Charging issues

kgsc

Having an issue with my all new batteries and new DPI charger. Bought new 6 volt 235ah batteries yesterday with all new cables. Hooked it all up and had 37.1 on the pack. Connected the DPI set in mode 1 which I read is 2.5 volt per cell charge and started charging around noon. Charger jumped to 18 amps and I let it go. At 8pm I checked it and it was around 9 amps. Checked again at 11:30 and still 9 amps. Batteries are not boiling over but they are definitely making noise. Checked this am and still 9 amps. Pack voltage on charge is 44.1. Each battery reads within .1 volts of each other.

I really don't think it should take this long to bring the pack up, am I wrong? Is mode 1 too much?

Thanks in advance.

BGW

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sportcoupe

New batteries can take up to 16 hours on the first charge, especially 235Ah batteries. You never stated the start time of charging.

44.1v is 2.45v per cell, let it keep charging.

kgsc

Thanks sc. I did say noon but it is still early yet so it has been roughly 21 hours. I will leave it on but just wasn't sure about all the noise coming out of the batteries.

JohnnieB

The initial charge on new batteries can take a very long time, so if the back-up timer shuts the charger off, unplug the charger from the cart, wait a minute or so and then plug it back in the recycle the back-up timer.

The 37.1V original voltage sounds like they sat on the shelf for a while before you got them, so the initial charge is going to take a very long time and they are going to be gassing noticeably, especially since the DPI uses dV/dT (Change in Voltage over change in Time) to determine when the batteries are fully charged.

You mentioned the On-Charge voltage is 44.1V and the charge current is 9A.
Since the Ammeter has dropped from the Max Amp rate, the charger has transitioned to the Absorption phase, but are you sure it is in Mode-1?
The constant voltage Absorption phase in Mode-1 is 2.5VPC, which would be 45.0V for a 36V pack and your charger is only 44.1V, which is the absorption voltage for Mode-4. (Shorting plugs on bottom two set of pins)

To check what mode your charger is in, unplug it from AC power, wait a minute or so and then plug it back in while watching the LEDs on the front panel. The number of times they flash before the come on steady indicates the mode it is in.

Also, is this a new charger, or has it been used successfully on other battery packs?
Except for the absorption voltage being wrong for Mode-1, it does appear to be operating normally, but want to be sure.

kgsc

I do have the top two sets of pins shorted which should be mode 1 but will go cycle it to be sure. And yes this is a new charger out of the box so first run. I may hook up the old ezgo charger just to see what it does and eliminate one of the "new" things. Batteries and charger change may be asking too much of my brain this weekend. Is it beer 30 yet ??

Thanks guys.. Will keep updating.

I also bought 2 sets of these so will probably go put an individual charger on those just to speed up the process once they hit their new cart.

JohnnieB

If it is in Mode-1, something may be amiss.

As I understand it, the DPI has specific trigger points for advancing from stage to stage and some of them vary, depending on what mode it is in and for a 36V DPI, I believe it works like this.
Stage-1: Detection. Checks polarity and voltage. If voltage is below 42V, applies a 5A constant current charge until pack voltage climbs to 42V.
Stage-2: Bulk charge. When pack voltage reaches 42V, the constant current is increased to about 18A and pack voltage is monitored.
Stage-3: Absorption charge. When pack voltage reaches the trigger point as determined by the Mode selected, the charger maintains that voltage (Constant voltage stage) until the charge current falls below a predetermined rate, but might be dA/dT (change in Amps over change in Time), I'm not sure which.
Stage-4: Finish charge. When the current flow rate criteria is met, the charger switch to a constant current at that rate and the voltage is allowed to increase until the dV/dT criteria is met, terminating the regular charge cycle.
Stage-5: Maintenance. Float charge and/or 28 day recharge cycle.

kgsc

Well. Just validated that it is in mode 1. Cycled everything and was sitting on 44.5 charge voltage at around 9 amps. But just made an executive decision and hooked up the old power wise. It is charging at 44.4 and about 9 amps. Gonna let that run for a while and see what happens. Just frustrated. This was supposed to be easy peasy and I have pretty much killed the cart use until it is done. I did however check the batteries with no charger after say 1/2 an hour and had 6.4 on each with a 38.4 pack..

Thanks all and I will keep after it.

JohnnieB

I didn't have to turn in my old batteries as cores, so I charged my new batteries before I put them in the cart.

Only letting the batteries rest for a half hour won't tell you much. Instead of waiting about 12 hours, you can burn off the surface charge by driving the cart for about a mile and then waiting about a half hour. That will give you a fairly good SoC estimate.

Since the DPI float charges, that is how I do it when I want to get a really accurate starting SoC for checking my cart's "Fuel Mileage" (kW/Mile).

BTW: There doesn't seem to be very much energy in the surface charge.
I've used whatever the voltage is fresh off float charge as 100% SoC for the start SoC, while at other times I've burned off the surface charge as described above and end up with about the same kW/Mile either way.

kgsc

Well, it is still pulling 8 to 9 amps but going to let goes till it finishes or blows up or maybe the battery store will be open tomorrow and will pay them a visit and let them load test them.

kgsc

Well, the standard power wise shutoff but was still at close to 10 amps. Tried 1 more time and did the same thing after about 30 minutes. Had 40.4 volts on the pack and took it out for a 3 mile spin. 38.4 after that. Gonna run it to 75% soc and start charging again..