Most electric bikes come with a single battery like THE BLACKBIRD here.
Now some bikes like THE LANCER have a single battery inside the frame.
But then they have an option for a second battery on the outside now what if you already have an
ebike it's not designed for two batteries but you want to put two on well that's what this is for.
A lot of you have been waiting for this dual battery parallel connector to get back in stock.
Not only are they in stock but it is a new upgraded version!
The internals are completely different and the outside has a new aluminum
case to shed heat, so this is going to perform much better.
The typical questions .....
How do these work?
Can I use batteries of different voltage?
Can I use batteries of different amp hours?
I'm going to explain all of those things and show you how to connect one.
This is a battery off of one of THE BLACKBIRD bikes and this is the cradle.
This is the portion that's mounted to the frame.
A lot of ebikes are going to have something like this.
If your bike doesn't have this, what it probably will have somewhere, is a red and black wire.
What sort of connectors at the end of this can vary a lot now I wanted this
connector to be as generic as possible XT90 meaning these are good for 90 amp.
These are common on aftermarket batteries which is I assume what you're going to be using.
Normally you'd have the battery connector go straight to your motor controller
and there's nothing in between those two connections that's where this guy comes in.
Let's grab two batteries and plug them in they each have their own connector
parallel module plug one battery in plug the second battery in and now the remaining
connection goes to your motor controller it really can be as easy as that if you have
XT90 connectors on your two batteries and on your controller so on something like the blackbird I
would take the battery and mount it on the rear rack now on something like THE LANCER if you've
got room in the triangle obviously that's another option and then we're just going to run this nice
long cable down to the parallel connector our second battery and the motor controller but if
you look closely at this production blackbird you'll see that uh-oh it doesn't use an XT90
it's actually using a slightly smaller XT60 now that's sufficient for the bike because that
connector is rated for 60 amps and the bike can't draw that much power but that means that this guy
doesn't quite match up it's not plug and play or is it we also have this XT90 to XT60 adapter set.
It's one two three adapters that come in the set
Let's say for example your blackbird battery has an XT60 connector well we can plug one of
these in and now that will plug directly into the stock blackbird battery but we bought an
aftermarket battery which uses an XT90 connector well no problem we can plug that one in right here
and looking at our controller oh well it also has an XT60 well that's not a problem we have this
adapter here and we can use an XT60 going to the controller so with these three separate connectors
you can use any combination of XT90 or XT60 now I fully understand that your bike may not have
either of those in aftermarket batteries like I said it's very very common but on stock batteries
you could get bullet connectors you could get Anderson connectors you could get some sort of a
generic plug that we don't even know what to call it and in those cases you will have to find some
sort of adapter or make your own now let's cover some of the technical specs for THE BLACKBIRD
example I have here I've got a 52 volt battery that is a 16 amp hour the second battery i have
sitting up here is a 52 volt 17.5 amp hour so the capacity of this one is a little bit bigger
than this one and that's okay you can mix two different batteries of different capacities
I could for example take the stock battery off move it to the cradle and i could mount a massive
you know 20 amp hour triangle battery in the middle and that's going to work perfectly
fine the voltage however does matter you cannot use say a stock 52 volt and a 48 volt the battery
voltage between the two batteries must be the same this is more than just a parallel circuit
so if you hooked two 48 volt 10 amp hour batteries in parallel you'd effectively have a 48 volt
20 amp hour battery you double your capacity the voltage would remain the same
that's not exactly how this little guy works now the end result is the same thing but it's a little
bit smarter than that with a standard parallel connector if one battery is charged up to 54 volts
and the other one had say a 50 percent charge and was it say 48 volts 47 volts if you connected the
two together there is a potential difference in voltage there that is going to equalize
it's going to happen very quickly and somewhat dangerously you're going to instantly drop the
voltage of one battery and raise the other until they are equal so it's an instant rush of current
from one battery to the other effectively discharging one and charging the other
at a higher rate than either of them can handle and potentially kill the BMS or the cells in both
batteries obviously we don't want that so this being a little bit smarter is also a little bit
safer you see if we have two batteries that are not charged evenly this will
draw from the battery with the higher voltage until the batteries equalize at which point it
can draw from both of them together and that's something that might look a little odd on your
display of your ebike if you have one battery that is halfway charged and one that's full
your motor controller that's plugged in is only going to see the battery that is fully charged
and operating you can always plug them in one at a time to ensure what your actual charge levels are
you can also run off of one or the other battery you don't have to have both of them plugged in
at all times this is good for anything from 24 volts up to 52 volts and you also probably want to
know how much current this can handle the maximum recommended current for this is 30 amps so just
something to be aware of it does have a very nice aluminum case that should shed the heat but it is
only rated for 30 amps so if you have one of those 35 amp controllers and you're going to use one of
these you may want to tune it down just slightly so it maxes out at 30 amps now that's going to
cover most stock electric bikes on the market usually 20 or 25 amps is as high as a stock
electric bike will go even the 1000 watt BBSHD equipped bikes those controllers are either 28
or 30 amps so can handle that without any changes these are in stock at BOLTON EBIKES DOT COM
The adapter set to the XT60s are also in stock
one thing I don't have quite yet is a specific mount designed for it to put it on
the bike and it's pretty small and compact it can go in a lot of places.
But if you'd like to see a custom designed mount for these let me know in the comments
i'm thinking about actually making one and putting it into production.
Just let me know if you're looking for a case or a mount
to put this on your bike and we'll try and get to work on that right away
If you're considering putting two batteries on your ebike you should probably know how
to maintain them for nice long life i have a great video on that right here.