Hello,
I would like to use a large 12V charger to charge my 4x12V battery string. This has many advantages : 12v charger are widely available and cheaper and balancing isn't a problem and I will be able to upgrade to 60V easily without need to get another charger.
So I'm looking for a convenient way to do this on my EVT. I think I have to find an high current 6 poles plugs or a strong toggle switch... The EVT controler is limiting current to 100A which is a lot. Any idea is welcome.
Jerome
I tried something like this on my charger bicycle. That is, have one 12v charger and charge the batteries in parallel. It's real tempting, automatically keeps the batteries in balance, etc.
However .. I suggest you draw the wiring. What I found is unless you disconnect the usual battery pack connections, when you hook up the 12v charger you'll see a short circuit.
What I do on my EVT is have multiple chargers. They are 24v but the same could be done with 12v. There is the normal battery pack harness, and on the EVT that is made with the beefiest of anderson connectors with heavy gauge wire to match. Then for the chargers I connected directly to the battery posts to form two 24v strings.
Here's a cheesy attempt to draw what I'm describing.
- David Herron, http://davidherron.com/
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
Thanks David,
I know about the short circuit issue. I want to prevent to have multiple chargers on board. Isn't it possible to have a system (switches, relays) to move from a battery serial arrangement to a parallel one ?
Yes, I imagine that would be possible. However the EVT battery harness is made with large connectors which would make this less practical. In my opinion. I'm willing to be shown to be wrong...
- David Herron, http://davidherron.com/
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
I think this could be done with some multi-pin plugs. A good electronics source should have some with the capacity you need. Attached is a prettty horrible drawing which I think will explain this. The idea is to have a female plug that is attached to your battery, and male plugs from your controller or charger. The male plugs have wiring that leads to the series / parallel connections.
Deafscooter is Here...
yes i done before
like this one it very good = but you have strong
connect on serie/parallel plug on electic scooter
Craig Uyeda
Deafscooter
deafscooter
Okay, yes, this could be done. But the thread is talking about doing this for the EVT 4000 (or 168). The EVT battery pack harness uses 150A rated anderson connectors, one for each battery, going to a wiring path that runs around the frame. To do this kind of connector arrangement as you drew would require connectors rated for a similar amp capacity.
- David Herron, http://davidherron.com/
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
David,
what kind of switch did you get on your EVT to have your 60V setup working. I remember you use a switch to add a 12V battery in the battery string whenever you want, right ?
I didn't do the system.. Electric Motorsport did, and mine is the only one they did this way. Today they sell a 60 volt battery harness and stuff a fifth 50ah battery in the under-seat compartment. In my case they stuffed an 18 ah battery into a space behind the seat. The design uses some relays to bypass the controller when you press the turbo button. However the 60 volt bypass circuit has nothing to do with the discussion on this thread about redoing the pack to use a single 12v charger.
- David Herron, http://davidherron.com/
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
Here is my rig.. which basically demonstrates the diagram above.
it connects 6 blocks of 12 Volts together for charging.
I use 3 Universal smart chargers.. each charger does 2 12V packs in parallel.
I use a 12 Pin Automotive plug to connect the battery pack to the chargers..
When I want to ride I have another 12 pin plug which basically joins up all the pins in series and then has 2 wires which go to the controller.
This solution is far easier than using switches and its only one plug to charge and one plug to ride.
The connectors are very stable if you use hot glue to secure the wiring.
The entire rig including batteries and chargers is concealed within a travel pack with wheels which straps onto the back of the bike..
it does look a bit too much like a BOMB so I haven't dared try to take this one onto a plane LOL.
this is a (theoretical) 72V 18AH pack and as you can see there is plenty of room for expansion. Id say it weighs about 10-12 KG
The other way to do it would be to get 4 or 5 individual chargers and just wire them all up. Some older "dumb" chargers might give you a problem if they are sharing the ground. I have 4 deltran chargers on a 48v bank and just plug them in with no issues.
I do like Alphi's idea of a plug that puts them in series or parallel, but running 60 amps though there you’re going to get more resistance then straight wiring and loose a good amount of power to heat in the plug. If you oversize the plug to safely handle 100 amps you should be good, but finding an 8 or 10 pole 100 amp connector might be tough and I am guessing wouldn't be very small.
Or you could even charge them one at a time with a single 12v charger, a pain but would work.
In response to the injury, shorting is capable of. The other day i was soldering the 48v SLA pack. I had trouble holding the copper wire to the battery tab while adding solder so I had a eureka moment of using thin copper wire to hold the tab and wire together while adding solder. Without looking it shorted between 2 pole of one 12v. Tiny wire instantly glow and burned huge line running down left index finger. I'm so glad i didn't shorted 48v all together because i can imagine the damages. All in all I make a habit of taping up all other open connection or battery tab and working on one connection at one time. Also i had dropped plier on 36 volt sla pack before by accident and It melted hole in the steel plier.
The high current versions aren't too difficult to come by they are used in all sorts of industrial solutions.
an example here:
http://http://www.bulgin.co.uk/Products/GenPurpose_Connectors/GenPurpose_Connectors.html
If you wanted a low cost yet reliable solution you could simply use a 3 or 4 IEC connectors.
http://http://www.globalsources.com/gsol/I/IEC-connector-manufacturers/b/2000000003844/3000000180791/22664.htm
The only problem with using IEC connectors would be that someone might accidentally plug in mains to your Electric vehicle and fry the controller.. so you would have to label it clearly..