Battery Switches.

[john61ct]

Originally Posted by smac999

A 1-2-all switch is not.

is not for directing charge current.

OK for directing "loads fed from" which bank.

[smac999]

Originally Posted by john61ct

is not for directing charge current.

OK for directing "loads fed from" which bank.

yes but the first post he wanted to use it on the alt output to direct charge to banks.

[coopec43]

Originally Posted by smac999

yes but the first post he wanted to use it on the alt output to direct charge to banks.

If you ever get around to building a yacht you will quickly learn to work on one problem at a time otherwise you will become overwhelmed.

Currently I am hooking up 24V and 240V systems to the battery bank having pulled the cables some time ago for the winch, macerator, bilge pumps, galley pump, blowers (engine room, bilge and toilet), inverter, microwave, HWS etc.

Someone else is currently installing the 24V alternator, pulleys/idler for me. When that is complete I will start working on the charging system but NOT before........
(I think I have found a Blue Sea "Battery Management System" but I'll worry about that when the time comes.)

[Wotname]

@Coopec43

FWIW, there are battery switches that incorporate a alternator field disconnect (AFD) function which essentially uses a another set of contacts inside the switch body that disconnects the the alternator field circuit before the battery switch is turned to the OFF position. This prevents the potential issue with blowing the alternator output diodes.

Here is one example https://www.bluesea.com/products/900...witch_with_AFD

[coopec43]

Thanks Wotname

That switch does look appropriate. (I have bookmarked the link for future use)

As far as an isolator switch for the starting bank is concerned would this switch be of sufficient amperage do you think? (Two factors I think should be kept in mind is that the system will be 24V and the starter motor will be heavy duty as it is to start a diesel motor)

https://www.ebay.com.au/itm/MINI-BAT...5?ssPageName=S


Thanks

Clive

[Wotname]

^^ marginal - I would say but it depends really on your engine. (and it's starter motor rating.

It would suit an easy starting small diesel say up to 30 hp and perhaps a new 50 hp engine that starts quickly (i.e. < 2 secs).

But it would be totally unsuitable say for a 100 hp hard to start engine where the starter motor might be grinding over for 5+ seconds drawing a couple of hundred amps.

[coopec43]

Wotname

I'll look for something a bit heavier duty. There's plenty of switches from China/Hong Kong that claim to have 500A capacity but I'm reluctant to accept that as fact. I'll pay extra and buy Narva or a recognised brand.

Many claim to have 500A capacity but when you read the fine print it is only intermittent.

I think this is the nearest I can see to what I want.
https://www.jaycar.com.au/profession...witch/p/SF2247

(The motor is a Perkins 4-108 1.7L 22:1 compression ratio 37hp continuous)


Clive

[coopec43]

Wotname


A bit more research.

Re: Starter motor current demand
My perkins 4-108 has a max starter current of 900amps ......according to the workshop manual.....(YBW


Perkins 4.108 Starter Solenoid 100 amp - Parts4Engines


https://www.parts4engines.com/perkins-4-108-starter-solenoid-100-amp/
We offer starter solenoids suitable for automotive' or a marine applications. ... Our marine version for Perkins 4.108 is a high quality, 12V solenoid rated to 100 amps continuous and 800 amp intermittent load, making it more than sufficiently robust for starting this range of engines.



Re: perkins 4.108

I have a feeling that you might benefit from a couple of handbooks.
http://spidybot.com/perkins/Bowman_P...SAP_201236.pdf
http://spidybot.com/perkins/4_108M_Parts_Manual.pdf
http://spidybot.com/perkins/Perkins%...20Handbook.pdf
http://spidybot.com/perkins/Perkins-...shopManual.pdf

The latter, pg. 23, state that the starter max draw is 900A so a starting battery with this rating in Cold Cranking Amps (CCA) would be my suggestion for a battery.

[Wotname]

Originally Posted by coopec43

Wotname


A bit more research.

Re: Starter motor current demand
My perkins 4-108 has a max starter current of 900amps ......according to the workshop manual.....(YBW


Perkins 4.108 Starter Solenoid 100 amp - Parts4Engines


https://www.parts4engines.com/perkins-4-108-starter-solenoid-100-amp/
We offer starter solenoids suitable for automotive' or a marine applications. ... Our marine version for Perkins 4.108 is a high quality, 12V solenoid rated to 100 amps continuous and 800 amp intermittent load, making it more than sufficiently robust for starting this range of engines.



Re: perkins 4.108

I have a feeling that you might benefit from a couple of handbooks.
http://spidybot.com/perkins/Bowman_P...SAP_201236.pdf
http://spidybot.com/perkins/4_108M_Parts_Manual.pdf
http://spidybot.com/perkins/Perkins%...20Handbook.pdf
http://spidybot.com/perkins/Perkins-...shopManual.pdf

The latter, pg. 23, state that the starter max draw is 900A so a starting battery with this rating in Cold Cranking Amps (CCA) would be my suggestion for a battery.

I'm making a couple of assumptions here

1. The above current draw figures are for a 12V starting system (??)
2. You have a 24 V starting system (yes??).

If both assumptions are correct, your starter motor will be using about half of the above figures.

The Jaycar switch looked OK.

I'm not sure of your location but I suspect you are not in a major metropolitan centre or near a major boat part supplier.

Here is switch from Whitworhs if that is of any help.

https://www.whitworths.com.au/swch-bat-sec-300a

Another BlueSea switch (better the above) would be 9003e (without AFD)
https://www.bluesea.com/products/900...Battery_Switch

or a 9004e (with AFD)
https://www.bluesea.com/products/900...Battery_Switch

[coopec43]

Originally Posted by Wotname

I'm making a couple of assumptions here

1. The above current draw figures are for a 12V starting system (??)
2. You have a 24 V starting system (yes??).

If both assumptions are correct, your starter motor will be using about half of the above figures.

The Jaycar switch looked OK.

I'm not sure of your location but I suspect you are not in a major metropolitan centre or near a major boat part supplier.

Yes my system will be running on 24V and yes the figures quoted are for 12V. I thought the Jaycar switch would do the job though I'm not completely sure of what "intermittent" means. (I imagine half a second)

I live in the country (Lancelin) but I often get to Perth and shop at Whitworths (Tomorrow I will be down there picking up another 150kg of lead)

I think I'll get a Blue Seas switch as I will be mounting it at the foot of the companionway steps and I want it to look decent.

Thanks for your help

Clive

[coopec43]

Well, apparently "Intermittent rating" is much, much longer than I thought.

But I bet every manufacturer has their own definition of "intermittent rating"


intermittent-duty rating

[¦in·tər¦mit·ənt ¦düd·ē ′rād·iŋ] (engineering) An output rating based on operation of a device for specified intervals of time rather than continuous duty. Also known as intermittent rating. (Free Dictionary)

[john61ct]

Originally Posted by coopec43

I think I'll get a Blue Seas switch

Yes, no doubts there, way to go.

[coopec43]

I'm progressing with hooking up all the electrical components (winch, microwave, inverter, HWS, blowers, pumps etc) to the battery bank. It is not all straight forward as I am finding the terminals are all a different size and, being large amps involved, I am taking care to match the lug sizes to terminals appropriately.

I have one of these battery isolator switches which has "Stop engine before switching to "off" position" (I understand that is to avoid destroying the diodes)

https://www.ebay.com.au/itm/12V-24V-...ZjA9:rk:1:pf:0

But when I look at the back of the switch I find three large terminals and two smaller terminals marked "Field". What are they for? (I've tried to find a wiring diagram on the internet with no luck and nothing came with the switch itself)

The three big terminals are marked BAT 1, BAT 2 and FEEDER. Would I be correct in assuming the positive cable from the Starting Bank would be connected to BAT 1 and the positive lead from the House bank connected to BAT 2. Then the negative leads from both banks be connected to FEEDER?


ON ANOTHER MATTER. I am wiring up the circuit breaker for the winch which has an LED and two wires coming out the back. Is there any smart way of wiring them into the system?



Your advice will be appreciated.


Clive

[john61ct]

Likely a feature to cut field power to the alt to try to prevent blowing alt diodes.

Better to find the documentation for that switch.

Or best of all, spend the extra on Blue Sea.

[coopec43]

[QUOTE=john61ct;2786939]Likely a feature to cut field power to the alt to try to prevent blowing alt diodes.

Better to find the documentation for that switch.

Or best of all, spend the extra on Blue Sea.[/QUOTe

Yes I think you are right regarding the field power but then why the instruction not to switch "off" while the engine is still running.

The switch is a quality/reputable brand sold by a reputable source so I will redouble my efforts to find a wiring diagram. (I guess I was being lazy). When they sell items on eBay they dispense with the original packaging to save postage.

Actually I think Wotname has the same switch so I might PM him.

Thanks for your advice

Clive