Need Battery help plz

[godskid]

Hi! I have a 350# "motorcycle weight" teardrop, from a 2-man shop but not a big name. The battery is labeled "universal battery" Non-spillable sealed lead-acid battery UPG UB12350 AGM Type 35 Ah. It is connect to a box labeled "GPC-35-MAX Smart Battery Charger 35amp". The only power draws are a ceiling fan (not Fantastic, but the other brand, as I recall, though it has no name on it) with a ring of LEDs around it for a light, and another light in the tiny "hatch" area. Three toggle switches for these have an LED each. There is an LED charge reading also.

I've had it plugged into house power (in a non-heated but shielded on all sides garage) all along, thinking that the Smart Battery Charger could monitor and maintain the battery. The battery disconnect switch was left connected since I didn't think it charges when disconnected.

The charge reading was 12 or 13 until recently (not that I looked very often, but occasionally). Now the LED light ring has too little power and won't light, and the charge reading is 6.11 (7.5 when I first noticed this).

A -Could house power outages or glitches have affected the charging? All fuses that I can see are fine. (2 30A on the charger box, and a few elsewhere for the individual devices). An ammeter on the battery does go up slightly when house power is plugged in, so I think the charging circuit is intact.

B - Is the battery salvageable or dead, at 6.1V ? I have a "battery tender" coming tomorrow, which has a "force" mode to try to recover a battery. Is it worth it or save my effort and don't bother?

C - if battery is dead, then maybe I'll buy a larger powered one, since I'm reading elsewhere on site here, that 35Ah will only run a fan for one night. I could get a 55Ah or maybe even bigger, though I might have to replace the plastic battery box too.

More side info: Unit was new Oct 2019 and used for 2 nights, but since it was December I didn't run the fan. Just the lights while reading. My usual June trip was cancelled; perhaps using it twice a year is better for it! Battery says 190116 on it, presumably a manufacture date. Anything else I've forgotten to say?

[saltydawg]

It maybe the charger, but the battery should run a 2 amp fan for 18 hours before it even hit 50% charge. edit I just looked up the charger, i think its a decent charger, so look closer at the battery. Also a 35 amp charge is way over kill for that battery, a 5 to 10 amp is more than enough.

I am starting to get a very bad dislike of lead acid batteries, which an agm is. They loose to much capacity if over discharged, and that is easy to do unless your looking at it every day. They are too easy to kill.

Now for a 35 ah battery a little 50 watt solar panel in the sun will recharge it 3 or 4 hours if its not too discharged.

Personally for the cost also one of the below battery monitor is a good idea. it keeps track of how much power is going in and out of the battery. it is a true gas gauge for a battery that does not depend on voltage. Also a better charger is always a good idea, as a cheap charger left attached can kill a battery.

I am going lifepo4 for my battery, sure cost is more but they have about twice the useable power for AH as a lead acid, plus 5 to 10 times the number of charge cycles

battery monitor
https://www.amazon.com/gp/product/B07CT ... UTF8&psc=1

charger
https://www.amazon.com/gp/product/B07TJ ... =UTF8&th=1

[godskid]

I've got this "battery minder/tender" arriving tomorrow. Hopefully it's good for something. Both my car and this trailer battery are getting less usage now; they can both share this. (The car battery stopped complaining when I unplugged the dashcam while the car is parked, but this battery minder might be useful anyway.)

https://www.amazon.com/gp/product/B07W46BX31

[godskid]

My question about how well a 35Ah battery would last came from this thread, found while searching for battery help. Starting with about the 5th comment, by "WannaBeFree". "BTennison"s post, further down, about adding a second 105Ah battery is very interesting to me:

viewtopic.php?f=30&t=39495

Although as you noted from my charging unit's name, I guess my charger will only do 35. What would that require to support a second battery?

[saltydawg]

Okay a 35 amphour battery should not be discharged past 50%, which is 17 amp hours. which per that thread the fan uses 1.8 ah on low. That gets you just over 9 hours of use only with the fan. The problem with lead acid batteries ( even agm ) is if you go past the 50% mark you effect the capacity even when on the next recharge. lifepo4 batteries are rated for their actual power they can put out with out damage.

I watched a video on a guy test 2 brand new 120 ah batteries until they where dead. He then charged them fully and then tested again and lost 30% of the capacity in just one over discharge. Thats why I went lifepo4, the only real draw back is if you try to charge them at or below freezing you severely hurt them, even just once. But my battery will be inside the trailer which will have some sort of heat, and I probably wont be out below freezing and if I do I own a generator I can use for power.

so my suggestion is buy a 60 amp hour lifepo4 battery, put it in side the trailer and keep it warm in the winter, ie charge it in the house. Just make sure you get a proper charger for it.

As an example I just did a test of my battery. I had a 500 watt halogen running thru an inverter and got about 1 hour 20 mins out of it. Thats some where around 45 amp load for almost an hour and a half.

my battery, with a discount code that out there was about 330 bucks
https://ampedoutdoors.com/collections/b ... es-capable

my charger coming in
https://www.amazon.com/gp/product/B07TM ... UTF8&psc=1

[RJ Howell]

First is the battery is 'not' a deep cycle battery and it's a small version of a starter battery. That plate (mat in your case) is very thin being incapable of giving you what you hope for. Sealed battery just means, tougher to get at the cells for maintenance. No Maintenance, just means when the media is gone the battery dies (great marketing tool to get you to buy again).

I typically stay with basic LA type batteries cause they are so hard to kill when properly used and maintained. I went LiFePO4 only due to weight! My LA's lasted me nearly 18yrs before I retired them, at which point they were down 30% of capacity, not bad at all.

I'm also a firm believer that if you go LA or gel, go dual 6v's if you wish for longevity. Costs are still nearly half of a LiFePO4.

Deep cell battery / proper maintenance/usage and your battery of choice will last many years.

[godskid]

Oh! I hadn't even noticed that the battery labeling made no mention of "deep cycle". That's a good cue that I should just scrap it, and buy one that IS deep cycle.

Do deep cycle batteries come in "no maintenance" varieties? I don't really want to do anything more than charge it properly.

I'm willing to run it & charge it once a month, rather than "always", if I have to. Although previous trailers have gotten the same "plug it in all the time" treatment, and survived for several years till I bought a new trailer. None of them required replacing the battery. What does it take, to find a no maintenance battery that will survive being plugged in all the time? Do I need a better charging circuit? (Maybe the Noco battery maintainer I just bought? https://smile.amazon.com/gp/product/B07W46BX31/ )

[saltydawg]

My opinion which will only cost hundreds of dollars. Esp sense your space limited is a lifepo4. The only real issue is the cold weather charge, and they are light enough to bring inside over the winter. ( i will link everything below )

Do you do cold weather camping? if so disregard everything I say below.

The amped out doors lithium battery I linked to is about the same physical size as you 35 ah but weighs 14 lbs ( from generic sizes found online ) but has 4 times the usable capacity and 4 to 5 times the life expectancy. It will take care of its self when charged properly and stored properly. What that means is unlike lead batteries which want to be stored at a full charge, lithium like 50 to 70% charge. They will put them selves in a sleep mode when not connected to a charger or load. They are very happy this way. Now you do want the proper charger for them, and due to the cost of the battery I dont recommend a cheaper charger. The victron one I linked to here somewhere is $121.

The other issue is if you charge while plugged in to the car/truck you need a battery to battery charger, as the lithium will take every bit of charge your alternator can put out. The amped out door battery will happily take 50 amp charge rate, your alternator in your car will happily give that until it cant any more and it dies trying. I am not providing a link as there are many options and some are very expensive. but there is cheaper options, like using the same victron charger and a small inverter in the tow vehicle.

So buy the amped outdoor battery, proper victron charger ( which is blue tooth so you can check on charging on your phone ) then the battery monitor so you have a battery fuel gauge that tells you how much battery is left. Then buy an anderson plug set for 10 bucks thats good for 50 amps then you have an easy to unplug no tool needed to bring inside system.

Side note, sense the lifepo4 batteries have many many recharge cycles ( thousands ) being able to bring it in side and use it for back up power is a nice option. Imagine being able to run your fridge for 8 to 10 hours from the one battery, or your laptop for days. Or if your a cpap user for 2 or 3 nights. I might have posted this already in this thread, I ran a 500 watt halogen work light for 1 hour 22 mins of the amped battery.

https://ampedoutdoors.com/collections/b ... es-capable
discount code "RXAngler" cost after code iirc $324

charger $121
https://www.amazon.com/gp/product/B07TM ... UTF8&psc=1

battery monitor
https://www.amazon.com/gp/product/B07CT ... UTF8&psc=1

anderson plug set

https://www.amazon.com/Mr-Brighton-LED- ... ljaz10cnVl

disclaimer, I have no connections to any of the above stores or seller and anything.

[godskid]

OK -- I'm looking at the battery and charger that you listed. Possibly with a carrying bag from the same site, and the battery would live inside the teardrop. Can I use my existing monitor?

The "monitor" pictured below is already installed in the trailer. Anybody recognize it enough to say if it's decent? It includes switches for
(1) an unused switch
(2) the ceiling vent Fan power
(3) a small LED light in the cubby (the size of an outlet plate) and
(4) a ring of LED lights around the ceiling fan.
I'd like to leave much of the wiring as is, so I'd like to use this monitor (even if it's not exact). (See front and back pics below, of this monitor / switch unit.)

I haven't thought through all the wiring details, but I'd disable the 35A charging box mentioned in post 1, and disconnect the wires to the tongue battery box (left empty), bridge instead to my new LiFePo battery inside the trailer. The exterior A/C input port would feed only the A/C outlet, for use in winter when I have a space heater and buy shore power at a rest stop along the highway.

Um, when I remember how to include pictures? Well, here's google-drive links:
Monitor-Switches https://drive.google.com/file/d/1bEQYjfrVGhaqgoUPY94nLkGU2nNbqIzo/view?usp=sharing

back of monitor plus cubby light (3) above: https://drive.google.com/file/d/1DzWM-RAIGhkOez0sUxSpNPpkga2HNAUI/view?usp=sharing

The existing charger box (mounted upside down) https://drive.google.com/file/d/1rIXVlmQ-w-p-jQPTUfy209-ZYO0Ti23P/view?usp=sharing

[saltydawg]

the google link is not public access requested

as for switches and stuff there is no reason to change it, I cant see the links but it should be fine.

I dont know why your calling it a monitor unless it has a voltage read out. You cant use straight voltage read out to judge how full a lifepo4 is as they voltage curve is too flat

oh, the 35 mp charger, dont get rid of it, you can use it with the new battery. you just cant leave it attached all the time. You can use it for the fast charge for when you need it. Lets say you bought the meter I linked to. After 2 days you see you have used 40 amp hours, you could hook it up and watch the meter until you see the battery picked up say 30 to 35 amp hours and it would do it in less than an hour. Then use the victron as the final fill it up charger.

also if you get the victron message me and i have the numbers for the "custom" charge curve that will keep the battery happy for 3000 charges.

[godskid]

I think the access is fixed.

The device has a digital readout which used to read 12.5 or so, and now reads 6.14 in the photo. Not sure if I should call it a meter, a monitor, or just a readout.

[godskid]

Also -- how does that LiFePo type of battery differ from the two below, both of which I've already bought to run my cpap while in the teardrop. These two both have chargers and monitors built in, and are thus more "consumer friendly" ..... but maybe they're not strong enough to run the teardrop fan and lights. I only use the DC outputs on them.

https://smile.amazon.com/gp/product/B07PF9S9NY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

https://smile.amazon.com/gp/product/B01M3S00H0/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Or this newer model they show me, would it suffice for the lead acid replacement, and run the fan and lights? It must have less power somehow, given that it's only $300 including charging & monitoring.https://smile.amazon.com/dp/B07VL7XYY6/ref=dp_prsubs_1

[saltydawg]

Okay if your charger voltage it states is correct 13.6 volts it would work fine with a lifepo4. Bulk charge on lifepo4 is normally 14.4 until the battery reaches 90% charge, then the float which you dont really need is 13.6. Lifepo4 only really needs 2 charge steps, bulk at 14.4 and equalization at 14.4 they are fully charged at that point. Thats why the float "spec" for them is 13.6, ie not really charging. They are considered fully charged at 13.6-13.8 after they settle.

Keep the charger you have, just use it as a bulk charger and buy the meter I linked to to decide when to take it on and off charge.

to calibrate the meter you either fully discharge it to 10.5 volts, then reset the meter to 0% then set the capacity to 60 amp. or fully charge it then set it to 100% charged and capacity of 60 amp hour ( I set mine at 55 ah to give me a little extra room )

I would probably keep that charger as the primary but check its voltage out put on the battery to make sure its actually a float of 13.6 and with any luck 14.4 bulk.

read this for some info on lifepo4
https://www.solacity.com/how-to-keep-li ... ies-happy/

[Shadow Catcher]

One way of saving on current, I substituted using two 180 mm three speed Antec case fans hooked up with a DPDT switch so that one or both fans.

[saltydawg]

One way of saving on current, I substituted using two 180 mm three speed Antec case fans hooked up with a DPDT switch so that one or both fans.

thats my plan