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guphware

Shore power battery charger in addition to solar

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Hi all,

 

We currently have 3 x 125ah leisure batteries powering the fridge, lighting (mostly LED) and water/waste pumps. The bank is charged by a single solar panel through an EPSolar MPPT charge controller. This was fine during the summer but with winter fast approaching we are finding that come the morning there isn't enough juice to power the pumps for a shower. We are mostly marina based so would like to add in a mains charger to top up the batteries once night falls. Electricity is metered so would only want to charge from shore power when necessary. Currently we achieve this by attaching a car battery charger using crocodile clips - it works but isn't a viable long term solution. The charger only has trickle or fast charge and is manually selected. I was also a little wary that I might be sending current to the solar panel instead of away from it, but it hasn't blown up yet wink.png

 

So, my questions are:

  • Is there such a device available that I can connect both the solar and a 240V charger to and it automatically selects which input to charge the batteries with, prioritising the solar? Maybe even with automatic health programming to allow the batteries to discharge periodically to keep them healthy?
  • Failing that, if I just get a decent 240V charger that automatically switches charge mode, will there be any problems permanently connecting that directly to the batteries in addition to the solar, and just turn it on when required? Or should I connect them via, say, a rocker switch to manually change from solar charging or 240V charging? What fuses would be required?
  • Can someone recommend a decent multistage 240V charger?

 

I'm sure I'll think of something else as soon as I've posted this, but it will do for starters :-) Thanks in advance.

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Victron, Mastervolt and Sterling all make good marine chargers with Sterling being UK based if you ever need support.

 

No problem with having the charger connected at the same time as the solar.

 

I suspect that you may have already killed your batteries however, judging from your first paragraph.

 

Tony

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I thought so too. If there is not enough power to run a pump it sounds like they are already shot.

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I agree with the above re damaged batteries but today at around noon my single (60W) panel was delivering half an amp so it would have made very little difference to the batteries sate of charge over the day, only a few amp hours. This of course supports the damaged battery idea but a single panel is never going to do overmuch for a livaboard on cloudy days at this time of year.

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Hi, i am at present fitting 4 100w solar panels, i am not experienced enough to go into all the technical stuff, but i have Viltron charger running off shore line, i have been advised that its a great charger and only charges batteries when they require, and that i could leave it plugged in 24/7 and would not fry the batteries, and no problem with the solar system. Having just bought the boat its a steep learning curve, but the people on here are truly amazing, and will happily advise with any questions you may have.Welcome to the family.

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Hi, i am at present fitting 4 100w solar panels, i am not experienced enough to go into all the technical stuff, but i have Viltron charger running off shore line, i have been advised that its a great charger and only charges batteries when they require, and that i could leave it plugged in 24/7 and would not fry the batteries, and no problem with the solar system. Having just bought the boat its a steep learning curve, but the people on here are truly amazing, and will happily advise with any questions you may have.Welcome to the family.

All spot on :)

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I'm using a C-Tek xs 2500 which pre dates the solar charging system I have. I just turn it on manually when required, which isn't often. It automatically goes into float mode once it detects the batteries are charged. Any decent quality 3 or 4 step charger capable of 20 amps would probably do .

Maybe not the fully automatic system you had in mind but it works for me

 

Top Cat

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By now in the calendar Your panels will be producing about 10% of their rated power. You need to charge those batteries properly or they will let you down. Until you have a suitable charger you could go for a serious cruise. Your batteries need 400AH put in that's ten hours of cruising at 40A. A charger by a prime maker rated at 30 - 50amps should be enough. Are you sure that your bollard supply will be adequate for a big charger?

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Question : am now plugged into shoreline. I have 2 large panels which normally power 3 leisure batteries running 240 v fridge, lights etc etc. when travelling. Can someone tell me if I turn over to inverter rather than landline the solar will override the mains?

It has a Sterling battery inverter/charger.

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Hi all,

 

Thanks for all the replies. Just to clarify - the batteries themselves are fine (as far as we can tell), but once the sun goes down and the solar is no longer topping up the batteries the charge in the batteries is used through the evening on lighting the boat, keeping the fridge on, use of the water pump for washing etc. By morning we still have charge but not quite enough to have the light/fan on in the bathroom, the shower pump and water pump going to shower 2 adults. During the summer we had no problems whatsoever, we even ran the TV on the inverter for a few hours as well as all the above.

 

We know we're not getting as much charge now, and as someone pointed out as liveaboards with only one solar we knew we would struggle, hence the need for a charger to top up as well. We did look at Sterling but were advised against them because, apparently, they don't play happily with our solar charge controller. Victron has been mentioned to us before, so we'll look at them. We were interested in how more experienced boaters managed it. Some great suggestions coming back, so thank you.

 

Good to know it is okay to have both solar charger and 240v charger connected to the batteries at the same time. Wasn't sure if the different charging algorithms would try and compete with each other or something.

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Question : am now plugged into shoreline. I have 2 large panels which normally power 3 leisure batteries running 240 v fridge, lights etc etc. when travelling. Can someone tell me if I turn over to inverter rather than landline the solar will override the mains?

It has a Sterling battery inverter/charger.

 

I'm not familiar with the Sterling, but assume that switching from "landline" to "inverter" will turn off the charger, and supply the boat's 240V system from the batteries, via the inverter.

At this time of year, this is not a good thing, unless you're doing several hours cruising per day. If you're moored, with shore power available, I'd leave it on landline. Any input from solar will still do the batteries some good, but see Tony's and Arthur's posts above.

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. By morning we still have charge but not quite enough to have the light/fan on in the bathroom, the shower pump and water pump going to shower 2 adults. During the summer we had no problems whatsoever, we even ran the TV on the inverter for a few hours as well as all the above.

 

​That means you have effectively killed them

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By have the landline connected all the time, and a smart charger, it will just draw the kWh you need/have used up anyway, using diesel and engine alternator to charge the batteries is not so cost effective as the land line charger, and killing the batteries isn't cheep either.

 

all the amp-houres you use up must be replaced one way or the other. by empty the batteries you kill them dead in a short time.

here Ctek is popular http://www.ctek.com/gb/en

 

Last time I had the boat in the dry dock, the staf there had left the 24v light on, and turned the simple battery charger off, flat as a salt lake.

I had just bought a 5 amp 8 step ctek for my car, used that restore funktion, one batt at the time, all 4 is still now 2 years later still good.

 

Edit, Just saw the Ctek Smart pass, under the 12 V big boat page.

Edited by Dalslandia

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Hi all,

 

Thanks for all the replies. Just to clarify - the batteries themselves are fine (as far as we can tell), but once the sun goes down and the solar is no longer topping up the batteries the charge in the batteries is used through the evening on lighting the boat, keeping the fridge on, use of the water pump for washing etc. By morning we still have charge but not quite enough to have the light/fan on in the bathroom, the shower pump and water pump going to shower 2 adults.

If your batteries aren't yet effectively dead they will be in a week's time from that description.

 

If you are using power it has to be replaced. Solar won't do it this time of year. You have a landline and therefore using a charger connected 24/7 will be by far the cheapest route moving forward. It's much cheaper than replacing your batteries every couple of months.

 

Don't know who told you that 'Sterling don't work well with solar' but it's complete rubbish

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The batteries have only dipped below 12v on two occasions, both in the last few weeks. When we notice them getting towards 12v the charger we currently have goes on to keep them topped up. The solar panel has actually kept them at around 14v for most of the day today as we've had a clear sunny day here, so we've had no issues at all, the batteries lasted fine over night.

 

We don't think they're shot, but agree that if we don't get a proper charger fitted then we will have problems in the foreseeable future. We've just ordered a C-Tek, for delivery tomorrow. Thank you for advising on the brand.

 

Just to clarify, our engineer advised the Sterling chargers, although brilliant, are known to have compatibility problems with certain solar control panels - ours being one of them, so he advised we looked at other brands.

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In your original post you indicate you have a theoretical 375 amp hours of leisure battery capacity. For this amount of capacity to be unable to run a pump the following morning with the little amount of electrical usage indicates the actual capacity is much much lower and that the batteries are probably goosed.

As for using a charger and solar at the same time, this is not a problem. If the batteries can except 20 amps for example and your solar is producing 10 amps then the charger will deliver the extra 10 amps. If the sun then goes behind a cloud and the solar amps drop to say 2amps then the charger will increase it current to 18 amps and so on.

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[*]Is there such a device available that I can connect both the solar and a 240V charger to and it automatically selects which input to charge the batteries with, prioritising the solar? Maybe even with automatic health programming to allow the batteries to discharge periodically to keep them healthy?

 

Why would you want to discharge the batteries periodically? That doesn't keep them healthy. I'm afraid that's an old myth. Keep them charged to keep them healthy. Some of the good 3 stage chargers will go through a full charge cycle after about a week if they sense no activity (discharge).

Edited by blackrose

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Why would you want to discharge the batteries periodically? That doesn't keep them healthy. I'm afraid that's an old myth. Keep them charged to keep them healthy. Some of the good 3 stage chargers will go through a full charge cycle after about a week if they sense no activity (discharge).

Batteries kept permanently on float can suffer a massive but temporary voltage drop when asked to supply load.

 

This is known as "coup de fouet". To prevent the this many critical power installations routine partially discharge the battery every year, usually by reducing the charger voltage to a point where the batteries have to supply some of the load, but not enough to drop the critical load if the battery voltsge collapses.

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