Deep cycle charger

[Digital2k2]

Anyone here know of a good charger for deep cycle batteries?

I run a 54 pound thrust motorguide on the biggest walmart deep cycle about 5 times a week lately... Anywhere from 35 to 90 minutes run time usually.
Been using an automatic 10 amp charger and my battery is already shot after 9 months.

I put the charger on a timer last month so it won't run much past the point it gets a full charge, but I have a feeling even a few hours of pulsing a charge into the battery every minute or so (its way of maintaining a full charge) probably overcharges it.

If there's anyone here that's doing what I'm doing, but more successfully in the charging department, please let me know haha.

 

[firefighter]

You want snapon charger model #EEBC500. It is almost $700 dollars on there website, but this is what we have at work and it is awesome. The problem with the way you are charging is 10amps is to much for the battery for any length of time. It needs to have a slow two amp charge for the correct time based on how much the battery is discharged. I have a feeling that when you are charging at 10 amps your voltage probably goes over 14.5, most batteries do not like this they get to hot from the constant amperage. Just because you have charged it to what you think is full, it is probably still not fully charged. The only way to really know a batteries state of charge is with a hydrometer. Even a two amp charge can cook batteries. the voltage can get to high. I don't think you would have that problem on the large deep cycle batteries though. The snapon charger puts out a constant voltage but it modulates the amperage so the battery has a split second to cool down. I veriified this at work with our lab scopes and amp clamps. it is really neat that is how they can rapidly charge a battery with out boiling it out. This may be out of your price range but batteries can get expensive. Look around there may be other chargers that do the same thing but I have yet to see them at this price point

 

[JHZR2]

+1 on the slow charge. Plus, deep cycles do funny things to the lead and additives on the plates - so you really want to have a desulfidation mode. I'd go for a battery minder 2,4,8A charger system, model 12248, and charge it slowly whenever you can. The efficiency of charge retention decreases as you go higher and higher current.

Recall that Vt=Voc-IR when discharging and Vt=Voc+IR when charging. Thus, at 10A the apparent terminal voltage is fairly high because the I term is quite high (10). A dumb charger may cut it off prematurely as a result of that, and so you may never actually top it off. Additionally, there is likely some charge transfer inefficiency at the higher rates.

You should charge at 2.25Vpc up to the point where only about 50mA is accepted. Then you can float, or send a high frequency ripple throgh to help clean the plates.

 

[J. A. Rizzo]

I'm a big fan of my Battery MINDer model 12248. It charges at 2, 4, or 8 amps (12v) and charges in 3 phases. There is a bulk charge phase at full power, followed by a saturation phase at steady voltage to let the plates "catch up," followed by a top-up phase that raises the voltage to the "full" level and then keeps it steady right there at very low or no current to prevent overcharging. It also transmits a sweeping high frequency waveform to the battery that supposedly helps reduce the sulphation level of the plates. Whether that helps or not, I don't know, but I have left flooded and AGM deep cycle batteries connected to it for months and they don't lose any electrolyte and remain 100% charged. It brought my Group U1 generator starter battery back to life after an accidental deep discharge.

Northern Tool stocks it for $100 here, Amazon.com sells it for $130 here, batteryminders.com sells it for $130 here, and batterystuff.com sells it for $137 here. If you want more info, check out all the links and read the product descriptions. The batterystuff.com site might have a slightly higher price, but they have some good information on how batteries and battery charging works.

Good reading and happy charging!

John

 

[Digital2k2]

Thanks for all the good info everyone! That EEBC500 would be pretty neat to have, but it's definitely way out of my budget. I also don't think it would fit in the box I use to store and charge my battery in.

The BatteryMINDer 12248 looks like a good charger. Did you guys get the optional battery temperature compensation sensor for yours?
How loud would you say the charger is? The one I have now buzzes so loud that you can hear it 40ft away from the box.

 

[Digital2k2]

I should have paid more attention to the description of the temperature sensor: "The BatteryMINDer 12/24 Volt battery temperature sensor can double the life of any type of 12V or 24V battery when used with Item#s 167988 or 167989"

The website listed it as an accessory for the charger, but the description for it doesn't list the chargers part number.

 

[Digital2k2]

Too bad the option to edit posts doesn't last very long.. Looking at the last two links, they actually include the temp sensor with the charger. The item number for the charger is on the top of the page and differs from the model number on the cheaper site.

Anyway it looks like getting the temp sensor would be the way to go.

 

[Digital2k2]

Got it with the temp sensor for just under 120 shipped.

I think I'm going to wait on using my new battery till this charger comes.

The everstart maxx-29 would charge on the flooded battery type selection, correct? It has vent caps but I don't think you're supposed to ever add water to it.

Sorry about all the posts. I got excited with researching and the thought of having a decent charger haha.

 

[JHZR2]

Yeah, flooded. Dont think it is AGM, and it is definitely not gel.

 

[J. A. Rizzo]

I don't have the temperature sensor but I should probably get it for the flooded RV battery I have because it could potentially lose electrolyte during cold weather due to slight overcharging.

To answer your other question, the charger is nearly silent. When it changes modes, starts up, or shuts off, you will hear a relay click. I haven't noticed any humming, but it's in my garage and there might be enough background noise that I can't hear it. Even if that is the case, it must be a very low volume hum.

If you have a maintenance-free or vented cap battery, it will charge on the "flooded" setting. The other two types are AGM (absorbed glass mat) and gel cell, and you would know if you had one of those batteries. The AGMs are completely sealed units - no vents at all. Gel cells are rare these days - they are more expensive than AGMs and require special charging techniques.

 

[brianl703]

Originally Posted By: Digital2k2

The everstart maxx-29 would charge on the flooded battery type selection, correct? It has vent caps but I don't think you're supposed to ever add water to it.


Yes, you are. All deep-cycle lead-acid batteries (other than AGM type) will need to have water added to them at some point, and the more you cycle them, the more water you'll need to add to them. This applies to golf cart batteries as well as deep-cycle marine batteries, and batteries used in off-grid energy storage applications.

If you've been using your battery as much as you say, and you've never added any water to it, well, maybe that's why it's shot.

If you hear liquid sloshing around when you move the battery, it's flooded, needs to be charged on that setting, and needs to have the water level checked on a regular basis and topped up if necessary, using distilled water.

 

[Cory]

I just bought a Diehard Marine battery from Sears this weekend and they told me that it was completely charged and not to open the battery under any circumstances. They said they would know if I did. This battery is replacing one from Napa that only lasted me but a year. That was with little to no use. It was connected to my battery backup sump pump. It was hooked up to an AC charger that was part of the system at all times. When the light turned yellow indicating a low charge, it never recovered no matter what I tried to charge it with. Opened the battery up and it was dry. Added nearly a gallon of distilled water.

Had no warranty whatsoever at NAPA. This Diehard however has a 1-year replacement with a prorating after that. We'll see how this one holds up. Maybe I should use my smaller BatteryMinder and keep it hooked up that way. Model 12117??

 

[brianl703]

Once a battery goes dry, it's ruined. The plates dry out, once they've dried out, adding water to them won't make them work again.

I don't know why Sears would tell you not to add water to a deep cycle marine battery. Maybe they have no idea what they're talking about.

These deep-cycle batteries are often used with outboard motors that have no voltage regulation whatsoever, so the charging voltage will sometimes climb as high as 16V, which increases water loss as well. (The average outboard motor's battery charging circuit consists of a stator coil and a bridge rectifier. No voltage regulation at all).

They do not have "maintenance free" chemistry in them, so they lose more water than a car battery (which typically does have the maintenance free chemistry--but doesn't work so well for deep-cycling).

 

[Loobed]

I have an old Sears Die Hard multi-charger. It is made in USA by Schumacher. It will do several different things. It will charge deep cycle and auto batteries with 2 or 15 amps, or can be used as a jump starter assist.

Mine is something like this, but is a different model ebay link

http://www.batterychargers.com/#

I also have a "Battery Tender Plus" battery charger maintainer. It is only 1.25 amps so it doesn't really charge the battery.

http://batterytender.com/automotive/battery-tender-plus-12v-at-1-25a.html

 

[mrsilv04]

Originally Posted By: Loobed

I also have a "Battery Tender Plus" battery charger maintainer. It is only 1.25 amps so it doesn't really charge the battery.

http://batterytender.com/automotive/battery-tender-plus-12v-at-1-25a.html



A Battery Tender can and will charge a full sized automotive battery... and the one that I have is only the .8 amp model.

I've used mine several times to bring fully discharged batteries back to a full and complete charge... it sometimes takes a day or so... but it will do it.

 

[brianl703]

A large car battery is around 70 amp-hours. You can figure out how long it'd take a .8 amp charger to fully charge a discharged battery like that..it's more than a couple of days.

I prefer to charge a deep-cycle battery at the 1/10th rate..which for a group 24 or group 27 battery is between 8.5 and 11 amps, depending on the amp-hour capacity of the battery. Since the closest you can get to that is a 10-amp charger, that's what I use.

The point is to avoid sulfation, which can happen if you use too slow of a charge rate. 4 days is too long. 3 days is too long.

 

[Win]

You might want to just build your own smart charger. Unitrode used to make a good controller chip, the UC3906N. I think TI still markets it, some of the chip makers will give you one or two as a free sample, but I don't know if TI does.

I have one of the mid priced Schumacher "computerized" smart chargers and it hasn't killed a battery yet.

edit: never mind, saw the OP already bought a charger.

 

[JHZR2]

Originally Posted By: brianl703

I don't know why Sears would tell you not to add water to a deep cycle marine battery. Maybe they have no idea what they're talking about.




Likely because if they tell you to maintain it, they are at lawsuit risk, so they hold your warranty in check with their lawsuit aversion technique. Try to open and optimize the battery performance, they are at risk, so theyll get you.

 

[JHZR2]

Originally Posted By: brianl703

The point is to avoid sulfation, which can happen if you use too slow of a charge rate. 4 days is too long. 3 days is too long.



You want to get a bulk charge in there as quick as you can, but to top it you want to go slow and careful. No point to overcharging it more than necessary. i think most chargers are smart enough to do that though...

 

[Digital2k2]

Originally Posted By: JHZR2
Originally Posted By: brianl703

The point is to avoid sulfation, which can happen if you use too slow of a charge rate. 4 days is too long. 3 days is too long.



You want to get a bulk charge in there as quick as you can, but to top it you want to go slow and careful. No point to overcharging it more than necessary. i think most chargers are smart enough to do that though...



I've read that a fast bulk charge is a good thing before... With this charger I ordered, I wonder if using it at the 8amp setting would be the best even though 2amps might be enough to have it at a full charge the next day? Seems with the temp sensor and the 3 stages it shouldn't really make a difference as far as worrying about overcharging.

Or maybe I should vary it depending on how far I've drained it.. 30 min run time day 2amps, 60 to 90 mins 4 amps, 90+ 8amps?

With the charger I have now, even after a lot of use, I could leave it on the 2amp charge and it'd indicate a full charge the next day when I needed it.
This is a 125 amp hour battery. I'm not sure how much the 54 pound thrust motorguide draws though.

If this motor ever breaks, I'll probably end up getting the variable speed 55 pound thrust motorguide. They advertise that it will run over 3x longer on a single charge than the motor I have. Still think that's a bit of an exaggeration.