Health and state of charge of Lithium Battery Testing

[lpattonSAT]

My 2017 RXV Elite in running out of charge by the time I return home from 18 holes of golf. With my old RXV flooded batteries, I could play 36 holes w/o charging. I purchased the RXV used, but I have a 3 year battery dealer warranty. Running the "pack diagnostics", the dealer says the single lithium battery tests normal. How do I establish the current State of Health (current estimated capacity vs. designed capacity) and the state of charge?

[Tom47]

Does your cart have a shunt connected SOC meter? If not, that would be a good investment. That acts as a fuel gauge and monitors the Ah usage and % of charge remaining.

It seems unusual that a lithium cart would not have a comparable or better range to a FLA cart. Something seems off. My cart got 20 miles per charge with the FLA and now gets 35 to 40 miles with the lithium only running it down to 20%. This is all flat, paved surface operation.

Are you sure you are getting the lithium charged fully? Your charger should charge to 58.4 volts and shut off. Then the charge should settle down to 53.6 volts or better after a period of time. This will give you a 90% charge (known as settling charge) which the SOC meter should be calibrated as 100%.

Since this was used and only 5 years old, you should have years of life left. However, what you may not know is how it was used previously. A former user may have run the battery down to 5% or lower repeatedly. This is not good for a lithium pack and will shorten it's life.

Good luck on finding a solution.

[Pat911]

A couple of questions before we can make informed comments.

1. What capacity lithium battery do you have?
2. Are you using a lithium battery charger or the original lead acid charger
3. is it a single 48v battery or multiple 12v batteries in series?
4. Is the cart modified at all?

As Tom said, it's possible the battery has been abused by the previous owner but a shunt (coulomb counting) SOC meter will tell you if you're pulling full battery capacity.

Cheers
Pat.

[lpattonSAT]

My battery is a single one. Both the lithium battery and charger are OEM Samsung for the 2017 RXV Elite with no modifications. Do not know about prior misuse.

[Tom47]

Does your cart have a dash SOC meter that indicated % charge and Amp draw and Amp-hour remaining? This is the only way to determine if your battery is charged completely.

RXV website says they are designed to play 36 holes and have 44% remaining. Unless you are driving a very long way home, you are getting nowhere close to that.

If you have a volt meter, check the battery voltage after the charger shuts off. Then check it again the next day before operating the cart. You should see near 54 volts when the charger shuts off. Next day you should see 53.2 volts if the cells are holding charge.

It appears a new battery under warranty will be needed. I hope you are able to resolve this with the seller.

Let's see what Pat911 has to say.

[Pat911]

Well at this stage the only way to check its health is to do a discharge capacity test. You’ll need a coulomb counting SOC meter to do that. Do you know the original capacity of the OEM pack?