New Battery Specific Gravity Readings

[chasenfish16]

I have (6) new US Battery US200XC2 with about 25 cycles on them (down to 75% then recharge) I just took a specific gravity reading on them 12 hours after a full charge while the pack voltage was 38.6 and each individual battery was between 6.40 and 6.43. I took the specific gravity readings with a EZ Red temp. compensating hydrometer and all the readings were 1.225 which on my chart shows 75% charged I was fully expecting to see 1.277 which indicates a full charge. My only guess for the low readings are that the batteries are not fully broke in yet. Is my thinking correct. Also if the hydrometer is temp. compensating I should not have to adjust for the temp of the battery acid being 60 degrees?

[JohnnieB]

Sounds like the electrolyte is stratified. The acid is heavier than water and tends to settle to the bottom so the SG at the top is lower than the SG at the bottom.


This is acid, so be careful when doing this. Wear a face shield or goggles.
Aspirate a bulb full of electrolyte and with the tip of the tube still in the electrolyte, squirt it back into the cell.
(Don't squirt when tube is out of the liquid, or it will splash and that stuff causes burns and blindness)

Do that several time in each cell before taking SG readings.

------------
You Subtract 0.004 for each 10°F below 80°F, so if your hydrometer isn't temperature compensated, your reading are higher than the actual SG.

--------------

Different battery manufacturers use different Acid concentrations (SG).
The SG reading listed on most of the charts seen around here are for Trojan batteries.
My new Exide batteries do not match the charts either.

From what I can tell, a new US Battery (Golf cart type) should read a minimum of 1.270 when fully charged.

----------------
Here is are Charging Recommendations from US Battery

[chasenfish16]

I did take and squirt the elecrolyte numerous times before checking the SG. So you dont think that because the batteries are not broke in yet that is why the SG is low? Also do you take the test after 12 hours or directly after charging?

[chasenfish16]

I just talked to the US Battery Engineer, now I am really confused. He said that my Powerwise charger was not bringing up the voltage high enough for long enough. He said that the Powerwise charger was set up for trojan batteries. At about 75% SOC my battery will charge until the Ammeter on the charger goes to about 4 then shuts off shortly after. He said it needs to stay at 4 for 1-3 hours. My pack voltage when it shuts off is about 45.5 and each battery is about 7.5 he says it should be more like 46.8 and 7.8. So is my charger shutting off prematurely. How long do most peoples chargers run after they reach about 4 on the ammeter? I also try to unplug the charger and reinstall it for a equalization charge and it will only run about 30 minutes. BY the way my powerwise charger model # is 28115 G04

[JohnnieB]

I use DPI Accusense chargers, which have 4 user selectable charge profiles.
1. US Battery
2. Trojan
3. Exide
4. FullRvr

I'm not sure what #4 is for, but the first three are pretty obvious.
(Anybody know what "FULLRvr" means?)

DPI Accusense chargers also go into a float charge mode after the regular charge cycle finishes. which keeps the batteries at 100% SoC.

Set to the Trojan charge profile, my 36V DPI charger is keeping six Trojan T-105 batteries floating at 39.6V.
Set to the Exide charge profile, my 42V DPI charger is keeping seven Exide GC-145 batteries floating at 46.4V.

[chasenfish16]

Thanks again Johnnie, I never new diferrent batery manufacturers required different settings on the same voltage batteries on chargers. Iam curious if my powerwise is bad or just set up for a trojan battery profile? I wonder what the differrence is between the trojan 6 volt and the US Battery 6 volt. Have you been happy with the DPI charger and where is the best place to buy one?

[Great white north]

I got mine DPI charger from Scotty , he has quality stuff
Good luck
Cheers!

[JohnnieB]

Originally Posted by chasenfish16

Thanks again Johnnie, I never new diferrent batery manufacturers required different settings on the same voltage batteries on chargers. Iam curious if my powerwise is bad or just set up for a trojan battery profile? I wonder what the differrence is between the trojan 6 volt and the US Battery 6 volt. Have you been happy with the DPI charger and where is the best place to buy one?

I knew different battery manufactures used different acid concentrations, plate thicknesses and/or plate composition and /or plate designs, as well as other differences. And I knew the Powerwise 28115 and many other ferroresonant transformer design golf cart chargers used the Trojan battery charging profile. But, I wasn't aware that it made that much difference.

Since Trojan is the only charge profile I've been able to find on-line, I figured the other battery manufacturers would publish them somewhere if they had significantly different charging requirements, but I haven't found any yet.

That tid-bit of information from the US Battery engineer, opens some new doors on proper battery charging and it looks like I've got some research to do.

---------------
I got my DPI chargers from Scottyb. http://www.cartsunlimited.net/48v_Battery_Charger.html

[chasenfish16]

There must be a difference since there are 4 different settings on the DPI charger. I just dont know what they do differently. I just know that my powerwise charger wont bring my Specific Gravity up past 1.225. Makes me wonder if my charger is bad or just set up lower to accomidate Trojan Batteries. I take that you leave your DPI charger plugged in all the time? Johnnie whay did you purchase 2 new DPI chargers where your old ones bad. I just dont want my batteries sitting in a stratificated state to long seeing that they are only 2 weeks old.

[JohnnieB]

Originally Posted by chasenfish16

There must be a difference since there are 4 different settings on the DPI charger. I just dont know what they do differently. I just know that my powerwise charger wont bring my Specific Gravity up past 1.225. Makes me wonder if my charger is bad or just set up lower to accomidate Trojan Batteries. I take that you leave your DPI charger plugged in all the time? Johnnie whay did you purchase 2 new DPI chargers where your old ones bad. I just dont want my batteries sitting in a stratificated state to long seeing that they are only 2 weeks old.

I've got two DPI chargers because I'm switching from 36V to 42V.
My plan was to sell the 36V one when I installed my seven new 6V batteries, but some medical issues can up last fall after I had already bought everything, so I've been keeping the new batteries on float charge (plus some other TLC) on my garage floor. Hopefully, the weather will warm up enough and not rain long enough to do the upgrades, but it has been either cold or wet so far this year.

If the PW charger jumps up to 15 to 20 Amps when it first clicks on and shuts off by itself, it is working normally.
The control board just shuts it off when the on-charge voltage climbs into the 44-46 volt range, which is below the 46.8V mentioned by the US Battery engineer.

I just sent an email to DPI, asking for the specifics of the four user selectable charge profiles. Maybe they will provide some answers.

I sent you a PM, check you box.