Load tested my US batteries- here are results

[Dwalls]

Originally Posted by JohnnieB

Get the weighted glass float type with a thermometer. Something akin to this: https://www.amazon.com/East-Penn-Tem.../dp/B0002KKTYU

OR a Refractometer akin to this: https://www.amazon.com/Refractometer...ZPMEJPYRZZQ8MW

Measuring the SG (specific gravity) of the electrolyte has art mixed with the science, so don't jump to conclusions until you've mastered the art and learned the science.

Haven't seen one like johnnieB recommends so maybe i'll have to put one of those on my list.
I do have the refractometer like he listed and then I have one of these
https://www.amazon.com/dp/B000JFHMRU..._t2_B0002KKTYU
They read within 5 of each other.

[JohnnieB]

Originally Posted by Dwalls

Haven't seen one like johnnieB recommends so maybe i'll have to put one of those on my list.
I do have the refractometer like he listed and then I have one of these
https://www.amazon.com/dp/B000JFHMRU..._t2_B0002KKTYU
They read within 5 of each other.

I don't actually recommend that particular hydrometer, I just used it as an example of the weighted float type with built-in thermometer. Same with the Refractometer I linked to.

Personally, I don't see all that much of a need for them since the individual cells in the batteries used in cars and carts cannot be replaced and a bad battery can be found with a DVM.

[Conradconrad]

Originally Posted by JohnnieB

6. 1.5VPC is the absolute minimum. That is 4.5V for a 6V battery or 31.5V for a 42V pack. That is the point where irreversible physical damage to the plates starts occurring.

During non-destructive load testing, the batteries are taken down to 1.75VPC, which is 5.25V for a 6V battery and 36.75V for a 42V pack.

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The tricky part of using the 36.75V and 31.5V numbers with the voltage readings seen in the data logs and a dash mounted DVM is that the voltage drop due to the resistance of several high current cables, connections and contacts is included with the voltage drop of the batteries, so there is some wiggle room when monitoring pack voltage.

The data collected in your tests will (hopefully) show how much voltage drop is in the cables connecting the batteries together to form a 42V pack.

So maybe I set the Alltrax voltage low safety feature (I believe undercurrent) to 32V?

[Mccoy38]

I was having same issues with 1 yr old US. Bought a Lester Summitt II Charger and has made all difference in the world. Has 3 phase charging and Bluetooth app so you can see the charge info and equalize if needed. The original charger was only getting pack to 80% for what ever reason.

[Dwalls]

Originally Posted by Mccoy38

I was having same issues with 1 yr old US. Bought a Lester Summitt II Charger and has made all difference in the world. Has 3 phase charging and Bluetooth app so you can see the charge info and equalize if needed. The original charger was only getting pack to 80% for what ever reason.

I will second that the summit II seems to be a great charger, I installed mine onboard.

[JohnnieB]

Originally Posted by Conradconrad

So maybe I set the Alltrax voltage low safety feature (I believe undercurrent) to 32V?

It is called Under Voltage on the screen save I made from Toolkit ages ago (May-2016), but that was software revision V1 and it may have been renamed in later versions of Toolkit.

I've upped the Regen amps since then and RPM limited the motor to 6500RPM.

[JohnnieB]

Originally Posted by Mccoy38

I was having same issues with 1 yr old US. Bought a Lester Summitt II Charger and has made all difference in the world. Has 3 phase charging and Bluetooth app so you can see the charge info and equalize if needed. The original charger was only getting pack to 80% for what ever reason.

Originally Posted by Dwalls

I will second that the summit II seems to be a great charger, I installed mine onboard.

The older generations of chargers that shut off at a specific, predetermined voltage are the one that had issues with chronically undercharging US Battery brand batteries. Some of them did okay, others didn't, it depended on exactly what voltage they cut off at.

Modern chargers that don't shutoff until the on-charge voltage stops increasing (dV/dT technology) do a better job and those that actually have a charging profile specifically for US Battery brand batteries do the best.

The DPI Gen-III the OP has is what I consider the gold standard since it has dV/dT shutoff technology followed by float charging, plus it has a step-down transformer instead of a solid state input stage for better reliability.

Unfortunately, the DPI Gen-IV doesn't do float charging, and neither do the DPI Gen-III that are currently being sold by DPI, or at least that is what I understand. I don't understand why DPI discontinued float charging, it prolongs the battery's lifespan.

When/If I go to 48V, I'll probably go with a Lester Summit-II or a Yewy.

[Conradconrad]

Will this one work for my needs?

https://www.amazon.com/gp/product/B0...KIKX0DER&psc=1

Also what is the process for using one of those in the intended way with minimal user error?

[Dwalls]

If you want to check the specific gravity of each cell then yes that should suit your needs. JohnnieB and some of the others just check with a Digital Voltmeter as he stated earlier.
They are pretty straight forward to use, just pull up some acid out of each cell and read the number, I also flush the tester between each cell with distilled water to get an accurate reading of each cell.

After checking the specific gravity of my new us batteries I contacted usbattery because my lester 2 charger was showing some high voltage during charging and after they looked at the specific gravity of each cell they determined that the batteries were still in the installation stage and as the specific gravity got higher then the high voltage that I was seeing will drop.
That may be one of the advantages of checking the specific gravity.

Check level every month and fill with distilled water only.

Good luck

[JohnnieB]

Originally Posted by Conradconrad

Will this one work for my needs?

https://www.amazon.com/gp/product/B0...KIKX0DER&psc=1

Also what is the process for using one of those in the intended way with minimal user error?

That is the one I use, when I use one.
Got mine at an auto parts store years ago, didn't know Amazon carried them.

The batteries have typically been sitting still overnight, or longer, when a hydrometer is used, so the electrolyte is stratified. In a nutshell, pure sulfuric acid has a SG of about 1.84 while pure water has a SG of 1.000 and the electrolyte is about 3 parts sulfuric acid to 7 parts water. The acid molecules are 85% heavier than the water molecules, so they are drawn toward the bottom of the cell while the lighter water molecules rise towards the top and the net result is the electrolyte at the top of the cell can have a significantly lower SG than the electrolyte at the bottom of the cell.

I mix the electrolyte by aspirating electrolyte from just above the plates and carefully squirting it back into the cell, and repeating several times, depending on how long the batteries have been sitting still. Then I aspirate enough electrolyte to float the float, read the numbers off the float at the air/liquid interface and add/subtract the number of points on the thermometer.

After taking the SG reading, be sure to squirt all the electrolyte back into the cell it was aspirated from.