Battery planning

[robtheplod]

Hi All

 

I'm starting to prepare and look at batteries since we've had the boat for nearly three years and wanted to have an idea what to get when they fail. I have never replaced them and have no idea how old they are. The boat spends most of the time on shore power mains, so on constant charge and this is probably why they have lasted?

 

The current ones are 4 x Vetus VESMF105 which have the following specs. They say they should last 7 years but presume this is in the hands of someone who knows what they are doing.....

 

VOLTAGE (V)                                      12 V
COLD CRANKING AMPS CCA (EN)    750 A
RESERVE CAPACITY (MINUTES)         160
WEIGHT (KG)                                      24
DIMENSIONS                                     345 x 175 x 230
CAPACITY C5 (AH)                              No
CAPACITY C20 (AH)                            110 Ah

 

Looking around I've found two ends of the spectrum with regards to price. Specs look very similar so just wanted to see if one of these is any better than the other. All will physically fit in the cradle. I thought also it would be better to get ones a little bigger (130ah rather than 105ah) if/when replaced - any issues with this?

 

12V 130AH 130 AH Leisure Battery DEEP CYCLE for Motorhome / Caravan / Campervan£ | eBay

 

or

 

Hankook XL31S Dual Purpose Leisure Battery – Battery Megastore

 

Is the Hankook worth £30 more than the Probat?  with 4 of these it all adds up..

 

thanks!

[ditchcrawler]

40 minutes ago, robtheplod said:

Hi All

 

I'm starting to prepare and look at batteries since we've had the boat for nearly three years and wanted to have an idea what to get when they fail. I have never replaced them and have no idea how old they are. The boat spends most of the time on shore power mains, so on constant charge and this is probably why they have lasted?

 

The current ones are 4 x Vetus VESMF105 which have the following specs. They say they should last 7 years but presume this is in the hands of someone who knows what they are doing.....

 

VOLTAGE (V)                                      12 V
COLD CRANKING AMPS CCA (EN)    750 A
RESERVE CAPACITY (MINUTES)         160
WEIGHT (KG)                                      24
DIMENSIONS                                     345 x 175 x 230
CAPACITY C5 (AH)                              No
CAPACITY C20 (AH)                            110 Ah

 

Looking around I've found two ends of the spectrum with regards to price. Specs look very similar so just wanted to see if one of these is any better than the other. All will physically fit in the cradle. I thought also it would be better to get ones a little bigger (130ah rather than 105ah) if/when replaced - any issues with this?

 

12V 130AH 130 AH Leisure Battery DEEP CYCLE for Motorhome / Caravan / Campervan£ | eBay

 

or

 

Hankook XL31S Dual Purpose Leisure Battery – Battery Megastore

 

Is the Hankook worth £30 more than the Probat?  with 4 of these it all adds up..

 

thanks!

Do ether of the ones you have listed specify how may cycles they should do if properly looked after

[Tony Brooks]

32 minutes ago, ditchcrawler said:

Do ether of the ones you have listed specify how may cycles they should do if properly looked after

 

The sellers should have that data but it can be difficult to prize it out of them, they also play silly beggars with the depth of discharge is rated at. Also watch out that you compare the battery capacity at the C20 rate. Some make C50 or C100 prominent because it legally gives an apparent higher capacity.

[Jen-in-Wellies]

24Kg to 25 Kg for a 110Ahr battery is typical for a leisure one. Weight being almost directly related to lead plate thickness. Almost anything will be cheaper than one with Vetus branding! The Hankook is a similar weight. The Ebay link doesn't have a weight given.

Jen

[Tony Brooks]

1 minute ago, Jen-in-Wellies said:

24Kg to 25 Kg for a 110Ahr battery is typical for a leisure one. Weight being almost directly related to lead plate thickness. Almost anything will be cheaper than one with Vetus branding! The Hankook is a similar weight. The Ebay link doesn't have a weight given.

Jen

 

I wonder why!!!!!

[Tracy D'arth]

I have used Probat for the last 8 years on several boats without any premature failures.

[ditchcrawler]

Gibbo use to rip the tops off and see what was inside.

[robtheplod]

ah ok so weight is a deciding factor?

I suppose i can ask the question?

[Jen-in-Wellies]

Not a deciding factor, but generally, a heavier battery of given capacity will have thicker lead plates. The thicker the lead plates, then the more resistant to warping they are and the less likely they are going to short out a cell. The chemistry is happening on the surface of the plate, where it interacts with the sulphuric acid. Most of the bulk of the lead isn't doing so much. Lead is also expensive, so battery manufacturers are always going to want to try and minimise the amount they use. Lead is about eleven times the density of the acid and plastic in a battery, so makes up the bulk of the weight. Weight is therefore a good guide as to how much lead you are getting.

The sort of cheaper lead acid batteries that will give two to three years careful continual boat use will weigh 20 to 25kg for a 100 to 110Ahr battery. Compare with this deep cycle AGM 12V battery from Trojan, coming in at 30kg.

Edited March 28, 2022 by Jen-in-Wellies

[pig]

16 hours ago, robtheplod said:

 

 

Looking around I've found two ends of the spectrum with regards to price. Specs look very similar so just wanted to see if one of these is any better than the other. All will physically fit in the cradle. I thought also it would be better to get ones a little bigger (130ah rather than 105ah) if/when replaced - any issues with this?

 

12V 130AH 130 AH Leisure Battery DEEP CYCLE for Motorhome / Caravan / Campervan£ | eBay

 

Hi robtheplod

I bought 4x135Ah Probat batteries from a different eBay seller in February 2019. They are still giving good service, with no noticeable degradation. 

I don't mollycoddle the batteries, apart from not letting them go below 50% SOC (according to my SmartGauge). They are charged from 500w solar, and a single 70amp alternator. They run a 240v full size fridge via a 1500W inverter, and an Eberspacher; they are the main loads.

I fully expected them to need replacing by now, but so far so good.

[WhiteSuit]

Having need of new batteries soon I looked at the probat ones linked by Rob. Seems a little strange that same make different rating 110 to 130 amphour all come in the same size case. The last time I replaced batteries, if I upped the amphour rating the case grew. One of the reviews also commented how light it was, I know that is subjective because I couldn't find a weight. The 130 rating was at c100.

[Tony Brooks]

2 minutes ago, WhiteSuit said:

Having need of new batteries soon I looked at the probat ones linked by Rob. Seems a little strange that same make different rating 110 to 130 amphour all come in the same size case. The last time I replaced batteries, if I upped the amphour rating the case grew. One of the reviews also commented how light it was, I know that is subjective because I couldn't find a weight. The 130 rating was at c100.

 

So the 130 Ah @ C100 may well be 110Ah @ C20, and maybe  80Ah @ C5. The higher the discharge the lower the apparent capacity. This gives the less than scrupulous suppliers lots of room to manipulate their customers.

 

My advice is to insist on getting the C20 rate so you are comparing like with like but perhaps the cycles to the depth of discharge is equally important when comparing batteries.

[Bee]

I suspect that a lot of batteries have the same innards and the only difference is the label. Interesting stuff on You Tube showing how in India or Pakistan truck batts. are opened up, stripped out and rebuilt by characters in bare feet surrounded by piles of lead and puddles of acid..... coming to a back street near you soon......

[Tony Brooks]

16 minutes ago, Bee said:

I suspect that a lot of batteries have the same innards and the only difference is the label. Interesting stuff on You Tube showing how in India or Pakistan truck batts. are opened up, stripped out and rebuilt by characters in bare feet surrounded by piles of lead and puddles of acid..... coming to a back street near you soon......

 

I used to do that in the UK for car batteries as well, but not bare feet, puddles of acid and the old plates went into a bin. It was known as re-plating. What stopped it was the advent of the all in one, glued on, battery lid.

[robtheplod]

I've asked the Probat seller what the C20 and weight are, so I'll let you know what i get back... thanks for the discussion on this its really interesting!

[robtheplod]

Probat battery is 20,3kg 

They omitted to reply to the C20......

[Alan de Enfield]

14 minutes ago, robtheplod said:

Probat battery is 20,3kg 

They omitted to reply to the C20......

 

That sounds quite 'light'.

My 200/220Ah batteries are 53-55kgs each

[robtheplod]

I think i may have decided...

[Tonka]

15 minutes ago, robtheplod said:

I think i may have decided...

What have you decided ?

[Alan de Enfield]

5 minutes ago, Tonka said:

What have you decided ?

 

He has decided he is undecided.

[robtheplod]

53 minutes ago, Alan de Enfield said:

 

He has decided he is undecided.

You know me well....... for the moment decided on the Hankook.... but as my batteries are still working currently, when I need to change I will have completely forgotten this thread and my notes and go into a mad panic....

[ditchcrawler]

7 hours ago, Tony Brooks said:

 

I used to do that in the UK for car batteries as well, but not bare feet, puddles of acid and the old plates went into a bin. It was known as re-plating. What stopped it was the advent of the all in one, glued on, battery lid.

Several years ago I visited Shield batteries in I think Bishops Stortford to be greeted by flames, heat and noise. I don't think they do that any more @Loddon may know

[robtheplod]

Following on from the battery choice I'm checking my mains charger. Its currently quite an old one and not very efficient so looking around to plan.

 

I notice that the Victron combi's seem to have pretty potent battery chargers - 50a to about 120a. The dedicated battery chargers seem to have much less capacity, around 30a and I wondered if i wanted to keep separates would something like 30a be suitable for 4 x130ah batteries (+ 1 x start and 1 x BT). The Victron manual for the 30w Smart Blue battery charger mentions about 300ah as the recommended max so wondered if this makes it work too hard with bigger loads or just take longer?   Can you get a battery charger that is too small?  thanks!!!

[BEngo]

My 25A WAECO charger happily keeps up with 4 x 115 Ah batteries.

 

A Like an alternator, you can't get more out i a battery charger than 8t will produce..  If it says 30 A then that is its max output, and good design will do that indefinitely.   Also like an alternator, a battery charger into a LA battery is only going to be at top whack for a while.  Once the battery terminal voltage starts to rise the charge current will start to fall off.

 

 The other thing that the charger might usefully do is to act as a power supply for the DC loads when on shoreline and with batteries charged. This avoids battery cycling.

 

So, set the size of the charger to be able to take your maximum DC load when on shoreline and which will put back your normal day usage in an acceptable time.  Try to get one where the absorption stage timing is user  variable, so you can match it to your capacity. Ignore smart charging abilities.  One with an equalization setting is useful too.

 

[ditchcrawler]

1 hour ago, robtheplod said:

Following on from the battery choice I'm checking my mains charger. Its currently quite an old one and not very efficient so looking around to plan.

 

I notice that the Victron combi's seem to have pretty potent battery chargers - 50a to about 120a. The dedicated battery chargers seem to have much less capacity, around 30a and I wondered if i wanted to keep separates would something like 30a be suitable for 4 x130ah batteries (+ 1 x start and 1 x BT). The Victron manual for the 30w Smart Blue battery charger mentions about 300ah as the recommended max so wondered if this makes it work too hard with bigger loads or just take longer?   Can you get a battery charger that is too small?  thanks!!!

What are you planning to do with your battery charger. If its recharge you batteries from a portable generator then as big a dumb charger as you can get because you wont want to keep the genny on to get into float, you will just want to hump it in until you decide they are full enough and switch it off. If you are going to be on a land line 24/7 then a 10 amp charger is more than enough as the batteries will never go flat. If you keep the boat in a marina, go out and a quarter of a mile down the canal on Friday, moor up and come back to the marina Sunday night with almost flat batteries then the big clever one is what you need.

 

Edited April 4, 2022 by ditchcrawler
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