72v charger on a 60v system

[Hostile-Makeover]

hey, just need some advice. My charger was stolen for my 60v bike. I have a 72 volt charger and a 48 volt charger, would either of these be safe to use for the 60volt bike until I can get a proper replacement?

 

[calab]

The 60v charger will charged your 72v(nom), 84v max/63v min battery FAR TOO LOW!
If 60v is 15s then its 63v @ 4.2v x 15s maybe you can up the max voltage charge.

 

[Bgt2u]

The only way that l know of to do this, is IF you happen to have a 12v lithium battery with the same amp hours as your battery pack, you could then connect it to your 60v battery (in parallel) to achieve 72v, and charge it that way. Otherwise you will either over charge (NOT recommended), or undercharge your 60v pack. You could probably use the 48v charger, but you will be topped out at 54.6v, (which is only about 35% charged).

 

[calab]

DC-DC up-converter for 48v charger

DC-DC down-converter for the 72v charger

* The cheap ebay converters are listed as too many watts (just like ebay flashlight 20k lumen sellers and some lithium ion can sellers (having 8000mah in 18650 format for example). If your charge rate is 48v 4a then maybe ebays 1000w converters could easily handle 200w if not 500w in stock form.

Another way to go with a 48v charger in series with a 12v charger if the ground negatives (-) are isolated, the Meanwells are.

As mentioned - Series a 60v battery + a 12v battery then use a 72v charger. Keeping the safety aspects in mind of mixing batteries.

 

[Hostile-Makeover]

The 60v charger will charged your 72v(nom), 84v max/63v min battery FAR TOO LOW!
If 60v is 15s then its 63v @ 4.2v x 15s maybe you can up the max voltage charge.

all my batteries are sla, I can't afford lithium unfortunately. they're 5 12v 20ah in the 60 pack.

 

[Hostile-Makeover]

DC-DC up-converter for 48v charger

DC-DC down-converter for the 72v charger

* The cheap ebay converters are listed as too many watts (just like ebay flashlight 20k lumen sellers and some lithium ion can sellers (having 8000mah in 18650 format for example). If your charge rate is 48v 4a then maybe ebays 1000w converters could easily handle 200w if not 500w in stock form.

Another way to go with a 48v charger in series with a 12v charger if the ground negatives (-) are isolated, the Meanwells are.

As mentioned - Series a 60v battery + a 12v battery then use a 72v charger. Keeping the safety aspects in mind of mixing batteries.

I do have a spare 12v 20ah that I can series in. I've actually been looking at adding it into the system for a bit more range. maybe now I have the excuse to do so. Thanks.

 

[Hostile-Makeover]

The only way that l know of to do this, is IF you happen to have a 12v lithium battery with the same amp hours as your battery pack, you could then connect it to your 60v battery (in parallel) to achieve 72v, and charge it that way. Otherwise you will either over charge (NOT recommended), or undercharge your 60v pack. You could probably use the 48v charger, but you will be topped out at 54.6v, (which is only about 35% charged).

in the immediate, I'll go with the partial charge from the 48 charger. That's actually a great idea right now as I don't have to go more than 10-15kms in a given day, which a partial charge should manage. Thanks

 

[eee291]

If you're using sla you could also charge each block with a 12v charger.
If you do go the 72v route make sure the controller can handle it.

 

[fechter]

You could put the 48v charger in series with the 12v charger to get 60v. This works better if you can bring the battery connection out so the 12v charger is directly connected to one 12v battery and the 48v charger goes to the other 4.

 

[amberwolf]

Keep in mind if your controller or DC-DC (for lights, etc) has parts not rated for 84v (approximate full charge for 72v) then using the 6th SLA in series and/or the 72v charger may damage or destroy them.

It's likely that a 60v system will have parts rated high enough, but there isn't a guarantee of that.

The only way that l know of to do this, is IF you happen to have a 12v lithium battery with the same amp hours as your battery pack, you could then connect it to your 60v battery (in parallel) to achieve 72v, and charge it that way.

If you parallel a 12v battery with a 60v battery, it's likely to start a fire in the 12v battery or the interconnect wiring, and it won't provide 72v.

They must be seriesed together to do that.

 

[Hostile-Makeover]

If you're using sla you could also charge each block with a 12v charger.
If you do go the 72v route make sure the controller can handle it.

I'll have to find the specs. The controller, and the bike are a 2020 tailg, chances are it can handle 72v, as there are 48v, 60v and 72v models of the same bike and there's a space open to fit another battery under the seat,... I imagine the manufacturer just built one bike and changed the price depending on how many batteries were put in it,...

 

[m3vuv]

ive used a lower voltage charger in series with a lab psu before,that worked well for a long time.