Battery Charger Question

I currently have three batteries- 2 in parallel for 12V TM and one cranking battery. Right now I have a 2 bank onboard charger and use one for the CB and the other I have charging across the 2 TM batteries. I am probably in the market for a new charger and was thinking of going up to a 3 bank onboard. My question is, since my 2 TM batteries are connected, do I have to disconnect them from each other in order to charge them individually (with the 2 banks - 3rd would be connected to CB)? Just wasn’t sure how the current would run in this scenario. Or, should I just stick with a two bank? Also, any suggestions on preferred brands/models of chargers?


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three bank each lead connected to a battery...10 amps plus each lead...charge faster. I have an older three bank Charge Pro that has two ten amp circuits and one 5 amp circuit. The theory was back then the starter battery had the motor alternator that kept that battery up and it was more than likely a 24 class starting or dual purpose battery.

But a lot of boats pull auxiliary power stuff from the starting battery (livewell pumps,radio,nav lights etc.) so it is best to put in the best dual purpose in the largest size in the starter position if that's the case. Especially if you don't run your main motor a lot but fish all day.

Throw the juice to them...do not leave the batteries in any state of discharge any longer than absolutely necessary. You want to bring them back fast ...then a low amp charge to maintain or as they reach peak voltage is okay...charging all the way from deeply discharged to full at a low rate is not ideal unless you have a small battery with low amp reserve.

You leave everything connected...parallel batteries are going to balance out...important you keep both batteries at very close to same performance capability. Both mules pulling evenly at the yoke.Or the other gets tired faster. You can unhook them occasionally from each other and check them for peak voltage and charge time...or use a specific gravity tester to see how they are doing.

My frustration is my condo docks don't have power and my battery charger doesn't give indication of where they are so I am always guessing. my son bought a solar for TM because of it but it isn't much and read you shouldn't leave them overnight as they will discharge battery. new to boat ownership and very frustrated. Now Cranking battery which has always been no problem as it is recharged by running suddenly was dead and it's two years old. it is a battery tender plus and supposedly is good but never indicates battery is charged and have no idea where I am in process.

any brands or suggestions would be helpful thanks.

Quote:

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Originally Posted by hdhntr

My frustration is my condo docks don't have power and my battery charger doesn't give indication of where they are so I am always guessing. my son bought a solar for TM because of it but it isn't much and read you shouldn't leave them overnight as they will discharge battery. new to boat ownership and very frustrated. Now Cranking battery which has always been no problem as it is recharged by running suddenly was dead and it's two years old. it is a battery tender plus and supposedly is good but never indicates battery is charged and have no idea where I am in process.
any brands or suggestions would be helpful thanks.

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First...get a digital multimeter. Most of even the budget models have very accurate DC voltage measurements. You can get one at Lowes or one of the auto parts stores. Generally steer away from the bargain bin ones....just a decent multi meter you can use all purpose.

Always double check them occasionally no matter what charger you have. As an all around rule of thumb...if you have around 12.7 volts you have a fully charged battery. 12.4 or so will act okay at first but you will notice you run out pretty fast,it's either a battery getting weak or ...your charger is shutting off before it's fully charged.Anything less.. considerably undercharged or bad cell or cells.

Put any battery you want to test on a charger first. When the charger shuts off...(if it doesn't your battery is probably definitely bad) and the see what voltage you have. You should have 12.7 or better...some chargers will leave a slight over charge of 13.1 volts or so. Put a small load on the battery for 20 minutes or so like a nav light. Then check to see if you have 12.7 or more...if you don't weak battery.

Generally speaking don't expect a lot from a 24 or even a 27 class battery. If you seriously need to power a troller and a multitude of devices...start with at least a 29 class or parallel smaller ones or multiple batteries for different loads . If you are going to stay on a budget with flooded cell batteries in the 100 dollar range...get the highest reserve capacity and best warranty you can. Wal-Mart batteries are not bad...it has a lot to do with treating them right. You will kill any of the low end batteries with incorrect maintenance . Three to five years tops out of them typically even when you treat them right.

centage of Charge	12 Volt Battery Voltage	24 Volt Battery Voltage	Specific Gravity
100	12.70	25.40	1.265
95	12.64	25.25	1.257
90	12.58	25.16	1.249
85	12.52	25.04	1.241
80	12.46	24.92	1.233
75	12.40	24.80	1.225
70	12.36	24.72	1.218
65	12.32	24.64	1.211
60	12.28	24.56	1.204
55	12.24	24.48	1.197
50	12.20	24.40	1.190
45	12.16	24.32	1.183
40	12.12	24.24	1.176
35	12.08	24.16	1.169
30	12.04	24.08	1.162
25	12.00	24.00	1.155
20	11.98	23.96	1.148
15	11.96	23.92	1.141
10	11.94	23.88	1.134
5	11.92	23.84	1.127
Discharged	11.90	23.80	1.120

Monitoring and Maintenance
The battery voltage should be kept at or above a 50% state of charge for maximum battery life. Keep the battery's electrolyte level to the indicated level and never let the plates be exposed above the electrolyte. Use only distilled water - not tap water, when refilling the batteries. Water is the only element used by your battery. You should never have to add acid to your battery. Do not overfill or fill when the batteries are discharged. Over-watering dilutes the acid excessively and electrolyte will be expelled when charging.
Equalization
Equalization is the controlled overcharging of a fully charged battery. This overcharge mixes the electrolyte, evens the charge among varying battery cells and reduces permanent sulfation of the batt

I would recharge that battery and then have it load tested at auto parts store
You might have left something on in the boat that drained it down
Like key lights fish finder pump etc
Don't know about solar panels but I would think they would have a diode in them to keep them from discharging battery at night
There are lots of them in use that are hooked up all the time


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Quote:

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Originally Posted by hdhntr

My frustration is my condo docks don't have power and my battery charger doesn't give indication of where they are so I am always guessing. my son bought a solar for TM because of it but it isn't much and read you shouldn't leave them overnight as they will discharge battery. new to boat ownership and very frustrated. Now Cranking battery which has always been no problem as it is recharged by running suddenly was dead and it's two years old. it is a battery tender plus and supposedly is good but never indicates battery is charged and have no idea where I am in process.

any brands or suggestions would be helpful thanks.

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If you can leave it in the boat and charge the batteries while docked or at home ... I suggest a onboard charger, with enough leads to connect to all batteries separately, and 10amps per lead. A digitally controlled unit is also a plus factor.

Then again, if you're like me and have to take the batteries out of the boat to charge them at home (apt complex, etc) and you have more than one battery ... the onboard chargers work in that scenario, too.

I wouldn't suggest a "cheap" battery charger of any type ... so if you only need to charge one battery, then you still need to get a good quality deep cycle charger that puts out 10amps and has some type of gauge or dial showing where your battery is at during the process.

The lower amp chargers will charge the battery, but from what I've read ... the higher amp chargers help keep the sulfate from hardening on the plates (causing the battery to not take a full charge). But, I would defer to the battery guru "CatFan" for confirmation or clarification on that. I just know that I've always used a 10amp charger (or onboard charger with 10amps/lead) and my Wal-mart deep cycle boat batteries have always lasted around 5yrs.

Thanks for all of the feedback guys. Yet another reason I love this site.


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gotta say...doggone gave you great advice :ThumbsUp

agree KF, this site IS the best, so much specific advice that you can use! Thanks so much guys i really appreciate the information.

Now how about the best bang for buck charger? so many out there with different reviews. thoughts?

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Originally Posted by hdhntr

Now how about the best bang for buck charger? so many out there with different reviews. thoughts?

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They are constantly changing technology and build design on chargers. This years model in a brand may be different next year. You may have trouble with one brand one year and the same brand a year or two later may be okay.

I have been through a lot of them over the years.

The one brand I trust above all others is Dual pro...buy the best level you can afford. This is there mid level charger.

Sportsman Series - Pro Charging Systems

I just changed out one of my trolling batteries in my bassboat...it was a Sears Die-Hard 29 class. It was 9 years old. But its twin bought at the same time is still going. I think that's a record for me. It has been on a Dual Pro professional series the entire time. The charger now is I think around 15 years old...also a record. I think it's time to for a new one though...it still works...but wants to shutoff a little below where I want them charged...and does not have an equalization mode. I do that every so often with a portable.

I would like to offer a couple of points to the battery charger discussion that might be important in one's decision of upgrading or adding an on board battery charger ...

Point 1: It has been proven that some boat setups using a "common on board charger" connected to TM batteries and connected to any other battery that supplies Sonar electronics can induce RFI back feed (thru the charger) that shows on Sonar unit display as interference ... The only remedy for this scenario (of possible back feed RFI) is disconnecting the charger leads to the Sonar electronics every time on the water ... or separate chargers for TM batteries vs electronics batteries ...

Point 2: There is advantage in having separate battery chargers = in the scenario that when 1 charger goes bad and has to be repaired/replaced - there is still a working charger in the boat that can be used (by temporary rewiring) to charge all batteries - while the non-working charger is being repaired/replaced ...

Rickie

again my problem is NO POWER on the dock. will have to take them in and out physically and looking for stand alone, not on board charger. thinking I will get another main battery as don't use trolling motor much and just haul them back and forth to keep them at optimum.

Quote:

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Originally Posted by hdhntr

again my problem is NO POWER on the dock. will have to take them in and out physically and looking for stand alone, not on board charger. thinking I will get another main battery as don't use trolling motor much and just haul them back and forth to keep them at optimum.

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I feel for ya, buddy ... like I said, that's how I have to do it when I bring the boat back home.

But, even if you do have to take the batteries out and haul them inside to charge them ... it's a lot less hassle to hook them up to a onboard digital charger and forget about them until your next trip, even if the "onboard" charger isn't "on board". Then you can hook up both batteries at the same time, which you can't do with a "regular" charger with one set of leads. Yes, they are a bit more expensive, but if you do travel & stay somewhere with electric at the boat slip, then you won't have to load/unload the batteries every day or have to go out late and switch the leads to the second battery. (been there, done that)

I'm only familiar with Schumacher manual battery chargers & Minn Kota onboard chargers ... and both brands have served me well, even though neither one of them are digital.

when I got back to condo, main battery was fully charged and good and boat showed charging fine on trial run, so don't have to buy another. think I am going to keep TM battery on maintenance charger at condo as we don't use it that often and BAA's it is better to keep it on and charged as I don't think it has been fully charged since I bought toon back in march. New to owning a boat so figuring this all out on the fly. Thanks so much for the tips from the CDC members!

Will look for a good digital multiple charger so when I do take it somewhere will be able to do both at once.

have been on battery plus blogs and don't see any reports of fires or issues like that so should be good to keep it on maintenance as it is 1.25 amps.

If you don't mind rotating the leads between batteries than a single charger will work. Two years ago I had 4 batteries (two group 31 deep cycle, group 24 starting, and 12v riding mower battery) in my garage that I kept charged all winter with a single charger. Every Tuesday and Friday I rotated the leads to another battery, worked down the line and started over. Never a problem. I still use the Schumacher Ship to Shore charger for my main battery, in fact it is hooked up right now keeping the charge on my motor battery. My Minnkota on-board 10amp dual bank (5 amps per bank) charger is hooked up to both my group 31 trolling motor batteries and is also plugged in right now. No issues there either.

I am debating about pulling the on-board charger and the batteries when I put the boat up for winter and charge them in the garage again. Or leave the batteries in and run an extension cord out to the boat for the winter. Might sell the dual bank charger and buy a three bank charger for next season. Or maybe buy a separate single bank charger for the motor and not worry about RF interference.

Quote:

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Originally Posted by hdhntr

Now how about the best bang for buck charger? so many out there with different reviews. thoughts?

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I have the same question.
What brand charger for 2 bank chargers, but now that I have read Rickies post, I may stick with my current rotation method, which Hanr3 suggests, and I use now. I have 2 batteries on fishing boat, plus battery off of pontoon is now in garage. I just rotate the charger every other day between the (3) batteries.
Would still like a good suggestion on (2) bank charger, I'll have both boats in water in spring, and will need to keep batteries on fishing boat charged. Pontoon stays charged with normal use.

Quote:

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Originally Posted by Lane47

I have the same question.
What brand charger for 2 bank chargers, but now that I have read Rickies post, I may stick with my current rotation method, which Hanr3 suggests, and I use now. I have 2 batteries on fishing boat, plus battery off of pontoon is now in garage. I just rotate the charger every other day between the (3) batteries.
Would still like a good suggestion on (2) bank charger, I'll have both boats in water in spring, and will need to keep batteries on fishing boat charged. Pontoon stays charged with normal use.

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NOCO Genius. Go through Walmart web site. Best price out there. Dang good chargers for the money.

Quote:

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Originally Posted by Lane47

I have the same question.
What brand charger for 2 bank chargers, but now that I have read Rickies post, I may stick with my current rotation method, which Hanr3 suggests, and I use now. I have 2 batteries on fishing boat, plus battery off of pontoon is now in garage. I just rotate the charger every other day between the (3) batteries.
Would still like a good suggestion on (2) bank charger, I'll have both boats in water in spring, and will need to keep batteries on fishing boat charged. Pontoon stays charged with normal use.

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I have a MinnKota and used the warranty once. During a trip to Canada the charger acted up and failed. I used my Schumacker to keep the batteries charged for the remainder of the week. When I got home I called MinnKota, they asked for the model and serial number. Told them the problem, they said it needs to be replaced. Emailed me a RMA through UPS and told me they would ship a new charger once they had confirmation my current charger was in the mail. I emailed them with the tracking number and they shipped the new charger the same day. 2 days later I was back up and running. Whole thing took less than a week and I was back on the water by the first weekend after I returned. They stand behind their product. This new version has not given me any issues.

Quote:

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Originally Posted by doggone

First...get a digital multimeter. Most of even the budget models have very accurate DC voltage measurements. You can get one at Lowes or one of the auto parts stores. Generally steer away from the bargain bin ones....just a decent multi meter you can use all purpose.

Always double check them occasionally no matter what charger you have. As an all around rule of thumb...if you have around 12.7 volts you have a fully charged battery. 12.4 or so will act okay at first but you will notice you run out pretty fast,it's either a battery getting weak or ...your charger is shutting off before it's fully charged.Anything less.. considerably undercharged or bad cell or cells.

Put any battery you want to test on a charger first. When the charger shuts off...(if it doesn't your battery is probably definitely bad) and the see what voltage you have. You should have 12.7 or better...some chargers will leave a slight over charge of 13.1 volts or so. Put a small load on the battery for 20 minutes or so like a nav light. Then check to see if you have 12.7 or more...if you don't weak battery.

Generally speaking don't expect a lot from a 24 or even a 27 class battery. If you seriously need to power a troller and a multitude of devices...start with at least a 29 class or parallel smaller ones or multiple batteries for different loads . If you are going to stay on a budget with flooded cell batteries in the 100 dollar range...get the highest reserve capacity and best warranty you can. Wal-Mart batteries are not bad...it has a lot to do with treating them right. You will kill any of the low end batteries with incorrect maintenance . Three to five years tops out of them typically even when you treat them right.

centage of Charge	12 Volt Battery Voltage	24 Volt Battery Voltage	Specific Gravity
100	12.70	25.40	1.265
95	12.64	25.25	1.257
90	12.58	25.16	1.249
85	12.52	25.04	1.241
80	12.46	24.92	1.233
75	12.40	24.80	1.225
70	12.36	24.72	1.218
65	12.32	24.64	1.211
60	12.28	24.56	1.204
55	12.24	24.48	1.197
50	12.20	24.40	1.190
45	12.16	24.32	1.183
40	12.12	24.24	1.176
35	12.08	24.16	1.169
30	12.04	24.08	1.162
25	12.00	24.00	1.155
20	11.98	23.96	1.148
15	11.96	23.92	1.141
10	11.94	23.88	1.134
5	11.92	23.84	1.127
Discharged	11.90	23.80	1.120

Monitoring and Maintenance
The battery voltage should be kept at or above a 50% state of charge for maximum battery life. Keep the battery's electrolyte level to the indicated level and never let the plates be exposed above the electrolyte. Use only distilled water - not tap water, when refilling the batteries. Water is the only element used by your battery. You should never have to add acid to your battery. Do not overfill or fill when the batteries are discharged. Over-watering dilutes the acid excessively and electrolyte will be expelled when charging.
Equalization
Equalization is the controlled overcharging of a fully charged battery. This overcharge mixes the electrolyte, evens the charge among varying battery cells and reduces permanent sulfation of the batt

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This is some good information and i believe this will help many people, Great job