Multiple Sterling Battery Chargers

[BargeeSpud]

Hiya,

 

Adding to the nearly exhausted, I suspect, topic of battery charging, I'm really keen on getting some sort of 240V battery charging installed & to that end, I've been exploring the range of Sterling products.

 

According to their blurb, I would need a 70A charger for my 675Ah battery bank. Now their range of digital chargers only go up to 60A, but they suggest that it is possible to link a combination of 2 of their chargers to make up the extra amperage required. In my case, probably a 40A & a 30A could be the cheapest option, according to their online prices.

 

Now, I can't find anything in their downloads for a document that outlines how this is done, so my question is, is there anyone on here who has linked 2 chargers together in this mannner, Sterling or otherwise?

 

Cheers.

[Leon 12]

That is what I'm looking at also but will stick with the 60 amp as I can't push to get two. I also have a 675ah battery bank. Trojan recommends 10 to 13% of bank capacity.

[Robbo]

What's the charger plugged into? If it's shore power and not a generator then it doesn't matter what amp output the charger has so forget about the 10% blurb..

 

More about sizing the charger here; http://www.smartgauge.co.uk/chargesize.html

[by'eck]

I ran two Sterling 50 amp chargers in parallel on a previous boat. Sterling even offered a double mount bracket to achieve such. Just connect them to batteries as you would a single unit with independent cables and fuses.

[ditchcrawler]

What's the charger plugged into? If it's shore power and not a generator then it doesn't matter what amp output the charger has so forget about the 10% blurb..

 

More about sizing the charger here; http://www.smartgauge.co.uk/chargesize.html

I am glad someone else agrees with me. If you have a shore supply why would you want to flatten your batteries and then recharge them.

[Richard10002]

My Sterling 2500W Pro Combi S inverter charger charges at up to 80A. It has 8 battery settings, one of which is equalisation, but no custom setting.

[BargeeSpud]

That is what I'm looking at also but will stick with the 60 amp as I can't push to get two. I also have a 675ah battery bank. Trojan recommends 10 to 13% of bank capacity.

 

That's interesting, I have the same batteries, how do you get on with routine charging, have you done an equalisation charge & if so, how long do they take?

 

What's the charger plugged into? If it's shore power and not a generator then it doesn't matter what amp output the charger has so forget about the 10% blurb..

 

More about sizing the charger here; http://www.smartgauge.co.uk/chargesize.html

 

It'll be into an onboard generator who's alternator also charges the battery bank. Great link, it just goes to show how complicated this issue really is & how much of a compromise charging time over battery life depends on what balance you want to achieve.

 

My Sterling 2500W Pro Combi S inverter charger charges at up to 80A. It has 8 battery settings, one of which is equalisation, but no custom setting.

 

Great, but unfortunately, I already have a Victron 2Kw inverter & the replacement Sterling product equivalent to yours, is knocking on the door of £1k.

[Robbo]

It'll be into an onboard generator who's alternator also charges the battery bank. Great link, it just goes to show how complicated this issue really is & how much of a compromise charging time over battery life depends on what balance you want to achieve.

 

What size generator and what type of batteries? With a 675ah traction type battery bank we can quite happy use a 150-170amp (25% of total ah) charger if your generator can handle it. If you have Gel/AGM/cheapo leisure we could push that further to 270amp (40% of total ah).

 

I would size the charger to push the load on the generator as you want short charging times, gennys run more efficient at around 75% load.

Edited February 13, 2017 by Robbo

[BargeeSpud]

 

What size generator and what type of batteries? With a 675ah traction type battery bank we can quite happy use a 150-170amp (25% of total ah) charger if your generator can handle it. If you have Gel/AGM/cheapo leisure we could push that further to 270amp (40% of total ah).

 

I would size the charger to push the load on the generator as you want short charging times, gennys run more efficient at around 75% load.

 

Beta 9Kw Genset & 6 x Trojan T105.

[WotEver]

 

Beta 9Kw Genset & 6 x Trojan T105.

 

Then I'd go for at least two of their 60A chargers. That way you'll cut down the bulk charging time.

 

To answer your original question of how to link them, as far as I know with the Sterling stuff you don't, as such - you just connect them up to the batteries effectively in parallel. When the batts need 120A or more during Bulk then they'll both be working flat out. Once the current demand reduces to <60A then one of them may shut down, leaving the other one to finish the charge.

[Robbo]

 

Beta 9Kw Genset & 6 x Trojan T105.

 

That's some genset and you'll put very little load on it from charging those batteries. The other question would be how many ah's do you use per day and do you use the genny regularly for anything else and for how long for.

 

How do you get your hot water?

Edited February 14, 2017 by Robbo

[BargeeSpud]

 

That's some genset and you'll put very little load on it from charging those batteries. The other question would be how many ah's do you use per day and do you use the genny regularly for anything else and for how long for.

 

How do you get your hot water?

 

No way of knowing Ah consumption I'm afraid, solar is hooked up all the time so any readings from Victron BMV are arbitrary & working out daily consumption I find confusing to say the least.

 

The genny is run for the washing machine & ironing (about an hour for each) plus immersion heating for showers (about 1 1/2 hours), kettles on stove for anything else. Also run the genny for battery charging when down to 12.3V until Amps are down to below 10 on the BMV. taking between 3 - 4 hours depending on how much solar has already put in. in the summer I don't need to gennny charge at all.

 

The primary reason I want to use a battery charger is to do equalisation charges from time to time plus I'd feel happier charging "properly" on a regular basis.

[Robbo]

The Victron BMV is properly most valid at this time of year as you know what is taken out of the batteries. If your running the genny for around 1.5hrs a day for other reasons like heating water, you could size the charger to get the majority of the charging done in this time as well. So if your only taking out 100ah daily then you'll need to put in around 120-130ah. If you had a 60amp charger this would take 2 hours (this is presuming charging the 30% "rule" of 50%-80% daily where you could get 60amps into the batteries), so if we up the charger size we can lower the amount of time the generator is running for just purely charging.

 

Hope that made sense.