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Charging Crown cr 235 batteries.


Billy Boy

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Has anyone used or using crown cr235 deep cycle batteries if so what charge settings are used. Crown leaflet says as far as I can work out is 14.2 for both and float, the closest I can get and what I'm charging at is 14.6 bulk and 13.7 float. Does that seem okay? 

Thanks in advance.

 

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To charge as per Crown’s recommendations is not as straightforward as “what voltage do I charge at?”  Robbo’s link goes into some detail and Crown’s own data sheet is here: http://www.crownbatterieseurope.be/assets/TDS_CR235-HD_ENG.pdf

 

Badically, they should be kept below the gassing voltage (14.22V) until the current reduces to around 3-4% of battery capacity. At that time the charge voltage should slowly increase in order to keep a constant current of 3-4%, up to a maximum of 15.9V at the end of charge. This constant current stage should be terminated after approximately 3.5 hours. A specific gravity reading of approx 1.27 will show a fully charged battery. 

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Sounds like Trojan as well when they spec a higher voltage at the end.   As your charging via generator float voltage doesn’t matter (as you won’t really be using it).  The higher the bulk voltage the more it will gas (so you have to fill with water more), but will charge quicker, although I don’t know how much quicker.

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10 minutes ago, WotEver said:

To charge as per Crown’s recommendations is not as straightforward as “what voltage do I charge at?”  Robbo’s link goes into some detail and Crown’s own data sheet is here: http://www.crownbatterieseurope.be/assets/TDS_CR235-HD_ENG.pdf

 

Badically, they should be kept below the gassing voltage (14.22V) until the current reduces to around 3-4% of battery capacity. At that time the charge voltage should slowly increase in order to keep a constant current of 3-4%, up to a maximum of 15.9V at the end of charge. This constant current stage should be terminated after approximately 3.5 hours. A specific gravity reading of approx 1.27 will show a fully charged battery. 

 

I find it most curious that good quality batteries need charge profiles like this, but nobody makes a charger to do it.

 

Or do they?

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3 minutes ago, Robbo said:

The higher the bulk voltage the more it will gas (so you have to fill with water more), but will charge quicker...

And corrode faster, but everything is a trade-off

1 minute ago, Mike the Boilerman said:

 

I find it most curious that good quality batteries need charge profiles like this, but nobody makes a charger to do it.

 

Or do they?

I’m sure they do. For those applications that specify such batteries, like buggies. 

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7 minutes ago, WotEver said:

And corrode faster, but everything is a trade-off

I’m sure they do. For those applications that specify such batteries, like buggies. 

 

A brief goggle suggests not.

 

Buggy chargers seem no different from any other 'intelligent' three stage charger sold to boaters and caravaners.

 

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6 minutes ago, Billy Boy said:

i was sent both leaflets from crown and they contedict each other so was not sure. I think it maybe an expensive new charger.

Don’t be too hung up on getting the perfect voltage.   I would argue using a higher voltage and higher current when using a generator source is “better”, but it’s not better for the battery.   It’s better as diesel and generator costs more than the overall battery lifespan.

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On a previous boat I had 8x Crown 31dc130  set up to give 24v,  when off shore power used to charge at 29.9v with a 70amp charger running from my Beta genset never left it long enough to go into float, meant that batteries charged fairly quickly. When on shore power it was  28.8v then 27.0v float. The mobile set up was timed absorbtion, shore line was adaptive to reduce heavy charging after a short power outage. The advantage of a completely programmable charger......

Edited by Loddon
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Thanks Julian, my charger is set for half of yours for 12v. Takes an age to get to 100%. Did they last as long as other deep cycle? My AC power is through a 2000w gen, not a cheep way but no other way of charging for a while. (Engine out for another week)

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8 minutes ago, Alan de Enfield said:

If your charger is set for 12v you will NEVER get them anywhere near 100%

12v is about 48% charged.

He said half of Julian’s. In other words 14.4V/14.9V. 

Edited by WotEver
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1 hour ago, Billy Boy said:

Thanks Julian, my charger is set for half of yours for 12v.

 

50 minutes ago, WotEver said:

He said half of Julian’s. In other words 14.4V

Yes - misread it as 12v.

Goes out into the yard, head down, kicking stones.

Edited by Alan de Enfield
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1 hour ago, Billy Boy said:

Thanks Julian, my charger is set for half of yours for 12v. Takes an age to get to 100%. Did they last as long as other deep cycle? My AC power is through a 2000w gen, not a cheep way but no other way of charging for a while. (Engine out for another week)

I sold the boat after 3 years with those batteries, had crown before that but didn't have a decent genset so cant compare.

Can't afford them now only really had them as I had good deals from my battery supplier.......

 

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5 hours ago, Billy Boy said:

for the extra £s these cost I thought I'd try and get the charging right.

Why not drop Crown a line pointing out that they have some pretty specific charging requirements which don’t appear to be met by any readily available chargers. Then ask them which charger they would recommend. 

 

Then please let us know their reply. 

  • Greenie 1
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11 hours ago, Mike the Boilerman said:

 

I find it most curious that good quality batteries need charge profiles like this, but nobody makes a charger to do it.

 

Or do they?

Yes our MV Combi seems to, in a rough sort of way. I can specify the bulk and absorption voltages, but it doesn’t aggressively try to achieve them. If I set say 15v it will mostly charge at perhaps low 14s and only when the current has fallen right off will the voltage rise towards the 15v set. Which is good, because that is what the Trojans like.

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12 hours ago, Mike the Boilerman said:

 

I find it most curious that good quality batteries need charge profiles like this, but nobody makes a charger to do it.

 

Or do they?

Not a mains charger, but there is an alternator controller that can be programmed to do this: http://arduinoalternatorregulator.blogspot.com/?m=0

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34 minutes ago, Tom and Bex said:

Not a mains charger, but there is an alternator controller that can be programmed to do this: http://arduinoalternatorregulator.blogspot.com/?m=0

Nope, that couldn’t do it either. You could get the correct curves but you’d never get the finishing voltage up to 16V. 

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