Recommendation for a Battery Maintain Trickle Charger

dlt123me · September 2012

Hi all, I wasn't going to ask this question here since it really isn't about solar power, but rather about a battery charger.

After researching for a battery maintain/trickle charger, I found that many had faults or died after about a year of two. With all the excellent knowledge here, someone surely knows of a good non-solar battery charger and will have a good recommendation.

I would like to maintain a correct maintenance charge on a 6 or 12 volt >100 amp deep cycle battery which will eventually be used for weekend camping then brought back home for maintenance charging... I haven't bought the battery yet but will be needing a tried and true trickle charger to keep it fully charged between outings.

In the research I've done, there seems to be a concern that some chargers either over or under charge batteries and can actually damage them because of faulty inefficient charging.

Does anyone have a suggestion for a good small battery maintainer charger?

Thanks in advance for fielding my non-solar question. :cool:

Dennis

RandomJoe · September 2012

Re: Recommendation for a Battery Maintain Trickle Charger

I have one of the 0.75A "wall wart" Battery Tender chargers. Works very well, and implements three-stage charging just fine.

I've used it to recharge the various smaller AGM batteries I have laying around, and when I had a company vehicle and almost never drove my own truck I kept the car "on life support" with it. (The small parasitic drain from the car's electronics would draw the battery down over time - coupled with my then-normal usage of 1/4 mile to the grocery store and back once a week... Winter was hard on the battery!)

I frequently use a WattsUp meter with it to watch how the battery is doing. That also told me the Battery Tender charged just fine. Voltages were fine, and when it's done - in float mode - it doesn't leave a constant "trickle", it pulses occasionally. How often it pulses depends on the battery. For an older flooded battery, or in my car where there was always a little load somewhere, it might pulse every few seconds. For a new AGM it might not pulse but once a minute or more. It just held the target voltage, and when the battery finally fell below that it'd give it a little juice until it was back over.

They have several sizes of them, I think this is the smallest one. It's all built into a wall-wart cube with a red/green LED on it.

BB. · September 2012

Re: Recommendation for a Battery Maintain Trickle Charger

I got one of these Battery Minder for my in-law's car that sits much of the time (and has computer/gps/low-jack type loads which will kill the battery in a month or two of non-driving--originally estimated at ~185 mA/0.185 amp load from vehicle electronics when parked).

Bought it from NAWS (when they sold them for awhile)--and the unit is working great. No dead battery, not much (if any) water usage.

My only, minor complaint, is that the "settings" (gel/agm/flooded cell, etc.) are reset when the battery is disconnected back to default (GEL battery, low current).

Not a big problem, but if you disconnect/reconnect fairly often, could be a bit of a pain.

-Bill

alyaz · September 2012

Re: Recommendation for a Battery Maintain Trickle Charger

I have several of the Battery Tender wall wart chargers. They have always maintained my m/c and car batteries well. Now that the m/c's are gone and I have a small panel and CC charging my vehicle batteries, I use one of the Battery Tenders to trickle charge my gen battery during the summer months when we have tons of power.... Mine are likely about ten years old now and both are going strong...

PNjunction · September 2012

Re: Recommendation for a Battery Maintain Trickle Charger

dlt123me wrote: »

Hi all, I wasn't going to ask this question here since it really isn't about solar power, but rather about a battery charger.

Actually it is related to solar. Having a backup charger is a good idea since you don't want to leave batteries in a discharged state any longer than you have to and sure enough, you wake to find your battery is discharged, and a week of rain awaits ruining your solar insolation. Break out the charger to keep that battery healthy.

I would like to maintain a correct maintenance charge on a 6 or 12 volt >100 amp deep cycle battery which will eventually be used for weekend camping then brought back home for maintenance charging... I haven't bought the battery yet but will be needing a tried and true trickle charger to keep it fully charged between outings.

For flooded, no problem. For AGM, with it's low self-discharge, one way to do it is to just make sure the battery is fully charged when you store it, and only top-charge it every 3 to 6 months or so rather than having it sit on a trickle. Your manufacturer's manual might even state that trickle over a very long period is actually not a good thing.

One thing I like to do is size the charger current just like I would for a solar panel to stay within a minimum and maximum requirement. Like meeting the typical C/12 minimum to C/8 max for flooded, and for AGM, a max of C/4. Again, your battery manual will guide you here. What if you bring home a deeply discharged battery - you'll want a real charger, not a wall-wart unit.

I have a Battery Tender "Power Tender 5A , 12V" unit that works well. 5 amps is quite a bit more effective than their smaller offerings.
I also have NOCO Genius 3500 and a 7200 charger which also do well, and like the options / configurability. CTEK is another popular charger to look into. Perhaps Tecmate/Optimate, although if I were to pick one up for a large battery, I would go with the largest Optimate 6amp.

In the research I've done, there seems to be a concern that some chargers either over or under charge batteries and can actually damage them because of faulty inefficient charging.

You've no doubt run across the difference of opinions between Battery Tender and Odyssey (and others) in regards to the minimum float voltage for agm's. Odyssey says that if you want to have a warranty, you'll be running a float of no less than 13.6. The Battery Tenders, especially the older ones, run at lower floats of 13.2 or so. Nearly all agm manuals require a 13.6v minimum, but you can make up your own mind by reading all those threads in outdoor wheeling forums. One way to avoid the controversy is to not trickle at all if you are using an AGM.

Glad you asked, since a charger or generator is yet another tool to keep your battery healthy especially when there is no sun!

dlt123me · September 2012

Re: Recommendation for a Battery Maintain Trickle Charger

Thanks everyone, there is some good information here which gives me a lot of things to look into.

I really appreciate the feedback and will make my decision after some more research.

Thanks again,
Dennis

dlt123me · September 2012

Re: Recommendation for a Battery Maintain Trickle Charger

Hi again... I did some research and ran into this unit which seems to get pretty good feedback. I thought I would share in case anyone is interested in another battery charger. It looks pretty good and I might end up getting this one.

What do you think of this unit.

It's made by a company called MegaWatt and is called the MegaWatt S-400-12 Power Supply. This guy sells them on eBAy as well..

Click here to go to their website.

Click here for some reviews

Click here for a review from a Ham Radio operator

Oh, and I've decided to also purchase a small inverter generator as another backup.

Just sharing,
Dennis

inetdog · September 2012

Re: Recommendation for a Battery Maintain Trickle Charger

dlt123me wrote: »

Click here for a review from a Ham Radio operator

This seems to be a common misconception, but the reviewer is not a Ham Radio operator (not a licensed user of the Amateur Radio Service). He is a CB radio user who illegally uses a high powered linear amplifier for his mobile transmissions. Some of these guys do know their electronics pretty well, while others do not, but they are not Hams.

niel · September 2012

Re: Recommendation for a Battery Maintain Trickle Charger

i concur with inetdog's statement. aside from that i would be interested in how well it does for you as that isn't a bad price for a switcher supply of those current ratings.

vcallaway · May 2013

Re: Recommendation for a Battery Maintain Trickle Charger

I have had way too much bad luck with various battery maintainer devices. Do yourself a favor and think a little differently.

What I did was to buy a xantrex C10 charge controller. Don't see those around any more but any decent solar charger would work. Instead of connecting to a solar panel I picked up a 5A 12v wall wart and connected to it. It is unregulated and actually puts out about 15v. Should be able to find something at a thrift store. My local one usually has a bin of these things to pick through.

A proper solar controller will cost a couple of bucks more but will do a much better job of maintaining the battery and last longer. I had my setup running for a couple of years on the battery backup on the house. Worked great and never fried the battery. NAWS has some morningstar controllers in that power range that are < $100.

I had the C10 connected to an 8d lead acid battery.

solar_dave · May 2013

Re: Recommendation for a Battery Maintain Trickle Charger

I have been very successful with the NOCO line of chargers!

http://www.geniuschargers.com/products

They do a multi step charge regime and claim some desulphation qualities, Take that with a grain of salt.

Here is an graphic to explain their charge regime:

PNjunction · June 2013

Re: Recommendation for a Battery Maintain Trickle Charger

I've got the NOCO 7200 with that setup and I've used all the features which have worked in some conditions - but not all.

Their marketing is pretty slick and can turn some off initially, but the features seem to work for *slight* sulfation. Instead of saying it will bring back the dead, they tell you to just pack it in if the features don't work on some totally abused battery and not waste any more time. I like that kind of honesty.

The "recovery" mode is nothing but trying to "burp" a low-voltage (but not totally dead) battery that is typically sulfated to above 10v or so, so that a normal charge can take place. For hard-core low-voltage problems, you can use the "supply" mode to get it up to 10v or more, and then start a normal charge. It can also be used as a power supply, or even a float for BIG battery setups since it will float with up to 5 amps.

The 16v "boost" mode is meant for AFTER a normal charge has completed, (but NOT all the time!) and up to 17v will be applied with a max capability of about 1.25a if needed. Although it looks like an equalization, the charger is really looking for an improvement in capacity from desulfation, and if it finds some, will stop the process and charge that new capacity back up normally. If it doesn't like what it sees, then it will stop and return to standby. I like that it at least tells you if the process was successful or not, and stopping rather than doing a true long-term equalization. Mainly meant for FLA batteries.

Of course for many batteries, this high a boost voltage will void the warantee, but if your battery is toast already, you've got nothing to lose.

I've used it on AGM's even, although manufacturers don't recommend it for obvious reasons.

Instead of using some specialized pulse system for desulfating, (other than the early recovery to burp the voltage high enough) they just do the more standard high-voltage / low current deal, and give you an indication if it worked or not.

The CTEK chargers seem very similar, although I have no first-hand experience.

Recommendation for a Battery Maintain Trickle Charger

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