48v Charger in Flames

[Ericfrickey]

I need a link on how to wire a plug on my charger
and how to wire it to my batteries. This is my first ebike build. I bought a 48v 1000w hub motor kit off ebay. And I just caught my charger on fire.

I bought 4 - 12v 25ah lead acid batteries and ran them in series to achieve 48v.

My problem is I have no idea how to charge them. What I did was I bought a 48v charger and cut the plug off. I put electrical connectors on the hot and neutral wires and ran the hot to my first battery positive terminal. I ran the neutral to the last battery negative.

When i plugged the charger in it immediately caught on fire. Yea, I feel dumb.

[max_volt]

Golf cart charger?

[powell]

China brand ebike kits are notorious for weird colour wires on chargers .
ON OUTPUT:
So weird - the use brown wire as PLUS wire
" I run the neutral to the last battery negative.." - quote
I am seeing it right????
you connect 120V neutral to the battery terminal???
Neutral in electrical standard means 120V NEUTRAL in NAmerica.
HOT means 120V phase hot in NAmerica.
or you call NEUTRAL minus ???
DIY ebike require some electrical knowledge, otherwise leads to disasters.

[Ericfrickey]

I'm ashamed to admit I never looked to see if it came with a charger. I assumed it did not since I had to supply my own batteries. I will look this evening.

[Fred]

I need a link on how to wire a plug on my charger
and how to wire it to my batteries. This is my first ebike build. I bought a 48v 1000w hub motor kit off ebay. And I just caught my charger on fire.

I bought 4 - 12v 25ah lead acid batteries and ran them in series to achieve 48v.

My problem is I have no idea how to charge them. What I did was I bought a 48v charger and cut the plug off. I put electrical connectors on the hot and neutral wires and ran the hot to my first battery positive terminal. I ran the neutral to the last battery negative.

When i plugged the charger in it immediately caught on fire. Yea, I feel dumb.

Here's my thoughts for what they're worth:
1. Bulk charging of 4 SLA's in series is quite common, especially with electric scooters that often use SLA's.
2. The charger will have a +ve and -ve output which should be connected to the corresponding +ve terminal on the 1st battery in the string and the --ve terminal on the last battery in the string.
3. It sounds like you did that and I assume you checked the polarities and voltage on the charger side
4. The chargers for "48V" lead acid are different than the chargers for "48V" lithium or "48V" LiFePO4. The voltage on none of them is actually 48V -- it is somewhat higher, especially the LiFePO4. Also the profile of what they do as they approach full charge is different.
5. So you may have been using the wrong charger or maybe it was defective.
6. As an aside, 4 x 25ah lead acid batteries weigh a lot! Are you using them on a bike? That's a lot of weight to lug around.

Hope this helps.

[Ericfrickey]

The batteries are heavy and they are going on a bike.

[powell]

there are even worst China brand 'standards" - they use female, sometimes male standard North American 120 V plugs as BATTERY TERMINALS - all most criminal in my view.
well on eBay is free for all, everything goes China crap.

[powell]

Fred,
read his post
he said he connected "hot" to battery positive terminal
IN any NAmerical electrical code "hot wire" means 120V phase wire.
IN any NAmerica electrical code "neutral wire" means 120V neutral wire.

[Ericfrickey]

That's correct. So how would that connect to a battery? And should it not be 48v output since it's coming from a 48v charger?

[JPLabs]

Hot and Neutral would be the power into the charger from A/C circuit. It sounds like you connected those leads to the DC battery instead. Agree, picture needed.

Also, using + on first battery and - on last is critical. 4 in series. If you do the opposite, you only have 2 in series. That would be only trying to charge the middle 2 packs, 24V worth. Also would cause trouble. Not sure you didn't do that...

[powell]

Ericfrikey
can you post pictures of charger and battery it would make advice so much simpler.