When to recharge batteries?

[PaulyB]

So I've read that you don't want to discharge a battery below 11.8 and you also don't want to charge it too soon with an on board charger.... So what is a good voltage for when to recharge?

 

[Murf'n'surf]

Get yourself a smart charger and plug it in when the boat is not in use. The charger takes control and will not damage your batteries as long as you have a "Smart" charger.

 

[Bruce]

This website has lots of good info on batteries http://www.solar-electric.com/deep-cycle-battery-faq.html

You do not want to go below 50% which is somewhere around 12.1 volts.

I use a Blue Sea m-LVD which disconnects the battery at 12.1 volts. I can press a switch to override the disconnect and start the engines.

As Murf says, the best option is to install an onboard smart charger and charge the batteries between outings.

 

[justason]

2x on the charger. Mine is plugged in all the time .
Heres a good thread on a plug install. Lemme find a charger thread. https://jetboaters.net/threads/noco-genius-charger-inlet-install.1716/#post-28870

 

[msavold]

"... I use a Blue Sea m-LVD which disconnects the battery at 12.1 volts. ...

Bruce:
would/could you use the LVD switch with a dual battery system?

 

[scokill]

My onboard smart charger is plugged in 24x7x365 (other when on the lake)

 

[Bruce]

Bruce:
would/could you use the LVD switch with a dual battery system?

Yes. I have two group 31 batteries on a dual battery switch. I do not use them in a traditional starter and house battery configuration. Both are connected to a dual battery switch where I can switch the batteries to off, either one to on or both in parallel. I have a refrigerator that draws an average of 1 amp. Between the two batteries I can run it for four days before I hit the LVD cutoff. I have only tripped the LVD once. When I did I was able to press the override button and start the engines without any problem. Our boats require very little power to start so I feel that having a large starter battery is a waste.

The LVD provides safety that I will not run the batteries so low that I damage them or too low to start the engines.

 

[PaulyB]

I have a Minn Kota 345PC, which is probably one of the best charges on the market.... Just wanted to make sure that I could leave it plugged in even if I dont discharge the batteries too much in an outing....

 

[ArmyChief]

Lol, well this may not be the BEST charger in the World. However, it is a great dual battery smart charger with all the various modes of charging and conditioning. It's what I kept on my glacier bay.

NOCO Genius GEN2 20 Amp 2-Bank Waterproof Smart On-Board Battery Charger https://www.amazon.com/dp/B003JSJS5I/ref=cm_sw_r_awd_Hgbovb0B8X2A2

 

[scokill]

I like mine except when everything is fully charged it turns green and says Go Fish..

http://www.basspro.com/Bass-Pro-Sho...attery-Charger-XPS-iT-10/10/product/10224686/

 

[David Analog]

It's true about the maximum 50% discharge on a consumer-grade deep-cycle battery.
A new and fully topped off 12 volt battery rests at 12.7 to 12.8 volts. For rating purposes, 10.5 volts is considered fully depleted.
What is a 50% level differs from source to source. Some say 11.8 volts. Some say 12.0 volts. Just keep it in that range as a minimum threshold.
You should recharge depleted batteries as soon as possible. It's never too soon. Allowing depleted batteries to stay in a discharged state for a long duration is unhealthy.
Sometimes it is 'too' soon to get an accurate reading before the elevated alternator/stator/charger level has had a period to dissipate. But that has nothing to do with charging. Charge immediately after the outing and NOT just before the next outing.

 

[jdonalds]

I leave my Battery Tender Jr. plugged in all winner. Then rely on the engines to keep it charged all summer.

 

[Kross]

two options for you.
1) learn more than you ever wanted to know about battery & charging technology, then spend a week reading every review on battery chargers, then decide to buy this: http://www.amazon.com/gp/product/B000FRLO9Y/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

or 2) just buy this http://www.amazon.com/gp/product/B000FRLO9Y/ref=oh_aui_search_detailpage?ie=UTF8&psc=1


I've been all the way down this road, and I've come back to tell you about it, so you don't have to go. Also, if there's any roads you've been down, please tell me about them so I don't have to go. To date, I've been a temporary expert in...
- boat trailers
- batteries
- battery chargers
- fiberglass repair
- sound systems
- custom cutting fiberglass
- anchors
- anchor rope & rope-to-anchor attachments

haven't we all? one of the things that makes this forum so great. Share the knowledge!

(seriously hope this helps)

- Kross

 

[jdonalds]

Or save yourself a bunch of money and buy a Battery Tender Jr. One of the highest rated products on Amazon ever.

 

[Glassman]

two options for you.
1) learn more than you ever wanted to know about battery & charging technology, then spend a week reading every review on battery chargers, then decide to buy this: http://www.amazon.com/gp/product/B000FRLO9Y/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

or 2) just buy this http://www.amazon.com/gp/product/B000FRLO9Y/ref=oh_aui_search_detailpage?ie=UTF8&psc=1


I've been all the way down this road, and I've come back to tell you about it, so you don't have to go. Also, if there's any roads you've been down, please tell me about them so I don't have to go. To date, I've been a temporary expert in...
- boat trailers
- batteries
- battery chargers
- fiberglass repair
- sound systems
- custom cutting fiberglass
- anchors
- anchor rope & rope-to-anchor attachments

haven't we all? one of the things that makes this forum so great. Share the knowledge!

(seriously hope this helps)

- Kross

I've got that CTEK charger (among about 20 other different ones) and I'll vouch for it's effectiveness. I use it to keep the "Consumable" rear battery in the Mercedes alive and well when it's not being driven. You should be able to find it for much less than Amazon has it for though. I think I paid around $60 delivered.

 

[ArmyChief]

Well I can tell you the charger I posted has all the bells & whistles too

 

[kthrash]

Lol, well this may not be the BEST charger in the World. However, it is a great dual battery smart charger with all the various modes of charging and conditioning. It's what I kept on my glacier bay.

NOCO Genius GEN2 20 Amp 2-Bank Waterproof Smart On-Board Battery Charger https://www.amazon.com/dp/B003JSJS5I/ref=cm_sw_r_awd_Hgbovb0B8X2A2

I have the same charger in my Yamaha Boat, my Yamaha Rhino and an extra one in the garage to keep the batteries charged during the winter..

 

[MikeyL]

I have a Minn Kota 345PC, which is probably one of the best charges on the market.... Just wanted to make sure that I could leave it plugged in even if I dont discharge the batteries too much in an outing....

@PaulyB - You own 1 of the FINEST on-board chargers made.
What most people do not understand is that the REAL BENEFIT of an on-board charger is not to "charge" the batteries, but to "MAINTAIN" them.
So, here's the deal: When you get off the water, Plug in your wonderful Minn-Kota (for those who do not know, this is a 3 bank, 15-amp per bank HEAVY DUTY on-board charger) and let IT decide what it needs to do.
Both you and your batteries will thank you. A device like your will also benefit you in that your batteries will actually last LONGER than if you did not "KEEP" them this way.
Best of Luck to you, And Best Wishes, Mikey Lulejian - Lake Oconee, GA

PS - And "battery tenders" do NOT have the charging capability to charge up, in a relative time period, boat batteries, especially if we are running sound systems for most of the day ! Period !

 

[MikeyL]

I've got that CTEK charger (among about 20 other different ones) and I'll vouch for it's effectiveness. I use it to keep the "Consumable" rear battery in the Mercedes alive and well when it's not being driven. You should be able to find it for much less than Amazon has it for though. I think I paid around $60 delivered.

X2 on all of this @Glassman. I have the SAME CTEK, and on the SAME car, our SL500. Since we don't drive it "alot."
However, I would never consider using this device on a set of boat batteries as it does not have the changing capability to handle normal boating needs.
1) It is only a single bank unit, so for those who have 2 batteries in their boats ........
2) And if you're running a sound system all day, a CTEK, or anything similar to it, is not going to charge up your batteries overnight.
My 2 cents worth. Best Wishes to all , Mikey Lulejian - Lake Oconee, GA

 

[Glassman]

X2 on all of this @Glassman. I have the SAME CTEK, and on the SAME car, our SL500. Since we don't drive it "alot."
However, I would never consider using this device on a set of boat batteries as it does not have the changing capability to handle normal boating needs.
1) It is only a single bank unit, so for those who have 2 batteries in their boats ........
2) And if you're running a sound system all day, a CTEK, or anything similar to it, is not going to charge up your batteries overnight.
My 2 cents worth. Best Wishes to all , Mikey Lulejian - Lake Oconee, GA

I knew you had good taste Mikey! And you are 100% correct, I wouldn't expect it to fully charge my deep cell batteries after a full day of blasting my polka music in party cove.
For that I have big Bertha - she's not installed in the boat due to the fact that I routinely remove my batteries after each outing and schlep them home with me. No power available where the boat is stored