BT batteries

[blackrose]

I'm looking at replacing my two 13 year old Hi-Fase BT batteries - yes they came with the boat but have finally died! 

 

I would replace them with he same brand/model but it doesn't look like they make them any more. They're 110ah wet lead/acid (refillable) and are labelled dual use (start/leisure). 

 

I'm a bit restricted in terms of the physical dimensions (max: L34cm x W17.5cm x H25cm) as I need to get them into the locker on the bow. Because of the voltage drop to the bow I've never seen them at more than 14.6v when being charged, so I'm wondering if I could use sealed wet/lead acids as there is a lot more choice and I'm more likely to find the dimensions I need. My understanding (which may be wrong) is that sealed maintenance-free lead/acid batteries shouldn't be charged higher than 14.4v because if they gas you can't replace the fluid?

 

I'm just looking at car start batteries so how about these? Are Numax any good? https://www.tayna.co.uk/car-batteries/numax/c31-1000/

 

Thanks.

 

By the way, I really don't want this thread to turn into a silly debate about the immorality of BTs, but I realise that some of you just can't help yourselves, so if you must then by all means knock yourselves out.... 

 

 

Edited September 8, 2018 by blackrose

[TheBiscuits]

Depends now you use your thruster.  If it's short occasional bursts it might better fit the profile of a starter battery rather than a leisure battery - high current draw briefly and irregularly.  

 

I have seen many people with either a dedicated solar panel or a mains powered battery charger to charge their thruster batteries to get around the voltage drop over the full length of the boat, but I would say that your 14.6V is enough.  Bung a couple of cheap sealed ones in and forget about them for years. 

 

 

Re silly debates - on a narrowboat they seem excessive to me.  Yours is a fat boat though, so seems fair enough.  The Dover ferries use them (well azipods technically) so they certainly have a place for controlled handling in tight spaces.

[Tony Brooks]

Those look like pretty much standard 110 Ah size to me except your dimensions look a few mm over size. You can always pack any smaller ones with plywood. make sure you specify the correct terminal layout, there are probably three options.

 

14.6 will be right at the end of charging with virtually no current flowing so voltdrop not an issue then. It is earlier in the charging.

 

There are many boats with Numax batteries and I had a set once when I could get trade discount on them. Just run of the mill leisures.

 

 

[blackrose]

3 minutes ago, TheBiscuits said:

Depends now you use your thruster.  If it's short occasional bursts it might better fit the profile of a starter battery rather than a leisure battery - high current draw briefly and irregularly.  

 

I have seen many people with either a dedicated solar panel or a mains powered battery charger to charge their thruster batteries to get around the voltage drop over the full length of the boat, but I would say that your 14.6V is enough.  Bung a couple of cheap sealed ones in and forget about them for years. 

 

 

Re silly debates - on a narrowboat they seem excessive to me.  Yours is a fat boat though, so seems fair enough.  The Dover ferries use them (well azipods technically) so they certainly have a place for controlled handling in tight spaces.

 

Thanks. Yes, my boat is fat and heavy and I'm single-handed. I can steer without it but it does help close quarters handling in marinas, etc. 

 

The only potential downside of start batteries as I understand it, is that they're less tolerant of being run down or left uncharged for long periods compared to leisure batteries, but on the upside they tend to produce higher cold cranking amps which should be good for short bursts required by a BT. 

[blackrose]

16 minutes ago, Tony Brooks said:

 

14.6 will be right at the end of charging with virtually no current flowing so voltdrop not an issue then. It is earlier in the charging.

 

Ok thanks, so I wouldn't be putting too much into the Numax batteries and causing them to gas?

[Rob-M]

We use sealed Numax batteries for both leisure and starter. Had the leisure batteries 4 years and the starter 3 years so far. Our alternater only appears to ever get to 14.2v so not sure about charging at a higher voltage.

[Momac]

Not knowing what power your bow thruster is but if it needs two x 110Ah batteries it must be enormous . 

My little bow thruster is 3kW and works fine off a single starter battery which I think is 80Ah or thereabouts .

 

The Ah capacity should not be very critical as the thrister is used only when the engine is running and generally speaking in very short bursts so a large reserve of energy is not required. The CCA rating is a guide to the ability to deliver high current for a short duration.

Something costing less may be equally suitable................. and not necessarily compromising Ah capacity

https://www.batterymegastore.co.uk/brands/hankook-batteries/starter-batteries/hankook-umf58000-ultra-high-performance-battery-uk-part-code-110.html

https://www.batterymegastore.co.uk/brands/hankook-batteries/starter-batteries/hankook-mf31-750.html

 

 

[blackrose]

It's a 95kgf bow thruster. I'm not sure how that converts to kW but I'm not sure that's really the point. It's not that my BT requires 2 x 110ah batteries to work, but like any battery bank the larger the capacity the more power there is available in reserve.  The charging system to my BT batteries relies on reasonably frugal usage which is fine, but it's good to have a bit of reserve in my opinion. Anyway, the builder set up the 12v electrical system and it's worked perfectly over the last 13 years so I see no reason to change the setup now.

Edited September 8, 2018 by blackrose

[blackrose]

36 minutes ago, MartynG said:

The CCA rating is a guide to the ability to deliver high current for a short duration.

Something costing less may be equally suitable................. and not necessarily compromising Ah capacity

https://www.batterymegastore.co.uk/brands/hankook-batteries/starter-batteries/hankook-umf58000-ultra-high-performance-battery-uk-part-code-110.html

https://www.batterymegastore.co.uk/brands/hankook-batteries/starter-batteries/hankook-mf31-750.html

 

 

 

Thanks for those - the CCAs don't seem as high as the Numax battery in my original post. Is that why they're cheaper?

[Momac]

10 minutes ago, blackrose said:

It's a 95kgf bow thruster. I'm not sure how that converts to kW 

That's about 6kW .

 

.

 

 

 

 

[Tony Brooks]

3 hours ago, blackrose said:

Ok thanks, so I wouldn't be putting too much into the Numax batteries and causing them to gas?

If they were lead antinomy (like Trojans) then yes you may but I think all so called leisure batteries will have lead calcium plates and they typically do not start to gas until at least half a volt above that figure.

Edited September 8, 2018 by Tony Brooks

[Murflynn]

if you remove all those silly sticky labels off the so called sealed battery you may well find there is a removable panel which will lift off with a bit of assistance from a thin blade screwdriver, exposing 6 holes.  Hey Presto - a refillable battery.

[Momac]

12 minutes ago, blackrose said:

Thanks for those - the CCAs don't seem as high as the Numax battery in my original post. Is that why they're cheaper?

Possibly 

 

[blackrose]

10 minutes ago, Murflynn said:

if you remove all those silly sticky labels off the so called sealed battery you may well find there is a removable panel which will lift off with a bit of assistance from a thin blade screwdriver, exposing 6 holes.  Hey Presto - a refillable battery.

Ok, well that's good news then. I'll speak to Tayna on Monday and ask them if they know which ones have removable panels

15 minutes ago, MartynG said:

That's about 6kW .

 

Ok so it sounds like 2 x 110ah batteries might not be completely over specified.

[Murflynn]

On 08/09/2018 at 19:54, blackrose said:

Ok, well that's good news then. I'll speak to Tayna on Monday and ask them if they know which ones have removable panels

Ok so it sounds like 2 x 110ah batteries might not be completely over specified.

I think all commonly used batteries have, but I may be wrong.  Tanya won't tell you, if they think you shouldn't be ignoring their recommendations/instructions.

[blackrose]

23 hours ago, Murflynn said:

I think all commonly used batteries have, but I may be wrong.  Tanya won't tell you, if they think you shouldn't be ignoring their recommendations/instructions.

You're right there. Rang them today and they said they don't know. Manbatt who I think are the main Numax suppliers in the UK, won't tell me either. I'm a bit stuck now because Tayna have nothing in the size I need in open wet lead acids and it seems like it's increasingly difficult to find them. They told me trojans or any other deep cycle leisure batteries aren't specified by CCAs. Is that true? 

[Alan de Enfield]

34 minutes ago, blackrose said:

You're right there. Rang them today and they said they don't know. Manbatt who I think are the main Numax suppliers in the UK, won't tell me either. I'm a bit stuck now because Tayna have nothing in the size I need in open wet lead acids and it seems like it's increasingly difficult to find them. They told me trojans or any other deep cycle leisure batteries aren't specified by CCAs. Is that true? 

I use 'Battery megastore' and they have always checked to see if the batteries are re-fillable (but always says you shouldn't need to)

 

Only starter batteries are specified by CCA (Cold Cranking Amps) as leisure batteries are not required for 'very high, short time, current draw' (ie not cranking an engine)

Edited September 10, 2018 by Alan de Enfield

[Momac]

4 minutes ago, Alan de Enfield said:

Only starter batteries are specified by CCA (Cold Cranking Amps) as leisure batteries are not required for 'very high, short time, current draw' (ie not cranking an engine)

Lots of 110Ah batteries sold as leisure type have  a good CCA rating.

My starboard engine starts off the domestic bank.

 

I have a pair of these as my domestics - they seem okay

https://www.batterymegastore.co.uk/hankook-xv110-x2.html

 

 

[WotEver]

4 minutes ago, MartynG said:

Lots of 110Ah batteries sold as leisure type have  a good CCA rating.

Thereby proving they are little more than re-badged starter batteries, surely. 

[Richard10002]

My perception is that almost all “leisure” batteries are rebadged starter batteries. Some suppliers actually market starter batteries as “deep cycle”.

 

 

[Momac]

9 minutes ago, WotEver said:

Thereby proving they are little more than re-badged starter batteries, surely. 

To be honest I don't much care if they do the job.

 

 

[blackrose]

18 minutes ago, MartynG said:

Lots of 110Ah batteries sold as leisure type have  a good CCA rating.

My starboard engine starts off the domestic bank.

 

I have a pair of these as my domestics - they seem okay

https://www.batterymegastore.co.uk/hankook-xv110-x2.html

 

 

Thanks, I'll give them a call. Those batteries are a bit too big to fit in my locker

[blackrose]

40 minutes ago, WotEver said:

Thereby proving they are little more than re-badged starter batteries, surely. 

Not necessarily. Deep cycle batteries still have a cold cranking ability, although generally not as high as a starter battery. They'll still turn over an engine or motor within their capability, it's just that some manufacturers don't specify the CCA of leisure or deep cycle batteries because that's not what they're primarily designed for. I agree some brands of deep cycle batteries are re-badged start batteries, but not all of them. 

Edited September 10, 2018 by blackrose

[WotEver]

22 minutes ago, blackrose said:

Not necessarily. Deep cycle batteries still have a cold cranking ability, although generally not as high as a starter battery

Yes of course they do. But if a manufacturer is designing a leisure battery then why would they quote a completely irrelevant CCA figure?

[blackrose]

7 minutes ago, WotEver said:

Yes of course they do. But if a manufacturer is designing a leisure battery then why would they quote a completely irrelevant CCA figure?

Some do and some don't. I've seen leisure batteries with CCA specs. The CCA figure isn't completely irrelevant. Many use their domestic batteries to jump start their engine if the start battery is dead for example. 

 

Anyway, contrary to what you said above, the fact that a leisure battery might have a good CCA rating actually "proves" nothing. If you look at the CCA of most leisure batteries they don't match that of the equivalent  a/h start battery. 

Edited September 10, 2018 by blackrose