Bow Thruster Batteries!

[nipper]

Hi all.

 

Right, I have killed my bow thruster batteries. Yes , come on then, get it over with!

 

Due to using the thrusters manoeuvring etc, then mooring up, for a few days, tends to leave these batteries in a wanting state!

 

I bought the current ones about 18 months ago. But today, having been standing for two days, they are now down to 23.2 volts, I hasten to add that they are wired for 24volts.

 

I try look after my domestic 2v deep cycle cells at 12v and my starter battery, which is a normal leisure battery that come with the boat 4 years ago and is still going strong.

 

But the thruster batteries are a different kettle of fish.

 

They are in a position at the bows being charged by a 24v charger sited a foot or two away, the 8 amp charger gets it's power by the boats 240v supply. Maybe I ought to say that the thruster batteries are 110 Ah leasure sealed.

 

What I would like to know is what sort of battery I should be using for the thruster, Starter batteries or Leisure batteries? and what size?

 

Am I right in thinking that a deeper cycle battery wouldn't get enough charge at the right level from my charger, so can be disregarded.

 

Also, because I turn off the charger when I finish with the engine, am I right in thinking that a 24v smart charger wouldn't help much?

 

According to the SidePower manual, such that it is, my 4.4 kw of Bow thruster requires 24V : 250 CCA DIN.

 

I hope this makes some sense and a least some can understand what I am amberling on about?

 

Nipper

[Alan de Enfield]

Have you considered not replacing the batteries and try and see if you can manage with a BT ?

[nipper]

Have you considered not replacing the batteries and try and see if you can manage with a BT ?

If you mean without a bow thruster? then yes i have thought about it.

 

I have also thought about getting rid of the gas oven and set fire to twigs on the tow path to cook me dinner!

 

Nipper

[Chewbacka]

Hi all.

 

Right, I have killed my bow thruster batteries. Yes , come on then, get it over with!

 

Due to using the thrusters manoeuvring etc, then mooring up, for a few days, tends to leave these batteries in a wanting state!

 

I bought the current ones about 18 months ago. But today, having been standing for two days, they are now down to 23.2 volts, I hasten to add that they are wired for 24volts.

 

I try look after my domestic 2v deep cycle cells at 12v and my starter battery, which is a normal leisure battery that come with the boat 4 years ago and is still going strong.

 

But the thruster batteries are a different kettle of fish.

 

They are in a position at the bows being charged by a 24v charger sited a foot or two away, the 8 amp charger gets it's power by the boats 240v supply. Maybe I ought to say that the thruster batteries are 110 Ah leasure sealed.

 

What I would like to know is what sort of battery I should be using for the thruster, Starter batteries or Leisure batteries? and what size?

 

Am I right in thinking that a deeper cycle battery wouldn't get enough charge at the right level from my charger, so can be disregarded.

 

Also, because I turn off the charger when I finish with the engine, am I right in thinking that a 24v smart charger wouldn't help much?

 

According to the SidePower manual, such that it is, my 4.4 kw of Bow thruster requires 24V : 250 CCA DIN.

 

I hope this makes some sense and a least some can understand what I am amberling on about?

 

Nipper

You probably don't use the thruster for more than a minute or two when mooring up. So worst case is two minutes at 250A would be 500A minutes which is only 8 AHr. Which - again worst case - would need 12AHr pushed into the batteries. So you could get that in a couple of days or so (thinking winter) from a 50W solar panel.

 

A thruster is like a starter motor and so a battery suitable for engine starting and leisure should be fine,

 

Solar with a cheap pwm controller will give you a much longer battery life.

Edited December 4, 2016 by Chewbacka

[by'eck]

Two 12 volt 110 amp hour batteries wired in series to give 24 volts sound fine. Not much to choose between leisure and starter batteries as they are similar construction. Agree that thick plate deep cycle batteries of similar capacity not really adequate to provide the short term high currents needed for BT.

 

Your 8 amp charging system seems feeble though even assuming the 240 volt supply is permanently available whilst cruising. A 20 amp multi stage charger would be better to quickly replace charge lost when using BT, and keep them fully charged ready for next use, especially if you use the BT frequently.

[MtB]

I'm curious about why you need more than a momentary touch of the bow thruster when finally mooring up and leaving the boat.

 

If its an awkward marina berth you have, do you have no shoreline to charge them with?

 

If not I'd have thought this was an ideal application for a solar panel.

[nipper]

Yes, Thanks Chewbacka.

I have 400Watts of solar at the back of the roof, but probably worth negotiating with swimbo for additional space amongs her veggy and herb patch at the front!

 

Thanks by'eck,

I was thinking about getting some heavier batteries like the Banner veriety, they do seem that bit heavier and built to last. The bigger multistage charger was looked at last year but it all got a bit confusing , so left it all alone. Perhaps, time to start again me thinks!

I'm curious about why you need more than a momentary touch of the bow thruster when finally mooring up and leaving the boat.

 

If its an awkward marina berth you have, do you have no shoreline to charge them with?

 

If not I'd have thought this was an ideal application for a solar panel.

Thanks Mike,

I cruise 1000/2000 miles a year and have no need for a marina berth as i can never stop still long enough!!

[Alan de Enfield]

 

 

I have also thought about getting rid of the gas oven and set fire to twigs on the tow path to cook me dinner!

 

Nipper

 

Probably not the best of ideas as that would appear to contravene the 1965 Bye Laws (section 31( B ) 'Improper Use of Towpaths')

 

(However, it would be a good skill to have, in the event of running out of gas)

[ditchcrawler]

If I have read it right you turn your charger to the bowthruster batteries off as soon as you stop your engine. does it go on again as soon as you start and how long does it charge for ever day?

[Robbo]

I read that spiral cell is best for bow thruster batteries, but one of the reasons was that they are usually on the end of a long cabke from the charging source and spiral cell has a good range for charging voltages. As your charging source is close you won't have that problem. The other reason is that they can supply the amps.

 

As bow thrusters need the amps, they need batteries that can supply it, so starter type batteries. I would get big capacity ones that can supply a large cca.

Edited December 5, 2016 by Robbo

[mross]

Nipper, great post with lot's of relevant info to help us. Perhaps do what you are doing and replace the batteries every 18 months with cheapos?

[cuthound]

The problem is you are using your BT batteries to moor and then turning the charger off. This causes them to sulphate.

 

Unless you can leave the charger connected when you leave the boat, you will always damage the batteries. If this is the case it is best to use cheap leisure batteries and replace them frequently.

[WotEver]

If this is the case it is best to use cheap leisure starter batteries and replace them frequently.

[Murflynn]

just run a pair of 6mm2 cables from the main battery bank to the BT battery, and they will always be charged up.

 

 

 

 

....................... unless your BT is 24V and the rest of the boat is 12V, of course.

Edited December 5, 2016 by Murflynn

[matty40s]

I moored up last night after dark in Atherstone. This jolly chap came up to me with a handful of twigs in one hand and a tin of spam in the other asking for matches and a firelighter.

 

 

 

 

Good to see you again nipper, small solar panel can't take up too much plant space.......remind your good lady it's for the GIRLY button...

[Chewbacka]

The problem is you are using your BT batteries to moor and then turning the charger off. This causes them to sulphate.

 

Unless you can leave the charger connected when you leave the boat, you will always damage the batteries. If this is the case it is best to use cheap leisure batteries and replace them frequently.

Or leave the boat and with a panel let the sun charge the battery back up.

I have a BT which I only use when mooring up at my home mooring, so not much charging after the last use of the BT. I have 20W of solar just for the BT and the battery (lucas leisure battery, so nothing special) is 5 years old and still fine.

 

Added - A BT uses a huge current so needs starter battery capability, but it does not (normally) run for more than a few seconds, so will only use a few amp hours. So to put that back does not need a big expensive charger. A 10A charger for a couple of hours should do it, or if leaving the boat a small solar panel.

Edited December 5, 2016 by Chewbacka

[cuthound]

 

If this is the case it is best to use cheap leisure starter batteries and replace them frequently.

My understanding is the 90% of "leisure" batteries are rebadged starter batteries (thin plates to allow large currents to flow from a given ampere hour capacity battery)

[by'eck]

 

Thanks by'eck,

I was thinking about getting some heavier batteries like the Banner veriety, they do seem that bit heavier and built to last. The bigger multistage charger was looked at last year but it all got a bit confusing , so left it all alone. Perhaps, time to start again me thinks!

 

 

You could also consider charging via engine alternator(s) if they are 24 volt. Suitably large charge cables will offer minimal volt drop especially for 24 volts. You could even use a Sterling battery module 12 -> 24 volt if main system is 12 volts.

 

I have a Nobels 12 volt BT and charge the two bow located 110 ah batteries via a 90 amp alternator. Any use is compensated within a minute or two by this robust charge system which has seen over 100 amps down the charge cables.

[MtB]

just run a pair of 6mm2 cables from the main battery bank to the BT battery, and they will always be charged up.

 

 

 

How is that going to work then? Surely...

 

1) The BT will just drag 1/3 of it's current from the main battery bank when operated, and fry the 6mm cables in the process.

 

2) There will still be nothing charging the depleted batteries after mooring up, unless you are expecting the 6mm cables to charge the BT battery just from the 'main battery bank'. Which won't work of course.

[WotEver]

My understanding is the 90% of "leisure" batteries are rebadged starter batteries (thin plates to allow large currents to flow from a given ampere hour capacity battery)

Yup, but if you don't specify 'starter' then the user might just well hit on one of the 10%

 

 

How is that going to work then? Surely...

 

1) The BT will just drag 1/3 of it's current from the main battery bank when operated, and fry the 6mm cables in the process.

 

2) There will still be nothing charging the depleted batteries after mooring up, unless you are expecting the 6mm cables to charge the BT battery just from the 'main battery bank'. Which won't work of course.

 

1) won't happen because of the voltage drop down the very long cable.

2) yes it will work.

But it can't be done if the boat is 12V of course.

[nipper]

Thanks for all your suggestions.

 

Taking a cable from the back of the boat to the bow would involve lots of greaf, especially as it's a 70 footer and the size of cables involved. That also gets into other problems well documented on this forum.

 

I would agree with the starter batteries and maybe better quality ones like Banner, but as ever they will sulphate because they wont be full when at rest.

 

I agree with the bigger battery charger, but 24 volt at 20 odd amps are buggers to get hold of, unless you go down the proper installed Victron or Sterling ones, and they will also present problems in fitting and cabling.

 

Mind you, I came across this one from Sterling that might do, at a reasonable price too!

 

It's a Sterling Pro Charger as in here - http://sterling-power.com/products/pro-charge-c-24v-20a-ac-to-dc-battery-charger-30-days-warranty?variant=24350473542.

 

Any good??

 

Maybe that charger above and a set of cheapos is the way to go, after all I don't want to spend a fortune on what is, after all, an aid, and I can use the boat perfectly well without it and prefere to spend on the back end of the boat that really matters.

 

Yep! nice to see you again Matty, that spam was good, but Mary prefers to heat it in the gas oven, she may go for the solar panel though! I havent ventured out to see if you have gone, but as the waters frozen this morning and we are in no rush, we will stay put and M can get more shopping!

 

Largo's electrics are 12v and 240v through the inverter and 240v using the Travel Pack also onboard are 400w of solar, which doesn't come into it's own until the sun rises higher in the sky of coarse.

 

Only the bow thruster being 24Volts.

 

Nipper

[ditchcrawler]

 

You could also consider charging via engine alternator(s) if they are 24 volt. Suitably large charge cables will offer minimal volt drop especially for 24 volts. You could even use a Sterling battery module 12 -> 24 volt if main system is 12 volts.

 

I have a Nobels 12 volt BT and charge the two bow located 110 ah batteries via a 90 amp alternator. Any use is compensated within a minute or two by this robust charge system which has seen over 100 amps down the charge cables.

How can he do that when the engine isnt running

just run a pair of 6mm2 cables from the main battery bank to the BT battery, and they will always be charged up.

 

 

 

 

....................... unless your BT is 24V and the rest of the boat is 12V, of course.

Not if the engine isnt running

Yup, but if you don't specify 'starter' then the user might just well hit on one of the 10%

 

2) yes it will work.

 

How?

[WotEver]

How?

I did say "... unless the boat is 12V" which it is, so it can't ;-)

 

If it weren't then the leisures would gently replace the few lost Ah from the thruster batts at no great loss to themselves.

[matty40s]

Ice is clear to Alvecote now.

[Murflynn]

 

Not if the engine isnt running

 

if the BT batteries are discharged at all, to a voltage slightly below the main batteries, they will be recharged by the main batteries, by a process of equalisation I suppose you could call it.