230v mains charger for 4x Trojan battery bank?

[Clodi]

As the title says I have been looking for a suitable charger for a bank of 4 (or maybe 6) Trojan 105's in a 12v Battery Bank. I've not got shore power on my mooring. I'm fitting 450 amp Solar with victron blue solar Mppt etc, Nasa BM2 battery gauge, cyrix split-charge and I don't want a combined charger/inverter.

All the chargers I''ve seen so far including Sterling only seem to go to 120-300 ah max .

[WotEver]

As you don’t have shore power what will you drive the charger with? That will probably determine the best size charger. 

[MtB]

You seem to be having trouble with your dimensions!

 

Solar panels are rated in Watts and chargers rated by voltage and current generally, so I suspect you are planning 450W of solar and should be looking at a Sterling Pro Charge Ultra 60Amp, perhaps?

 

 

 

(Assuming you are configuring the Trojans as 12v)

[MtB]

11 minutes ago, WotEver said:

As you don’t have shore power what will you drive the charger with? That will probably determine the best size charger. 

 

This is a good point. Either a portable petrol generator or a built-in diesel genset are the only options I can think of. If its going to be a pertol genny it needs to be reasonably meaty one like the Honda Eu20i in my experience. I have a 2kW Loncin that runs my big Pro Charge Ultra very well but it hunts on part load, which is most irritating.

[MtB]

 

 

18 minutes ago, Clodi said:

All the chargers I''ve seen so far including Sterling only seem to go to 120-300 ah max .

 

This suggests you are unsure about how to specify a charger. The size of the battery it is charging is only loosely related to the size of the charger. You can almost fully charge 400AH of Trojan (or any other battery) with pretty much any well designed three stage charger, but the smaller the charger the longer it will take with the genny running.

 

I say 'almost' because as far as I know, there are no chargers on the market that will charge your Trojans properly in accordance with the Trojan instructions. They say to finish each charge with a high voltage of about 16v or slightly less IIRC, and no battery chargers ever do this strictly in accordance with the Trojan manual.

[Clodi]

I'm really thinking of times I call into a marina overnight (or 2) using shore power. I do have a genny but it's only a small one used mainly to run drills etc.

I want to get a decent charger to future-proof in case we find ourselves spending longer periods moored up with shore power available.

[MtB]

3 minutes ago, Clodi said:

I'm really thinking of times I call into a marina overnight (or 2) using shore power. I do have a genny but it's only a small one used mainly to run drills etc.

I want to get a decent charger to future-proof in case we find ourselves spending longer periods moored up with shore power available.

 

In that case I'd suggest one of the Sterling Pro Charge Ultra chargers. To get the size right you'll need to do an energy audit, or we are just guessing in the dark.

 

(The charger size in this situation has much more to do with your energy consumption than the size of your batteries.)

[OldGoat]

Popping into a marina 'occasionally' isn't going to do much good to your batteries, so how's about  fitting a higher output alternator to your engine - with an alternator to battery module if needed?

[MtB]

2 minutes ago, OldGoat said:

Popping into a marina 'occasionally' isn't going to do much good to your batteries, so how's about  fitting a higher output alternator to your engine - with an alternator to battery module if needed?

 

I took the OP to mean a mains charger for when he stops cruising, and holes up in a marina for a few days.

[OldGoat]

1 minute ago, Mike the Boilerman said:

 

I took the OP to mean a mains charger for when he stops cruising, and holes up in a marina for a few days.

I'm obliged m'lud

[Clodi]

22 minutes ago, Mike the Boilerman said:

 

In that case I'd suggest one of the Sterling Pro Charge Ultra chargers. To get the size right you'll need to do an energy audit, or we are just guessing in the dark.

 

(The charger size in this situation has much more to do with your energy consumption than the size of your batteries.)

Rather guessing at this stage, the only definite fixtures so far will be diesel central heating, 12v Larder fridge, LED lighting mi-fi & a couple of laptops mobile phones.

[Clodi]

5 minutes ago, Mike the Boilerman said:

 

I took the OP to mean a mains charger for when he stops cruising, and holes up in a marina for a few days.

 

9 minutes ago, OldGoat said:

Popping into a marina 'occasionally' isn't going to do much good to your batteries, so how's about  fitting a higher output alternator to your engine - with an alternator to battery module if needed?

I may well go down that route at the moment I've go a Bukh DV36 with a standard alternator fitted, an upgrade doesn't seem to be very costly & I'll keep the standard one as a spare.

[OldGoat]

6 minutes ago, Clodi said:

 

I may well go down that route at the moment I've go a Bukh DV36 with a standard alternator fitted, an upgrade doesn't seem to be very costly & I'll keep the standard one as a spare.

Ah! - a well loved engine, but I don't know how easy it is to fit a larger alternator - braketry,  belt size, pulley size etc   

[Psycloud]

I have the same engine but it only has a 30A alternator and am also considering an upgrade in the future for when we go travelling.  I presume it would be OK to go to 60A although not really sure what model/part number would suit so interested to see what the OP decides upon.

[MtB]

I think a 30a alternator will be just fine for the frugal use you describe. Bear in mind unless you are really caning the batteries each night they won’t need a lot of charging the following day cruising. 

[Clodi]

In the manual it simply states 700 watt alternator  which I thought is about 58 amps. I've been told that a VolvoPenta 80 amp alternator fits ok. I think I'll get a Sterling Pro Charge a bit later when I have a better idea of whats what.

[OldGoat]

17 minutes ago, Clodi said:

In the manual it simply states 700 watt alternator  which I thought is about 58 amps. I've been told that a VolvoPenta 80 amp alternator fits ok. I think I'll get a Sterling Pro Charge a bit later when I have a better idea of whats what.

The Volvo alternator will be a rebadged something-or-other. The challenge if any will be that the crankshaft pulley is small so you need a unit that will produce output at low speed. From the pics in Google there seems to be a lot of room at the top of the engine to fit something.

[dmr]

I suggest you need to think through your overall battery charging strategy before even thinking about the battery charger selection. A bigger alternator would make sense.

 

If you are going to install a big inbuilt diesel genny then a big battery charger (maybe a combo) might make sense, but if you are going to use a small low cost petrol genny then a smaller charger would be more cost effective.

 

Specifying a charger size based on battery amp-hours is a bit indirect, better to decide how many Amps you would like to, and are able to, put into the batteries.

For 6 Trojans I would suggest 60 amps is about the minimum charge current for a reasonably timed charge, ideally quite a bit more.

 

If you are happy to run the main engine for a lot of hours then maybe you don't even need a genny, a lot of boaters, including myself, do it that way, but this makes more sense if you like to cruise extensively.

 

When you do choose a charger I personally would avoid Sterling and go for something like Victron. I always thought Victron stuff was arm and leg prices but I recently got their little 30 amp "IP22" charger and its good and reasonably priced. Sterling stuff is ugly with too many flashing lights, Victron is a not too pleasant shade of blue but I think it is better thought out ?

 

..............Dave

[dmr]

1 hour ago, Mike the Boilerman said:

I think a 30a alternator will be just fine for the frugal use you describe. Bear in mind unless you are really caning the batteries each night they won’t need a lot of charging the following day cruising. 

If the op wants 6 Trojans (a nice setup) then he needs a lot of amps. He might be able to go several days without a charge but when he does charge them he won't want it to take all day (and half the night).   80 to 100amps is about the limit before getting into multi or polyV belts. If there is space then fitting two alternators of 70 to 80 amps each might be better than one big one. Maybe an engine alternator and a domestic alternator with optional alternator combining, its not the biggest engine in the world!

 

.................Dave

[Richard10002]

3 hours ago, Clodi said:

All the chargers I''ve seen so far including Sterling only seem to go to 120-300 ah max .

 

With respect, why on earth would you want a charger "bigger" than 120A, never mind 300A???

 

On average, "we", (boaters), tend to use between about 70Ah and 120Ah per day, (there will be exceptions who are more frugal, or more profligate). I use about 100Ah per day.

 

I am off grid, with no access to shore power, and never go into a marina. I have a Honda EU20i genny, and a Sterling Pro Charge Ultra 60A charger. I fitted 500W of solar with an MPPT controller in September. Up until last Saturday, I had a bank of 4 x Trojan T105, (replaced with a bank of 3 x Rolls S-170 130Ah each).

 

Since about mid April, apart from a few days, my batteries have been fully charged daily by the solar. Running the genny or engine for charging is rare.

 

During Winter running the genny and 60A charger, the charger obviously starts off charging at 60A but, after about 30 minutes, it is usually down to about 40Amps, and continues to fall until it reaches a tail current i'm happpy with, (2-4A), after a few hours. This, even if I charge every other day, rather than daily, (maybe an hour at 60Amps, then falling). I dont ever plan to charge less frequently than every other day, as it has destroyed my batteries over the years  It obviously wont be the end of the world if I go a bit longer, occasionally.

 

I also have a Sterling Inverter Charger which charges at up to 80A. If I use this, rather than the Pro Ultra, it charges at 80A to start with but, after about 30 minutes, it's usually down to about 40Amps, and so on........

 

Thus, given normal useage, it is rarely, (never???), necessary to have a charger of more than 60A to 80A. I have had 25A chargers and 30A chargers, and found both too "small", in terms of charging time. My alternator charges at around 35A to start with, and is good if cruising for the day, but takes a long time if charging on a mooring.

 

I understand some peoples resistance to Sterling products, preferring Victron and Mastervolt... they are generally a bit less well made, and have a few more bells and whistles that might be necessary, and Charles Sterling definitely sells the sizzle, and not the sausage, so some of his claims should be taken with a pinch of salt.

 

However, I chose the Pro Charge Ultra for 1 specific reason, that I could not find on any other chargers:

 

It has a custom setting where both float and absorption voltages can be set by the user, (up to a limit I cant recall, 15.6V???). I have both Float and Absorption set to 15.0V for my new Rolls, (14.7V for the Trojans). This leaves the decision as to when to stop charging in my hands - I dont need the traditional float mode as, when my batteries are fully charged, i turn the genny off. I definitely dont want the charger deciding to go into float after an arbitrary period, (usually 1 hour with the Sterling inverter charger  ), and having to remember to reset it every hour for about 3 or 4 hours of charging.

 

The Victrons I was comparing with seem to go into float after 4 hours of absorption, which ought to be plenty, but I still preferred the flexibility of the Sterling.

 

I also liked the fact that you can vary the maximum charging current, 45A, 30A, 15A, IIRC. This isnt particularly special as some charger have the facility to set an actual number for max charge current, rather than merely percentages.

 

I guess my point is that, if you are a "normal" user of power, you dont need a charger with a max of more than 60A to 80A.

 

 

Edited June 19, 2018 by Richard10002

[dmr]

5 minutes ago, Richard10002 said:

 

With respect, why on earth would you want a charger "bigger" than 120A, never mind 300A???

 

 and Charles Sterling definitely sells the sizzle, and not the sausage, so some of his claims should be taken with a pinch of salt.

 

 

The OP was, I think, referring to Amp-Hours. Some chargers are specified in terms of amp-hours, maybe to make life easier for non-technical folk, but more likely because big numbers look good in the advert!

 

As for sausages and sizzle, well that's a very nice way of putting it. My wife is more down to earth and would say "all codpiece and no bollocks".

 

...............Dave

[Richard10002]

8 minutes ago, dmr said:

The OP was, I think, referring to Amp-Hours. Some chargers are specified in terms of amp-hours, maybe to make life easier for non-technical folk, but more likely because big numbers look good in the advert!

 

As for sausages and sizzle, well that's a very nice way of putting it. My wife is more down to earth and would say "all codpiece and no bollocks".

 

...............Dave

Aha! Presumably, if a charger refers to Amp Hours, it is related to the size of battery bank it can charge, which is something I struggle to get my head around. Within reason, any charger can charge any size of battery bank, (within reason). Your 30A Victron charger is easily capable of charging a 600A battery bank, (is C/20 a term used?), albeit it would take some time if it was depleted to, say, 50% SOC. I agree that a Cetrek 5A charger would not be appropriate for the same bank.

 

The other night my wife used the phrase, "all fur coat and no knickers".... it was in relation to the pub/restaurant we were eating in

 

 

[nicknorman]

31 minutes ago, Richard10002 said:

Aha! Presumably, if a charger refers to Amp Hours, it is related to the size of battery bank it can charge, which is something I struggle to get my head around. Within reason, any charger can charge any size of battery bank, (within reason). Your 30A Victron charger is easily capable of charging a 600A battery bank, (is C/20 a term used?), albeit it would take some time if it was depleted to, say, 50% SOC. I agree that a Cetrek 5A charger would not be appropriate for the same bank.

 

The other night my wife used the phrase, "all fur coat and no knickers".... it was in relation to the pub/restaurant we were eating in

 

 

I think the point about specifying the AH range of batteries suitable for a charger is only to do with how they decide when to switch float. The charger doesn’t know what the capacity is when you connect it. It will have some number of amps set as the tail current to trigger switching to float. This may be too high a current for a small battery and so it will never get fully charged. For a very big battery it might be too small and never reach that tail current and so never go to float.

3 hours ago, Clodi said:

Rather guessing at this stage, the only definite fixtures so far will be diesel central heating, 12v Larder fridge, LED lighting mi-fi & a couple of laptops mobile phones.

When making a decision about chargers, as well as the things already mentioned one has to consider the type of usage. If you are plugged into shore power for days at a time, you only need a charger to cover the average daily consumption and probably 20A would be plenty (and cheap). But if you want to charge from a genny, it would have to run for hours and hours with a 20A charger and therefore a much larger charger is better, provided the genny can power it.