CE ROHS charger

[Notso ezgo]

IMG_8655.jpg

Hi again all, hopefully consecutive questions by a Newb are cool. '85 Marathon 36V cart (new) owner here. Cart came with above charger. I tried to ask in other threads concerning this but couldn't post.

1) At what voltage should this thing shut off? Charger came with cart, not sure of model but it's a cheapo import charger rated at 5 amps. Currently still charging at 44.2 volts measured over batteries wired in series and currently charging.

B) I read in another thread that I couldn't join that 5 amps is too low for a charger. Will using only a 5 amp charger be detrimental or just not be strong enough to pick up a low battery pack?

If helpful, batteries are a hodgepodge of new and very old. Most have been disconnected, charged with 6V charger, and watered.

TIA, I appreciate the knowledge of those here!

[JohnnieB]

Originally Posted by Notso ezgo

Attachment 204727

1. Hi again all, hopefully consecutive questions by a Newb are cool. '85 Marathon 36V cart (new) owner here. Cart came with above charger. I tried to ask in other threads concerning this but couldn't post.

2. At what voltage should this thing shut off? Charger came with cart, not sure of model but it's a cheapo import charger rated at 5 amps. Currently still charging at 44.2 volts measured over batteries wired in series and currently charging.

3. I read in another thread that I couldn't join that 5 amps is too low for a charger. Will using only a 5 amp charger be detrimental or just not be strong enough to pick up a low battery pack?

4. If helpful, batteries are a hodgepodge of new and very old. Most have been disconnected, charged with 6V charger, and watered.

TIA, I appreciate the knowledge of those here!

1. Not sure why you couldn't post in other threads.

2. It depends on what type charger. Some older one shut off at 45V +/-1V and newer ones using dV/dT (change in Voltage over change in Time) technology shut off at higher voltages. (When the On-Charge voltage stops increasing.) I suspect it is the later type.

3. A couple of problems with a low amp charger.
First of all, they take a long time to recharge the battery pack and if you use the cart daily there may not be enough down time to completely charge the battery pack.
Secondly, there will little, if any, gassing (bubbling) so the electrolyte doesn't get de-stratified during the charge cycle like it should.

Other than that, it won't hurt the batteries.

4. Mismatched batteries is an issue. They are typically charged and discharged in series, so they need to be closely matched sets or they become imbalanced and some batteries will be overcharged and others undercharged while charging and some will be discharged further than other when used.

You can charge the lower voltage ones with a 6V charger to equalize the pack.

You don't have to disconnect the batteries from the pack to charge them individually with a 6V charger.

[Notso ezgo]

“ 4. Mismatched batteries is an issue. They are typically charged and discharged in series, so they need to be closely matched sets or they become imbalanced and some batteries will be overcharged and others undercharged while charging and some will be discharged further than other when used.

You can charge the lower voltage ones with a 6V charger to equalize the pack.

You don't have to disconnect the batteries from the pack to charge them individually with a 6V charger.”

Thank you. Yes the mismatched batteries are not ideal. I am charging the older ones individually with both a 10amp car style charger (set to 6v) and also a smaller 4amp maintenance charger afterwards. Time consuming and not ideal. But it works for now until I get others replaced.

Thanks for the tip on being able to charge individual batteries (wired in series) with battery cables still attached. That is a time saver. I wondered about that as I can get an individual battery voltage using multimeter with batteries still connected.

Off to water them now!

[JohnnieB]

Originally Posted by Notso ezgo

I wondered about that as I can get an individual battery voltage using multimeter with batteries still connected.

Yes.

A voltmeter measures and a charger charges whatever is between the two leads. For example, you can go across two 6V batteries and use a 12V charger.

[Notso ezgo]

Johnnie,

Thanks again. First thing is that your avatar makes me laugh every time I see it. Bravo! And who is that? Honeymooners?

I've got my batteries within .1 volt from each other, charging now and will monitor.

I've searched and scoured, but I can't find the post i read recently regarding the minimum pack voltage (without charger... charging) after letting pack sit for 12 hours. Not sure if it was you and i don't see it in stickies or battery threads that I could find.

Was it 39.8? And was that a minimum threshold or does it signify a healthy pack?

I've saved and printed the Carts Unlimited State of charge chart, and it's quite different from the "Trojan recommended on-charge voltages" chart. Just trying to figure out which one to go by.

[JohnnieB]

Originally Posted by Notso ezgo

Johnnie,

1. Thanks again. First thing is that your avatar makes me laugh every time I see it. Bravo! And who is that? Honeymooners?

2. I've got my batteries within .1 volt from each other, charging now and will monitor.

3. I've searched and scoured, but I can't find the post i read recently regarding the minimum pack voltage (without charger... charging) after letting pack sit for 12 hours. Not sure if it was you and i don't see it in stickies or battery threads that I could find.

4. Was it 39.8? And was that a minimum threshold or does it signify a healthy pack?

5. I've saved and printed the Carts Unlimited State of charge chart, and it's quite different from the "Trojan recommended on-charge voltages" chart. Just trying to figure out which one to go by.

1. I'm not sure where the original photo came from, but a forum member photoshopped the JohnnieB monogram onto the jacket and I've been using it since. Ironically, there is some resemblance to pictures of me decades ago.

2.

3. That is called a SoC (State of Charge) chart.

4. That is higher than normal.

5. Those are two separate charts showing voltages at different times under different conditions.

There are three separate battery voltages that are useful in troubleshooting:

At-Rest: Measured roughly 12 hours after the charging stops or about an hour after being used. This is the voltage SoC estimates are made from.

On-Charge: Measured while a charging current is passing through the battery. Used to determine if charger is working right.

Under-Load: Measured while a number of amps are being drawn from battery. How many Volts the battery voltage drops per a given number of amps of discharge are a indicator of the batteries health.

Attached are the SOC data and the On Charge data from Trojan battery User Guide . The former is for At-Rest voltage measurements and the latter is for On-Charge measurements.

I also attached SoC charts for three different brand batteries, Trojan, US battery and Crown. As you see the 100% SoC voltage varies by battery brand.