Small portable fanless charger for a 48v ping pack?

[mingonn]

Hi all,

I have a 48V 4ah v2 ping pack (400 km and going great) and would like a small 240v backup/topup charger to carry around. The stock 2A chargers are fine at home but bit chunky and fragile for life on the road. Fan is a bit too noisy for the office too.

From what I understand the stock charger just pumps out around 61v at 2 amps until the BMS open circuits when the cells reach the cut off voltage. Is this the case or are the chargers a bit smater?

It might be a bit simplistic but would something like this work with a laptop power supply?

http://cgi.ebay.com.au/12V-to-24V-D...yZ100184QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Derek

 

[ejonesss]

me i wouldnt worry about fan noise unless the fan motor is going bad and squealing or you have several chargers going and the fan noises get out of phaze.

 

[dogman dan]

Just get another cheap sla charger. If it has a fan, pop it open and unplug the fan, and maybe drill a few extra vent holes in the case so air can rise up out of the top of the case. The charger won't fry in a cool room if air can flow in and out of it easy. I've got about 90 cycles using nothing but sla chargers on my ping pack with no problems. All it does is undercharge it a half a volt or so. If you are worried about balancing, you will still get it every other charge with the lifepo4 charger at home. I keep thinking I'll need to get another charger from Ping to keep my pack balanced, but the dang thing won't get unbalanced! So I put it off another month. The reason my ping charger fried was my fault.

 

[ping]

Hi,

From next month, our 48v charger will be upgraded to smaller and more quiet, just like a power supply for laptop computer. However, there will be still a fan.

Of course, we will sell it on our coming web store.

Ping

 

[nicobie]

Hi,

Of course, we will sell it on our coming web store.

Ping

Two things...

First, I'm really glad to hear about the up coming store. No use letting ebay and paypal make money off of your sales if it is not necessary.

Second, Nice to see a manufacturer answer questions about their products in these forums. It adds a lot to their credibility and makes one feel more comfortable when ordering from them. In fact, I need to send you a email asking about making a 48v/20Ah pack that is split into two pieces so as I can put them in both sides of my saddle bags.

It would be nice if GM answered questions asked here. *hint* *hint*

Nick

 

[mingonn]

Great to hear about the store and the charger Ping, look forward seeing all the goodies.

Do you think it is OK to disconnect the fan in my current 2A charger? Ambient temp here in the office never gets above 25 C.

 

[Pete]

Great to hear about the store and the charger Ping, look forward seeing all the goodies.

Do you think it is OK to disconnect the fan in my current 2A charger? Ambient temp here in the office never gets above 25 C.

Ping is obviously your authorative advice, but the fan on my 24v charger has begun to not spin when power is applied. If I blow through it to get it started it continues to run. Anyway, when it first happened my battery had been on charge for about half an hour. When I noticed the fan problem the charger case was very hot to the touch. Once I kick started the fan the hot air exhaust was hair dryer hot for the first few minutes.

I now stand my charger on it's end with the fan on top such that convection airflow will help cool things if the fan decides to stop after I kick start it.

In the process of converting to 36v so the problem will go away with the new charger

 

[mingonn]

That sounds like alot of heat Pete, might crack the case on my home charger and have a look if there is a spot for a heat sink.

 

[Pete]

That sounds like alot of heat Pete, might crack the case on my home charger and have a look if there is a spot for a heat sink.

I wouldn't bother. The current heatsinking is perfectly adequate for the job. With the fan running I can barely feel any heat rise in the exhaust air. The only reason it got that hot was because the fan never started spinning and when the charger is laying flat there is minimal convective airflow.

I posted it mainly to trigger others to check their fan's actually start spinning. My fan has always been silent so I had no clue it was a bit sticky.

 

[mingonn]

Thanks for the info Pete, will look at imporving the cooling and disconnect the fan. Will stick a thermocouple in the housing to see what happens.

 

[dogman dan]

My soneil 36v charger has no fan, and I charge in a pretty warm place, the garage. Drilling some quarter inch holes in the case really helped it cool off. The vents in the case were pretty small, not good enough for New Mexico.