Need Battery help plz

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Re: Need Battery help plz

Postby godskid » Mon Sep 21, 2020 11:02 am

Marvelous! I shall print that out.

Do I want to take the monitor inside too, if I charge in the house? So that it continues to know what's in the battery? That could be arranged, I think.

Can I install at BB instead? I think that equivalent, in the circuit. Not sure I want to put an expensive LiFePO4 on the tongue, where it's easily stolen.

The size of trailer in question, ~ 4x6 ft plus tongue. The car is a MINI Cooper, Clubman so long-style:
https://drive.google.com/file/d/1kC3oMu ... sp=sharing
https://drive.google.com/file/d/1AkgvCj ... sp=sharing
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Re: Need Battery help plz

Postby saltydawg » Mon Sep 21, 2020 12:37 pm

Sure if there is room inside you can put the battery there at BB. No reason why not to as fumes are not an issue.

As for bringing the monitor I would not bother. Just use math, if the battery is say at 10 % when you bring it in, you know its happiest at a 60 to 70 % charge. So from 10 % to 70 % is about 40 amps, if the charger does 10 amps charge it for 3 or 4 hours and let it sit until your ready to go camping. Then charge it when the charger shuts down the charge when you are ready to go camping. When you put it vback in the camper just tell the monitor it is at 100%. It only takes a second.

Thats another reason why lifepo4 is nice, it does not need to be kept 100%.
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Re: Need Battery help plz

Postby godskid » Sun Oct 04, 2020 12:35 pm

Thanks for all the help! New battery is finally wired up and powering the teeny teardrop quite nicely. :D

Got any English translation for the monitor's instructions for setting values? The only part I can interpret is to press % to view percentages, and then pres % again for 3 seconds to set it to 100%. I've somehow managed to set the A value to 100, rather than the 60 max of the battery. Oh well!

Ahh -- I may have gotten it. I've set the Ah to 60 max when the percentage is at 100. I'm repeating the use-it-down-by-12AH and hope to see that it now read 80% there. Yesterday, my 100Ah max setting meant that 12AH down was only 88% so I used up some more AH's before I realized that was because of working from the wrong max-AH. I think I've set the two things that matter now -- 60AH and 100%.
Last edited by godskid on Sun Oct 04, 2020 11:38 pm, edited 1 time in total.
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Re: Need Battery help plz

Postby MickinOz » Sun Oct 04, 2020 5:02 pm

saltydawg wrote:
MickinOz wrote:8 awg is around 10mm2.
Way overkill, in my opinion, assuming you are using copper wire. (All bets are off if you are using aluminium wire.)

My Renogy 20 amp solar charge controller will accept maximum wire size of 6mm2. That's 10awg.
12 AWG is 4mm2. I'm using that to connect battery, solar panel and fuse block.


Sorry I am an electrician who used to do a lot of work on electrical for sailboats, so lots of solar and batteries. I always tended to make it future proof and as safe as possible.

The one that used to get me was people wanted solar on their boat, stores would tell them here is you 200 watts of panels and hook it up with 12 gauge. I measured at the panels around 17 to 18 volts, 30 feet of wire later 15 volts, thats in full sun. Amazing after I would run new wire and the system started working better I never had more than a half volt drop.

I have seen people run 50 feet of 18 gauge wire to the other end of the boat for a 2 amp fan, and then wonder why it never worked right. Of course it was only seeing 10 volts at the fan.

Dropping 3 or 4 volts on a 120 volt circuit, which is the max legal is one thing. dropping 2 volts on a 12 volt system is another.


Hi just saw your reply. I should have qualified my opinion somewhat. I meant 8 AWG was overkill at the short runs you'd be using in a teardrop.
I calculated my runs at no more than 0.5 volt drop at 20 Amps. (Expected charge from controller to battery is 15 amps)
I used the Rainbow Power Company formula. (They were one of the early pioneers of stand alone solar and hydro here in Oz.)
https://www.rpc.com.au/pdf/Wire_Chart.pdf

Can see why a 30 foot run would be "sub-optimal" running 9 metres of 12awg on 200 watts of panels. :D
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Re: Need Battery help plz

Postby saltydawg » Sun Oct 04, 2020 5:28 pm

godskid wrote:Thanks for all the help! New battery is finally wired up and powering the teeny teardrop quite nicely. :D

Got any English translation for the monitor's instructions for setting values? The only part I can interpret is to press % to view percentages, and then pres % again for 3 seconds to set it to 100%. I've somehow managed to set the A value to 100, rather than the 60 max of the battery. Oh well!


Yay youkind of need to just play with it and figure it out. I do know when it is showing % of charge a long press iirc maxs it out. Unless you press a different button then it zeros it. Play and learn.

How do you like the size and weight of the battery? and the monitor ( once you figure it out ) is a nice addition.
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Re: Need Battery help plz

Postby MickinOz » Sun Oct 04, 2020 6:11 pm

Scott/saltydawg, you do seem to know your stuff.
Some of the 12V advice on the forum runs along the lines of "yeah, xx AWG will do it", "don't/do need a fuse here", "that much is plenty".
Rules of thumb, wet finger estimates, some plain old misinformation. I blame auto parts stores a bit - you walk into their electrical sections here in Oz and you'll see a roll of wire marked 15 amp. "Yeah? Over what distance with what voltage drop?"

I admit I am not good with the search function. Still, I find it difficult to find what I consider a decent wiring diagram here.
The generic Benroy plans have probably helped dozens, maybe hundreds of people build a teardrop.
They have certainly helped me, but they are missing wiring diagrams.

We need someone qualified (hint, hint) to design a generic standalone 12V system, with a wiring diagram (not a block diagram with a single black line between blocks) that shows wire sizes, max run lengths, fusing and fuse locations, etc.
There isn't a "typical" system of course, but most people seem to want a couple of reading lights, a fan/dome light and a power outlet in the cabin, a porchlight and a power outlet and light in the galley. Around 100AH of battery storage (or 30AH or so of lithium) and a 100-200 watt solar panel would round out a system that keeps the lights on and the iphone charged.
Of course, this might already exist and I just can't find it.
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Re: Need Battery help plz

Postby saltydawg » Sun Oct 04, 2020 6:33 pm

Mick I will be honest, I have thought about it. But I have not done it for a few reasons.

Who do he think he is coming in here and trying to tell us how to do it, we have done it this way for so long and it works fine ( it may, but it can be better )
There will always be someone who says I am wrong, over building, making it more/too complicated
I try to help when I can, but dont want to over step.

Simple things like the 40 buck battery montor, not needed but very nice to have ( need it with lifepo4 batteries in my mind )
Stupid things like anderson connectors, while not needed are very nice to have, can be used as a shut off/disconnect

Funny thing about my first reason up top is most people wire things like they do to save a little money, but doing it right will cost less than 100 bucks more.

Also I am horrible with drawing things on a computer, yet I use them everyday to do my job. And I use them to look at electric drawings.
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Re: Need Battery help plz

Postby MickinOz » Sun Oct 04, 2020 10:26 pm

I get what you are saying, believe me!
It is a pity, because things like anderson plugs cost very little over here, and we are not talking about a lot more money all round by upgrading from just thick enough wire to well and truly tick enough.
Just having someone who knows how to estimate what "thick enough" is for each circuit drawing up a generic plan would be a bonus.
And your particular background means that you can easily differentiate between the nice to have, the essential and the actually detrimental.
Still, I do understand why you are a bit reluctant.
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Re: Need Battery help plz

Postby godskid » Fri Sep 17, 2021 8:33 pm

Urk. Is it possible I have plateaued my expensive LiFePO4 battery at 80%? I installed it almost exactly a year ago. Haven't had a chance to run the trailer, though.

But I've been faithfully charging it up to 100% the first of every month, and then running a light to bring it down to the 80% desired storage value, plus or minus a few percent. Then I disconnect the A/C power cord, so it shouldn't have been affected by any house power glitches.

Now it seems to be shutting down *AT* 80%, as if that's as low as it can go. While it's above 80%, it'll output power. At 80%, it cuts out. Have I re-baselined it to the 80% level?

Maybe running the lights from 100% down to 80% isn't "exercising" it enough? Was I supposed to take it down to 15% or so, occasionally?

Most importantly: IS THERE A WAY TO FIX THIS? I'm taking a trip in 7 days (of course).

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Re: Need Battery help plz

Postby saltydawg » Fri Sep 17, 2021 9:46 pm

godskid wrote:Urk. Is it possible I have plateaued my expensive LiFePO4 battery at 80%? I installed it almost exactly a year ago. Haven't had a chance to run the trailer, though.

But I've been faithfully charging it up to 100% the first of every month, and then running a light to bring it down to the 80% desired storage value, plus or minus a few percent. Then I disconnect the A/C power cord, so it shouldn't have been affected by any house power glitches.

Now it seems to be shutting down *AT* 80%, as if that's as low as it can go. While it's above 80%, it'll output power. At 80%, it cuts out. Have I re-baselined it to the 80% level?

Maybe running the lights from 100% down to 80% isn't "exercising" it enough? Was I supposed to take it down to 15% or so, occasionally?

Most importantly: IS THERE A WAY TO FIX THIS? I'm taking a trip in 7 days (of course).

Deb


I doubt it, what I would do is a full charge, double check the settings on the charger and the battery monitor. Then let it rest over night and check the voltage at the battery. Then turn stuff on and let it discharge until shut off. Then turn the charger on for 30 seconds, this should wake the battery up. turn the charger off and check the voltage.

do the above and get back to us.
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Re: Need Battery help plz

Postby godskid » Sat Sep 18, 2021 6:08 pm

Charged. Resting now. The meter, connected as per above diagrams, reads 13.26V now with 0.010A current even when the trailer "disconnect from battery" switch is thrown. (0.022A of LEDs inside trailer, before that.) The charger has no settings. It was bought from the battery seller (maker?) ampedoutdoors.com and is specifically for this battery.

Unless I get a friend to visit with an ammeter, I can't measure the current/voltage directly AT the battery. I'm moving house in 7 days and everything is packed up. Including, unfortunately, my ammeters. Is that step going to be imperative?

I did do some of the above steps last night, before getting any replies. Well, sort of: I put the charger on WHILE running the trailer fan to exercise the battery. It charged to 100% just fine. Then I turned off the charger and left it overnight with the fan still running (no rest period, as you later advised). It stopped providing power at some point; and the meter read 80% when I woke up. No, actually, the meter read NOTHING (blank screen) until I turned on the charger again for a few moments, to get it above the shut-off point. With charger on, it read 80%.

I've sent this same question to the seller (maker?) too, but it's Saturday so no reply yet.

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Re: Need Battery help plz

Postby saltydawg » Sat Sep 18, 2021 8:14 pm

The 13.26 is okay for rested battery. Hook it back up to the charger and leave it for 24 hours. Are you basing it being 100% off the ali meter setting, or is there no more current flowing ?

if off the meter it might be off in its calibration, if it is no amperage flowing then it should be charged.

What is the voltage on the meter saying when its charging. It should be around 14-14.4?
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Re: Need Battery help plz

Postby godskid » Sat Sep 18, 2021 9:12 pm

Ok. Charging over night, or till 9:30 tomorrow night (CDT) if nobody says otherwise. It registered 13.73V during charging .... but it was steadily rising. It reached 13.95V after 30 minutes.

Come to think of it .... a few months back, I did wonder why the charger still sounded like "full blast" when the meter read 100%. But I'm not sure I know what it sounds like at rest (keep-charged).

It's a 60Ahr battery, so 80% charge should be 12Ahrs down. My 10Ahr charger should therefore (I thought) need a bit over an hour to charge it to full again. So I charged it for 90 minutes to 2 hrs, and then left a light on overnight to discharge back to 80%.

BUT maybe the meter is lying to me. It didn't occur to me to charge it longer, as you've requested. Fingers crossed this fixes it all!

Deb

And yeah, I was basing the 100% off what the meter read. I did set it to be 100% when full a year ago, when it was new. At least, I'm pretty sure it was really full then. Meter could have drifted tho. The charger doesn't have any "current flowing" register (nor any readings at all; just a power on LED and one other.) Would the meter as described above register current flowing into the battery?

Almost 2 hours after start: meter says 13.99V - 14.00V toggling. And yes, the current shows about 9A of current flowing. AND the charger's non-power LED is supposed to be red for charging, green for done-charging. It's still red.
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Re: Need Battery help plz

Postby saltydawg » Sat Sep 18, 2021 10:13 pm

godskid wrote:Would the meter as described above register current flowing into the battery?


Yes hit the button with the A or center button, it should give you a amp number plus or neg. Plus is charging, neg is discharging. Press it again and it will show you the number of AH left, it at least what it thinks.

That is one thing I do like about the ali monitor. Even if it does drift, the next full charge will "zero" it out at 100%.

What the other thing you can do in the future is when it shuts down ( hopefully you dont run it that low again ) is you can hit the A button and set the meter to 0%. You will need to play with it to do that, but then when you charge it you will see the number of amps the battery takes until the charger decides its charged.

A discharge test is a better way to she how charged the battery is, but lets not worry about that right now.
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Re: Need Battery help plz

Postby saltydawg » Sat Sep 18, 2021 10:17 pm

godskid wrote:
Almost 2 hours after start: meter says 13.99V - 14.00V toggling. And yes, the current shows about 9A of current flowing. AND the charger's non-power LED is supposed to be red for charging, green for done-charging. It's still red.


I did not see this when I replied, I am stupid sometimes.

Yes your meter was off I bet. The meter is your best bet right now to figure fully charged and thats by the amps, not what % it thinks its at.

edit, where the error in your meter may have come from is self discharge, plus not a real charge. Ie if you lost a few % a month that the meter does not see after 12 months your meter could be say 36% off. So you would be at 64& charged, thats fine, but anymore from your exercise that did you did not really put in can add up tp more.
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