Eberspacher 24v

[jay]

For reasons that I 'd rather not go into - I have a D1L 24v unit that I want to reinstall on a yacht with a 12v system. I have 2 domestic an d 1 engine battery - all 12v. There is a set of relays etc that alledgedly used to convert the 12v to 24v but its a bit of a mystery on how to connect it all up without frying myself, the boat or most importantly all my electronics.
Has anyone experience of using a 24v heater on a 12v system - or know of anywhere I can get any ideas?


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[xstucker]

No questions asked, but it sounds like you may have bought a used Truck heater just like I did (eBay £85 - Heated my boat just fine) with a dedicated 24v battery.

In order to get the thing fired up, you do need 24volts output and at a reasonable AMP level as well (about 20amps). It may be possible to get a 12v to 24v Step-up transformer, but most I have seen will provide no more than 3000milliamps, like the one at this link...

http://www.m-99.co.uk/Electrical/12v_Car_to_24v_Stepup_Converte/12v_car_to_24v_stepup_converte.html

Simon



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[jay]

Simon - i've considerd putting in a dedicated 24v battery just for the heater - but how do I then charge it? The rest of my system/alternator etc is standard 12v

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[TrueBlue]

Re: Eberspacher 24v - KISS

I think you're going to have insurmountable opportunities with this one...

Here are some suggestions - but which have difficulties in executing them:-

1. Switching batteries
Arrange a switching system to charge the 24V bank by connecting the two batteries in parallel for charging, and then in series when using the heater.

Downsides
1.1. The circuit is relatively simple, but as you need relatively beefy switches to carry the charging and glow plug current, you will have difficulty in obtaining a switch bank to do the job. Most commercial switches are simgle pole 'make' and switch bank systems (build your own stack) are only light current. Try Radiospares / CPC to see what's available.
1.2. Not withstanding the negatives in the above, you now have three battery banks in your system:
I. Engine start
II. Domestic battery
III. Heater battery bank
You will have to use a battery management system - and one of the top end variety to boot to do this.

Messy and expensive - forget it.

2. As you've sourced a S/h truck heater, what about getting a s/h 24V. alternator and attaching that to your engine.

Downsides
Extra belt(s) and pulleys required

positives
Simplest and possibly least expensive solution

3. 12V to 24V convertor.
I'm not aware of any available; there used to be motor generators which could do the job - some radio ham might have one - but they're going to be WWII vintage

4. inverter / battery charger (separate units, back to back)
Not quite such a potty idea as it may first appear, but wouldn't be cheap

KISS means Keep it Simple, Stupid. A reminder to us all not to let ideas run riot!

Perhaps others may run with the above suggestions - and improve on them.

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Stop what you're doing and wait my signal

 

[Blue_Blazes]

Re: Eberspacher 24v - KISS

Or, simplest of all, sell the 24 volt model to me Reeeeally cheaply, (cos my boat's 24V) and buy a 12volt model on ebay!

Bill

<hr width=100% size=1>One of these days I'll have a boat that WORKS

 

[xstucker]

Hi,

The suggestion by Trueblue is the most sensible. You need to have two 12v batteries which can be connected in series to make 24v when needed for the Heater. Then when you need to charge, you should switch them back so that the 12v charge works (shore power or alternator). You could of course connect a new battery and your engine battery together (likely to be using the heater when not using the engine), but you do then risk running the engine battery down. Don't connect the new one with the Domestic, as you probably need heat and light together. Ultimately the best option is to have 4 batteries in total and switch the 2 heater batteries into series for heater and parallel for charging.

Simon

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