E-Max charger failure

Hey Starvid,
I don't know about Emax, but I had the same problem with my 48 Volt Smart Charger, the Batteries might be too low for the Charger to kick in.

I had to charge each individual 12 Volt up to about 12 volts, and then use the 48 Volt Smart Charger. I used a 12V/1500mA AC-to-DC Power Adapter and a Hobby Power Leads Adaptaplug and several small alligator clips.

It's also a good time to see how unbalanced your Batteries are.

Peace Out,
Gman

Now that we have clarified our beliefs, your invited to join us as we begin building on them to define our Community Mission Statement

The e-max charger has a logic circuit that requires a minimum battery voltage to initiate charging, but I'd think this voltage would be pretty low. As Gman wrote, you may need to charge the batteries individually with a cheap 12 volt charger...

But then the question becomes, how did you pack become so discharged? I've left mine sitting for more than a month in temperatures as low as -20C with very little discharge.

And, if has become so discharged (presumably less than 10 volts per battery) then, sorry to say, the batteries are probably ruined. So much for those "silicone" batteries - one more product of Chinese-style free enterprise....

...and I would not normally use both chargers - such rapid charging is never good for the batteries - regardless of the claims made by e-max - who were, in turn, taken by fraudulent claims by the Chinese battery manufacturer "guineng".

The silicone batteries can be replaced with lead acid batteries of comparable battery dimensions and capacity. You will get comparable or better performance. Because of unavoidable variability in eight batteries taken from stock, I consider using battery balancers like the "powercheq" or "smartspark" to be mandatory in a replacement battery pack. The batteries should also be rewired into four pairs-in-series, rather than strings of four in parallel. I recommend BB battery model EB20-12. So far, my e-max is running fine on these, but I haven't ridden it more than 15-20 km on a charge yet.

Actually, it's pretty easy for the batteries to lose all charge. All it takes is a VERY small unswitched load, such as a "battery low" LED, left on for months. Let us know if you get them off zero volts!

As PJD said, buddy pairs are the best way to hold eight batteries, though you want to make sure each pair is equally loaded, with one lead to the rest of the pack frm each battery of the pair.

Battery balance is also important, and Powercheq's are one way to do this. You can also use four 12V chargers in parallel, or a series/parallel switch arrangement.

Mark

Why would you mix batteries? The pack is only as good as the lowest common denominator, in this case 10AH. Because your lowest common denominator is 10AH you can only use 10AH to match it from the 19AH batteries so your total AH rating in this configuration is 20AH. This means you can only get 10AH of useful power at 50% discharge. If you just use the 19AH batteries you can get 9.5AH at 50% discharge and carry less weight. Using only the 19AH batteries will save money and with the weight savings you should get about the same range with better performance.

I have always been told "Never mix batteries".

ILBCNU
V is for Voltage
Moderator Captain

"What technical specifications of the batteries are important, which should I control?"

Well, obviously they have to fit in the scooter. The e-max has very specific places for the batteries, so there is not much room for improvisation. Obviously you are looking at the 181 x 76 x 167 mm, 6.3 kg, 80-413 (298,00 kr) which should fit perfectly. Second attribute to look for is if they are made for deep cycling (they seem to be) and are made for installation in a vehicle - with regards to vibrations etc. (seemingly yes, that as well). Thirdly when comparing performance, you need to look at the capacity at the expected discharge current. In the case of the e-max that is around 40 A, or 20 A per string, with peaks up to 72 A (36 A). The specification says the capacity at 18 A is 8.1 Ah. That's not great, but at least it's honest. The best comparable batteries could give 12 - 15 Ah when discharged at 18 A. So don't expect great range if installing these batteries (8 of them). Otherwise they are a perfect fit. (Other parameters such as charge voltage and current should be checked as well but they are similar for most of these batteries. Should be OK in the e-max.)

Best regards,
Rolf

There's a long thread about e-max batteries and recommended replacements.

If it is really an e-max 1500 and not some clone or modified unit it should have space for 8x20 Ah batteries, 181x76x166 mm and about 6.5 kg each. You can verify this by lifting out the seat and the "bucket" beneath it, and see for yourself. Only need to unscrew three screws, takes a few minutes. (The complete manuals can be found here.)

The biltema batteries will fit and it will work, but range will be limited, a lot worse than with the OEM units. You'll be the judge if you can live with replacing the batteries after 250-550 cycles, depending on how deeply you discharge them. Also count on that the listed cycles are measured in lab environment, in room temperature, and with low discharge current. Real world number of cycles will be a lot less. So I guess it depends on what you need. If you use the scooter daily, for 20-30 km trips or more, avoid biltema and expect to pay around twice as much for a set. If you'll only drive a few km on sunny Sundays, biltema batteries should work fine.

The e-max chargers are labeled "10A" but deliver around 6 A each, or maybe a bit more at the start of the charge when battery voltage is low. With two chargers that would be more than the 5.4 A recommended by biltema. One charger should be fine.

However, remember that the charging current is divided between either two series-strings in parallel in the factory setup, or divided between parallel-pairs in the "improved" setup. So, assuming even a 10 amp charging rate, this is only 5 amps per battery, so the e-max charger is OK.

The recommended re-arrangement of the batteries, with the powercheq battery balancers if you can find them, is shown here:

PJD:
Will your battery wiring diagram work without the powercheq's? I've installed the lead acid batteries you reccommended, but I wanted to be sure that your diagram would work w/out the PCHqs before I attempted it. Thanks for all the help!

It will work without powercheqs. The original pack didn't have them.

But, I had figured that the battery packs was originally assembled with batteries that were tested and matched for similar performance, or the pack was made batteries of the same lot numbers or sequential serial numbers to increase the chances of consistent charge/discharge behavior between each battery in the pack.

This stuff is standard part of QC if you are a manufacturer. But it is difficult for a retail buyer to do it, so I figured the use of powercheqs takes on additional importance for a home-assembled battery pack.

The manufacturer of powercheqs is here:

http://www.powerdesigners.com/powercheq.htm

And another product that seems to be an improvement over th powercheqs here:

http://www.smartsparkenergy.com/prod_batteq.htm

You would think that some sort of battery pack equalizer product would be available in Europe. Have you tried an internet search?

But absent powercheqs, you may want to check the batteries for serial numbers, lot numbers, or date/time stamps on the case. Hopefully, they were manufactured on the same production line and same shift.

Please be aware the PowerCheqs must be disconnected when the batteries are in storage. They will continue to balance the batteries right down to 2-volts. This in itself will cause a stored pack to discharge faster than normal.

When storing lead acid batteries it is a good idea to give them a charge about once a month. I plan to disconnect mine, then using simple jumper wires connect them in parallel and use a 12-volt battery minder on them. I have a battery minder on my backup generator which keeps the starting battery charged and ready for use at all times. The battery on my generator is 7 years old and still starts the generator every time. The battery minder has been on the battery from day 1 and has never been disconnected.

Chas S.
My Bicycle Pages

My e-maxs were left up to a month and a half without charging and the powercheqs connected last winter. They had discharged only a small amount - less than a half-hour recharge needed to top them off.

PJD,

I am glad you were much luckier than I. My batteries were in storage for about 3 months and now they are junk. They were new last year at the beginning of the summer and still had lots of life when I parked the bike at the end of the riding season. I only got 137 cycles from them last year, according to my DrainBrain, so they should have been good for at lease another season. My other bike has no PowerCheqs and it batteries made it through the winter without loosing much charge like yours. Those batteries are 3 years old and have about 60 to 80 cycles and still going. Both bikes use the same 12-volt 12AH bricks in a 36-volt configuration. The only difference are the PowerCheqs.

One other note for all - The bike with the PowerCheqs defiantly has the better performance in both range and power.

Chas S.
My Bicycle Pages

` :?
Why not purchase the B&B Batteries EB SERIES for Mobility Wheel Chair, Scooter & Bicyclies?
I just purchased four EB12-12 locally for $122.56.
CSB also has a EVH 12150 12V 15AH Battery that the specs look good, but I don't know that much about there Batteries. Since they are also available locally, I might try out a set for a backup pack latter.

Peace Out,
Gman

Now that we have clarified our beliefs, your invited to join us as we begin building on them to define our Community Mission Statement

These batteries are not as good as the EB20-12. The cycle life is at least 50% worse and the price they quoted you is quite high. The EB20-12 has a 50% DOD cycle rating of 800 while the BP18-12 only has 400. It only weighs 13.56 lbs compared to 14.22 lbs for the EB20-12 which is likely due to thicker lead plates that will probably hold up to EV usage(abuse) much better. Make sure that you get the bolt terminals and not the faston connectors. You can probably beat their price by alot on such a general purpose 18ah SLA battery online even after shipping on ebay (search rbc 11) or at vendors like batterygiant and still get a 1 or 2 year warranty. At that price the EB20-12 at places like electricrider, thunderstruck-ev, or batteryplex will cost only a little more than the BP18-12.

`
B&B Batteries EB SERIES for Mobility Wheel Chair, Scooter & Bicycle Spec Sheets
I noticed that, but the EB20-12 would not fit in my under foot Battery Compartment.

Peace Out,
Gman

Now that we have clarified our beliefs, your invited to join us as we begin building on them to define our Community Mission Statement

BB also makes a "EVP" series which have exactly the same performance as the 'EB" series. They have been on the market longer and might be more available.

Any prospects of mail or internet ordering from a dealer elsewhere in the EU?