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-   -   Which charges more efficiently? Fast Charge or Trickle Charge?? (https://www.sailnet.com/forums/electrical-systems/331562-charges-more-efficiently-fast-charge-trickle-charge.html)

MarkofSeaLife 10-08-2019 05:33 AM

Which charges more efficiently? Fast Charge or Trickle Charge??
 
500 amp hour battery bank with 2 different chargers: a 25 amp charger and a 4 amp charger.

Which is more efficient for a battery to suck up?

Please don't make it more complicated than the question is :)


Merci!


Mark

outbound 10-08-2019 07:15 AM

Re: Which charges more efficiently? Fast Charge or Trickle Charge??
 
Depends on how charged batteries are to start with. My understanding is from 50% to 70-80% makes little difference. After that unless you have Li and have Pb based batteries the batteries can only accept a decreasing amount as they come to full charge. The rest of the energy is in part released as heat. So ultimately depends on the design and sophistication of the two different chargers. The one that presents just enough energy that can be efficiently absorbed will be the winner.

Minnewaska 10-08-2019 07:18 AM

Re: Which charges more efficiently? Fast Charge or Trickle Charge??
 
If you're charging a nearly full bank and not using more than 4 amps at the time, I would think the difference would be negligible.

If you're charging a discharged bank that will accept more than 4 amps, I'd have to say the larger charger, which will run fewer hours. For that matter, I don't think a 4 amp charger would ever properly recharge a deeply discharged 500 Ahr bank, especially if the "trickle" charger only does so in float voltage.

Maine Sail 10-08-2019 09:21 AM

Re: Which charges more efficiently? Fast Charge or Trickle Charge??
 
The 25A will be your better choice. You're looking at an effective charge rate of just 0.05C (5% of Ah capacity) and most AGM's can easily be charged much, much faster, typically in the .4C or 40% of Ah capacity range...

The problem with the trickle charger is that your bank may be full before the trickle charger can even get to the limiting absorption voltage. 4A is just .8% of capacity and this does not include on board loads which could easily make it a charger smaller than .5% of Ah capacity.. A 100% chock full Lifeline AGM is considered full at .5% of Ah capacity at 14.4V.

Also, if this is a true "trickle charger", meaning constant current only, no absorption and no float, it can actually damage the batteries. Stick with a true multi-stage marine charger.

colemj 10-08-2019 09:57 AM

Re: Which charges more efficiently? Fast Charge or Trickle Charge??
 
On our boat, 25A is a trickle charger.

My answer is run both together (if you were asking which to run).

Mark

Don L 10-08-2019 11:46 AM

Re: Which charges more efficiently? Fast Charge or Trickle Charge??
 
Quote:

Originally Posted by MarkofSeaLife (Post 2051630086)
500 amp hour battery bank with 2 different chargers: a 25 amp charger and a 4 amp charger.

Which is more efficient for a battery to suck up?

Please don't make it more complicated than the question is :)


Merci!


Mark

the 25 amp charger (that's the simple answer to me)

but that's making assumptions of SOC and charging source

but a 70-100 amp one would probably be even more efficient for the first couple hours

what good is a 4 amp charger anyway? My refrigerator uses more power than that

BTW - I didn't read anyone else's answer because I don't care, this is MY answer

john61ct 10-08-2019 12:56 PM

Re: Which charges more efficiently? Fast Charge or Trickle Charge??
 
Actual trickle chargers are traditionally totally crippled-stupid, no concept of stages at all like a PSU really. Very much not recommended.

If by "efficiently" you mean lower heat losses, not using so much input power, that does not depend on current rate throughput and is not important with mains as your upstream source, nor even a genset in practice.

If by "efficiency" you mean time taken charging from a depleted state to 100% Full, then higher amps will make a difference.

But not as much as you'd think with lead chemistries, especially with FLA. With GEL you don't want to fast charge anyway.

AGM has a very high CAR, but still takes 7+ hours no matter how much current you throw at it. might save 20-30min doubling amps offered.

https://marinehowto.com/how-fast-can...ry-be-charged/

If this answer - simple as I could make it - was not comprehensive, please clarify your question.

john61ct 10-08-2019 12:57 PM

Re: Which charges more efficiently? Fast Charge or Trickle Charge??
 
Quote:

Originally Posted by Don0190 (Post 2051630130)
what good is a 4 amp charger anyway?

Fast charging a very tiny battery 8-)

Or maintaining a Full SoC on a large bank in storage.

john61ct 10-08-2019 01:03 PM

Re: Which charges more efficiently? Fast Charge or Trickle Charge??
 
Quote:

Originally Posted by MarkofSeaLife (Post 2051630086)
500 amp hour battery bank

Yes with a 500Ah bank, beside the 4A charger taking 100 hours

depending on the chemistry, **dropping to 5 or 10A** may be the specification for knowing that you're at 100% Full.

Since the max charge is 4A, there is a real danger that rate being **too** low will result in overcharging.

MarkofSeaLife 10-09-2019 01:03 PM

Re: Which charges more efficiently? Fast Charge or Trickle Charge??
 
I made a mistake by thinking that a question simply put would give the wanted answer. I see I was wrong and didn't realise assumptions would be made that throw my question off course.
Sorry... so... here is the amended question that I think has been answered by 'heat' but I'm not sure.

I am in a marina in London for all of winter with *Extremely* expensive electricity. US 30 cents per kilowatt (GBP .245 cents per KW).

I have solar panels in a reasonably sunny position. But I need to augment that with a bit of shore power charging.

I generally only drop the batteries down 10% per day... about 50 amp hours on the meter. This will be made up by the solar on a normal sunny day. But when its not due to ice, snow, grey clouds ect I need to put in about 50 amp hours per day.

I only turn on any charger on demand and turn it off before fully charged (I get to fully charged on sunny days at least once per week).

So the question is does a battery accept charge better faster or slower?

The answer appears to be the by-product of heat produced by the units. Where heat is generated there must be an inefficiency in the charging unit.
The longer the charger is on the more time for heat to generate.

If the 25 amp charger is a marine, new technology and claims very little heat generated its shorter charging time (say 1.5 hours) it would be more efficient than a much longer, 8 hour, changing time at lower amps with heat generated from the trickle charger which is a cheap auto charger.

It may just be a few cents per hours, but over 6 months a dinner with a few beers...


Mark


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