Need help: E-max amperage

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stockdoct
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Joined: Thursday, May 10, 2007 - 17:59
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Need help: E-max amperage

Take pity on me. I bought 2 e-max scooters. They actually both run reasonably well, but the chargers have almost all died. I had 4, now down to one, so I checked out "electricscooterparts.com" and ordered a charger, in case my last one blows.

E-max chargers are 48 Volt, 10 A ....... and the largest charger the store had was a 48 Volt, 2.5 A. Its about half the size of my original charger.

Can I use it?? Will it charge my scooter, only more slowly, or will my battery explode if I plug it in? I don't know squat about Amps and would hugely appreciate your knowledge

Mike

jbird
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Joined: Saturday, January 20, 2007 - 08:33
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Re: Need help: E-max amperage

Don't waste money on junk chinese chargers. They often have higher than recommended voltages and poor reliability as you have discovered. On top of this most online sellers know this and quietly only offer about a 2 week warranty on this crap. You can get a soneil 48V 3.5amp charger that has a real warranty online under the brand name or the rebadged battery sentinel version. If charging time is crucial two would work in parallel. BTW the stock E-max charger is rated less than 10 amps. It really only puts out 5-6 amps if I remember correctly. You will need to check polarlity and install your own connectors on the chargers though. I speak from experience as I had a replacement 4.5amp charger that lasted 2 months and would cause my batteries to vent in the summer heat.

PJD
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Re: Need help: E-max amperage

Most e-max chargers can be repaired and made into reasonably good chargers with the replacement of a couple key components and the addition of some provisions for extra cooling: You need to do the following:

1. The "NTC 5C" inrush supressor always fails sooner or later. This is almost always the cause of a dead charger. Replace it with a Thermometrics CL-40 inrush supressor.

2. The two 470uF rectified-output filter capactors, are cheap-chinese and overheat and fail due to inadequate ripple current rating. The symptom of this failure is a slow fan speed and abnormally slow charging rate.

These capacitors should be replaced with better quality 680 uf 200V high-ripple capacitors, I also add parallel .39 uF polyester film capacitors to each of the big capacitors. (they fit on the underside of the PC board with addition of stub of wood dowel next to them to prop the board up a bit).

There were some chargers in the Jan '06 shipment with a slow fan speed of unknown cause - some were also missing the thermal protection switch, had incorect power-cord polarity and other forms of incedibly poor Q/C, but these are less common. I have some ideas for a work-around for the slow fan.

3. Drill three or four holes, at least 1/4" in diameter, on either side of the indicator lights (near the ends of the heat sinks) on the front face of the charger to improve cooling.

4. Cooling fans sometimes fail. They should be replaced with a ball-bearing type of comparable wattage.

Links for buying the parts:
http://www.mouser.com/search/ProductDetail.aspx?R=527-CL40
http://www.mouser.com/search/ProductDetail.aspx?R=5985-380-200V681
http://www.mouser.com/search/ProductDetail.aspx?R=5989-250V.39-F
http://www.mouser.com/search/ProductDetail.aspx?R=433-BP501012H

Considering the kind of summer temperatures the southern tiers of US states get with increasing frequency, I can't guarantee these fixes will always work down there if you are regularly charging in the mid-day heat - I thing these are a pretty clear-cut case for putting the blame on global warming. My fixes worked fine through last summer in westerm Pennsylvania.

If you don't want to do the work yourself, i have been offering to fix these chargers for a flat $25 per charger including return shipping. I am strictly doing this as an amateur and promise no warranty or delivery date. PM me if you are interested.

Since this is an important issue, I will re-post a discusson of e-max charger reliability issues under a separate topic.

andrew
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Re: Need help: E-max amperage

stockdoct, I have a Soneil 48v 3.5a charger that has not been used more than a few hours. I purchased it about a yr ago. $150 w/shipping if your interested.

---
Avatar taken from http://www.electricmotorbike.org/
Anyone got one they might want to sell?
My KZ750 Project: here E.T.A. 1 mo

[url=/forum-topic/motorcycles-and-large-scooters/587-my-kz750-electric-motorcycle-project]KZ750 Motorcycle Conversion[/url]
[url=/forum-topic/motorcycles-and-large-scooters/588-fixing-my-chinese-scooter]900 watt scooter[/url]
Pic from http://www.electri

PJD
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Re: Need help: E-max amperage

Or, to make my previous post more concise and less technical, don't throw out your inoperable e-max chargers - they can easily be repaired and made relaible.

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