72 volts with a 24volt charger

[02jze]

i just bought 6x 12v 33ah sla batteries for my next project they look like this..

im going to run 72volts but i dont want to buy a new charger. Whats the best way to charge these with a 24volt charger is there something you can buy that will make it work. Atm with my 48volt set up i just seperate the 2x24volt packs and charge them seperate..

 

[amberwolf]

That's pretty much all I'd do with the 72V setup, same as your 48. Split in 3 sections to charge in parallel.

You could do it via switches if you can find some that are heavy duty enough, but if you forget to throw a switch sometime when switching modes things won't work right--hopefully never a problem enough to damage anything.

At one time I wanted to use a set of relays (contactors) to switch my CrazyBike2 batteries around for charging, and have it automatically switch them back when done. Decided not to do that when I got a second 24V charger for the other pair.

 

[02jze]

yeAh looks like ill do that then. doesnt take that long to charge so not a big problem. ive never had the right charger. When i was running 24v i had a 12v charger ten when my 24v charger came i went 48v charger cost me 100 bucks so i dont wanna upgrade that yet..
im undecided weather i want to get that mobility scooter or knock myself up a trike, either way i want it to be super powerful on the hunt for a high powered motor now.

 

[dogman dan]

Even without switches or contactors it can be easy to charge at 24v. You simply need a charger plug for each set of two batteries. The charger plugs can be permanently wired into the harness that series connects the batteries so all you do is plug into each one with the charger one after another, till all three sets have been charged. The charger plugs would be connected to the + terminal on one battery and the - terminal of the other battery in each set of two. Simple splicing hardware of some kind can be used to connect. There are two wire connectors avaliable to connect to the battery terminals, or you could simply solder a wire to the wire in the harness after stripping a 1/2 inch of insulation.

 

[02jze]

i know what you mean. I had spare spliced wires on my last pack. but the joining wires still need to be broken dont they ?
The littke black box needs to be broken or just use a switch, and the red box being the charger.

 

[Hyena]

I essentially do this with my 18S lipo packs and I'll post the same picture and advice I always do.
In your case solder/wire your batteries in 3 banks of 24v and terminate each one with an anderson plug. Slide the 3 together to create a 6 pin plug on your battery. Then you make a series discharge lead you plug into your bike and a parallel lead for charging.

This pic shows the battery and parallel charge plug

 

[amberwolf]

i know what you mean. I had spare spliced wires on my last pack. but the joining wires still need to be broken dont they ?
The littke black box needs to be broken or just use a switch, and the red box being the charger.

If you are only charging one 24V set of batteries at a time, then no you don't have to break the connection between sets. If you want to parallel charge all three 24V sets at the same time, then yes, you do have to break those connections during charging.

 

[Hyena]

Unless you're allocating plenty of time to charge each set I'd do them in parallel. If you need to use the bike short of a full charge you can because each battery will be fairly evenly charged (vs maybe 2 fully charged and 1 nearly flat - which won't trip your LVC but will overdischarge the weak one and damage it)

 

[02jze]

1 24volt pack only takes a little over an hour after most rides i go on. thats at 3 amps. if i run out of time and need it charged quick i charge it on 6 amps which is about 20 mins.
i would love to be able to charge the lot and leave it for say 4 hours how would i do that ??
And amberwolf are you saying that in the second pic there i could leave that connecting wire (with the back box) connected while having the charger hooked up. charger being the red box ??

 

[dumbass]

i just bought 6x 12v 33ah sla batteries for my next project they look like this..

im going to run 72volts but i dont want to buy a new charger. Whats the best way to charge these with a 24volt charger is there something you can buy that will make it work. Atm with my 48volt set up i just seperate the 2x24volt packs and charge them seperate..

It's really a peace of cake if you use Andeson or simular connectors. Run each set of 24v wires to one location using Anderson connectors on the ends. Make a matching set on the bike but on this set use jumpers (I always prefer to use fused wires for this) to create the series connection to create the 72v. Now make a 3rd matching set all wirred to the 24v charger. I do this all the time with 24v packs using 12v chargers. To ride you plug in the bike plug to the pack and it automaticly sets up the 3 24v packs to a series connection for 72v. When you want to charge unplug from the bike and plug in the charger. you will be charging all 3 24v packs at the same time. the end results will be perfectly matched charging voltages on all 3 24v packs and it only requires 9 Anderson connectors, 2 fused wire jumpers and a little time to put it all together. The switch from riding mode in (72v) to charging mode (24v) takes only seconds. Hell all your doing is switching plugs. You could do the same thing and use a 12v charger too but it would require more connectors and jumpers.

here's a pic of my 24v setup. Your 72v is almost the same because while mine is only 24v I am using a 12v charger. As you can see I have 1 fused jumper and you would need 2 jumpers and of course you would have 3 sets (red/black) of connectors whereas, I again have only 2. The setup in the pic is the one on my bike.

 

[02jze]

Dumbass. Please draw what you mean on the battery pic i have there..

 

[dumbass]

Dumbass. Please draw what you mean on the battery pic i have there..

OK, as soon as I finish watching my movie (gotta think so I don't screw it up for ya).

 

[dumbass]

Dumbass. Please draw what you mean on the battery pic i have there..

OK, I hope you can read my sketch and understand it. It's one of those things that are easy to build but hard to explain.

This is the "fuse jumper" I am refering to. You could just use a peace of wire but I like the added protection of a fuse and it's only $2v each.

Three connector sets x 1 connector set

Pluged into the bike. 2 - 12v batteries converted to 1 - 24v pack using a series jumper as per drawing (drawing is for 3 - 24v packs to creat 1 - 72v pack)

I hope this helps. It really isn't that difficult once you understand it. Bob

 

[02jze]

ok yeah i get it now thanks. But anderson plugs are so exspensive and i dont like the ones i have. At 12 dollars each i bought 3 for my 48v bike and the terminal keeps coming out of the plastic holder, not enough so that it falls out but just enough that it loses connection.. I push the terminal in as hard as i can is there a certian way to get them to work ??

 

[Mark_A_W]

1. Eventually, when someone has to configure the pack one way for charging, and another for discharging, they screw up and fry stuff. If you go this way, you have to think it through, so you CANNOT plug the charger in unless the packs are in parallel.

2. If your Andersons are working well, you are doing something wrong, they are very good connectors. But...$12 each? Umm, you got scammed. Justin at ebikes.ca has them for 80c each: http://www.ebikes.ca/store/store_connectors.php

 

[02jze]

yeah 12 dollars gets you both ends. i think they are a little bigger then those 80cent ones but still i feel stupid now. Thats the last time i go to JAYCAR ELECTRONICS they were really helpfull once apon a time but now they are shit heads and their prices well see..
Ill take some pics of what im talking about later on tonight..

 

[Mark_A_W]

Oh, you're in Oz.


Go to http://andersonpower.com.au/store/



Yes, Jaycar screws us on the Anderson price.


Sounds like the cable end of the metal bit is too fat and can't get all the way home in the housing.

 

[Hyena]

What dumbass posted is the same as what I said, just the long way around :lol:
With the connectors you need to make sure the little tongue bit is pushed right forward and cliped over the little tab/spring thats in the connector. Getting 10ga wire into 45a connectors does require a bit of swearing if you';re nto using a proper crimper.

You're getting raped if you're paying $12 - jaycar really are a last resort for this sorta stuff.
As Mark said check out the aussie site for andersons, or failing that I'm going to place an order with powerwerx soon which works out ever cheaper if you want to split postage on that. Probably around $20 for enough to do your whole project (vs $200+ at jaycar :lol: )

 

[02jze]

i have the wire crimped into the steal terminal thing its getting that terminal thing to stay right up in the plastic thing.. I push and push and tap and get it up there as far as i can but it still comes out either from vibration or when i pull the plug apart.. Any tips as to how to get it deeper into the plastic?

 

[Mark_A_W]

It's not crimped enough. (I would solder it too).


There is a little ridge inside the plastic housing, they get stuck on that if the metal bit is not crimped enough.

 

[02jze]

oh really. That makes sense. Ha ill give that a try. thanks for your help.

 

[Hyena]

I found I couldn't solder and crimp my 30a ones, if I soldered them I couldn't fit the contact all the way into the plastic surround.
Check the pin isn't bent or it won't hold on either.

See this for more info

http://pages.ripco.net/~ormos/sarc-ema-anderson-powerpole-assembly-0210c.gif

 

[dumbass]

i have the wire crimped into the steal terminal thing its getting that terminal thing to stay right up in the plastic thing.. I push and push and tap and get it up there as far as i can but it still comes out either from vibration or when i pull the plug apart.. Any tips as to how to get it deeper into the plastic?

One of the problems people have when they use Anderson connectors is the crimp must be round. If it's not it will be very difficult to insert. So make sure that your crimp is nice and round. You can try to insert a very small screw driver into the plastic with crimped wire. You can sometimes push on the back of the crimped metal and push it in.

I have used the 30a connectors on both 12g and 10g (the 10g needed to have the covering thinned a bit though) so if you are using the 45a connectors you shouldn't have any problem even with 10g wire.

Of course you know now that you over paid for them. I don't remember where I bought mine but the 30a were $35 for 50 sets (50 red & 50 black) and a cheap crimpoing tool was $15 or $18.

Most of the places selling them on Ebay and Amozon are rip offs just look on the internet and compare prices and shipping. I would recommend you buy extras remember the shipping is high if you only need a few more because you damaged some.

If you crimp them in correctly you don't need to soder them. As you found out it makes it even harder to get into the plastic.

 

[dumbass]

What dumbass posted is the same as what I said, just the long way around :lol:

Yeah, your right but I thougt our student needed as much info as he could get. We all have those kind of days and projects........well at least I do..LOL