Seeking advice on proper configuration 12V 140ah

**lkruper** · 07-01-2015, 07:59 PM

Originally posted by ThXinc

Hello everyone

I registered here to begin discussing the configuration I have put together for camping. I wanted to build a portable, modular system that can be set up and taken down easily. I want it to be able to run small entertainment options, radio, maybe a laptop, a couple small fans for keeping cool. and some string lights.

The concept revolves around using milk crates for the batteries and electronic components so they can stack and transport easily in the truck.

I have two 12V 35ah batteries in each milk crate, in parallel. They are then connected via the quick connect to create a 12V 140ah power source. All power source cables are 4ga.

I'm using the Harbor Freight solar power kit for the solar power (3x15Watt) 45watt array and the included charge controller (It has a output cutoff of 11V and a charge cut off at 14.5 V)

Access to this page has been denied

http://www.harborfreight.com/45-watt-solar-panel-kit-68751-8527.html

px-captcha

For the inverter, I'm using a Samlex 600 watt pure sine wave inverter

My dilemma is the charging process. I cannot get the batteries up much past 12.1 volts. 12 V should take up to around 13 when FULL? They were 12.4 when I originally tested the inverter load. I ran two fans (70 watts total consumption) and some minimal LED light strings. Voltage dropped from 12.4 to 11.3 in 6.5 hours without simultaneous charging (night scenario test)

I'm using a balanced connection for the inverter. Positive connection at battery #1 and Negative connection at Battery #4

Here are my questions:

Do I hook up the charge controller to the OPPOSITE of the balanced configuration ( Positive at Batt#4 and Neg at Batt #1) or do I connect the charge controller to the same terminals that the inverter is connected to?

My Batteries charged back to 12.1, but I can't get them back up to 12.4V (almost 13V FULL)

My other concern is that the 45 watt input from the panels may not be enough to push this battery connection to a MAX charge. ( I wanted to test the charge controllers shut off point and it never got there.

Sorry I don't have the knowledge to provide a wiring diagram, but here are some pics. I would appreciate any input.

Thanks[ATTACH]7179[/ATTACH][ATTACH]7180[/ATTACH][ATTACH]7181[/ATTACH]

What kind of batteries are they? Also, your hf panels only output 3 amps. You will need about C/10 [140/10 = ] 14 amps to charge lead acid batteries. If you take your batteries down 20% and thus use 28 ah capacity it would take 28/2 + 2 hours (16 hours) to charge, IF the batteries can be charged with such a low amperage. Also, look at some of the stickies on batteries on this site regarding the perils of parallel hookup for batteries.

Oh, and I am but a newbie. Seek out the experienced Sunking on this forum for good explanations and advice.

**ThXinc** · 07-01-2015, 09:31 PM

Hi, thanks for replying.

I bought 4 of these lead acid batteries

Error Page | eBay

http://www.ebay.com/itm/35AH-12V-DC-DEEPCYCLE-SLA-SOLAR-ENERGY-STORAGE-BATTERY-/281475578512?hash=item4189407a90

I would not think I have any other choice but parallel config because of the 12V inverter.

**lkruper** · 07-01-2015, 10:09 PM

Originally posted by ThXinc

Hi, thanks for replying.

I bought 4 of these lead acid batteries

Error Page | eBay

http://www.ebay.com/itm/35AH-12V-DC-DEEPCYCLE-SLA-SOLAR-ENERGY-STORAGE-BATTERY-/281475578512?hash=item4189407a90

I would not think I have any other choice but parallel config because of the 12V inverter.

I am not familiar with those batteries. The bigger problem will be your lack of sufficient amperage from your panels to charge those batteries effectively. I don't know what you budget is, but something like these flexible panels (http://www.amazon.com/RENOGY%C2%AE-B...e+solar+panels) would give you the amps you need and also be easy to transport and set up when camping.

I have not used these panels, so perhaps someone on this forum with more experience can comment. I know that flexible panels have less of a warranty, but in 5 years, who knows what kind of products we will have to work with and what price point.

From looking at the documentation, it appears the charge controller handles multiple battery banks, so depending on your load, perhaps you could split up your bank and alternate between the two banks, thus eliminating some of the parallel cables.

### Edit ###
BTW, I don't like what I see on Amazon regarding the charge controller. However I do think that flexible panels like this lend themselves to quick deployment and storage for camping.
####

**jony101** · 07-01-2015, 11:00 PM

I have to agree your solar panels are too small. With an mppt and your panels connected in series you might get a little more power out of them. I dont think your even getting 3 amps out of them in the midday sun. 3 amps will never replace what you are using. For your system I think you need at least a minimum 120 watt panel and very good sunshine in your area, which will give you 7 amps.

Right now, your draining your batteries too low, you have agm batteries and they shouldnt ever go below 12.1 volts. For agm, 12.1 is 50 percent which is the lowest you should drain them for long life. 12.7 is fully charge. 140 ah battery is actually only 70 ah of usable power. Which is plenty of power for your needs.

As an example i have a 102 ah agm battery and run bigger fans than what you have, also charge my laptops and run my lights etc. But on my system I have a 240 watt solar panel connected to an mppt controller. It charges the battery at 12 amps. But even on this system if I get several cloudy days the battery will get down to the 12 volt area but I never let it get below 12 volts. But by noon time on a sunny day I can see the charge controller putting out 14.4 volts, which is what you should see. When you see 14.4 the battery is almost full, if you see 13.6 the battery is in float mode and is fully charged. If the most you ever see is 13 volt when being charged by the solar panel, your not even reaching float mode. For a proper charge the battery has to be at 14.4 for at least 2 or 3 hours.

The smartgauge.co.uk website it shows you different ways to parrallel your batteries for best efficiency. But in your case no matter how you connect your batteries they will never be able to get a full charge until you get bigger panels.

I recommend you get a dc wattmeter and connect it between your controller and your battery, it will tell exactly how many amps your system is putting out. They cost about 15 dollars and is better that a voltmeter.

Attached Files

a dc wattmeter.jpg (69.3 KB, 8 views)

**SunEagle** · 07-02-2015, 11:09 AM

Originally posted by ThXinc

Hello everyone

I registered here to begin discussing the configuration I have put together for camping. I wanted to build a portable, modular system that can be set up and taken down easily. I want it to be able to run small entertainment options, radio, maybe a laptop, a couple small fans for keeping cool. and some string lights.

The concept revolves around using milk crates for the batteries and electronic components so they can stack and transport easily in the truck.

I have two 12V 35ah batteries in each milk crate, in parallel. They are then connected via the quick connect to create a 12V 140ah power source. All power source cables are 4ga.

I'm using the Harbor Freight solar power kit for the solar power (3x15Watt) 45watt array and the included charge controller (It has a output cutoff of 11V and a charge cut off at 14.5 V)

Access to this page has been denied

http://www.harborfreight.com/45-watt-solar-panel-kit-68751-8527.html

px-captcha

For the inverter, I'm using a Samlex 600 watt pure sine wave inverter

My dilemma is the charging process. I cannot get the batteries up much past 12.1 volts. 12 V should take up to around 13 when FULL? They were 12.4 when I originally tested the inverter load. I ran two fans (70 watts total consumption) and some minimal LED light strings. Voltage dropped from 12.4 to 11.3 in 6.5 hours without simultaneous charging (night scenario test)

I'm using a balanced connection for the inverter. Positive connection at battery #1 and Negative connection at Battery #4

Here are my questions:

Do I hook up the charge controller to the OPPOSITE of the balanced configuration ( Positive at Batt#4 and Neg at Batt #1) or do I connect the charge controller to the same terminals that the inverter is connected to?

My Batteries charged back to 12.1, but I can't get them back up to 12.4V (almost 13V FULL)

My other concern is that the 45 watt input from the panels may not be enough to push this battery connection to a MAX charge. ( I wanted to test the charge controllers shut off point and it never got there.

Sorry I don't have the knowledge to provide a wiring diagram, but here are some pics. I would appreciate any input.

Thanks[ATTACH]7179[/ATTACH][ATTACH]7180[/ATTACH][ATTACH]7181[/ATTACH]

You are not getting enough charging from that 45 watt panel array. Also that charge controller is not very good quality.

With a 140Ah battery system you need at least 14 amps of charging which is about 150 watt of solar panels using a PWM 20A charge controller.

Usually the charge controller and inverter are connected to the same battery terminals. You should also include the appropriate sized fuses in those circuits to protect the wires.

**ThXinc** · 08-26-2015, 07:09 PM

Thanks for the input everyone. SO I gathered for the most part that the HF beginner Solar panel kit, just wast enough to charge 4 ea. 12V /35ah sealed lead acid batteries.

So I upgraded another 500.00 in getting this panel. (120 Watt version) http://gpelectric.com/files/gpelectr...ccessories.pdf

Charged in full sun today and only went up from 12.25 to 12.65 volts across the bank. I really need to get back to a FULL 13+volts in order to run the desired accessories in the evening for the length of time.

Using 6Ga wire that's no longer than 2 feet to connect each battery and from panel to first battery. Getting quite expensive for little result. I'm afraid it's possible I may have battery issues. They're brand new, but my earlier experiment drained them to 11V. Would this have damaged them and prevent from receiving a full 13+V?

**SunEagle** · 08-26-2015, 07:52 PM

Originally posted by ThXinc

Thanks for the input everyone. SO I gathered for the most part that the HF beginner Solar panel kit, just wast enough to charge 4 ea. 12V /35ah sealed lead acid batteries. So I upgraded another 500.00 in getting this panel. (120 Watt version) http://gpelectric.com/files/gpelectr...ccessories.pdf Charged in full sun today and only went up from 12.25 to 12.65 volts across the bank. I really need to get back to a FULL 13+volts in order to run the desired accessories in the evening for the length of time. Using 6Ga wire that's no longer than 2 feet to connect each battery and from panel to first battery. Getting quite expensive for little result. I'm afraid it's possible I may have battery issues. They're brand new, but my earlier experiment drained them to 11V. Would this have damaged them and prevent from receiving a full 13+V?

Draining a 12volt battery to 11 volts usually means they are toast. You might be able to get some life out of it using a commercial battery charger but IMO no solar charging system will be enough.

**ThXinc** · 08-26-2015, 10:34 PM

Thanks. That sucks. Would you think that taking one of them in for testing could determine the state of the entire bank? the cool thing about this batt bank is that I can split it via Anderson connector. My plan for the AM is to try to charge 2 battery module and see what the result is. If I can't get to 13+ volts, is it safe to say I need to replace them? The inverter I was using DID have protection and it never activated. I shut down before protection kicked in.

**PNjunction** · 08-27-2015, 02:03 AM

STOP spending money now, and do more reading instead.

Actually DO spend money on the next few items:

1) Decent multimeter
2) P3 International Kill-A-Watt meter
3) A decent smart charger to actually validate that your low-end agm's are not just highly sulfated "new-old-stock" and/or have varying degrees of aging and storage conditions.

It is unfortunate that you didn't check each agm prior to putting them in parallel for charging. If the terminal voltage of any of those upon receipt was sitting any less than 12.5v, you got some old stock or abused stock stored in a high heat condition. New agm's right from the factory read 12.9 to 13.2v. Since agm's have low self-discharge, if you find them at less than 12.5v they should have been rejected.

Do note that some places that sell batteries accept the shelf-queens rotated out of stock from good distributors at a fire-sale price, and then jack those prices back up to new just for you - or at some slightly reduced sale price. I'm not saying this place you got them from does that, but man I wish you would have checked the terminal voltages individually first.

Without going into the entire issue of solar project construction here, I can say this: get yourself a good smart charger, and see if each battery will charge up individually without problems. Ideally one buys a single battery of the proper size from a *reputable* dealer, and treats it right from the get-go. But if you are going to mess around with ups-style agm's and don't know how to recognize problems off the bat, I can say that this charger is a good investment especially for the low-end 12v solar user:

Tecmate-Optimate 6, model TM181

Why? Noco, Ctek and the like are good, but the Optimate will actually show you the status of a test result afterwards, a minimum of 12 hours after full charge, and now you can spot issues with your parallel batteries before you start. Obviously, it is great for your vehicle when not playing around with your solar agm's.

There is a plethora of issues when you want to start to get serious. The first is actually measuring your power over time which will dictate your battery capacity. You'll need your multimeter, or clamp-on ammeter, the kill-a-watt for your ac loads, and knowing if you are going to be messing around for only 2 hours, or if you are going to stretch things through the night like 12 hours!

For instance, those two dc-fans - what current do they pull at your desired fan speed? Multiply that by the hours you intend to use it. Now we add the rest to get your power needs.

When we know that, then you'll know if you just wasted another $500 on those portable panels or not. In fact, you may actually do better with only TWO of those batteries in parallel - it all depends on your power budget. Fortunately you are in Houston and not the North Pacific, so your "solar insolation hours" are much better. These solar insolation hours are far different than just sunrise-to-sunset. We'll save that for later when you measure how much power you actually intend to use during your operations.

First off - if you want to play around with those agm's instead of just killing them outright, grab a charger to at least start out on the right foot and charging each individually before releasing them to your solar system.

**ThXinc** · 08-27-2015, 12:25 PM

Thanks for your detailed input!

Your recommendations are noted. I have a multimeter and will look into the recommended charger.

I took the batteries up to a battery specialty shop for testing. 3 out of 4 were toast. Lesson learned (don't buy batteries on Ebay) So I bought a single 12v 100ah battery from this reputable dealer.

From what's been discussed, the 120watt panel might not be enough for the 140ah parallel bank I had originally configured. So, this might be a better fit. Now my system looks like this:

Go Power 120 Watt portable panel (includes 10A controller)

http://invertersupply.com/index.php?main_page=product_info&products_id=2418&cPath=0_453&gclid=Cj0KEQjw6vquBRCow62uo-_J_YYBEiQAMO6Hiic6YRtKMZD8rAYFZG8HZWwYksxXSwaI4thm9OwXKOoaAnN08P8HAQ

Samlex PST-600-12 pure sinewave inverter

Duracell 12V x100ah SLA battery

Now the question is, how much draw will two 45watt vornado floor fans pull and for how long? The inverter alarm for low voltage doesn't activate until voltage gets below 10.6...so are my batteries toast before the alarm even goes off? That Kill a Watt meter seems like good tool.

Thanks for your help and wish me luck...my sister will kill me if I don't bring her enough power to 'Glamp out' . LOL

**PNjunction** · 08-28-2015, 01:43 AM

Originally posted by ThXinc

Duracell 12V x100ah SLA battery

Thats a GREAT step in the right direction. Thing is, Duracell makes a few different types and chemistries. Is it a GEL or an AGM? Hopefully agm, unless you really know what you are doing with gel. This is critical to know, since you'll be setting your charge controller to the right voltage depending - get it wrong and you burn up a gel, and undercharge an agm. A Duracell is usually a re-badged Deka / East Penn, so that is much better - but is it really Duracell or a "Duracell equivalent"? I just don't know your battery shop.

Samlex PST-600-12 pure sinewave inverter

Good choice. Best docs in the industry.

Now the question is, how much draw will two 45watt vornado floor fans pull and for how long?

About 6 hours give or take with that battery on a full charge.

Quick rundown - we're going to use the power formula (P/I*E) , aka (Watts / Amps * Voltage) and stick to watt-hours as the result.

* How many watt-hours is the battery good for? (trick question)

100Ah * 12v = 1200 wh.

* How many watt-hours do I REALLY have to play with?
Only HALF that. To get any reasonable cycle life out of a battery, we don't take them down more than half-way, or 50% DOD.

1200wh / 2 = 600 wh available real-world!

Your two Vornado's total up to using 90w per-hour that is. So, for just the fans alone running full-blast that would be:

600wh / 90 = 6.6 hours. With a small amount of inverter inefficiency, the best you would do is about 6 hours in reality.

For an agm, 12.2v *rested for about 4 hours or more* is about 50% DOD.

So total up all the watts your gear is rated for, add this to your overall total, and use 600 / total wh calculated. That will give you napkin-calc results.

The 10.6v inverter cutoff is NOT TO BE USED as an automatic cutoff under normal circumstances. It is a dead-man switch to help prevent catastrophic damage to your battery. 10.6v is basically beyond 100% DOD. It does not mean that it is ok to use this under normal circumstances. If anything, NEVER let your agm get lower than 12.0v, and recharge immediately.

Use the Kill-A-Watt meter to measure your Vornados at other lower fan speeds if you want to estimate the time based on those settings with a max of only 600wh usable. Likewise do the same for your other gear. Next time, consider a dc-powered fan with similar vornado type qualities such as an Endless-Breeze / Fantastic fan. I have both the vornados and Endless Breeze, and when running battery power, the endless breeze fans allows for a dc connection with nearly the same amount of air. Power up the vornados one at a time if you have them on an extension cord outlet setup.

From what's been discussed, the 120watt panel might not be enough for the 140ah parallel bank I had originally configured. So, this might be a better fit. Now my system looks like this: Go Power 120 Watt portable panel (includes 10A controller)

If you take your battery down to 50% DOD, and expect to charge it back up daily with that panel, especially in winter, you won't make it.

The solar-insolation hours for Houston are only about 4 hours in winter. These hours center around noon, and are NOT sunrise-to-sunset. Thus, with only 6.5A max coming from the panels, with only 4 hours, you could only put back 24ah into the battery, but you have drawn 50. It will take you two days or more to get a full charge.

So, either draw less from the battery daily by conserving, or get an even larger panel array, (with these batteries you should not go beyond 30A or so (or 350 watts with nominal 12v panels), or allow for a few days to charge back up.

That's the quick gist of it. We haven't even spoken of peukert-effect on batteries, where your runtime is lower than expected when you run heavy loads (about more than 1/10th their ratings. In this case, when you start pulling more than 120w from that inverter-battery combo, peukert is going to reduce your calculated runtimes by a sometimes surprising amount. Here, we are keeping it simple for the milk-crate application.

**ThXinc** · 08-28-2015, 09:44 AM

You rock man! I will be printing off this information and saving it in my solar project file. I do hope to eventually expand the system, adding some additional panels and maybe another 12v/100ah battery. But I think this will get me though MOST weekend camping trips. One of the reasons I chose GoPower is the ability to modularize and expand the system as needs dictate.

I did get the Kill a watt meter and set it up directly on the inverter so I can monitor total draw as devices are used from the power strip I have plugged into the Kill a watt meter. This shouldn't cause any issues?

I'm making sure my new battery get a full charge from the battery shop (Batteries Plus). (I recommend them, I was served by courteous and knowledgeable staff) before utilizing. I took your advice and had it measured over the counter, (12.6) so I had them top it off. Good call.

Thanks again for all your help and I'll be sure to provide feed back after I return from the maiden voyage of my first portable solar power project.

**ThXinc** · 08-28-2015, 09:49 AM

Originally posted by jony101

I have to agree your solar panels are too small. With an mppt and your panels connected in series you might get a little more power out of them. I dont think your even getting 3 amps out of them in the midday sun. 3 amps will never replace what you are using. For your system I think you need at least a minimum 120 watt panel and very good sunshine in your area, which will give you 7 amps.

Just for clarification and having a lack of technical jargon at this time, what is 'MPPT'

**lkruper** · 08-28-2015, 12:05 PM

Originally posted by ThXinc

Just for clarification and having a lack of technical jargon at this time, what is 'MPPT'

Multiple Point Power Tracking ... what this means is that the controller uses all the voltage your panel puts out and steps it down in a nice 12v bundle to charge your battery. So for example if your panel puts out 36v with 5 amps you get 36/12 * 5 amps to your battery.

The PWM controller just takes the voltage it needs and discards the rest, thus wasting some of the panel power. It does not always make financial sense to pay the premium for MPPT, you need to analyze your panels to see if it is economical.

Seeking advice on proper configuration 12V 140ah

Seeking advice on proper configuration 12V 140ah

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