Battery Charger Help

[ezrablu]

Thanks Dennis...I'll grab some of that. I sure appreciate this kind of information.

[rlaggren]

> starting w/charger connected...

The bus don't care, but the charger might. Starter motors draw a very large current and some chargers don't have much over-current protection so a few good cranking episodes might kill it dead.

OTOH, I've never worried about it with my cars and haven't actually destroyed anything yet. <g>

Rufus

[Sharkey]

Here's something related from a solar installer mailing list:

http://lists.re-wrenches.org/pipermail/ ... 33258.html

In 2007 I was at a campground and heard an explosion. The owner of an RV a few spaces down from me was opening the battery compartment as I walked up. Inside he had un-vented batteries in the same compartment as the inverter and other switch gear. His batteries were obviously gassing when something sparked it off. The top was blown off a 6 volt battery and he had electrolyte everywhere and a damaged cargo door.

[stuartcnz]

A friend of mine had a gas explosion in his boat, while charging his batteries. The batteries were under the sole of the main cabin, and he had a diesel heater going in the cabin. Big bang, leaving all of the inside of the cabin black.

He also had to jump into the tide, because he got splashed with acid. the explosion lifted the floor boards, exposing the battery compartment.

[Rudy]

Well, it's time to tell you about when a battery exploded on me. It was in the military when I was charging a battery on a tug. Those are the tractor vehicles you see towing the luggage trailers at the airport.

This tug had a 24 volt battery. I had a charger on it for about two hours. I went to disconnect the charger from the battery without (foolishly) unpluggung the charger. While removing one of the leads, it made a spark and did indeed ignite the hydrogen gas escaping from the battery.

The blast threw me off the fender of the vehicle. I landed on the ground ten feet away from the tug. Fortunately I was wearing safety glasses. Also, fortunately, no acid got spit up onto my face. The flame, however, burnt my hair and eyebrows.

After I got up to see what had happened, I noticed that all that was left of the battery was the bottom. The top and sides flew every where and were just pieces of broken, burnt plastic.

Oh yes, batteries can and do explode.

[Bob]

I am hoping to get some sort of resolve in my dilema here.. I have 4 75 watt panels..a pro-sine 1000 inverter and have been using a morningstar 30amp charge controler. My batteries are only about 2 years old. (six interstate golf cart batteries).but lately I have had to run the generator to keep them up. Sucks. Yesterday I noticed the the positive lead from the solar panel wire was blackened and so was the inside of the charge controler. Being on a bit of a budget I opted to get a Sunforce 30 amp from camping world for about $90. It doesnt have digital readouts and it clicks off before batteries get up to 12.5 volts....then they slowly go down...the charge light doesnt work (Bulk Charge) ..and the unit seems to be getting warmer than I think it should. I think I am going to take it back and spend the extra $ on something that has digital readouts.
Any suggestions? Anybody else ever have one of these? I liked the old SCI meter controlers..I have used solar for many years and never had issues like this before.

[Sharkey]

Bob, if your batteries aren't regularly getting up to nearly 14 volts, then they are being chronically undercharged and are being damaged. 12.5 volts should in no way be considered "charged". Even a fully charged battery at rest should be closer to 12.6.

First of all, "economy" battery chargers are no bargain. Put up the extra $$ for a good one, three state charging is best.

Second, if the wire from your panels got hot and blackened, either cut the wire back to where it is bright copper or replace the wire. You'll never get a good connection on wire that has oxidized.

4x75 watts = ~16 amperes of charge current, which would be considered adequate for one set of GC batteries, and barely enough to keep four alive. Trying to run six batteries on that much charge current is a stretch. If you are able to supplement the PV's with shore power or the genset, you might be able to get by.

Three paralled sets of two series connected GC batteries is a problem waiting to happen. Rule of thumb is no more than two paralleled sets. It's much too difficult to keep all the cells (individual cells, not batteries) equalized with more.

Speaking of equalization, are you doing it? At least once every two months or so, or more often if you discharge past 50% DOD regularly, the batteries should be taken up to 15+ volts and held there for an hour or two. This destratisfies the electrolyte, makes sure that every cell is fully charged, and removes sulfur deposits on the plates before it hardens. EQ'ing batteries is an essential part of battery maintenance.

You definitely want a charger (or a system monitor) that gives you more accurate information on the state of charge of your batteries. Blinky lights are not a good path to battery health. Check out a "TriMetric", this is a much more adequate solution to keeping your cells topped up.

[Bob]

I was hoping you would have some input on this! Thank you sooo much! I used to have only 4 batteries on a slide out tray..I discovered that by romoving the tray I could fit 6 in there...so thats what I did...I figured more is better. I cant afford more panels right now but they are on my wish list. Do you think it might be wise to get rid of 2 batteries in the meantime? I am wondering if 4 fully charged batteries are better than 6 under charged ones.

[Bob]

I like the trimetric unit and I will get one soon. It is not a charge controler though...that is something that I need to address right away. When I do the equalization...should I take the batteries out and charge them one at a time? Is like "boiling" the batteries...such as charging to the max with the vent caps removed? If I remove 2 batteries that might be a good time to try that.
btw...I did clean up the wire ends..seems to charge fine but this #$@! controler keeps clicking off before I think it should.

[Sharkey]

I am wondering if 4 fully charged batteries are better than 6 under charged ones.

Bob, the emphatic answer is "Yes!", although now that you already have them, finding a way to keep them all topped up would give you more storage capacity, meaning that the DOD (depth of discharge) will be lower overall. Making sure that the pack is fully charged at least once a week, if not more will keep them operating longer and better.

When I do the equalization...should I take the batteries out and charge them one at a time?

Removing pairs of batteries and charging them fully and then EQ'ing them would be a fine idea, it would mean that your panels have more than an adequate amount of power to complete the job in a short time frame. If you do this, make sure you do it to all three pairs before you put them back into a parallel pack, otherwise the "freshened" batteries will lose their charge to the slackers that didn't get the treatment.

Is like "boiling" the batteries...such as charging to the max with the vent caps removed?

Yes, basically. Once a pair of batteries has reached full charge (13.8 volts while charging), you could then initiate an EQ. It really wouldn't take more than one of your 75 watt panels in full sun to do this, so if your panels can be separated, you could do all three packs in one day.

What you want is to get the battery terminal voltage up to or above 15 volts for a couple of hours. They will boil and fizz like crazy, that's what you want. I always loosen the caps and set them back on the cell opening kind of cock-eyed. This will minimize the amount of electrolyte that splashes out of the cell while allowing the cell to vent freely.

#$@! controler keeps clicking off

It needs replacing. If you can separate the PV panels, do your EQ'ing by just connecting one PV module to a pair of batteries. If your panels are Seimens SP-75 (AKA ProCharger 4), they have an open circuit voltage of about 22 volts. The charge current will taper off some at 15V. Maximum current will be about 4 amperes, more than needed for an EQ. If EQ'ing, you could try partially shading the module to reduce the charge current some but keep the battery fizzing. Look into each cell to verify that all are gassing.

You could also bypass the charge controller for an EQ and let the four modules charge the six batteries directly. The issue is, can the PV's drive the battery voltage up to 15 and hold it there for two hours in one day?

Running without a charge controller is no good full time, but if you are there to keep an eye on things, monitor voltage and disconnect when the job is done or when the light goes away, you don't need a controller to get this EQ job done.

Overcharging batteries (EQ'ing) won't hurt them once in a while, in fact, it's necessary. It will consume water from the cells, at the end, top each cell up wiht distilled water to the bottom of the split ring inside the cell. (NEVER add water to a battery that's not fully charged!!!!!!!!! If it's below the plates, add only enough to immerse the plates, then charge until full, then top it off).

Yes, the TriMetric is a battery monitor, not a controller. Is your old controller fried? For sure? The Morningstar controllers are very robust, and the right tool for the job.

[Bob]

We are all very lucky to have you, the site and your knowledge at hand!
I think I will tackle this in Bisbee while staying at an rv park and plugged in. There are some very cheap ones there. I think that the controler could be fixed by someone..the block that holds the + wire from the panels got fried and perhaps a conecting wire running from it.
I would LOVE to have more panels...but I am going to try just 4 batteries after this job and see how that works. At least I have a plan now...thank you again!!

[Bob]

After staying in a truckstop for a couple of day I found a coupon on my door for 3 nights free resort camping...so I took advantage of that to plug in and charge things up. After 2 days the batteries got charged and today I disconected the charge controler and am running the bank up to 15 volts. Its a pain to take them out and do the as 3 seperate batteries...but this seems to be working fine. I hear some gurgling...I think thats a good thing.
After todays sunshine they will still be charged up until morning (around noon ) and I am going to drive to El Paso. I will give a report on how this may make a difference in them holding a charge.