Mixing BB EB20-12's with E-max Silicones - Problem...

15 posts / 0 new
Last post
PJD
PJD's picture
Offline
Last seen: 1 month 2 weeks ago
Joined: Wednesday, November 22, 2006 - 05:44
Points: 1416
Mixing BB EB20-12's with E-max Silicones - Problem...

Well,, I just replaced half of my silicone battery string with the BB batteries - the No. 2 and No. 3 "buddy" pairs being the BB's. I am having some problems.

Charging the half-new pack resulted in the powercheqs working awful hard. So, checking the charging with the powercheq's disconected yielded 16.2 volts for each of the BB's and about 13.9 volts for the silicones during equalization charging, and about 14.4 volts for the BB's and 13.6 for the silicones during float.

16 volts is well into the gassing range - not good for the new batteries at all.

What is happening here, that the total bulk-charging voltage (59.5 to 60 volts) is disproportionately going to the BB bateries?

I'm still looking into the problem, but for now, the BB don't seem to be bulk-charging compatable with the silicones. But, I think by buddy-pairing the BB with a still-good silicone battery, and using the powercheqs, the condition will be tolerable.

Any ideas? Thanks!

NickF23
Offline
Last seen: 10 years 5 months ago
Joined: Saturday, November 18, 2006 - 10:25
Points: 184
I'm not 100% sure I

I'm not 100% sure I understand your battery array. If you have differing resistance batteries in a series string then the voltage going to each battery will be different. The batteries with the higher charge resistance will have a higher voltage. For the basic electronics see "resistors in series" on this page http://www.play-hookey.com/dc_theory/series_resistors.html. Hopefully someonce will come along with a greater knowledge of lead batteries and answer your question. Are you sure that the batteries were roughly at the same state of charge before charging? If one set had a lower discharge resistance, then they would be doing all the work and would be at a lower state of charge before you plug in the charger.

PJD
PJD's picture
Offline
Last seen: 1 month 2 weeks ago
Joined: Wednesday, November 22, 2006 - 05:44
Points: 1416
The probelm

It is eight batteries - four pairs in series, two of the pairs being the new SLA's, and so basically a series string. I likewise suspect that the conventional SLA mist have a higher charging resistance than the silicone batteries. Likewise when discharging, the voltage sags more on the sLA's than the silicones.

The importance of this is that although the guineng silicone batteries used in the e-max seem to have been made under poor QC with a lot of defective batteries. They seem to have some superior characteristics. But as far as I know, silicone batteries are no longer available unless you are willing to import a bunch of them from China.

So, I was hoping that, as individual batteries go bad, they could be replaced with SLAs. While there are probably workarounds, it looks like e-max owners might have to replace all eight silicones with sla's as soon as the first one goes bad - Here on the east coast, if you want to replace them with BB's that is a >$550 expense when shipping is included.

chas_stevenson
chas_stevenson's picture
Offline
Last seen: 8 years 1 month ago
Joined: Wednesday, December 6, 2006 - 17:14
Points: 1309
E-max Silicones

Paul,

Have you thought about selling the good batteries on eBay to another E-max owner with the same problem? This would help the wallet and might save a few dollars for the Lead.

BTW Mixing battery types in a string is never a good idea when charging but will work if they are discharged in parallel.

One other thought - if you isolate the 2 strings and charge them with 2 different charges they should run in parallel with no problem. Another charger would cost less than 4 more batteries. You would only need to disconnect one end. The only problem with this is the Powercheqs you are using will not work with both strings. Maybe not such a good idea after all.

Good Luck,
Chas S.

NickF23
Offline
Last seen: 10 years 5 months ago
Joined: Saturday, November 18, 2006 - 10:25
Points: 184
like you say, try using one

like you say, try using one SLA one Silicon for each parallel array. Then try charging and see what happens - make lots of voltage readings so nothing goes wrong.

On discharge strange things are going to happen, the lower resistance batteries will do more work when you accelerate but when you release the throttle energy will flow back to them from the high resistance batteries. Its a bit of an experiment but better than your current setup. See if you can find a discharge chart for both batteries and then you can guestimate what happens.

PJD
PJD's picture
Offline
Last seen: 1 month 2 weeks ago
Joined: Wednesday, November 22, 2006 - 05:44
Points: 1416
...

Actually I already have a second scooter still with all good silicone batteries - so I'll be saving any good batteries for it.

Giuneng has some discharge curves - all captioned in Chinese. I am bench-testing (at about 5.2 amps) the four replaced silicones as I speak, so far, only one is obviously bad one.

PJD
PJD's picture
Offline
Last seen: 1 month 2 weeks ago
Joined: Wednesday, November 22, 2006 - 05:44
Points: 1416
e-bay?

Actually e-max owners are such a tiny community, e-bay will not be such a good way to go. I'll use this forum or the e-max forum wwwemaxscooters.com, which for some reason is still being kept up by Larry Malz, who owned the now-defunct e-max distributorship in the US. His Texas-E-rider business is likely going down as well...

chas_stevenson
chas_stevenson's picture
Offline
Last seen: 8 years 1 month ago
Joined: Wednesday, December 6, 2006 - 17:14
Points: 1309
E-Max owners

I almost bought an e-max just before they went away last year. I just didn't have the extra cash at the time or I would be part of the small group of owners too. I even had setup a time with a dealer and test drove one of the sport models. I thought it was a nice ride but I was not completely convinced to buy. I was going to go back to the dealer with my Merida and ask the owner to let me compare the 2 rides. The only advantage the e-max had was distance and comfort. I think the Merida might have the edge on acceleration but the e-max might have had a few more MPH. I didn't get a chance to find out. I hope the new version is around soon.

Chas S.

davew
davew's picture
Offline
Last seen: 3 years 8 months ago
Joined: Monday, November 20, 2006 - 20:13
Points: 85376
Which model of BB?

What was the part number for the BB batteries you used? I'll be looking into replacement soon and the fear of picking the wrong size or the wrong terminal type or the wrong color is causing me, well, great fear.
--
Full time ebiker
BionX and Wilderness Energy

"we must be the change we wish to see in the world"

rgx
Offline
Last seen: 10 years 3 months ago
Joined: Tuesday, November 21, 2006 - 13:01
Points: 137
Don't we prefer EVP20-12

I haven't replaced mine myself, but people used to refer to the EVP20-12 as the replacement battery of choice for the e-max. The EB20-12 (in the thead title) have the same dimensions and will fit physically. BB's homepage says the EB series is for "mobility use", and the EVPs for "high power, high cycle use".

The e-max OEM batteries are 181x76x166 mm, and here's the link to BBs home page again
http://www.bb-battery.com/productsevp.asp

Regards,
Rolf

JDELUNA
Offline
Last seen: 4 years 5 months ago
Joined: Tuesday, November 21, 2006 - 05:39
Points: 230
How about these ???

These seem to be the same dimensions as the STOCK EMAX battery but has much more capacity. Instead of 20AH it has 26AH. Please let me know what you all think. God Bless :)

http://www.batteryspec.com/ecomm/cart.cgi?action=link&product=26

chas_stevenson
chas_stevenson's picture
Offline
Last seen: 8 years 1 month ago
Joined: Wednesday, December 6, 2006 - 17:14
Points: 1309
Here are the discharge

Here are the discharge charts for both and they look very close to me. I do not see an extra 6AH for the extra $30.00 in price.

eb_20_12_chart.gif

Chas S.

PJD
PJD's picture
Offline
Last seen: 1 month 2 weeks ago
Joined: Wednesday, November 22, 2006 - 05:44
Points: 1416
My results....

I ran tests on my worst-four silicone batteries from the pack, I also tested one of the new BB batteries. The BB tested at 17.2 AH, at a bit more than 5 amps - pretty good for C/4.

The BB battery might be a pound lighter each compared to te silicones, so they will save the scooter a bit of weight.

The old silicones ranged from 6.0 to 11.7 AH - only one I would still call "good" at 15.7 AH - but then again they had 200 or so cycles and almost 3000 miles on them...

rgx
Offline
Last seen: 10 years 3 months ago
Joined: Tuesday, November 21, 2006 - 13:01
Points: 137
The BAB26 seems to be a starter battery?

Since the text says they are for motorcycles, snowmobiles and jetskis, I guess they are not made for deep cycling. You would probably want to look at these instead (from the same site)
http://www.batteryspec.com/ecomm/cart.cgi?action=link&product=68
But as Chas said, the capacity is basically the same as the BBs if you study the discharge diagram.

PJD
PJD's picture
Offline
Last seen: 1 month 2 weeks ago
Joined: Wednesday, November 22, 2006 - 05:44
Points: 1416
As far as I can tell from

As far as I can tell from looking at their respective datasheets, the EVP series and the EB are identical in performance but the The EB's are being specifically marketed for scooter use - look here:

http://www.bb-battery.com/productpages/EB/EB%20Series.pdf

I think either are fine, so the decision should be based on cost and "freshness" - i.e time spent in the (possibly very hot in summer) warehouse or shipping container since manufacturing. The EB's, being a newer model, are more likely to be fresh.

Log in or register to post comments


Who's online

There are currently 0 users online.

Who's new

  • skler
  • Jim Caudill
  • nikity
  • slartsa
  • olivergeorge

Customize This