Reply
 
Thread Tools Search this Thread
 
Old 09 August 2012, 01:31   #11
ncp
Member
 
ncp's Avatar
 
Country: USA
Town: California
Make: Avon 5.4m Searider
Length: 5m +
Engine: Yamaha 90
Join Date: Aug 2011
Posts: 1,191
Quote:
Originally Posted by jyasaki

All the proposals cut, sorry. Too many beers to make sense of it all right now.
Best line all night!

Quote:
Originally Posted by jyasaki
Seems to me that if your base system is 24 volts, you should be able to find something that will reliably convert 24V to 12V, and run the electronics off that. Leave the motor on whatever 12V conversion you have now (especially as it seems to be working.)
I do have a reliable 24v-12v converter already. Though, it allows for the voltage drop to get through which messes with the Lowrance and sometimes the Standard Horizon VHF . The proposals would (a) hopefully avoid allowing the voltage drop to occur because the 12v accessories would be running from a dedicated house battery or bank and (b) keep me from stressing out about running down my starting batteries (2x 12v in series) when the engine is off. Right now I carry a 12v automotive jump start pack (Harbor Freight but at least I know it will get me out of a bind)

If you get a chance tomorrow, let me know what you think of 3 options! Thx
__________________

__________________
ncp is offline   Reply With Quote
Old 09 August 2012, 21:40   #12
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
Well, I looked at the design proposals, and I have to admit, I have *very* little knowledge of 24V systems.

But, a couple of things:

The reason you won't find many 12V input chargers is because they'd have to convert the 12VDC to something higher (15 or so, ideally) in order to get enough potential to charge. And if you've already got 12V, well, that's the point? So, low availability means higher price (suppply/demand curve), plus you've got a lack of selection of replacement components should it not work out the way you want.

If you're going to run a 2 x 24V pair of banks, you don't need to regulate the 12V; use a VSR (your Blue Seas unit would do it) and simply tie in to half of the switched bank. On startup, that bank will be isolated, and should not see any voltage drop. Once running, the VSR opens, and charges both banks.

A non-mentioned option would be to use the existing 24V bank, and parallel half the bank with a second 12V battery on a VSR.

Does that make any sense at all?

jky
__________________

__________________
jyasaki is offline   Reply With Quote
Old 10 August 2012, 07:56   #13
Member
 
Country: UK - England
Town: Gloucestershire
Boat name: Osprey
Make: Osprey Vipermax
Length: 5m +
Engine: E-tec 300 G2
MMSI: TBC
Join Date: Dec 2006
Posts: 4,013
I might be getting confused her but if you have 2 x 12V batteries in series running the 24 volt system why bother with a converter.?

Why not just take a 12volt feed from one of the batteries to run the 12 volt circuit.

I can't think why you would need a converter if you already have 2 12v batteries on board.

I would certainly remove the converter from the equation if you can as I suspect that the source of the problem.

Chris
__________________
---------------------------------------------------
Chris Stevens

Born fiddler
Chris is offline   Reply With Quote
Old 10 August 2012, 13:26   #14
Member
 
Country: UK - England
Town: York
Boat name: Sugar Free
Make: Tornado
Length: 5m +
Engine: Yam 115
Join Date: Sep 2009
Posts: 119
Quote:
Originally Posted by ncp View Post
I like this idea because it seems simple (and cheap). But will the small 12v battery that add be properly charged by my 24v-12v converter? Or, will that converter just keep pumping 12v into the aux battery?

I have other 3 options, below.
The idea is that the diode allows charging but if there is a short or voltage drop then it cuts of and isolates the small battery. This only happens for a short time until the charge voltage is maintained.
__________________
GaryC is offline   Reply With Quote
Old 10 August 2012, 16:17   #15
ncp
Member
 
ncp's Avatar
 
Country: USA
Town: California
Make: Avon 5.4m Searider
Length: 5m +
Engine: Yamaha 90
Join Date: Aug 2011
Posts: 1,191
Quote:
Originally Posted by GaryC View Post
The idea is that the diode allows charging but if there is a short or voltage drop then it cuts of and isolates the small battery. This only happens for a short time until the charge voltage is maintained.
I understand this part about the schottky diode cutting out when a voltage drop is sensed. Setup with schottky diode:

24v DC / 24v alternator ---> 24v-12v converter (existing) --->schottky diode (NEW ADDITION) ---> 12v house battery (NEW ADDITION) ---> 12v switch panel ---> loads

Since the 24v-12v converter is putting out a constant volts & amp (I am guessing), will this charge the new 12v batter correctly? Overcharge it? How does it know when the 12v battery is charged and start trickle charging or providing a maintenance charge?
__________________
ncp is offline   Reply With Quote
Old 10 August 2012, 16:21   #16
ncp
Member
 
ncp's Avatar
 
Country: USA
Town: California
Make: Avon 5.4m Searider
Length: 5m +
Engine: Yamaha 90
Join Date: Aug 2011
Posts: 1,191
Quote:
Originally Posted by Chris View Post
I might be getting confused her but if you have 2 x 12V batteries in series running the 24 volt system why bother with a converter.?

Why not just take a 12volt feed from one of the batteries to run the 12 volt circuit.

I can't think why you would need a converter if you already have 2 12v batteries on board.

I would certainly remove the converter from the equation if you can as I suspect that the source of the problem.

Chris
I don't know! This was the way the US Navy had the boat set up.


---> (A)12v battery(B)--->(C)12v battery(D)--->

In a 24v system, if you run your leads off (A)&(D), you're running on 24v.

But, can you run 24v items on (A)&(D) and 12v items on (A)&(C)??????
__________________
ncp is offline   Reply With Quote
Old 11 August 2012, 01:23   #17
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
Quote:
Originally Posted by ncp View Post
In a 24v system, if you run your leads off (A)&(D), you're running on 24v.

But, can you run 24v items on (A)&(D) and 12v items on (A)&(C)??????
Yup. Assuming both batteries are in decent condition, that is.

jky
__________________
jyasaki is offline   Reply With Quote
Old 11 August 2012, 01:55   #18
Member
 
Country: UK - England
Town: Gloucestershire
Boat name: Osprey
Make: Osprey Vipermax
Length: 5m +
Engine: E-tec 300 G2
MMSI: TBC
Join Date: Dec 2006
Posts: 4,013
Quote:
Originally Posted by ncp

I don't know! This was the way the US Navy had the boat set up.

---> (A)12v battery(B)--->(C)12v battery(D)--->

In a 24v system, if you run your leads off (A)&(D), you're running on 24v.

But, can you run 24v items on (A)&(D) and 12v items on (A)&(C)??????
I think you mean A&B or you could run off C&D if my understanding of you layout is correct.

Basically all you do is pick one battery and connect to the positive and negative on that battery.
__________________
---------------------------------------------------
Chris Stevens

Born fiddler
Chris is offline   Reply With Quote
Old 11 August 2012, 04:58   #19
Member
 
Country: UK - England
Town: York
Boat name: Sugar Free
Make: Tornado
Length: 5m +
Engine: Yam 115
Join Date: Sep 2009
Posts: 119
Quote:
Originally Posted by ncp View Post
I understand this part about the schottky diode cutting out when a voltage drop is sensed. Setup with schottky diode:

24v DC / 24v alternator ---> 24v-12v converter (existing) --->schottky diode (NEW ADDITION) ---> 12v house battery (NEW ADDITION) ---> 12v switch panel ---> loads

Since the 24v-12v converter is putting out a constant volts & amp (I am guessing), will this charge the new 12v batter correctly? Overcharge it? How does it know when the 12v battery is charged and start trickle charging or providing a maintenance charge?
If its already doing that it should not be a problem. My understanding is that the charge level voltage should be 13.8 rather than 12.
__________________

__________________
GaryC is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 18:55.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.