Chargers and Split Diodes

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andythilo

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Hi

Ok again as part of my boat 'upgrade' I'm need to install a charger and wot not.

Firstly, would this be ok as a charger?

http://www.caravantechnology.com/CandL20ABatteryCharger.aspx

Seondly, at the moment I have 2 batteries, 1 for engine and 1 for boat. If I bought a 3 output split diode, could I leave the 3rd output unconnected for the time being and only connect it when I get a 2nd boat battery and have them in parallel? Or does it have to be connected from the start?

Also Is it wise to have a split diode between the alternator and batteries, as well as between the charger output and the batteries? At the moment, on the alternator is charging the batteries as a car would.

Any advice would be greatly received.

Thanks

Andy
 
The common set up these days is to have a VSR rather than a diode from the alternator to split the charge to the two banks. Suggest you have a look at the BEP Marine clusters which switch each bank separately and have a parallel switch and VSR.

The charger looks very basic and will only charge one battery/bank. A "proper" marine charger will charge 3 or more batteries independently - essential if you are installing a split bank system. Have a look at Merlin www.power-store.com for a range of suitable equipment from budget upwards.
 
It would be Ok as a charger but cannot comment on its suitability for the marine environment.
A substantial output therefore suitable for largish battery banks (they say 100Ah +)

You can charge three batteries independently with a diode splitter but the trouble with diodes is the volts loss across them (typically a minimum of 0.6 or 0.7 volts but increasing as the current increases.
Voltage sensitive relays (VSRs) do not suffer from this volts loss.

You can leave the third diode disconnected or parallel it with one of the others but would you be charging the third battery independently and therefore be needing the third diode or combining it with one of the existing batteries to make a larger bank.

Would need to verify that the charger can be used with a diode splitter.

Compare with marine chargers and also consider a charger with two (or three) outputs rather than using a separate splitter or VSR.

a splitter or VSR between the alternator and the batteries would ensure they are charged independently without the possibility of a duff one discharging a good one.

Also look at all the electronic controllers available* for optimising the charging of multiple battery banks.

*Merlin, Sterling, Adverc, Driftgate. Numerous others aimed at road transport too. Mastervolt?
 
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Good advice and yes a decent output from it. I have a 20a charger which copes nicely with a 220a bank. My goodness Vic almost forgot Mastervolt that would upset the editor of one popular Sailing mag !!
 
VicS said:
a splitter or VSR between the alternator and the batteries would ensure they are charged independently without the possibility of a duff one discharging a good one.

Also look at all the electronic controllers available* for optimising the charging of multiple battery banks.

*Merlin, Sterling, Adverc, Driftgate. Numerous others aimed at road transport too. Mastervolt?
Click to expand...

I know I am being very negative, and not spending Andy's money but.

All he needs a bi-directional VSR between the engine battery and the service battery, connect his single output reasonably priced charger to the service battery. He can connect his second battery in parallel with the original service battery at a later date.

When Andy starts his engine, he will charge the service battery.

When he switches his mains charger on he will put the engine battery on charge.

Brian
 
bi-directional VSR
Click to expand...
Good Idea I never remember those things!

I assume though you mean that the engine will initially charge the starter battery and then the service battery and that the charger will initially charge the service battery and then the starter battery
 
VicS said:
Good Idea I never remember those things!

I assume though you mean that the engine will initially charge the starter battery and then the service battery and that the charger will initially charge the service battery and then the starter battery
Click to expand...

Yes, I tend to think / type in shorthand, sorry must try to think longhand.

I do find it sad, we bought out bi-directional VSR's in 1981, and still everybody forgets them.

Link to 1982 hand out http://www.kddpowercentre.com/P4000_1.jpg

One day it may catch on.

Brian
 
Excellent choice - I have installed them in two boats. You might also look at their Synergex chargers for the mains charging bit. Worth the extra over basic caravan stuff.
 
Just one question, with the service batteries, if I have 2 in parallel, will the chargers be ok to charge both batteries at the same time?, obviously you can't charge each one separatly as the pos and neg are all joined, I think?
 
yes you can charge the two together in parallel. Just regard them as one battery but twice the size.
 
Batteries in parallel

I would suggest when you fit the second battery in parallel that you install them with isolation switches in the positive lead.
Those terminals with a screw down switch built in would be ideal. Leave them normally both on so both in parallel but with the ability to isolate one battery if and when you think one may be dieing of old age.

This way you can charge and discharge each separately so decide if each battery is good or bad. olewill
 
Seems pretty cost effective way of doing it all tbh. Just got to get a charger now and a couple of new batteries!, Oh and an invertor, mains switch... oh the list never ends :D
 
I put a Sterling 30 amp charger in my first boat and it worked so well I moved it to the second and third boats. It was such a boon when tied up in a marina that I wouldnt go cheap and compromise by buying a siomple car battery charger which like as not wont have a proper float setting nor be able to charge to max.
 
Battery terminal switch

andythilo said:
Have you got a link to the screw down terminal your talking about?

Thanks

Andy
Click to expand...

Sorry Andy being in the antipodes the link may be a bit remote

http://www.biasboating.com.au look for cat no 2530 it is listed as $11.95 or about 6 squid to you.

From my experience the switch is OK for high currents. It simply screws down to clamp a copper washer onto the terminal body. good luck olewill

Er sorry that link works but the clamp does not show up. I got it from a printed catalogue.

Try http://www.whitworths. com.au look under electrical switches etc. I feel sure UK chandlers should have them. If not email the above for details. deduct 10% for local tax and add UK tax and postage. good lcuk olewill
 
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