BatteryMINDER not enough?

[jawilson]

I'm starting a new thread, just so I don't hijack the other one about battery charging...


After doing research on various forums and websites I believe I know the answer to this question already, but just to be certain...

My trailer is a 2001 that was bought used 2 years ago. The original battery, with a date code of 6/01, was still on it (Interstate 24M-RD, with a paltry RC of 75). I have no idea how/if it was cared for by the previous owner.

Having been a tent camper for years and years means I'm quiet familiar with dry camping, and had intended to do mostly that even with the trailer. However, with a wife and 3 daughters "convincing" me that things like an A/C or microwave were mandatory it soon became apparent that we were going to be camping on electric sites more often then not. As such, we had only used that battery on rare occasions.

This year, with all but one of the girls feeling as though they were too old to camp with us, I made the push to do a little more dry camping. But heat, lights, water pumps, etc. do take juice -- even for a measly weekend camping trip -- so I bought an Interstate SRM-24, with an RC of 140. Not too shabby for a group 24. Based upon feedback I also bought a BatteryMINDER to keep it charged, and up until recently I thought it was doing that job quiet well. Apparently, I was wrong...

When I got the new battery home the first thing I did was check the water level, which was just about perfect. I added a small amount of distilled to 1 or 2 cells, but even that was minimal. The BatteryMINDER took about 2 days to get to the fully charged state, but in total it was hooked up for 12 days before we went camping.

The maximum voltage during charging was 13.49, which "settled down" to 12.51 after the battery had been disconnected from the charger for 24 hours. From all I've read that seemed to be on the low side; most information implies that after 24 hours off the charger the voltage should be closer to 12.80, so I was already concerned.

The weekend (3 days, 2 nights) we went camping had cold evenings -- into the low 40's one night -- but we only used the heat while we slept. Light and water pump usage was very minor, so I assumed we should be fine with the brand new battery. We weren't; about 3AM on the 2nd night we were awoken by the propane detectors low voltage alarm. Essentially, we ran out of battery

When we got home I disconnected the battery and let it sit for 24 hours, at which time it measured a ridiculous 11.82 volts! The water level was still fine, and after about 36 hours on the BatteryMINDER it's reached the fully charged state again.

Obviously something is wrong, and I suspect it's that the BatteryMINDER isn't fully charging the battery because it only puts out around 13.50 volts. Most of the posts regarding three-stage charges indicate that they're putting out 14.50 (or more) volts.

At this point it appears to me that I need to get a "real" battery charger. Is that what it sounds like to you as well? I found the Vector 1093A for $80 at Northern Tool (it has a list price of $120, which seems like a pretty good deal), so I'm thinking about getting that to charge the battery and just using the BatteryMINDER to keep it "topped off".

[AustinBoston]

The BatteryMINDER isn't really a charger, it is meant to "hold" the charge that's already there.

All-in-all, trickle chargers are not the best thing for a battery, even a fully charged one that's in storage.

Do you tow with the fridge on 12V?  Depending on the charge line from your tow vehicle, that could end up partially draining the camper battery.  Using 12V is OK if you are going to be plugged in, but I use propane while towing if I expect to be dry camping.  I don't use anything if I'm only towing a couple hours or less.

Austin

[chasd60]

The battery minder is floating at 13.5V, it is doing fine.
 
http://www.thebatteryminder.com/12v133abatteryminder-p-29.html
 
The website states that it DOES charge at 14.2-14.4V then float at 13.4V
 
I suspect your battery is toast. Let it fully charge then disconnect for 4-5 days. I think you will find it is a goner or close to it.
 
If you want a good 3 stage charger, check out WalMart. They carry a Black and Decker brand that is manufactured by Vector. It has charging algorithms for wet, AGM and GEL. It also has desulfate and equalize modes. You may be able to run your existing battery through a couple of desulfate cycles (~24 hours each) then equalize charge it and still get some good use out of it.
I recommend buying a battery hydrometer to find the true state of charge and equalize until you have the cells close to the same.

[AustinBoston]

I suspect your battery is toast. Let it fully charge then disconnect for 4-5 days. I think you will find it is a goner or close to it.

Did you read his post? The battery is brand new.

Austin

[chasd60]

Did you read his post? The battery is brand new.
 
Austin

New batteries that go flat dead before you buy them are no different than old batteries that go flat dead after you buy them. A brand new battery that takes two days to get to full charge with a charger that puts out 1A isn't a good sign. Best to check the datecode on the battery and the voltage prior to buying it. The batteryMINDER maintains the battery based upon demand and is in the milliamps, not a trickle charger.
 
BTW, the furnace uses 4-5A when running.

[Nemesis56]

I'd be looking at how much peak draw you're pulling out of the battery before doing anything else.  I have an Interstate SRM27 with RC 160.  With 2 lites, a cooling fan, and a cell phone hooked up I'm drawing just under 3 amps.  I actually had everything hooked up in the back yard to test.  Ran everything nonstop for the entire weekend from friday nite around 5pm thru sun nite on just the battery and they were still going strong ( fan seemed to be a little slower) when I checked them sun nite about 9pm.  It finally drained down sometime Monday morn cause it was dead when I checked at 9am Mon.

[AustinBoston]

A brand new battery that takes two days to get to full charge with a charger that puts out 1A isn't a good sign.

Is that a typo?  Two days at 1A is 24 amp-hours.  That's not much on even a small group 24 battery.  I expect my group 24 battery (which is in good condition) to draw 6 amps for 24 hours or more when it goes below 12 volts.

Also, if you put 14.4 volts on any battery (even a fully charged one) you would get a lot more than one amp.  After reading the site, I think the batteryMINDER may give pulses of much higher current (at 14.x volts), but that they are short pulses that average only one amp (i.e. 4 amps for 1/4 second, 0 amps for 3/4 second).  If it really charges the battery, it takes a loooong time to do so.

Austin

[jawilson]

Do you tow with the fridge on 12V?  Depending on the charge line from your tow vehicle, that could end up partially draining the camper battery.  Using 12V is OK if you are going to be plugged in, but I use propane while towing if I expect to be dry camping.  I don't use anything if I'm only towing a couple hours or less.

I actually have a TT, so the refer doesn't work on 12V's only. I do tow with it using propane, but the amount of current draw off the battery for that should be minimal. The charge line fuse has been pulled because I was always leery of stopping someplace and having it drain my TV's battery, leaving us with no way to start the truck.

[jawilson]

The website states that it DOES charge at 14.2-14.4V then float at 13.4V

That's actually one of the reasons I bought it, because I was under the impression it would charge at 14+ volts. But it doesn't; the highest voltage I've ever seen was 13.50. Once it reaches the fully charged state it bounces back and forth between 13.48 and 13.49, but never higher then 13.50.

I suspect your battery is toast. Let it fully charge then disconnect for 4-5 days. I think you will find it is a goner or close to it.

I certainly hope not! The darn thing is brand new.

If you want a good 3 stage charger, check out WalMart. They carry a Black and Decker brand that is manufactured by Vector. It has charging algorithms for wet, AGM and GEL. It also has desulfate and equalize modes. You may be able to run your existing battery through a couple of desulfate cycles (~24 hours each) then equalize charge it and still get some good use out of it.

I was strongly leaning towards this one.

[Nemesis56]

If the heater draws 4-5 amps when running, and the water pump if it's similar to a bilge pump on a boat draws about 1-2 amps and say 1 amp for lites  were talking around 6-8 amps draw.  Now all we need to know is about how long each was used.  I'd use an ammetter to find out what you're actually using as far as power. Definitely get a hydrometer to check your battery state too. You can't just go by voltage readings alone. You may have a battery with a weak cell, but I'd do specific gravity readings and some calculating first.  I'm thinking you either have too much tail and not enough kite or you have a weak battery.
Replacing the battery may or may not solve your problem.
Just my opinion, but that's how I'd approach the problem.  Anyway good luck and let us know what you find.

[Nemesis56]

That's actually one of the reasons I bought it, because I was under the impression it would charge at 14+ volts. But it doesn't; the highest voltage I've ever seen was 13.50. Once it reaches the fully charged state it bounces back and forth between 13.48 and 13.49, but never higher then 13.50.


I certainly hope not! The darn thing is brand new.


I was strongly leaning towards this one.

That's a great charger.  Been wanting one for awhile.

[Nemesis56]

Here's a link that is very helpful....

http://www.ccis.com/home/mnemeth/12volt/12volt.htm

Good luck.

[tknick]

I'm not sure b/c I own a Ford, but IIRC I remember hearing the Chevy guys saying something about having to purchase/install a relay under the hood to get the charge line hot.  In my Ford, the relay came with the brake controller pig tail and there were instructions about installing it under the hood.  That being said, if you do have a relay installed, it kills power to the charge line when the TV isn't running.  Therefore, no worries about a dead starting battery b/c it's disconnected automatically.  You can check that with a test light or a multi-meter if you aren't sure.  I'd be surprised if you don't have the relay....If you don't, you can install it and that would stop your worries.  But, seeing that you've pulled the fuse, I guess you don't have any worries about it anyway

travis

[wavery]

I certainly hope not! The darn thing is brand new.

New batteries go bad too. Don't live in denial..and don't drive yourself crazy  :banghead: trying to guess what the problem is. It's easy to test the battery, to be sure.

You might want to get yourself a hydrometer. Charge the battery then let it set for 24 hours. Check the specific gravity of each cell with the hydrometer. Each cell should read pretty close to the same, if one cell reads lower than the rest, it's bad (or at least weak). A bad/weak cell will drain the other cells down.

If the battery is under 12 months old, they will probably just exchange it for a new one. If it's over 12 months, they may prorate it.

If the specific gravity tests good on every cell......well.... then you can start :banghead:

[AustinBoston]

New batteries go bad too. Don't live in denial...

I agree...don't deny that a ONE AMP charger is a tiny trickle charger that can take weeks to bring a battery up to charge.  My cheap manual charger has a low setting...that is 2 amps.  Whether or not the battery is good, the device he has does not qualify as a battery charger, even for a group 24 battery.

Austin