Tidal Force S-750 Build by mikeross

Show off your Ebike creation here.
pvorlicek   10 W

10 W
Posts: 78
Joined: May 04 2009 6:55pm

Re: Tidal Force S-750 Build by mikeross

Post by pvorlicek » Jun 17 2010 1:28pm

frodus wrote:you mean peak at 3.65V?
Yes

pvorlicek   10 W

10 W
Posts: 78
Joined: May 04 2009 6:55pm

Re: Tidal Force S-750 Build by mikeross

Post by pvorlicek » Jun 17 2010 2:03pm

Mike:

See my latest battery post here:

http://endless-sphere.com/forums/viewto ... =6&t=19201

User avatar
mikeross   1 W

1 W
Posts: 50
Joined: Jan 25 2010 2:32pm
Location: Monmouth, Oregon

Re: Tidal Force S-750 Build by mikeross

Post by mikeross » Jun 28 2010 4:31pm

Wanted to put in an update on my Headway *experience*. I ordered 3 replacement cells from EV Assemble on June 11th, but they aren't here yet. My replacement 24v pack developed a nice bulge, so had to quit using it - that's ripped apart on my workbench now as well :( . In order to have something to power my new bike, I soldered some wires across the places where the bad cells were removed from my Headway pack and turned it into a 10s pack. What the heck, no reason it shouldn't work - kind of a cross between a 24v and a 36v pack. So far it's getting me around just fine. Once my cells get here, I'll put it back to a 12s pack (36v 10ah).

So, I decided to try the single cell charger directly connected across the individual cells again. For some reason, the cells were willing to take a charge this time....sheesh. Same charger, same cells, same everything. Different result. It is true that some of the cells accept a full charge to 3.63 - 3.65v then settle back to 3.4 or thereabouts. Some cells stay up around 3.5v. But they all would at least cycle the charger - by that I mean the charger light would turn red when first starting a charge, then would later turn green. The cell would then measure correctly at 3.63 - 3.65v. That never happened to most of these cells before - the charger light would just stay red seemingly forever. It makes me hopeful that they will settle down and be usable after some more break-in time. Or maybe somehow a bad cell was screwing up the works - I'll probably never know.

At this time, the Ping Signalab BMS is sitting on my workbench, and the balancing wires are routed out the back of the battery case so I can monitor each cell. In a normal day I only ride about 4.5 - 5 miles, so if I check each cell daily that should help prevent hosing off any more cells. I'll probably put the BMS back on once the cells settle down, and once I'm back to a 12s pack.

I'll try and post a few photos of my 10s battery soon.

Mike
Current bike: Tidal Force, 9C Rear Hub, Maybe a 36v 10ah Battery Pack

pvorlicek   10 W

10 W
Posts: 78
Joined: May 04 2009 6:55pm

Re: Tidal Force S-750 Build by mikeross

Post by pvorlicek » Jun 28 2010 5:38pm

Mike:

I'm in a very similar state to you. However, my single cell charger died on me ... and they are on backorder with Voltphreaks ... so I am just being gentle with my pack until I can get them to the same lever. I am going no more that 5 AH on the pack (50%) which is more than enough for my daily needs.

Good luck with the BMS ... I'll never go back to them. At this point, even if I got one to work, I would never fully trust it to be reliable and I would hate to get stranded somewhere and have to open up that pack.

User avatar
mikeross   1 W

1 W
Posts: 50
Joined: Jan 25 2010 2:32pm
Location: Monmouth, Oregon

Re: Tidal Force S-750 Build by mikeross

Post by mikeross » Jun 28 2010 6:08pm

Preston: Thanks for the information. I've got a Tenergy charger from Ebay - so far, so good, but without that I'd be up a creek. My bulk charger just would not charge up the pack, so I left it on for a long time (12 hours at least) and that's when I blew that one cell that is bad - at least that's what I think killed it.

For me, the verdict on the BMS is still out - it did cut out my pack - several times - and each time it was because of a low cell voltage. So, it was trying to work. At first, I blamed the charging problems on the BMS, but they continued even after it was removed, so the BMS was not the problem. I'll probably hook it back up once I get this pack working and see what happens.

From what I read of your experiences, it seems like the pack keeps getting stronger as it is used. I like your idea of 50% discharge - for starters. Then try for a higher discharge rate as the cells learn to work together better. At first, I was going for 70% and that was obviously too deep of a discharge.

Also, a Cell Logger would be a good thing to have. It is a pain checking each cell through the balancing plug, one at a time. I made up a little 2 pin, 2 wire device that connects to the balance plug, and that has helped out some.

My conclusion: These cells are weird. :roll: But they have lots of potential.

Mike
Current bike: Tidal Force, 9C Rear Hub, Maybe a 36v 10ah Battery Pack

pvorlicek   10 W

10 W
Posts: 78
Joined: May 04 2009 6:55pm

Re: Tidal Force S-750 Build by mikeross

Post by pvorlicek » Jun 29 2010 10:32am

Mike:

Yes, I am happy with the 48V pack that I use on a regular basis. I have more than 300 cycles on it and never had to do individual cell charges. Always on a bulk charger. I don't think I have gone below 60% DOD just because that is my commute and I am able to charge at my office. So, maybe I am not the best "tester" for these cells, but I am quite happy with them.

My beef with the BMS is that you have to be an EE (or spend alot of time) figuring out what is wrong. The big issue as I understand it is the FET's which switch the flow of current on and off. I am not knowledgeable to test to see if the FET is working or working properly .... and replacing one?!?!?! I just don't have the time ... and have not seen the benefit based on the way I use my pack.

I fought my BMS battles with a Headway BMS. One of the "fixes" was to reset the BMS by disconnecting it and letting it sit for 30 minutes. Ya sure!

I STRONGLY ENCOURAGE THE CELLOG. Hobby king has the monitor only for under $15 and you can buy the connector with 8" leads on Ebay for about $5. I love this little guy (I have 3).

I will follow your BMS progress. I'd really like to see you succeed with it as I feel it will be quite valuable if you need to get close to 100% DOD.

Preston

User avatar
mikeross   1 W

1 W
Posts: 50
Joined: Jan 25 2010 2:32pm
Location: Monmouth, Oregon

Re: Tidal Force S-750 Build by mikeross

Post by mikeross » Jul 12 2010 12:51pm

Time for an update. I'm still waiting on 4 more single cell chargers from Voltphreaks, and my replacement cell order has not worked out so far (I don't want to talk about it). Therefore, I currently have a 10s Headway pack, no BMS installed. I am discharging the pack 3-4ah only, then charging back up with a single cell charger. Some of these cells are taking more than 10 hours to charge up, I don't know why. Others will recharge in a couple hours (which is about what I'd expect).

Right now I've been reading a lot of threads on LiPO batteries. At first I did not want to go that way because of fear of burning down the garage and house. However, these cells don't seem nearly as dangerous as I first thought, and there just happens to be an old Weber kettle grill out back where I could charge them....hmmm. Also, it is fair to say I am thoroughly bummed with my LiFEPO4 experiences so far. My SLA powered LaFree has the charger and plug right on the bike. You plug it in, it charges the batteries - every year or two you replace the batteries. End of story. After spending at least $500 on my EV Headway pack, I've never gotten more than one 7ah discharge out of it. And, I've spent many hours tearing it apart, balancing, etc. etc. etc. Also, a used 24v 20 ah LIFePO4 duct tape pack I got from ES member Steveo gave me about 3-4 discharges to roughly 70% DOD before it developed a huge bulge on one side. (I was using this pack while working on the Headway pack.) So, I am not so thrilled with these things to this point. But, I'm just a bit discouraged, not giving up by any stretch. Once a stable pack is put together, charging, monitoring, and BMS issues have been ironed out, then the pack should be really nice - with long range, low weight, and many life cycles. In my case, that has not yet happened. It is really a great learning experience in the long run.

When I do get to ride my S-750, it is a nice improvement over my Giant LaFree. It is a lot of fun to ride and I like to go without pedaling sometimes. My goal is still to do 100 miles in one day before I turn 60 (> 1 year from now). I'm not limiting myself to one bike, one charge, or anything like that - 100 miles in one day, however I can do it is the goal.

Mike
Current bike: Tidal Force, 9C Rear Hub, Maybe a 36v 10ah Battery Pack

User avatar
ambroseliao   100 kW

100 kW
Posts: 1221
Joined: Apr 27 2009 3:34pm
Location: Washington, DC, USA area
Contact:

Re: Tidal Force S-750 Build by mikeross

Post by ambroseliao » May 12 2011 10:36am

Hi Mike,

Haven't heard from you in a while. Any news on your TF S-750 and the batteries? Have you tried to make your goal of 100 miles in one day?

Ambrose
http://www.ebikes.ca/ is the best!

TidalForce M-750X, Tidalforce S-750 with Crystalyte HS3540, 1x TF iO-X Cruiser. E+ 1000W hybrid bike. ebikes.ca DrainBrain & Cycle Analyst meters. GoPro HD Hero2 camera. Bosch Fat Packs, 37V 10Ah LiPO pack. Turnigy Multistar batteries
My blog: http://ebikerider.blogspot.com
Remember LiFEPo4 HVC is 3.65V and LVC is 2.7V

User avatar
mikeross   1 W

1 W
Posts: 50
Joined: Jan 25 2010 2:32pm
Location: Monmouth, Oregon

Re: Tidal Force S-750 Build by mikeross

Post by mikeross » Aug 28 2016 4:10pm

Hello Again, everyone. I have been off the list for a while! What I finally did to solve my battery issues was to buy a different 48v 10ah pack, and also put the 36v pack back together with no BMS, balance charging once in a while with the single cell chargers. Then went out for a ride on my bike - just got back! The bike has served me well and I commuted to work on it every day until I retired a few years ago. The 36v pack is now in the recycling, finally I just got tired of messing with it, and another cell or two went bad. I am in the process of "fixing" my 48v battery, for which I will start a new thread. The rear spokes are starting to pull through the rim, but other than that this bike is still ready to go! It was fun to look back and recall building this bike, plus all the issues both good and bad. Thanks again for all the advice!

Mike :)
Attachments
IMG_0909Med.JPG
IMG_0909Med.JPG (187.05 KiB) Viewed 863 times
Current bike: Tidal Force, 9C Rear Hub, Maybe a 36v 10ah Battery Pack

ElementX   1 W

1 W
Posts: 54
Joined: Jul 25 2009 12:16pm
Location: SoCal

Re: Tidal Force S-750 Build by mikeross

Post by ElementX » Aug 01 2018 5:11pm

S750 update?

I've been off the list longer than you were. I just dug out the S750 I put together like 8 yrs ago and was searching for info on what everyone else did with theirs. I bought a pair of frames from oatnet way back then and built up the silver frame. Still have the red frame lol.

Post Reply