No hill climbing power

[JohnnieB]

Originally Posted by bowmanfence

1. 38.1 starting is 50% charge for 36v? I thought 38.2v is 100% or am I reading the chart wrong.

2. is there a rule of thumb for what the 6v battery should be under load?

3. the voltage varied so I took the lowest reading, the voltage was probably .3 higher going up the hill as opposed to what I had at the peak of the hill.

4. I was hoping if I needed to replace the batteries I could get away with changing half now and the rest in spring.

5. I don't know the age of the 5 Trojan batteries but the 1 powertron that tests the highest voltage is 2 years old

1. For Trojan batteries and their clones, 36.3V is 50% SoC (State of Charge) and 38.2V is 100%.

2. No, because what voltage a battery drops to depends on its SoC is when the load is applied as well as how many amps are being drawn from it.

The batteries in a 36V battery pack, in and of themselves, tends to drop 1.0V for each 100A of current being drawn, but when you measure the pack voltage between the battery pack's main positive and main negative terminals, you typically see about a 2V drop per 100A of current draw.

However, there are some limits to how far the voltage should be allowed to drop. During normal operation, try to stay above 1.75VPC (Volts per Cell), which is 31.5V for a 36V pack and never drop below 1.50VPC, which is 27.0V for a 36V pack. If you go below 1.50VPC, irreversible physical damage to the plates starts occurring.

3. You want the lowest voltage. If you have a DVM with Min/Max function, it work great for this type testing.

The batteries are being charged and discharged in series, so they should all charge to the same voltage, or close to it. And when they are discharged, the all ought to end up with the same voltage.

The voltage spread when your batteries were sitting was 0.16V and on the hill the spread grew to 1.32V.

4. As mentioned, the batteries are charged and discharged in series, so they need to be as closely matched as possible. This is typically done by have all the same make and model batteries that are as close as possible to the same age.

The rotten apple phenomenon applies to mixing batteries.

A good apple quickly goes bad if placed in a bushel of bad apples and a bushel of good apples quick go bad in a bad apple is place in the bushel.

A new battery quickly become old in placed in a pack of old batteries and a pack of new batteries quickly get old if an old battery is placed in the pack.

It appears that a Trojan battery went bad and somebody replaced it with a Powertron to get more use out the the five good batteries. The new Powertron was a sacrificial battery, meaning it was to be replaced at the same time as the other (older) five batteries.

5. The two character date code for Trojan batteries is stamped in the negative terminal.
The letter is the month (A-L = 1-12) and the number is the last digit of the year. (IE: L1 = Jan-2011)

[bowmanfence]

Well it was bugging me that coming up the hill I had such a big range from bottom to top so I went ahead and bought a battery tester with 100 amp load so I can double check my numbers. All batteries were 5.9 right on the line of weak and good or better while one dropped off to 5v. these batteries were already mixed like that when I bought this cart last week, I was hoping to get at least a year out of them. I'll have to price some new Trojans and have them all replaced, I was going to replace half now and the rest after Christmas but I may just have to bite the bullet and do it right.

[bowmanfence]

Originally Posted by JohnnieB

It appears that a Trojan battery went bad and somebody replaced it with a Powertron to get more use out the the five good batteries. The new Powertron was a sacrificial battery, meaning it was to be replaced at the same time as the other (older) five batteries.

5. The two character date code for Trojan batteries is stamped in the negative terminal.
The letter is the month (A-L = 1-12) and the number is the last digit of the year. (IE: L1 = Jan-2011)

From what I was told the battery that was replaced had a loose connection at some point and damaged the connector so they replaced that battery so I assumed all Trojans to be older then the Powertron. All I can make out on the date codes was the month, which should have been a red flag to the condition of the batteries. Little old men just aren't as honest as they used to be I guess.

[scottyb]

A 100amp battery tester won't match the draw created by the cart motor uphill. The cart may draw 300 amps at times. Next test you can use is specific gravity. Specific gravity tester (not floating balls) will give readings also on the chart posted relative to how actively charged each cell is. If SG and voltage are low then you can be certain the battery(s) are degraded. I never depend upon one method or the other, a combination that agrees is pretty bulletproof.

As for people being honest, most people can't remember how old their batteries are much less be able to tell somebody the true condition.

[kgsc]

I see you are from Greenwood so make sure to call battery outlet in Newberry. They sell a battery with better numbers than the Trojans for about the same price..

[bowmanfence]

We have everything to test Specific Gravity in our Quality Lab at work but I priced some Trojan T-605 and T-105 here locally and they run 600-690+ tax so I will probably just end up replacing them all since I know at least one to be bad and a few others to be borderline at 100 amps. I plan on upgrading the motor and most likely the controller and solenoid over the winter. Think I may start off with Plum Quick Bandit upgrade and get with ScottyB on the XCT400PDS or XCT500PDS controller upgrade but I'm still researching a little bit.

[scottyb]

Originally Posted by bowmanfence

We have everything to test Specific Gravity in our Quality Lab at work but I priced some Trojan T-605 and T-105 here locally and they run 600-690+ tax so I will probably just end up replacing them all since I know at least one to be bad and a few others to be borderline at 100 amps. I plan on upgrading the motor and most likely the controller and solenoid over the winter. Think I may start off with Plum Quick Bandit upgrade and get with ScottyB on the XCT400PDS or XCT500PDS controller upgrade but I'm still researching a little bit.

The 105 has a greater AH capacity, well worth the extra $ in service and longevity

[bowmanfence]

Originally Posted by scottyb

The 105 has a greater AH capacity, well worth the extra $ in service and longevity

I figured so too, they are only $90 more for the whole pack locally and if I drive about 50 miles they are only $30 more. Thanks for all the help with this too!

[kgsc]

The Bulldogs are 235Ah and they have a 245Ah.. Just saying it may be worth the phone call..

[cgtech]

Always skip the "605" (and all other brand's "low end" friends), always buy the best AH battery you can get to fit in your budget. I'm not saying you have to buy Trojan T-145's, but dont "shortchange" yourself by buying anyones "lower than 225ah" cheapo batts, it wont pay off in the short term, or the long term. The less you discharge a battery every time you use it, the more years it will last.