SailNet Community banner

1 - 20 of 49 Posts

·
Registered
Joined
·
248 Posts
Discussion Starter #1
I was reading that it shouldn't be charged to fast. The charger I bought the other day is a 10amp charger which I guess isn't a "trickle charger."

What kind of charger do you guys use for your FLA batteries?
 

·
bell ringer
Joined
·
4,817 Posts
10a charger, you think that is fast, if my batteries are down to accepting only 10a they are charged already. I use a 70a charger and could use a bigger one.

But to the question, FLA will really not accept too many amps for the battery. The internal resistance and state of charge will control t.
 

·
Registered
Joined
·
4,713 Posts
The more important question is this an "automatic" charger that will charge at a high rate then reduce the current as the battery gets close to charged, finally ending at maintenance/trickle charge. Leave a manual charger on high too long and you can damage the battery.
 

·
Registered
Joined
·
1,399 Posts
First 20-30 cycles keep to lower C-rate

both charge and discharge

is the common wisdom guideline

if an expensive bank and you want to try for max longevity

Won't matter if other care factors are abusive though
 

·
Registered
Joined
·
248 Posts
Discussion Starter #7
The more important question is this an "automatic" charger that will charge at a high rate then reduce the current as the battery gets close to charged, finally ending at maintenance/trickle charge. Leave a manual charger on high too long and you can damage the battery.
the one i bought from Canadian Tire is just a "simple" battery charger so I guess I'm okay. Thanks for that, good to know.
 

·
Senior Member
Joined
·
12,234 Posts
Yes...You need a three stage charger or you burn them up or shorten their lives
Read up on three stage charges and the battery controlling acceptance it’s important
Bulk, absorption and float.r

if you deplete your battery 50% ( that’s dead ) and say that means that you need to put 110 amps back in . A ten amp charger will take a long time. Chances are you are using an overnight shorepower , but still too long. I know it’s a couple hundred or $300 for agood onebut it will handle even bigger bank in the future. It will save you buying new batteries all the time. Boats aren’t cheap. If you throw cheap at something like this in the end run it will cost you.....plus the aggravation of constantly replacing.


 
  • Like
Reactions: Vagab0nd

·
Registered
Joined
·
21,800 Posts
First 20-30 cycles keep to lower C-rate.....
gotta remember, when some asks a basic battery question, they likely don’t know what c-rate means, or .005c, etc. I don’t know how one would ever get back to proper full charge, with too low an amperage.

As for the question, I’ve never seen manufacturer recommended discharge rates for new batts. Many years back, I do recall believing we should do a few full cycles 100-50-100-50-100 state of charge, to exercise the batts in. I’m not certain that wasn’t an old wives tale but everyone I knew did it.
 

·
Registered
Joined
·
5,101 Posts
My advice is do not let batts get very discharged... turn your motor on when you are sailing for a bit.] if you have to... Discharge cycling is what shortens a battery's life.
 

·
Senior Member
Joined
·
12,234 Posts
My advice is do not let batts get very discharged... turn your motor on when you are sailing for a bit.] if you have to... Discharge cycling is what shortens a battery's life.
I disagree with this advice

We NEVER just turn our motor on when sailing to keep a charge in the batteries.

That’s the whole reason to have a sufficient bank. Besides being a waste of fuel and taking hours of engine life ( you know it is finite) and also running an engine with no load isn’t a great idea. Besides the batteries after 85% charged only accept very small absorption charges from a good 3 step regulator on the alternator.

you don’t have to keep the batteries at the top of hill all the time. The point to fully recharge back to 100 % is a good one as it “remembers” that as it’s limit and won’t self impose a lower high limit.

We sometimes go 3 days without charging the batteries. That means sailing only for three straight days. ( we should be so lucky) We don’t have solar. It has never affected our battery life nor it’s top end charge.? A small panel is one thing I’m thinking of adding over the davits, clear of the boom shadow just
 
  • Like
Reactions: SchockT

·
Registered
Joined
·
1,399 Posts
I expect people to google or ask if there is a term they don't grok.

The "commissioning protocols" and breaking in period are not at all wive's tales, in fact even more applicable to LFP than lead.

Manufacturers and vendors know the more "full information" they volunteer about care requirements, the lower their sales compared to the "don't worry be happy" crowd.

Few owners care about longevity enough to let themselves be inconvenienced anyway.

And that's fine, but for those who do, the information is out there.

Just need to ask.
 

·
Registered
S2 7.9 Bear Lake, UT
Joined
·
2,517 Posts
the one i bought from Canadian Tire is just a "simple" battery charger so I guess I'm okay. Thanks for that, good to know.
I think you should slow down and study electrical needs and design your system and build it from scratch. Based on your recent conversations you are likely to spend at least a grand on your upcoming 'battery upgrade', you might as well do it right. Stop running out and buying stuff from Auto Parts stores, unless you need it for your car. If you already own auto battery tools you can use it in a pinch but a good quality marine charger is a separate entity from what you will get at an auto store and using the wrong tool/part on a boat can be dangerous.

Here is a good 3 stage charger. The right charger will ensure the batter is best maintained for optimum long life.


If I had a bigger boat this is what i would install but since i have a simpler boat and also a truck with a deep cycle battery I have an older version of this. It allows me to carry it from one vehicle to the next and charge my cars as well. It has a variable chemistry setting so I can charge both my lithium and flooded lead acid batteries. If I had an AGM or Gel batteries it could do those also. What is really nice about this charger system is its flexibility. The charger terminates in a plug that can be plugged into a variety of attachments. I have rings on my truck and boats batterie's terminals and can just plug it into my charger when needed, it also has an alligator clip option you can use if your car battery dies or you need to charge a new battery at home. It also has a slow charge "repair" mode.

 

·
Registered
Joined
·
2,870 Posts
If the boat has a Charles 30 amp charger installed why would you go out and by a cheap 10amp charger when you have one of the best in the boat
 

·
Registered
Joined
·
2,412 Posts
On my last boat I installed a Xantrex 2TB10 charger which did very well maintaining the group 27 FLA house battery and Group 24 engine battery. It is a 3 stage smart charger meant mainly for battery maintenance while the boat is on shore power, but 10 amps was plenty for such a small battery bank.

An automotive smart charger is fine if all you are looking for is maintaining your batteries when the boat isn't in use, although alligator clips are not ideal because the connection is not great and is prone to voltage drops. They also have a habit of popping off. It is easy enough to snip the alligator clips off and replace them with crimp ring terminals that can be screwed onto the battery posts.


Sent from my SM-G960W using Tapatalk
 

·
Senior Member
Joined
·
12,234 Posts
I stand by what I said and the experts say. 10 amps for sure to small. Especially for the anticipated 220 ah battery bank immediately, and then you intend to expand. With refrigeration probably 440 ah. expand.This is exactly what happens when you don’t plan ahead.

It would be like filling the replacement water in your batteries with an eye dropper. Eventually you do fill it, but eventually your arm or the eye dropper gets tired😀😀
 
  • Like
Reactions: SanderO

·
Registered
Joined
·
1,399 Posts
Yes, the charger should be sized to output at a minimum 0.1C rate if FLA, and at least double that for AGM, even 0.4C is not too much.

And higher is better if future expansion is anticipated.

But if the only use is long sessions on mains power, it really does no significant harm to go a bit lower.

If used with a genset, then size to 80% of its max rated output, or the max that still supports "eco mode". . .
 
1 - 20 of 49 Posts
Top