Solar powered battery chargers???

[Spork]

I ended up with the litefuze 20 watt panel and the 1270 upg battery (7.2 ah). As I mentioned before all I want it to do is power a battery and phone charger. If this one poops out and I'm still into the solar thing maybe I will pickup a lithium battery. I am also curious about running a small fan. Are there any that work well with direct drive from the panel? Maybe a large pc fan might work with a regular setup.

I also ordered a mc4 connector , blade fuses, and a female cigarette adapter but other than that I'm not sure what size wiring to use. Where do you find the nice premade cables with the rings? Also unsure of what I should use for the battery connectors. Maybe my questions are quite basic but I just want to make sure its done right.

 

[hiuintahs]

Be sure to bite the bullet and get a decent charge controller...........like the Morningstar 10L................and all will be well provided you wired it up good :devil:. With a good charge controller (which is the brains of the operation), you can rest assured that all is going well and your battery will never get over charged and so you can just leave it and not worry about it.

Let's see a 20w panel is around 1 amp max. You could get by with 20 guage but I'd use 16 gauge wire. If your wire length is long, use 14 or 12 gauge.

Look into some type of container, contraption or small wooden platform to mount everything on so that it's fixed and not moving around. Once you know your physical or mechanical position, then you can neatly route your wires. I'd use connectors between solar panel and the charge controller so that your solar panel can be disconnected easily and also so that the panel can be placed according to sun while the rest of it is under cover in case of rain. The rest of it just hard wired together without connectors. If the battery has screw terminals then I'd get some crimp style ring terminals from Lowes or HD.

Once you get it built and working, you may then see ways to improve things..........like mounting a 12v receptacle instead of having it dangle off of the leads of the battery. Also may want to have blade fuse in series with this 12v receptacle.

Fun stuff!

 

[Spork]

thanks everyone for the help! It was around $150 for the 20 watt panel, 10L , and 7ah battery. I also added a C401FS and a 2.1 amp car plug charger for android / apple phones and ipads. I can't wait to put it all together.

I don't own any gas tools. I use a electric mower too. So a generator is not something I want to mess with. I'm in the midwest and we've had storms knock out power for 1-2 weeks although its rare. I won't be able to run the fridge so I guess I would leave the door closed or start up the grill and use what I could.

 

[ChrisGarrett]

thanks everyone for the help! It was around $150 for the 20 watt panel, 10L , and 7ah battery. I also added a C401FS and a 2.1 amp car plug charger for android / apple phones and ipads. I can't wait to put it all together.

I don't own any gas tools. I use a electric mower too. So a generator is not something I want to mess with. I'm in the midwest and we've had storms knock out power for 1-2 weeks although its rare. I won't be able to run the fridge so I guess I would leave the door closed or start up the grill and use what I could.

The good thing about solar panels is, is that you can daisy chain them together with the right connectors, so having 20w now, doesn't mean that you're stuck with 20w tomorrow and the Morningstar 10L can handle up to 10A of current, so you've got plenty of room to grow with that controller.

You can even upgrade mother batteries, or buy additional ones. I'm looking at 2 PowerSonic 18Ah scooter batteries for $75 shipped, that would be plenty, even a single 18Ah coupled to my 12Ah would give me ample daily capacity for my particular needs.

Chris

 

[independent]

Had big solar panel setups in the past with fridge freezers, made all my charge controllers... I live off my micro solar setup here is a rundown on what I've found..

• 90% of store bought solar chargers are glorified external batteries with a token amount of solar thrown in.
• The Powerfilm AA chargers are good little panels but the wires at the folding parts do break. Unless you are checking to see the current output of the panels they will appear to work even though the output is seriously hampered. I've ruggedised mine. It is a USB AA modified with a six panel - um - panel and the hinge wires have around 5x more tiny copper flex for durability.
• The Nokero Single AA charger is very usable, cheap and reliable. Gang them up for multiple cell batteries (2, 3 & 4).
• I have the Nokero Raycell arriving soon by mail and looking forward to seeing how that works out direct charging cell batteries (camera batteries might work in it as well)
• Voltaic series of chargers and panels are really well thought out. Their service is excellent. Cool people.
• Using solar to charge a battery --to charge a battery is redundent. A friend and I have a (15-20w max) MPPT regulator design (with adjustable power point) to look like a regulated output. It works in real -world terms about 80+% efficient. Ie out of a 5w 12v CIGS panel I can achieve an 800mA charge into 5v USB (measured). When finished testing we will upload the EagleCad file so anyone can build it (CC licensing).

 

[SemiMan]

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[SemiMan]

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[SemiMan]

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[ChrisGarrett]

Good advice here. In solar battery charging, battery failure is mostly due to battery undercharging, not over charging. Bumping up the absorption voltage is a good way to alleviate sulfation.

Semiman

I use the Morningstar 10L and a PowerSonic 12Ah SLA/AGM battery, but I've kept the jumper on, as that's what I thought I should do.

Should I remove the jumper when topping off my seldom used battery? Won't hurt it?

Chris

 

[Slazmo]

Hmm - wonder what I would need on top of my 10 Watt PV panel to charge up Sanyo Eneloops AA's the 'environmental' way... Anyone got some simple instructions on what you would need on top of a Kemo solar charger regulator plumbed into a 10 Watt PV panel as to charge AA & AAA batteries.

 

[mousewizard]

Hmm - wonder what I would need on top of my 10 Watt PV panel to charge up Sanyo Eneloops AA's the 'environmental' way... Anyone got some simple instructions on what you would need on top of a Kemo solar charger regulator plumbed into a 10 Watt PV panel as to charge AA & AAA batteries.

Make sure you have a battery plugged into the Kemo. That way the Kemo is constantly charging the battery. At 10W, you don't have a lot of solar panel there, so you need to constantly charge a battery at a low level and then charge your AA and AAA batteries by hooking up a 4-AAA battery charger to it.

If you haven't already committed to the Kemo, then I recommend you switch to the Morningstar. The Kemo doesn't have a "load" connection so you wind up with your charger in parallel with the battery. There exists the possibility of damaging your battery through overuse that way. The Morningstar will disconnect the load when the battery drops its voltage, thus preventing damage.

 

[IonicBond]

I use the Morningstar 10L and a PowerSonic 12Ah SLA/AGM battery, but I've kept the jumper on, as that's what I thought I should do...Should I remove the jumper when topping off my seldom used battery? Won't hurt it?

Not at all provided that if you run your gear while charging the SLA, it can handle 14.7v. Most of my nominal 13.8v gear has no problem with 14.7 since that fits between the typical +/- 10% of 13.8 v rating.

In the jumpered position, the default to "sealed" is a protection mechanism for users that don't know their battery chemistry and will protect sealed gels. If you KNOW you are running an agm, removing the jumper - even though the silkscreen indicates flooded - the actual proper voltage of 14.7 volts will be applied for absorption for agm's. If you ask Morningstar about it, they will tell you to follow the right voltage, and not necessarily the silkscreen label.

The smaller Morningstar Sunguard 4.5a and also the PowerFilm RA9 (rebadged Sunguard) default to the lower 14.1v which is not ideal for agm either. It will work, but for those using them, they may want to consider upgrading to the Morningstar 6L series that provides the jumper.

Reaching the absorb voltage of 14.7 volts is crucial for agm's. You could play it safe and use the sealed setting, but it just means you'll be buying batteries more often as the agm's are never getting a *full* charge. By never getting a full charge, the capacity is "walked down" by sulfation bit by bit. And just merely reaching 14.7v is just the *start* of the absorb cycle. Now that the maximum voltage is limited, the battery finally gets fully charged and is indicated by a natural reduction of current as dictated by the battery itself.

Put it this way: when an agm leaves the factory, it has been charged to 14.7v first.

 

[IonicBond]

WARNING - forgot to mention that these voltages are at a 68F temperature. Fortunately the morningstars are temperature-compensated. Just wanted to mention this so nobody goes into their 100F garage and starts charging an agm at 14.7v with a lab supply. See your battery's spec-sheet for temp comp.

The end of the absorb cycle is usually when the battery current is .03 * C. That would be about 210ma for a 7ah agm.

State Of Charge SOC voltage:
While the following test will tell you nothing about your agm battery's health or capacity, you can get an idea of how well your solar setup is doing. With NO CHARGE and NO LOAD, let the battery rest for 4 hours and take an open-circuit voltage measurement:

100% = 12.9 to 13.3v
75% = 12.6v (good cycle life)
50% = 12.2v (ok, but limits cycle life)
25% = 12.1v (try not to go here except in emergencies)
Dead = 11.9v (damage / dead)

The actual manufacturer's spec may differ a little bit, but this is a very close ballpark.

 

[hiuintahs]

The actual manufacturer's spec may differ a little bit, but this is a very close ballpark.

The specs on my Dekka AGM battery with no load:
100% = 12.80v or higher
75% = 12.60v
50% = 12.30v
25% = 12.00v
0% = 11.80v and below

Note they say to take the measurement after the battery has been sitting with no load for 24 hours.

 

[independent]

@semiman. Yes 5w panel. It's difficult to explain here the answers to the rest of your question here. But the purpose of (was "an" but corrected to "our") our MPP regulator is to provide a voltage regulated output. Essentially a solar panels is a current regulated output which makes them great battery chargers. However a solar panel will not maintain provide a proper output for variable loads (remember a battery presents itself as a dead short for most it's charge depending on the chemistry). However we are only charging batteries through a circuit we are not supplying 5v regulated to a circuit which depends on it, to do this you would need to up the source (solar) massively guessing 5-10x basic requirements. Anyway, the circuit I am trying to describe "fails" honorably. It holds 5v as well as it can and current supply drops as the energy input lessens. You want it to maintain 5v well. The main question is how does the load (phone/tablet) respond to the ability of a source to provide the current. The phone I tested staggers it's current and will not go beyond what the source will supply. Yes you need light to use this charger!

 

[independent]

@slazmo I would highy recommend building yourself a "ghurd" controller for your AA NiMH battery. I have built two of them and other than having a great deal of respect for the man I have no other connection. Its a kit 15-17$US shipped anywhere in the world. LSD NiMH make the absolute best micro solar batteries. Adjustable voltage cut off the can be built as LVDs, simple slam-bang controllers or proper diversion controllers. I've built them as the last two types. Really good, reliable controllers with decent componentry. Regarding battery chemistry types, the eneloop stress tests to 1000+ recharges would kill any SLA in a dozen or two cycles using the same procedures. Deep cycles flooded probably wouldn't handle much more (SLAs, VRLASs, and deep cycles should not be used beyond %50 DoD at any rate). LiFePo4 act like normal lithium and charge resistance doesn't rise appreciably as SoC rises. They need complex controllers with cell management even in single series batteries (yes tried it). LSD NiMH for simple long lived micro- and nano- solar setups.

 

[IonicBond]

Note they say to take the measurement after the battery has been sitting with no load for 24 hours.

That long of a wait will be very accurate! I'll bet that if you check after 4 and then check again after 24 hours, you might opt for 4 hours as close enough.

Dekka is a good brand of AGM. Good docs too - usually an indicator of quality manufacturing.

 

[hiuintahs]

Ya, you're right 4 hours is probably good enough. Dekka was handy as there is an East Penn distributor in town and so no shipping costs. When my truck battery finally bit the dust, I replaced it with Dekka's Intimidator (rather than go the Optima route). The Intimidator is a combo starting battery / AGM. It wasn't cheap though!

On my portable battery, to keep the voltage from dropping too low and damaging it, I have an adjustable trip point that opens up and disconnects the battery from the output port connections.

 

[independent]

@slazmo again. I misread your post sounds like you are looking at charging AAs and AAAs independently for use in other devices. I wrongly assumed you were making a 10xAA (ie 12v) battery. 10w is a good sized panel for AAs (half an amp of solar) and a ghurd controller. So IMO Your only realistic option is either a 12v battery (like an SLA or 10xAA NiMH) battery option an a simple maha type independent cell charger like the venerable 401fs charger. OR something like a MPP solar direct Linear Current Booster (LCB) like the one I mentioned several posts back running batteryless and the LCB as a kind-of psuedo-battery..

 

[SemiMan]

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