping me through this baffling subject that are deep cycle batteries. Good to hear from users rather than retailers. Funnily enough I have left my batteries off mains charge for 48 hours (just relying on solar charging) and they are behaving impeccably, never dropping below 12.5v and the battery monitor never going below 75% and this with the fridge running so I am going to see how long I can nurse them along. However I have decided that when they eventually die, I will doctor my battery box and fit 2 x Trojan 105s. Now for the Jabsco toilet leak :-(

Good to hear you're sorted for now but, think about what will happen when you get to the Med and the fridge runs for much longer, along with fans in the cabin. I just scraped through with 200w in Algarve summer sun but last winter uprated to 320w and it's made a hell of a difference, 4 x T105 now being fully charged, I think undercharging killed the previous set after 5 - 6 years.