27DCs and SG Lag Problems

[BFL13]

Here is what I mean. Got two rebuilt 27DCs from Interstate as "Econo Power" models, which means they are whatever brand and type they decided to renew and sell at under half price. So just right for my purpose. But first to get them up to speed at home same as any battery first thing off the shelf before using it.

The batts seem to be Johnson Controls, all black, weigh 58 lbs, and are marked 27DC-845. Original date 5F (assumed to be June, 2015)

Doing one at a time, put the VEC1093 40 amper on them and let it get to "Full", which I know isn't quite full. I then ran an Equalize as I normally do to get to "real full" and it ran for a couple hours at 15.7v until it said Full.

SG all across was 1.300, so looking good. Then I ran my 10 hour 20 hour rate load test in hopes of finding out what the AH capacity is of the mystery battery (no rating shown--the 845 is no doubt the marine cranking)

It did take 10 hours to get to 50% SOC at 5 amps (I picked 100AH as most likely result) and proved 50% by seeing 1.200 SG and bounce back overnight to 12.17 volts. AH down from full was 51.6 by Trimetric, so Capacity came out as 103.6 AH at the 20 hr rate.

Now the fun part--recharge from 50% after ONE deep draw down, never mind after doing several 50-90s in a row.

Put the charger on same as before starting at 40.4 amps and let it run at 14.8v till it said "full" Sure enough SG was only 1.245ish in the white. So ran an Equalize which took a couple hours at 15.7 and SG was now 1.260ish. Ran a second Equalize for another couple hours till it said Full, and SG now 1.265ish, just barely into the green.

Rats! This is just like old times with 27s 😞 I used to tip them on their sides at this stage to try to get them up to full SG. But today I have a new weapon I did not have eight years ago-- my PowerMax Adjustable that can do 16.5 volts (with 15 minute shots, so you have to be there to keep doing that. It drops one volt after the first 15 minutes, and then stays at that--15.5 in this case, so unplug and start again at 16.5)

So after two of those--30 minutes at 16.5, the darned SG has hardly moved up at all still 1.265ish. I decided to give it time to cool down when SG will go up a bit with colder fluid, and I will leave the batt on float overnight at 13.8 and give it another kick or two tomorrow.

So what's with these 27s anyway???? There they were at 1.300 and you do ONE drop to 50% and it is like pulling teeth to even get back into the green, never mind 1.275 or above. I hate 27s !!!!!!
-------------
Background info--not needed unless you are bored 🙂
Eight years ago, I swore off 27s because of my difficulties getting them back to proper full as seen by hydrometer readings. No such problems with 6s or the Trojan 12v T-1275s I have been using since. They come right up. No fuss.

I just got these two 27DCs as a stop-gap for rounding out the battery bank now that my two T-1275s finally died, and I need two batts to go with my six-year old pair of 6s that are still going but for only another year most likely. (I need about a 400AH bank) Then next year I can start over with all new whatever.

[MEXICOWANDERER]

Krap stuffed into a car battery jar is OK for weekend warriors. For off grid boondocking nyet, nein, no. No one can make a flooded car battery nowhere near as good as a flooded golf car battery. Good means easier to charge, more resistant to sulfation, longer lived, more efficient, you name it the car jar battery loses.

Even premium manufacturers like Trojan cannot build a forgiving car jar RV battery. Call them. It's toll free.

Group 24, group 27, and group 31 batteries are weekend-warrior specials.

To each his own -- I'm cheap and lazy...

[lawrosa]

BFL13 wrote:
I keep reading here about 6s going for about $90 in the States at Costco or Sam's, so whyinheck would you pay the same for a couple of 24s that are so hard to charge properly and are only 150AH when you can get easy to charge 225AH 6s for the same price?

You said you were nervous about 6s. IMO get them anyway--you will be glad you did.

You will have very limited use of those from the inverter with the two 6s, which you will want to run the normal rig 12v things for the whole gang on a long weekend.

I cant remember if they were hard to charge since I have owned them. Only last year.

But I havenot been doing these tests before either. When charging in previous years all I know is I could have been at 1.250 anytime charging..

But yes. 6,s..

215 ah $100
225ah $115
235 ah $130




$259.08 - 24 core = 235.08 / 2 =118 a battery..

It was just a money thing why I posted.. Thought was too good a deal to pass up..

[landyacht318]

I had a big red style of hydrometer. I found when new it was repeatable but once used and rinsed several times was inaccurate,
and imprecise and not very repeatable.

I now use an OTC 4619 glass turkey baster style. Precise and repeatable as long as no bubbles are sticking to float, jury's till out on accuracy.

5 years is pretty good on a set of 24's, but they might have some service left in them. Might not be worth the 24$ core return. I've had three chances to turn the screwy31 in for a core charge and put that cash in my pocket, but it still has enough capacity for my workshop LEDs and fans.

I'll core charge it when it shorts a cell.

[BFL13]

I keep reading here about 6s going for about $90 in the States at Costco or Sam's, so whyinheck would you pay the same for a couple of 24s that are so hard to charge properly and are only 150AH when you can get easy to charge 225AH 6s for the same price?

You said you were nervous about 6s. IMO get them anyway--you will be glad you did.

[lawrosa]

One last thing to add..

Umm duracells if I did the 12 volt jig again, ( everyone likes a good jig right?) what do you think of this?

I can get at my local store 89.99

https://www.batteriesplus.com/cart

10% off bought online and pick um up with code they give.

x2 = 198.30 with tax less core.( NJ taxes)

2- cores 24 bucks = $174.20.

And they running rebate 10 clams a battery...

http://bpb.apfco.com/new/R9608.cfm

Thats 154.30 / 2 = $77.15 a battery...

Good deal?

[MEXICOWANDERER]

Got 8 Megawatt 400s. With pot shorted 16.11 volts.
They did improve the fan quality.
Some ads say 13.8 volts
Some say 14.0 volts
Everything with regards to ads these days is opinionated by people who have never seen more than a photo never mind used one.
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Real MegaWatt not a China Clone










Now all Power Supplies come with Double Ball Bearing 60,000 hour dust proof Cooling Fans.





Actual voltage adjustment 10 to over 15 VDC "13.8"

This Power Supply is made for powering HAM Radios, CBs and Linear Amps. The output section of the power supply is highly filtered to eliminate RF.



**** 36 amps at a 90% duty cycle

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**** Will run up to 40 amp peak output

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**** The power supply is 9 X 4 5/8 X 2 inches

**** Each unit comes with a power cord



Thanks for stopping by.

[BFL13]

"I have enough solar now, Stop using high use appliances like toasters, coffee pots, and microwaves....LOL"

You will have very limited use of those from the inverter with the two 6s, which you will want to run the normal rig 12v things for the whole gang on a long weekend.

Since our MH does not have room for more flooded batteries to do normal work, I got two 100AH AGMs that can go inside (no fumes) where there is lots of room. I put the big inverter on them strictly to do all the 120v stuff such as MW, TV, toaster, kettle, etc. (All goes under the kitchen counter out of sight)

So that took care of that. Still can live like a regular human being, but no fear of running the batts down that run the furnace and lights by using the TV and MW etc.

[BFL13]

MEXICOWANDERER wrote:
Not 13.8 it's adjustable 10.0 - 15.6 volts.

DO NOT TRUST ANY INSTRUMENT OR METER

VERIFY VERIFY VERIFY

Silly me, I went by that photo showing DC output is adj. 10-13.8
Good thing you verified it goes to 15.6 🙂

[MEXICOWANDERER]

Not 13.8 it's adjustable 10.0 - 15.6 volts.

DO NOT TRUST ANY INSTRUMENT OR METER

VERIFY VERIFY VERIFY

[BFL13]

When you go from 15.4 volts down to 14.4, it takes time for the higher voltage to bleed off. During that time the 14.4v charger will not do anything because the battery voltage is still above the charger's voltage.

Once the battery voltage falls below 14.4, then the 14.4 charger will kick in to maintain that 14.4.

You did get 5 years out of those two 24s, which is pretty good for that kind of battery in an RV. RIP 24s, hello 6s 🙂

[lawrosa]

time2roll wrote:

lawrosa wrote:
Understood. 14.4 wins out..

So riddle me this..

I have these 12volters on the sears charger. Charging 10 amp setting @15.4 volts and 4 amps going in. SG is now at 1.250.

Its been 2 hours.

Can I conclude any information from this?

Why wouldnt the PD put in the amps @ 14.4? I know you say about the false voltage so just trying to grasp it.

Not yet fully charged. Look for less than 1 amp per battery to call full charge.

PD will put in the amps at 14.4, just slower.

You can get a PD-14.8 to be a little faster. Quite frankly I like the IOTA algorithm but it does take time. Fully charging also takes time. Fully charging a battery that has been bouncing up to 90% for a week or three takes more time. Boost charge to 90% is fairly quick as you get into 14.6+ volts.

It is an electro-chemical process. Not the same as filling your gas tank or winding a spring.

The whole thread was about lag, but is this a truth, or what scientific issue are we talking about.

Case in point. Me with these two 12v boat anchors...

5 hours on 15.3 charge @ 4 amps in. SG still 1.250. Not moving.

I give up.

Took off charger and hit button on PD. 14.4 volts, 1 amp in.

Will leave like this as I am frustrated. Maybe its normal. sg 1.250 is what? 90%? 85%? 80%?

So yes my batts will get to 1.275. Maybe in a few days, maybe not. but i've I seen it happen.

But the PD could not get them to said sg 1.250. It hovered in between 1.225 and 1.250 ( 1.242 ?) on an overnight charge on shore power. False voltages as mex stated?

If I cant them up on 17 hours plugged in, ill never get them up in the field with generator.

So to conclude.

Lag?

Batteries shot? ( but my drawdown test shows different in that respect.. Who knows... (" Third base? Whats on second? whos on first?.....Naturally!!!!!)

Beating a dead horse?

IDK reading old threads, all you gents here were a part of years ago, (2011-etc it seems like you discussed this to death. BFL, mexwanderer, timetoroll, land yacht etc etc..

So I am the newbie asking stupid stuff...

Yes get 6 volts, stop worrying and enjoy camping...

I have enough solar now, Stop using high use appliances like toasters, coffee pots, and microwaves....LOL.

[time2roll]

lawrosa wrote:
Understood. 14.4 wins out..

So riddle me this..

I have these 12volters on the sears charger. Charging 10 amp setting @15.4 volts and 4 amps going in. SG is now at 1.250.

Its been 2 hours.

Can I conclude any information from this?

Why wouldnt the PD put in the amps @ 14.4? I know you say about the false voltage so just trying to grasp it.

Not yet fully charged. Look for less than 1 amp per battery to call full charge.

PD will put in the amps at 14.4, just slower.

You can get a PD-14.8 to be a little faster. Quite frankly I like the IOTA algorithm but it does take time. Fully charging also takes time. Fully charging a battery that has been bouncing up to 90% for a week or three takes more time. Boost charge to 90% is fairly quick as you get into 14.6+ volts.

It is an electro-chemical process. Not the same as filling your gas tank or winding a spring.

[BFL13]

lawrosa wrote:
Yes adjustable... I would need access to the dial though....And be able to read the meter.. Dont know if I can do it...


http://www.bestconverter.com/Boondocker-BPCM-60-60-Amp-Adjustable-Power-ConverterCharger_p_585.html#...

You want this one instead. Does the same thing but has internal fan, can be mounted so you only need to get at the side with the holes in it, not the top. The right hand hole lets you adjust the voltage pot. The left hand hole is for a switch to choose between fixed three stage standard profile and the adjustable mode where you use the right hand hole to set your voltages. Note the price and free shipping! What a deal!

https://www.amazon.com/Powermax-PM3-75LK-Power-Supply-Light/dp/B01MT636SX/ref=sr_1_24?ie=UTF8&qid=15...

[BFL13]

Mex, that seems to be 36 amp 13.8v, so what is it for?