DPI 48 volt charger shutting off too soon?

[tomtt2]

CGTech,

Interesting changes in charger function. I changed the jumpers to Mode 1 which is listed for US Batteries. The voltage started at only 51 VDC, which had me worried, but has climbed to 61 VDC as the charge cycle has continued. I think this is what the Crown batteries are needing. It will be interesting to see what the float voltage turns out to be.

Tom T

[tomtt2]

I've contacted the support folks at DPI trying to determine what jumper setting on my DPI 48014C19-005 charger are the best match for my Crown CR155 batteries. The response was that "this older charger does not support Crown batteries directly". I'm not sure what "directly" means. I did notice that the newer 48V DPI Accusense Charger Model 48C017E18-00 does have a mode specifically for Crown batteries (Mode 4 on the new charger). I've asked the DPI folks if they could let me know which mode on my older charger best matches the Mode 4 on the newer charger. No response yet. So if anyone knows anything about the charge profile in Mode 4 on the newer DPI charger, I would appreciate the information.

[tomtt2]

Update: I set the charger mode to Mode 1 (US Battery profile) and started the charge. After 6~7 hours on the charger, there was a good deal of gassing of the batteries, but the charger never flipped over to the 95% charge phase (orange and green LEDs). I finally pulled the charger plug before going to bed. I didn't want to fry the batteries over night. I checked the specific gravity in the morning and all cells were up to 1.275 indicating a full charge. I don't know why the charger never completed the normal cycle.

Today, I put the jumper in to the Mode 2 position (J3 jumper). The charger went through its initialization then quickly went to the solid green LED indicating a full charge.

Tomorrow, I'll run the cart for a while then try the Mode 2 charge profile. Afterward, I'll check the specific gravity to see if Mode 2 leads to a full charge. I'll post my findings.

I liked the charge voltages I was seeing with the Mode 1 profile, but got worried about charging taking so long and never reaching a full charge point or even 95%.

If I try Mode 1 again, I plan to put a thermometer in one of the cells to check the electrolite temperature and keep it below 125 F/.

[tomtt2]

I'm currently back to trying the Mode 1 charge profile. I put a thermometer in one of the cells to monitor battery electrolite temperature. I don't want things go go above 125F, but so far after a few hours of charging (and gassing) the temperature is still below 100F. Hopefully, the Mode 1 profile will complete and I'll see the solid green light before long.

[tomtt2]

The Mode 1 charge cycle finally completed. It took about five hours. The charge voltage was 61.5 or so and there was a noticeable amount of gassing. I monitored the battery electrolyte temperature during the charge cycle and it climbed to about 98F (well below my 125F limit).

The Mode 1 charge profile is noticeably more aggressive than Mode 2 or Mode 3 and (I think) packed more power into the batteries.

The float voltage is 52.4 which is very similar to what DirtPit HC is getting.

It will be interesting to rake a run in the morning and see what the battery drain vs mileage is like compared to the Mode 2 and Mode 3 charge profiles.

[TrickCart]

This is all really good and specific detailed info for those of us getting into this Hobby. Please continue updating this thread!

[tomtt2]

I did get a chance to take a spin this afternoon. Drove about 3.5 miles at around 15~19 MPH. Based just on the little LED meter on the cart, I only dropped one bar. Normally, on this route I'll drop two bars by the time I reach home. I know there are a lot of variables, so this is only a anecdotal account. Tuesday, I'm playing at a course that is about 3.5 miles from home. With 18 holes, I will log about 16~19 miles round trip. That should be a better indication of battery range using the Mode 1 charge profile. Hope it gives a little more range.

[tomtt2]

Recharging after a 3.5 mile trip took approximately 4 hours with a voltage of around 61.4 VDC. While the recharge time seemed a bit excessive (considering that the battery meter on the cart indicated 80% remaining), I monitored the electrolyte temperature and never reached 100F so the high charge voltage and heavy gassing didn't lead to overheating. Tuesday, the long drive

[tomtt2]

Today, I drove to the golf course that is 3.6 miles from home, drove 18 holes then home again. The overall mileage was about 16 miles with speed ranging from 19~20 MPH on the streets and about 12~15 on the course.

The batteries were fully charged using the DPI charger on Mode 1. As noted, this charge profile seems to take a lot longer than Mode 2 or Mode 3 and there is a good bit more gassing of the batteries (although no overheating).

Normally, this run will take the batteries down to about 45~50% based on the little green LED bar indicator on the chart. I've made this run a number of times, so know the typical discharge.

Today, I made the run and reached home with over six bars left. I figure I had about a 65~68% charge remaining. This is a big increase from what I was getting using Mode 3 on the charger (the factory default).

I'm pretty impressed with the range of these batteries when they finally get a full charge. I was under the mistaken opinion that the "smart" charger just charged until the battery was fully juiced, but it seems that, depending on the battery manufacturer, different charge profiles actually have a big impact on range.

I still have not heard back from DPI regarding which charge Mode on my charger equates to the Crown battery mode on their newer chargers. It would be nice to confirm that Mode 1 is correct for these batteries.

If you have one of the older DPI 48 volt chargers (the one without a meter), you may want to look into which mode best matches your batteries. It certainly appears to make a difference in battery performance.

Thanks to all those who offered up advice and suggestions on this. I think I learned a lot in the process and have a better performing cart as a result.

Tom T

[tomtt2]

I've still got the DPI charger set to Mode 1. Charging typically takes around 4~5 hours to complete. I noticed that there was a lot of gassing during the charge and the battery cases got pretty warm. I began testing the electrolyte temperature (hope my wife doesn't need that candy thermometer). The temperature of the electrolyte has never exceeded the 120 degrees F mark, but gets close. I read that electrolyte temperature shouldn't be allowed to exceed 125 F. So far, it hasn't but it gets very close.

Does anyone have any experience with charging and electrolyte temperatures? Is allowing the temp to reach 120F on a regular basis when charging detrimental to the batteries?