US Battery State of Charge table

[rlw]

I had a good conversation this morning with US Battery's Senior VP of Engineering, Fred Wehmeyer. There was an earlier thread (that I can't find right now) where JohnnieB said that the state-of-charge characteristics for my US Battery 1800XCs was slightly different than those for Trojans. I noticed that after a full charge and 12 hour rest, my batteries were at about 38.4V, slightly higher than the 100% SOC for Trojans (38.2V).

I dug around on US Battery's website, but couldn't find a specific document that showed that, so I called them and spoke to Fred. Fred generously sent me the following table and gave me permission to post it on Buggies Gone Wild.

Hope this helps someone else to properly maintain their USB batteries, and could be made a sticky if the board admins think it's worthwhile.

RLW

fantastic !!

hopefully a mod/adim will add this to http://www.buggiesgonewild.com/elect...batteries.html

[JohnnieB]

Fantastic info.

Since it is labeled "Table 1", I suspect it is going to be part of a soon to be published Technical Service Bulletin (TSB).

Ironically, the VPC (Volts per Cell) is 0.03V higher at all SoC percentages than what I received from them a few weeks ago. (I got it from Fred also, so I suspect they did some reviewing and refining on the numbers.)

BTW: Fred's title is: Senior Vice President - Product & Process Engineering, so the table he sent rlw is about as authoritative as we are ever going to get on the subject.

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Ladies and Gentlemen, I believe were are on the brink of something big.
In a nutshell, there are a lot of battery chargers out there that don't fully charge US Battery battery packs.

If you have US Battery batteries, make sure they are being charged to the voltage on the US Battery Voltage vs SoC chart, or upgrade to a charger that will do it.

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[rlw]

JohnnieB,

In the email where Fred gave me permission to put this on BGW, he said he was going to see about getting this info on USB's website. I told Fred I had US1800XCs, so this table may be specifically for the "XC" class of batteries. Supposedly, the XC batteries use a process that gives them higher voltages after they're fully charged.

RLW

Johnnie ... are you saying that us batteries are better than trojan ? looking at the chats i think they are or do you think they are rigging them ?

[JohnnieB]

Originally Posted by rlw

JohnnieB,

In the email where Fred gave me permission to put this on BGW, he said he was going to see about getting this info on USB's website. I told Fred I had US1800XCs, so this table may be specifically for the "XC" class of batteries. Supposedly, the XC batteries use a process that gives them higher voltages after they're fully charged.

RLW

That may be a possibility. Like I said, the number I got were 0.03V lower across the board.
Attached it the chart I made from them. As you can see, there really isn't much difference between the two set of numbers from US Battery, but both are higher than Trojan.

If only managed to take a quick look, but I spotted that the SG is lower than Trojan, while the VPC is higher.
That is an interesting conflict since I thought the VPC was SG + 0.845.
Guess it is time for me to do a little looking and reading.

[JohnnieB]

Originally Posted by crash test dummy

Johnnie ... are you saying that us batteries are better than trojan ? looking at the chats i think they are or do you think they are rigging them ?

I'm just saying they are different. One is probably as good as the other.
My belief is that comparable AH batteries by the top tier battery manufacturers (IE: Crown, East Penn/Deka, Exide, Trojan and US battery) are pretty much the same.
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BTW: Voltages would be hard to rig since they are readily measurable by anyone with a DVM, so why do it.

[rlw]

Originally Posted by JohnnieB

...If only managed to take a quick look, but I spotted that the SG is lower than Trojan, while the VPC is higher.
That is an interesting conflict since I thought the VPC was SG + 0.845.
Guess it is time for me to do a little looking and reading.

Fred did say in his email that the SG numbers would rise as the batteries aged (those numbers are for NEW batteries). That makes some sense, as I'd guess the electrolyte builds up impurities that are denser than H2SO4 as the battery ages.

Could also be due to whatever voodoo-magic they do with their lead alloy and the "XC" process.

It's nice to have the freezing point on the table he sent me, too, just for grins'n'giggles (SE Ohio doesn't get cold enough in the winter to freeze an 80% SOC battery!).

BTW, I modified the table he sent to kinda match your SOC table - yellow highlight @ 50% SOC, red/pink below. Also added the text at the bottom just to make sure folks know it applies to US Battery products.

RLW

[Bill]

Is this for the XC or the XC2's or both ?

If You guys come up with a revised finish voltage for this updated chart please post it up.

[rlw]

Originally Posted by Bill

Is this for the XC or the XC2's or both ?

If You guys come up with a revised finish voltage for this updated chart please post it up.

Bill,

I'm not sure -- I was making an assumption that it was for the "XC" batteries based on my conversation with Fred and JohnnieB's observation that the voltages differed from the data he had from USB.

If we come up with a definitive SOC table, I'm sure it will be posted here.

Might not be a bad idea to gather ALL the data we have on various battery manufacturers and create a sticky where it can all be put in one place.

Just a suggestion,

RLW