Battery life lessons

[Mike90250]

If your hydrometer is reading higher than factory SG, something is wrong. It just can't. When a batch of electrolyte is mixed up, it has a specific amount of sulfur in it, and is what ever the factory says it is supposed to be. Some factories use 1.257, some use 1.3, some use 1.2. But the amount of dissolved sulfur is there, at 100% of what the Mfg used.
The battery box has only lead plates in it, no sulfur, till the acid is poured in.
If the hydrometer reads overcharged, something is wrong, either the SG you are assuming is incorrect, the electrolyte is contaminated with something, or the Temp Comp is inaccurate. When you recharge a battery and drive all the sulfur back into solution, you can only get to 100%. It's real hard to dissolve lead into weak battery acid, so getting more than 100% indicates something other than "overcharge".

[Sunking]

SunKing, I see what your saying about float and Solar chargers ... but I run into the problem of not getting fully charged according to SG with my inverter-charger too ... UNLESS I set the volts higher than manufacture. I have no realistic absorb time cut off, the system just stops charging too soon unless I have the volts set to 30.8v

I understand what you are trying to say, I am right. .

You are getting there but still not quite on the same page. When you turn the voltages up, you are forcing the controller to stay in BULK or more technically correct is called Constant Current. Bulk is just a catchy marketing term. To be completely accurate with solar it Bulk is really constant power, as much as the panels can possible generate under the current conditions.

Here is a KISS example using a 100 watt model panel on a discharge 12 volt battery. Current = Power / Voltage. So initially the battery voltage is 12 volts and thus initial charge current is 8.33 amps. In a few hours later the battery voltage is 13 volts and charge current is 7.7 amps. When we reach say 14.3 volts current is down to 7.0 amps. Power remained Constant. An AC Charger is constant current. So if it were say 8.33 amps charge power is 100 watts if the battery under charge voltage is 12 volts, but at 14.3 has to be 120 watts.

By turning the voltage up you are forcing the controller to stay in Bulk or Constant power from sunrise to sunset harvesting every watt possible. That will minimize undercharging, but may or may not fully charge the battery by sunset. It just gets you every bit of power possible. Otherwise as you have experienced if you use 3-stages, you never come close to full charge.

Once you hit the Absorb stage, charge current will taper to 0 amps when and if the battery ever fully charges. Duing Absorb, you are NOT harvesting al the power, something less, much less. There are not enough sun hours in a day to ever get fully charged in winter unless you have more panel wattage than required. Very rare anyone has enough panel wattage. That has to be deigned carefully. In a DIY environment, 99% are grossly undersized. Tuff even for a pro because of the guess work involved, but pros are better guessers.

[Matrix]

If your hydrometer is reading higher than factory SG, something is wrong. It just can't. When a batch of electrolyte is mixed up, it has a specific amount of sulfur in it, and is what ever the factory says it is supposed to be. Some factories use 1.257, some use 1.3, some use 1.2. But the amount of dissolved sulfur is there, at 100% of what the Mfg used.

Manufacturer says 100% = 1.277. But ur saying I need to go until all cells stop rising in SG... Regardless of my hydro reading (assuming everything is working correctly)??


And then when my cells all stop rising while charging.... I can assume That number according to my equipment (whatever that number is) will be my fully charged SG? So I should charge all batteries until all cells stop rising? And what ur saying is, that then all SG numbers across all cells will b the same. (at least in the same battery)?

[Sunking]

Manufacturer says 100% = 1.277. But ur saying I need to go until all cells stop rising in SG... Regardless of my hydro reading (assuming everything is working correctly)??


And then when my cells all stop rising while charging.... I can assume That number according to my equipment (whatever that number is) will be my fully charged SG? So I should charge all batteries until all cells stop rising? And what ur saying is, that then all SG numbers across all cells will b the same. (at least in the same battery)?

Yes.

I agree with what Mike is saying, I just interpret the results differently. True your hydrometer may have some inaccuracy, no big deal as long as you are aware of it. Lets back up a bit and rehash what Trojan told you, and what any battery manufacture instructs you on how to EQ batteries.

Trojan told you the difference in SG is normal for new batteries because the plates have not fully formed right? A spread of 15 points is normal and nothing to worry about and expected right? So relax.

Mike is right in saying the SG can only go so high, and that happens when the batteries are fully charged up. It cannot go any higher. Trying to do so is a significant over charge that only corrodes the plates. So now look at Trojan's or any manufacture EQ instructions. What do they say? EQ until SG stops rising right?

So even though your hydrometer may read a bit to high, who cares as long as you know what that number is. Now if you want a very accurate hydrometer I can help you with that. It will cost more than $8, more like $50 to $90 using a lab qual;ity hydrometer and if you demand exact accuracy a Master Hydrometer but now we are talking $100+ and a good battery thermometer. Not really needed as long as you know what your hydrometer reads when SG is saturated.

So relax, I am positive you are OK. You just need some time and experience to gain confidence and knowledge. You are way ahead of 90% of folks who come here. Those folks do not know how to spell a hydrometer or what it does.

For now lets not hyjack the thread. Start another one and I will help you.

[Matrix]

Thanks SunKing and Mike ... excellent info as always. Not trying to hijack the thread, just realizing that my real life inexperienced example and questions could possibly add some detail and (hopefully) additional clarity to the OP's initial question. So @Woutah, I hope this discussion has helped you with your batteries as much as it helps clear up some thoughts in my mind. My apologies if I hijacked the thread.