PINNED - AGM & GEL battery info lead battery info

[Burgerman]

If they are old and knackered try this. Discharge each fully by which I mean about 11v slowly. Recharge at 14.0V CV until current stops falling and begins to rise again. Leave it to cool for half a day outside. Then charge at .1A (100mA) for a few days as a one off. It will add 1Ah every 10 hours. It will turn any sulfate back to acid, and increase battery capacity. Do it outside. Volts don't matter. It may gas. It should increase capacity if sulfates are the biggest issue. At least temporarily. Or it may finish it off...

[Burgerman]

ProMariner 63140 ProNauticP Series 1240P 12-Volts 40-Amp Battery Charger

Search google/ebay/amazon

Decent charger that charges gel or agm or odyssey properly.

[Gnomatic]

Finally got one of my chairs wired up with an Anderson connector.

I have the PL8 connected to the chair as well as my PC. The PL8 software is installed and I loaded the settings file posted here to preset 1.

There are a ton of options in this software. I think before I begin charging with the PL8, I want to set it to monitor while I charge with my main dumb charger, just to see its behavior. I'm not sure how to do this with the PL8 software though.

[Burgerman]

Easy.

Load the profile from here for the gel? Choose to start and after that a box will ask if you want to charge, discharge or monitor. Obviously click monitor. It will ask a few daft questions and start. Watch the graph, for a couple of mins, then plug in your mobility charger and leave it to do its thing. You will only be able to monitor volts of course.

[Gnomatic]

Got it thanks. I thought hitting Start would begin charging so I was hesitant to do it.

[Burgerman]

Did you tick the advanced box?

[Gnomatic]

No what will I see there?

[Burgerman]

Most of the settings on many tabs...

[Gnomatic]

Yeah I see those .....

[Burgerman]

So what did the other charger do?

[Gnomatic]

Well LOL .... let me back up a minute. I wanted the PL8 to Monitor first. I decided instead of my main charger first, I'd try my two small Schauers. Because out of my two portable Schauer chargers, only one works now, and I want to toss the bad one. They look the same, so I just stopped using altogether. The bad one charges for 45min then kicks to float so bats remain mostly uncharged. So I'm using the PL8 to help determine which one is bad. Not that the PL8 was fully necessary for this, but I wanted see more info on what was going on with the bad one instead of just knowing the green light pops on way too early with the bad Schauer.

The first Schauer I tried happened to be the bad one. In less than 45min, the green light was on and the PL8 was reading 27.3XXX volts. I wanted to view the graph for the session, but file that saved at the end of the session, I see no graph when I open it, just the PL8 software window .....

Yeah, I'm a rookie.

[Burgerman]

You open the graph and watch in real time.

[Gnomatic]

Yeah that worked.

[Burgerman]

Then save it (and all the data) if you want to. Or do a screenshot, image etc.

What voltage did it get to, and how long for before it went to float?

[Gnomatic]

I'm discharging the chair now via the PL8, watching on the graph. Currently reading 24.65v and slowly dropping. How low should I take it before recharging?

[Burgerman]

Till it starts to drop like a stone as thats the last of the charge. You will recognize that. What is the charger set to? That can be all kinds of voltages depending on discharge rate, ah, internal resistance, battery type, etc. Usually about 10.8v. But it will recover over the next 20 hours or so to about 11.5 to 12v.

[Gnomatic]

All I did was load the charging presets for Gel you posted above, hit Start and selected Discharge. So far 19ah pulled out of these lead bricks with the PL8(I turned the lights on too). Right now sitting at about 24.26v.

[Burgerman]

How are you going to measure Ah with the lights on?

[Gnomatic]

My focus so far is just to see charger voltages, so just running the batteries down a bit before graphing the dumb charger's volts. Next one I try maybe I'll measure the capacity as well.

[Gnomatic]

After taking 30+ ah out of the bricks, plus whatever the lights draw, I set the PL8 to monitor and plugged in a charger just like this. The voltage rose to around 28.36. Float registered at ~27.24v.

This wasn't taken right at the terminals. There's about 2ft of AWG running from the terminals to the Anderson I mounted on the chair, which is what the PL8 was plugged into.

[Burgerman]

Thats garbage!

It should rise smoothly to about 14.1 (28.2V) for gel, and sit there for a few hours at least if heavily discharged. It should have stayed at 28.2V from 7.3 hours to 11 hours. And there should be a straight flat line at this voltage until charge ends. And then float if it does, begins.

That just looks like it couldn't be bothered! Its not fully charged, it didn't hold it steadily at CV and just went slowly to float! And all spiky... This is why most mobility-chargers are rubbish. In this case there's little point in quoting a specific charge voltage specs, as it plainly doesn't actually have one!

[Burgerman]

When you charge with that powerchair charger you SHOULD see exactly this above, if it was any good... Sadly few are.

When you charge with the PL8 you will see exactly that above, for the first 2 stages. But no float stage.

Instead we can fine tune the termination current, so instead of going to 'float' far too soon, it charges at CV for longer and so fully charges in stage 2 which is faster). In this way, at the end of stage 2 its done to 99.5 to 100%! (unlike with the powerchair chargers).

And to be sure its very slightly overcharged, we can add a bit 'extra' to ward off or remove sulfation, we add a short CC 3rd stage instead. That gives a short sharp carefully controlled fixed low current (so called fast termination or fast ending). This works best in the short time the we have available overnight, ensuring the best charge possible in the limited time available.

[Burgerman]

Or... This is an idealized drawing.
But its what the PL8 does. And your chair charger tried to do... At least A and B.

The only part your charger got right was C. Which wouldn't be needed if it got A and B correct!

[Gnomatic]

Yeah I thought that charger's CV stage ...... left much to be desired. Well, time to see what the others look like. I still have an old Invacare, new Invacare, and Schauer to graph. I'm guessing those won't turn out to be sunshine and roses either.

So far I've learned my 4C24080A charger is a POS.

[Burgerman]

I admire your optimism! And why I say people need to MEASURE what their charger does.

And this is why I charge lead either with my 40A bench power supply set to 14.4, 14.1, 28.8, 29.4 as required, or a bit less in summer usually, or my hobby chargers, that are absolutely accurate and do a proper 2 stage plus CC fast finish stage charge. Configurable with huge accuracy in the settings.

Every one you test will do something different. Its not so simple. The other important figure is the charge current when it decides it done with CV. Which are all over the place and some not at all, mostly way too soon or just a timer...

You know when someone pops up on a forum and says "how long should a battery last" or "how much range should I get", or "why is my battery all deformed and smells bad", much of the reason now!

[Burgerman]

https://www.google.co.uk/url?sa=t&rct=j ... 6g&cad=rja

Heres the supposed CTE charger spec that it plainly doesn't follow. Your MK safe charger. Because it doesn't actually do the 28.80V and only goes a bit too high for a while (as its CV stage plainly isnt!) its actually nearly gel safe! Claims: Charging Method: Constant current. two stage constant voltage


But it undercharges them, allowing sulfation unless you charge for 16 hours or so per night. I suspect anyone charging with that on an overnight cycle will soon have range issues. It must be faulty.

[Gnomatic]

It must be faulty.

Maybe, you'd think MK wouldn't sell that for their batteries. At least one would hope not. Anyway, this is one I bought used from a DME while traveling, as the charger I had with me went kaput.

[Burgerman]

MK don't much care. They will say you can charge from 13.8v to 14.6v CV stage, and you can. They used to say it voids the warranty above 14.1v. All changed when they saw that 99 percent of batteries and existing modern chargers are now 14.4 to 14.6v... It was costing sales! So those spec sheets all disappeared and new ones with wide voltage ranges and hardly any tech info appeared instead. So you CAN charge with everything from a car to a power-line. It will *work*... But they don't mention that it screws up the battery and its cycle life.

[Burgerman]

viewtopic.php?f=2&t=1813&start=1920

The graphs here are 8 separate cell voltages curves by expresso today on his 105Ah lithium. Each cell set to 3.600V exactly. Note the CV voltages are flat and stay flat! And on the Amps graph you can see the current fall to the 320thC point I set before it terminates. And the charge details. No mobility charger comes remotely close to this.

[Gnomatic]

Expresso's graphs look good. Hopefully by next summer mine will look similar.