24volt.

G

Guest

Guest
Hi, does anyone know if it is possible to run 24v equipment by utilising the 24v potential across the starting circuit on a diesel cruiser. I have been offered a hydraulic pump with integral 24v motor and it set me thinking , yet again; on the hydraulic winch debate. All thoughts greatfully received.
Regards Gareth Jones '97 1-HDFT Newport S.Wales.
 
G

Guest

Guest
Gareth
It would be rather difficult to connect this pump up to 24v using both
batteries on a cruiser.The negative terminal of the 12v system is connected
to the ground of the vehicle, and the positive terminal is connected the
other positive terminal of the battery until you hit the start. Then a
solenoid connects the positive to the negative thus giving 24v. This is
called parallel for the 12v setting and series for 24v.
It should be possible to replace the motor or the windings in the motor of
the pump and would probably be a lot easier.
Dave Harris
[Email address removed]
97 VX 1HDFT Devon UK
----- Original Message -----
From: "Gareth Jones" <[Email address removed]>
To: <[Email address removed]>
Sent: Wednesday, June 23, 2004 5:24 PM
Subject: [ELCO] 24volt.
Hi, does anyone know if it is possible to run 24v equipment by utilising the
24v potential across the starting circuit on a diesel cruiser. I have been
offered a hydraulic pump with integral 24v motor and it set me thinking ,
yet again; on the hydraulic winch debate. All thoughts greatfully received.
Regards Gareth Jones '97 1-HDFT Newport S.Wales.
 
G

Guest

Guest
Gareth
Hi, does anyone know if it is possible to run 24v equipment by utilising the 24v potential across the starting circuit on a diesel cruiser. I have been offered a hydraulic pump with integral 24v motor and it set me thinking , yet again; on the hydraulic winch debate. All thoughts greatfully received
It would be possible, but would require a fair bit of rewiring.
The starter switchover relay completely disconnects the 2nd (left hand) battery from the normal 12v parallel electrics, and connects it instead in series with the starter at 24v. While starting the right hand battery remains "as is", with its -ve earthed to the chassis; but the -ve of the left hand battery connects to the +ve of the right, and its +ve then gives 24v for starting.
When you release the starter the two batteries revert to being connected in parallel.
You could intervene downstream from the switchover relay and have a "starter or pump" changeover switch of some sort, but it would require that relay to be energised all the time you used the pump - possibly causing overheating. The switch would also have to be in quite an exposed location somewhere between relay and starter motor if the starter wiring run is to remain short.
I think I would leave all that as it is, and instead have a separate, manual isolator-come-changeover switch for the 2nd battery which effectively replicates the function of the starter switchover relay, with the difference that it would feed 24v directly to your hydraulic pump.
In order to isolate the battery completely the switch would have to be two way, double pole, "break before make"; and capable of carrying the starter current, which must be around 2.5kW (ie100+ Amps). I don't know if such a beast is available - if not you'd have to have 2x single pole, two way switches. The latter might be cheaper and easier to wire up anyway.
Either way you would have a manual switchover between "starter" and "winch". The normal 12v electrics would continue to work fine with the left hand battery disconnected, and the engine would continue to run if already running, but you would not be able to start the engine.
I suppose the 3rd alternative is to have a separate 12v battery, and to connect it in series to the unmodified 12v system. But it would be a pain finding a location for the battery. This would save having to have changeover wiring capable of handling starter current though.
In all cases you will need to be dead careful about shorts and earthing. If you accidentally feed 24v back through the 12v system you will fry a whole lot of expensive stuff!
Christopher Bell
Devon, UK
1996 1HD-FT
 
G

Guest

Guest
Gareth Jones said:
I did a quick scan of some archives and get the impression that it is
possible to wire things up for 24volts from the two batteries, but you
need to do some major rewiring.
Your better bet is to fit a 3rd battery, which can be used with one of
the front ones (can't remember which) to give 24volts.
--
Regards,
Julian Voelcker
[Email address removed]
Mobile: 07971 540362
Cirencester, United Kingdom
80less at the moment - Roll on June!
 
Don't like the adverts? Remove them by becoming a supporting member.   Click here
G

Guest

Guest
Hello guys,
One point to consider is that you can't have two batteries connected in
parallel AND in series at the same time, as one battery will have to be
shorted. Another point is that using an electric winch to recover a vehicle
that has to be deliberately turned into a dead donkey (no engine, no
alternator, no lights, no nothing ....) is an interesting but pointless
exercise.
--
Rgds,
Roman
London UK
'92 HDJ80
Quoting Gareth Jones <[Email address removed]>:
 
G

Guest

Guest
roman
You don't need to disconnect both batteries, only one.
If the engine is already running you can disconnect either battery and it won't have any effect 'cos they are wired in parallel. You just won't be able to (re)start it. (But never disconnect both while it's running - if the voltage regulation on the alternator runs wild you are in fried electronics territory.)
Christopher Bell
 
G

Guest

Guest
Thanks for all the replies. I'm sure there is a way that this can be done. Christopher Bell seems to be thinking along the same lines as me. Somehow I need to "mimic" the starter by substituting the pump motor. I have a 12 / 24 switch unit made by monark diesel - www.monarkdiesel.co.uk possibly this may do the job. Incidentally suitably located diodes would protect the 12v system from frying in the event of a short ?? Regards Gareth Jones.
 
G

Guest

Guest
Christopher,
But it's not only about disconnecting one battery, it's also about discharging
that battery. What you end up with is one battery supplying current and being
recharged by the alternator, the other only supplying current. When it comes
to restarting the engine you reconenect both batteries in parallel and
immediately notice that voltage across both batteries drops because the
batteries are trying to equalise potentials. At that moment the alternator is
of little help because you first have to start the engine, but then you
haven't sufficient energy stored in the batteries. ........
--
Rgds,
Roman
London UK
'92 HDJ80
Quoting Christopher Bell <[Email address removed]>:
 
G

Guest

Guest
roman & Gareth
I guess that's true. From what I can make out a 12v electric winch draws around 100 to 200 amps under load, but what does a hydraulic one draw? It could be a lot less if you accept a slower winching speed.
My batteries are each 80 AmpHours, which must be typical, so if you are pulling 100 amps you have probably got half an hour of active winching before you are getting into "can't restart" territory. I suppose it depends on what you intend to use the winch for.
[snip]
Thanks for all the replies. I'm sure there is a way that this can be done. Christopher Bell seems to be thinking along
the same lines as me. Somehow I need to "mimic" the starter by substituting the pump motor. I have a 12 / 24 switch
unit made by monark diesel - www.monarkdiesel.co.uk possibly this may do the job. Incidentally suitably located diodes
would protect the 12v system from frying in the event of a short ?? Regards Gareth Jones.
Gareth, I don't know the switchover unit - but if it is designed to handle starter current it should be up to the job.
Diodes would theoretically suffice, but they would have to be seriously heavy duty. I've just had a look in the RS catalogue and the biggest rectifier I can find is 130A, and costs about ?70 (I couldn't find any individual diodes). Also bear in mind that:
(a) A silicon diode has a minimum forwards voltage drop of about 0.2v. At 100 Amps that means 20 watts or more of heat to dissipate, as well as the voltage loss.
(b) Diodes can fail.
(c) If they do fail .....
I'd use a switch!
Christopher Bell
 
G

Guest

Guest
Hello Christopher ,
That also depends on the rope layer ... 350A is not an exagerated current draw
but what does a hydraulic one draw? It
A hydraulic winch draws 1 - 2 amps - just enough current to operate a solenoid
valve. With the hydraulic winch it'd be a bit funny to design a 12v/ 24v
switchover installation when all that is needed is replacing the solenoid coil
with a 12 volt one, which would cost a few quid and half an hour work :)))))
80amph is a ballpark figure, CCA is a better measure of battery capacity. But
in reality a two year old battery has little of its theoretical capacity left.
Rgds,
Roman
 
G

Guest

Guest
Gareth,
I am a bit late chipping in here but I don't usually care. I have looked in
to the winch bit and favour hydraulic. I do not know how I will drive it yet
but it will not be from the standard PS pump. In your position I would get
the motor re-wound to operate at 12v. this is not a costly exercise.
Clive Marks,
West Sussex, (very close to Gatwick)
HDJ81 (import), 1997
 
G

Guest

Guest
Thanks, but I shall leave it at 24v as I can also get hold of 12v unit
comprising pump,motor and tank from a taillift unit. Regards Gareth.
 
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock    No Thanks