2 batteries, 2 chargers?

[brownsox]

Our previous boat had only one battery (outboard engine) and we got a small, neat Cetek battery charger which together with the solar and wind, worked great.
New boat with diesel engine needs 2 (new) batteries. We could get a big charger that does two batteries, and is quite large eg a Cristec (Barden) for £250 (or the ubiquitous Sterling), or two Ceteks - either 2x£50, or one bigger one, so £50 plus £100.
Is there any diasadvantage to having 2? Do these more expensive chargers actually do something else as well as charging from shore power? There are so many electrical bits of kit in the catalogues and they all talk features, not benefits. We're confused!
We're planning on a 70 and a 110 a/h battery.
Thanks

 

[asj1]

The more expensive ones - sterling etc seem to me to do two important things:
fisrtly take the charge down to a trickle/ top up level so that you can leave it on permanently ( I don't but many seem to)
secondly put a much higher amperage charge into your batts. Having said that I have a sterling one that is officially one size too small for my set up but works absolutely fine.
They all have split charging so that at least two, if not three, sepertae battery banks can be charged.

Regards

 

[JKay]

The Forum Electrikery bofs recommended THIS and its working brilliantly /forums/images/graemlins/smile.gif

Cheers Joe

 

[DaveS]

I have one of these and it seems to work fine - with one slight reservation: they claim 3 independent outputs, i.e. one for each battery. Well, i've found some very strange voltmeter readings which do not sit happily with this claim. In short, I'm not at all convinced about the independence of the outputs.

 

[halcyon]

They say 3 isolated outputs, not seperate outputs.

Battery charging, one big can of worms.

Brian

 

[DaveS]

And the distinction is...?

 

[halcyon]

3 isolated outputs is one regulated output feeding 3 blocking diodes, to give you 3 outputs that cannot backfeed. So all batteries are at the same voltage.

3 seperate outputs, are 3 outputs that are independently controlled. You may have the service battery on high charge, but engine batteries on maintenance charge.

Brian

 

[DaveS]

[ QUOTE ]
3 isolated outputs is one regulated output feeding 3 blocking diodes, to give you 3 outputs that cannot backfeed. So all batteries are at the same voltage.

3 seperate outputs, are 3 outputs that are independently controlled. You may have the service battery on high charge, but engine batteries on maintenance charge.

IBrian

[/ QUOTE ]

I understand that, but do not think that it explains what I have observed is going on. However, rather than waste time here, I'll take some readings and post again in a few months.

 

[JKay]

I have the "new"chinese model so it must be better /forums/images/graemlins/laugh.gif

cheers Joe

 

[milfordman]

I have the Sterling 3 output 20amp smart charger which is charging 2 110amp bateries in parallel (service battery) and a 100 amp engine starting battery. I have been very satisfied with the service provided by this equipment. Also I initially had a problem with the Alternator regulator from the same company. I can say that the help I recieved from them was all that you could expect. So I can recomend their equipment.

 

[DaveS]

Being slightly more sober now than when I posted last night, I've now remembered what was happening! /forums/images/graemlins/smile.gif

Two of my Sterling charger's outputs feed batteries. I had the notion of using the third output to power the coil of a relay which controlled the fridge and a dehumidifier: the idea being to avoid draining the battery if either the shore power or the battery charger failed. This cunning plan failed, however, since the relay stayed closed when the charger was switched off, i.e. it was being powered by one or other of the batteries. Hence my doubts about the independence (or isolation) of the charger outputs.

I perhaps should have tried swapping wires around (which might have identified a single short circuited diode), and I'll maybe try that some time. Meanwhile I'm using a 240V contactor which protects against power, but not charger, failure.