First Top Charge

[sjturbo]

I finally got my volt/amp meter wired in to my Mega Watt and started my first Top Charge. Initial battery voltage was 13.2v. Mega Watt was set to 15v. Turn-on voltage was 14.8v @ 33a. It quickly went to 15v @ 4.8a. Within 15 minutes it had dropped to 3.5a. I thought I would check readings in about an hour? I will also check for modest bubbling. Can I shut off the MW at that time to measure the battery voltage?

[NinerBikes]

OK, some observations by me.

I will pretty much see champagne sized bubbles, albeit, very very small volume of them, coming to the surface on my T-1275 by the time it will only a 7 or 8 amp charge rate from the Mega Watt S35-12, when set at 15.0v. I have never seen the T-1275 have much of anything resembling a roily boil.

I have seen a much higher volume of champagne bubbles on my old manual Sear 12V 6 amp charger when doing an equalization charge, mainly because it will put out 16.0V, and the battery will take it, but only for a short while before the voltage starts dropping off back to 15.7 or 15.6V.

Someone should do a video of batteries, and bubbling observations based on state of charge. A picture or a video from an expert is worth a thousand words.

I know Mex Wanderer now has a video camera feature on his smart phone. All he'd need to do is host it somewhere like YouTube after setting up a free account, or on PhotoBucket.

[MEXICOWANDERER]

Then Again...

Ho Ho Ho

[mena661]

BFL13 wrote:
I get to use this again! 🙂

https://www.youtube.com/watch?v=mlCiDEXuxxA

Oh God! LOL!

[sjturbo]

Hola MW, rolling boil no bueno! Pero dos bubbles per/sec si bueno? What size? I do remember you talking about it but the size escapes me. I have a Victron meter but not real familiar with it yet. Grasias!

[MEXICOWANDERER]

No roiling boil por favor. Two bubbles per second is fine. I thought I had covered this a few times ???

A positive reading on an amp hour or kWh meter would really ease the job. Example: +34 amp hours the cells should be bubbling at 15.0 volts. Amperage, time, voltage, hydrometer, they all fit and make things predictable and precise. Then you get to summarize, walk by the amp hour meter, note it, then twist the dial on the Intermatic timer then go pop a brewskie.

[sjturbo]

Sorry jrnymn7 I do not recall the voltage. Great video BFL13, was he in float or top charge:)?

[Salvo]

That brings back memories from the 60's when living in Hawaii. That's what the tourists came to see.

[BFL13]

I get to use this again! 🙂

https://www.youtube.com/watch?v=mlCiDEXuxxA

[jrnymn7]

sjturbo,

Do you recall what the battery voltage was at before putting them on the 13.2v float for 24 hrs ? I'm wondering whether or not the batts were very near full before you started the top charge?

[sjturbo]

MEXICOWANDERER wrote:
The Mega is plenty big enough. I mused this for a bit and came up with an idea. Apply the Mega. 15.0 volts. This time disregard the amperage. Instead monitor the acid in all cells. When all cells are bubbling slightly note the time elapsed between start to finish. This can easily eat a couple of hours, so don't worry. Just ensure you are starting from a level of battery charge that is easily repeatable. That way you can top charge with a timer. I'm soooooo lazy I use an interval timer, but one with a battery backup (I further cheat and use a cheap 12 volt voltage regulator and timer and suck power off the 24 volt bank - not likely to run out of memory). A weatherproof timer is inexpensive and you will look for a lawn sprinkler TYPE timer, which is called an INTERVAL TIMER. While I'm doing important things like reading, snoring, or staring out across the sea the timer and charger is doing it's thing. Not important whether your timer is AC or DC, but it is important that it not lose it's mind (timing cycle) because of a power outage.

Let those batteries bubble a little. If one cell is reluctant, find out why. Usually it is a sign of sulfation. Do an equalization. Then try it again down the road. Bubbling the start of which is an incredibly underused tool in battery management. Use it to VERIFY your perception of state of charge.

APART: I would love to see - it would be my reward to see declarations here "Gee I followed this stuff, it was simple, and it apparently doubled the lifespan of my batteries". Then I will have accomplished my goal. Vamos A Ver.

The increase of sophistication of these threads puts a smile on my face - thanks guys, for the time being, that is reward enough 🙂

Ok Let's talk bubbles! Are we talking champagne, (tiny bubbles) or Lawrence Welk (maybe not quite that big, bubbles). When I was top charging I was getting a good flow of tiny bubbles mixed with occasional larger bubbles. Never got to a rolling boil but the tiny bubbles were significant in number. So, once I get to this bubbling on all cells should I continue to charge until? Remember my TC took ~11hrs to reach 14.7V.

[MEXICOWANDERER]

Bubble-bubble-bubble

This will tell you where you are at, fast and easy. The time consumed in top charging vs bubbling or not is easy to manage. Use a watch or a clock. Top charging should be effortless, not a chore.

[NinerBikes]

sjturbo wrote:
Thanks niner! That is what I was doing during the Top Charge, (turning it off to read the battery voltage). It just sounded like something else.

You need to let the battery sit for a while, like 24 hours, to get rid of the surface charge voltage, which will give you an artificially high voltage reading, usually right after recharging a battery to near full 100% capacity. So don't rely on that voltage meter sitting on top of your Mega Watt for what the current battery voltage is, if you just turned the Mega Watt off. As I said before, it is only a rough barometer reading, voltage. It bounces around quite a lot. Use that voltage meter on the Mega Watt only for setting the charge voltage on the Mega Watt, when the Mega Watt is disconnected from the batteries, and the switch to the Mega Watt is turned on. You may want 14.8 V at times, and you may want 15.0V or maybe even perhaps a bit more than that. Spreading slightly over 15.0V occaisionally on all the batteries you have, with their amperage capacity, would be nothing more than a stirring charge to mix things up, if you've been in storage, or are not using the batteries daily.

With some time, practice, and logging V while camping or living off the grid, the voltage reading on the Mega Watt might provide you with some insight, you'll notice what is to be expected, what is normal, and what is abnormal.

[sjturbo]

Thanks niner! That is what I was doing during the Top Charge, (turning it off to read the battery voltage). It just sounded like something else.

[NinerBikes]

sjturbo wrote:
I just ordered the Freas, looking forward to being able to read through good glass. One of the many puzzles I have not been able to answer is when charging with the Mega Watt how do I need to wire in the volt/amp meter so it is reading what the battery charge is vs the Mega Watt output? I have the meter tied to the shunt on the negative output of the supply now. So how should I have it?
Thanks.

If you shut the Mega Watt off, but leave it attached to the batteries... it will continue to only give you a voltage reading, to the 1/10th of a volt, until you disconnect the Mega Watt cables from the battery terminals. Voltage readings will sag or drop based on amount of load applied currently to the battery, or if there is a surplus surface charge if no load is on the battery, the voltage could read higher. That voltage meter is only a barometer for the voltage of your battery and state of charge. The only thing absolute is what your specific gravity is, per battery. Forget what the voltage is for final determination for state of charge.