[MemphisPapa]

Am I the only sucker on the forum to spend some money with BestGo and get taken for a ride?
I bought a 2000W charger that ended up defective. I was constantly told that the trouble was my CANBUS, but if i paid the freight to return the bad charger, they would send me a new charger. They sent me a used charger as a replacement that is clearly not functional. Now I wonder if this is all intentional to delay any warranty returns on my 160 Ah BestGo cells. After purchasing in Feb, I still haven't been able to charge the cells that struggled through Customs and received in July at 2.8V.

I want to know if I am the only sucker to have trouble like this or if this is normal for DIY regularEV'ers.

If anyone else is using BestGo batteries, please reply and let me know if I have anything to look forward to or if I made a horrible choice with the most dishonest company in China.

Thanks.
dh

 

[kennybobby]

...
If anyone else is using BestGo batteries, please reply and let me know if I have anything to look forward to or if I made a horrible choice with the most dishonest company in China.

Thanks.
dh

Sorry to hear about your troubles. i am helping a friend with his EV build and tested some of his Bestgo 100Ahr cells. He's using 44 to build up his pack to go into a Toyota Celica and is about 80% finished. They all came in at 3.355, which we later determined was OCV for a full charge. i was surprised that they would ship them fully loaded thinking it might be a safety hazard.

i built up a 12 volt battery using 4 cells and took them thru 2 complete discharge and charge cycles, and they were slightly better than the advertised 100 Ahr capacity. i didn't pull them below 2.5 and only charged to 3.65 using an adjustable power supply and monitoring temperature. After sitting a few days they settled in around 3.35.

Based upon our testing i don't think the cells would drop to 2.8 if they were shipped fully charged, so maybe they were shipped with a low SOC for safety reasons? i was so impressed with these cells during testing that i want to use them for my EV build after Paul completes his, but your story gives me pause.

As you probably already know, Jack Rickard is an EV battery expert just up the river from you in Missouri. i am over in huntsville and would be happy to help you get them charged and sorted out.

Do the plastic cases of the cells seem to be puffed out or are the sides all straight and parallel?

 

[MemphisPapa]

Thanks KB for your reply. I am building an AC system in a 82 Rabbit Convertible. My cells looked fine when I put them in the car. I have been charging them four cells at a time with a standard 12V charger @12Amps, but I have only gotten them to about 50% SOC (according to my Orion BMS). I am curious about how they will do in a full duty cycle. Another concern is the time frame of delivery. I waited a long time and through a lot of empty delivery promises that ended in a customs case in Memphis. They definitely didn't come to my door as promised. So far they have seemed okay, but I haven't really been able to test them and I haven't pulled them out of the battery boxes to check for bulging since I first put them in a few month ago.

 

[Ziggythewiz]

Just be sure to take them all up to the same voltage, then the BMS should be able to finish the balance for you. How high does your l2V charger go?

 

[MemphisPapa]

Ziggy, my charger has pre settings for standard lead acid, AGM, or gel. The highest I've seen is 14.1V, but I suspect that the current output drops as it approaches the 14V.

Having a drivable car with no charger really is frustrating.

 

[Ziggythewiz]

Mine goes to 14.2 (3.55 vpc) so that's as far as I took them for balancing. Plenty high enough for me or if you're using a BMS anyway.

 

[MemphisPapa]

Do the plastic cases of the cells seem to be puffed out or are the sides all straight and parallel?

I took these cells out to put them in parallel over the Thanksgiving holiday while I was out of town. I don't think the cells were bulged, but none of the sides are straight or parallel.
My cells are of the 160Ah variety. Maybe the 100Ah cells are better quality.
I read of others having cells that balance to ten-thousandths with no need for a BMS. I think it would have been smarter to stick with a more reputable company than BestGo. I'm going to discharge them down to around 2.9V and bottom balance and see if they stay within a hundredth for tolerance.

 

[kennybobby]

bottom balance

I took these cells out to put them in parallel over the Thanksgiving holiday while I was out of town. I don't think the cells were bulged, but none of the sides are straight or parallel.
My cells are of the 160Ah variety. Maybe the 100Ah cells are better quality.
I read of others having cells that balance to ten-thousandths with no need for a BMS. I think it would have been smarter to stick with a more reputable company than BestGo. I'm going to discharge them down to around 2.9V and bottom balance and see if they stay within a hundredth for tolerance.

We took all 44 cells down to 2.5 while under 60 amp load, then used lesser load to bleed them after they bounced back up. It definitely took awhile to get a feel for how much they would bounce after the sag under load. Got them in the 2.75 region by connecting all in parallel and pulling a 5 amp load, then let them sit for a couple of days. Disconnected and after several days they are drifting back up toward 2.8, but they are all the same voltage within 1-2 mv, and they are all empty at the bottom. Not sure that they will parallel balance without some sort of load to move charges around--the delta between cells nearly the same is too small for any useful current flow. Put the pack together but haven't charged it yet. Charging will be at 15 amps constant current until it hits 3.65 per cell, then adjust voltage to 3.65 /cell and monitor current to tail-off at ~5 amps. Will be counting and timing all the current to calculate Ahrs put in.

 

[onegreenev]

Re: bottom balance

You can parallel to get the bulk of the pack sort of in balance but you will need a tool to bring them all down to a matching voltage. I use the power lab 8. Works great.