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Post by oldhome7 on Dec 19, 2015 18:27:44 GMT -8
This is my first toe in the solar pool and I just recently bought the 100w + 30A PWM charge controller kit, setup went smoothly and have it hooked up to an old Optima D34M that has seen better days just to get started. My question is this, during the day I've had it just with the panel, controller, and battery, but at night the battery sags quite rapidly and I'm just wondering if it would be safe to hook up a standard automotive trickle charger to float the battery until sunrise again without having to completely disconnect the battery from the controller?
Also, off topic of the original, I read in the manual for the PWM30CC that it's 12/24v compatible, yet haven't really read any where other of people running 24v on these. Just looking for confirmation is all as I do plan on probably running 6 or 8 panels eventually, manual says 360w at 12v or 720w at 24v though I've seen people say 400w is fine on 12v for this so would 8x 100w panels be fine as well or should I just stick with 6 for now until I get a better controller?
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Post by spiderbob on Dec 20, 2015 8:50:39 GMT -8
Your going to be limited with your 30a PWM, just so you know. To answer your charger needs, my system in the RV has not only the charger charging the batteries, but also there is a converter/charger doing it as well as the alternator in the engine doing it, as well as the generator doing it, so I am assuming that using a trickle charger will do no harm. Only my opinion of course, but you see what I put my charger through.
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Post by oldhome7 on Dec 20, 2015 10:20:34 GMT -8
Well thank you. I know I'm going to be limited with the 30a PWM just was curious with what I can do with it for now, and if it truly is 12/24v capable, until I absolutely need to upgrade to something more capable. I think by the time I get up to the 6 panels, if it is 24v capable, I should be ready to switch to an MPPT controller then.
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Post by spiderbob 2 on Dec 20, 2015 11:20:54 GMT -8
When and if you decide to go 12 or 24, it all depens on your needs. The panesl are either 12v or 24v when you order them. I have panels in both my RV's and they are all 12v.
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Post by oldhome7 on Dec 20, 2015 11:54:13 GMT -8
It's not a matter of if I bump up the voltage, it's when lol. Just want to be sure this CC can handle 24 like it says. Eventually I plan on a 72v battery bank, but for now I'm just working with what I've got and will push it as far as I can before I am forced to upgrade.
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Post by spiderbob on Dec 20, 2015 13:39:18 GMT -8
Just courious what does a 72v battery bank consist of?
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peggy
New Member
Posts: 12 
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Post by peggy on Dec 20, 2015 14:40:49 GMT -8
ideally speaking a Home should have a 12 volt system and a 24 volt or higher system. I dont know of any household item that is not 12 volt. oh we live completely off grid! yes all renogy here. we run generator during grey days. we use a 10 amp bAttery charger and let it go. a battery can only accept a certain amount of voltage as it gets closer to full voltage when using a battery charger. ahh mother nature here at home we have nights that get to 20 below zero. and the batteries are in that weather. they have a "sag" in voltage because of temp outside. from experience it sounds that the battery you are using is bad. they will take a charge but wont hold a charge. we loose .5 volts on 250 ah at night knowing batteries are fully charged.. brand new batteries. we are running lights and heater for 8 hours at night. you also might be getting a false reading. when batteries get closer to a full charge they may show a high voltage because of the solar panel voltage/ cc output voltage and as soon as the solar panel VOLTAGE(the sun goes down) drops so does the metered voltage because of the stage of charging the cc is in. confussed? we live it every day. once again thanks renogy.
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Post by oldhome7 on Dec 21, 2015 6:09:52 GMT -8
spiderbob, a 72v bank would be 6x 12v or 12x 6v in series.
peggy, after running a desulfation cycle with my ctek charger, it seems to have brought the battery back into a more usable state. I should point out that this battery did come from my summer car that is currently winterized, it had been sitting for a bit before I decided to use it. At first it would lose a whole volt or more in just a couple hours, I let it go last night for 14 hours and only dropped .3 volts. Then again, I'm only running a few phones on it right now on an inverter that is completely overkill, as I mentioned this is my first step into solar and I know my setup is not exactly efficient. The panel is just hanging in a SW facing window and there are a few trees that shade it a bit during the day, but it does seem to at least float the battery during the day and not cause it to drain though some days it will charge it a bit.
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Post by Admin on Dec 22, 2015 8:33:10 GMT -8
Hello Sir,
Yes the PWM 30A CC can support up to 360 watts while charging a 12 volt battery bank and 720 watts charging a 24 volt battery bank. I would recommend upgrading the charge controller after 600 watts. Connecting a trickle charger to the battery bank should not affect the charge controller so you can leave it connected overnight.
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Post by oldhome7 on Dec 23, 2015 7:03:52 GMT -8
Thank you Admin, it's nice to have a little reassurance. Also, I've been running the trickle charger a few times and haven't had issues. Only thing is when I forget to shut it off and it plus the charge controller are charging the battery in the morning tends to get the battery voltage high enough to set off my inverters high voltage alarm.
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Post by Admin on Dec 23, 2015 9:15:11 GMT -8
Hello,
Most inverters high voltage alarm will go off at around 15 volts. Is the trickle charger rated to output more than 15 volts? The charge controller should output no more than 14.6-14.8 volts.
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Post by oldhome7 on Dec 23, 2015 20:53:58 GMT -8
I'm not quite sure what the trickle charger's voltage output on the AGM setting is when at the 2 amp rate but it is a smart charger and by the time it causes the inverter to go off it pretty much immediately shuts off as it sees that as full, it's just the alarm keeps going until I reset the inverter, so there hasn't been any harm yet on the battery. If anything I think it has actually helped the battery floating it at almost 15v as it really does last almost a couple days without needing the assistance at night, which I would assume has been desulfating it.
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Post by Mleeatx on Jun 20, 2017 7:08:03 GMT -8
Based on Peggy's response It appears hooking up my 10 amp deep cycle charger to batteries as well as PV via charge controller will work perfectly fine. Need boost, I can fire up 120v genset and turn on Charger. Preferably let PV panels charge daily unless rainy days last for several days.
I have searched internet completely for diagram showing this but to no avail.
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Post by spiderbob on Jun 20, 2017 9:14:58 GMT -8
Check online RV info forums, they do it all the time. I'll look into my folder to see what I can fine, but won't be back home for a couple of days.
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