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2 batteries

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Jameshambleton
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2 batteries

Post by Jameshambleton on Tue 10 May 2016, 2:59 pm

So I'm going to be going wild camping for a week in Scotland in the summer and I'll be taking my gopro's with me. Now the issue is that I'll be needing to transfer my footage onto my laptop, I have 2 laptop batteries but I'm worried that it won't be enough power to get my footage transferred and my cards emptied by the end of the week so I'll need to charge it up at some point. 

So I want to run my bike with a spare battery that I can charge up as I'm riding along to then charge my laptop battery at night/when I'm using it. Is there any way of doing running 2 batteries at the same time without making the electrical circuit 24volts. 

I want one battery for the running of the bike and another for charging my laptop. I want both of them to be connected up at the same time to the bike when I'm riding to charge them but can easily be disconnected when I need it to be. 

Has anyone done this before on the forum or had any experience at doing this?
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Tricky.
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Re: 2 batteries

Post by Tricky. on Tue 10 May 2016, 4:36 pm

i ran two batteries once when racing as i had an unknown charging issue. just connect + to + and - to -
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Beresford
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Re: 2 batteries

Post by Beresford on Tue 10 May 2016, 9:55 pm

@Tricky. wrote:i ran two batteries once when racing as i had an unknown charging issue. just connect + to + and - to -

It's called connection in parallel.
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Jameshambleton
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Re: 2 batteries

Post by Jameshambleton on Tue 10 May 2016, 9:57 pm

@Tricky. wrote:i ran two batteries once when racing as i had an unknown charging issue. just connect + to + and - to -

Is it really just that simple?
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davebike500
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Re: 2 batteries

Post by davebike500 on Wed 11 May 2016, 11:47 am

Yes just that simple but Careful! start bike and warm before switching off and connecting discharged betters and beware of sparks !
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eternally_troubled
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Re: 2 batteries

Post by eternally_troubled on Wed 11 May 2016, 12:42 pm

The simple solution is just that simple - positive to positive and negative to negative.

The even better bit is that on the CB500 there is enough room for the second battery in the storage box behind the main battery.

I would use fairly thick cable (say 2.5 mm squared) and make it fairly short - if you can put crimp-on ring terminals on either end of the cable and then you easily attach the ends to the two batteries.

To add to dave's warning above (and this applies to anything to do with big-ish batteries) be really carefull not to short anything out - even the small motorcycle battery like we have on the cb500 can souce hundreds of amps (all be it for a fairly short time) which can easily set fire to things and burn you - and most definatly melt the insulation on whatever cable you are using.

I wouldn't anticipate you having any problems but it pays to be carfull when using screwdrivers (or other metal things) around batteries to make sure you don't do something stupid.

Also (just wandering), I'm guessing you are going to take a separate inverter so you can 240V AC power the laptop from the spare bike battery?
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Jameshambleton
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Re: 2 batteries

Post by Jameshambleton on Wed 11 May 2016, 1:10 pm

This is the inverter I'll be getting https://www.amazon.co.uk/dp/B00AX0OAZI/ My laptop is very hungry and it requires a 503watt power supply (it's a pretty powerful laptop). I'm planning on getting a bigger battery (YTZ14s) as @davebike500 recommends in his thread and then using my existing battery as the one for charging my laptop. 

Next change is going to be the reg rec to a RR690 from electrex when they come back in stock as they're a series and not a shunt type.
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Jameshambleton
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Re: 2 batteries

Post by Jameshambleton on Tue 28 Jun 2016, 11:25 am

So back to this little project, I'm in the stage of ordering my battery. 
I'm going to connect the terminals together using crimp-on ring terminals as ET suggested. I'm wanting to connect the two positives with a fused circuit, what amp fuse should I be using 10,15 or 30?

I've made a little diagram to explain it a little better. 

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Re: 2 batteries

Post by Beresford on Tue 28 Jun 2016, 11:58 am

I meant to ask earlier, what sort of memory does a GoPro use?
30 amp for that job, there should be a 30 in the positive lead from the reg/rec also.
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Re: 2 batteries

Post by eternally_troubled on Tue 28 Jun 2016, 12:43 pm

Yes, if you connect it like that 30A would be right - the starter will be using both batteries so you'll need that big fuse. Also, use some nice big cables. At least as big as the ones the main battery connection uses...
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ashcroc
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Re: 2 batteries

Post by ashcroc on Tue 28 Jun 2016, 12:50 pm

There's not actually any need for a fuse there. All you're effectively doing is doubling the size of the battery.
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Re: 2 batteries

Post by eternally_troubled on Tue 28 Jun 2016, 1:05 pm

@ashcroc wrote:There's not actually any need for a fuse there.  All you're effectively doing is doubling the size of the battery.

Strictly no, but given that James is going to be connecting and removing this to power his laptop (I think) having a fuse there might well stop the worst happening if the flying leads from the battery (which is what they are really) get shorted by accident.

If you wanted to do this really properly then you should probably get something like some suitably sized Anderson Powerpole connectors which would reduce the change of accidental shorting etc, however they aren't quite as easy to source or easy to crimp as ring terminals, so I didn't suggest them earlier.
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Re: 2 batteries

Post by ashcroc on Tue 28 Jun 2016, 1:32 pm

Ah yeah I'd forgotten he's planning on removing the extra one.

I think if it were me, instead of a fuse (or possibly as well as) I'd put in a switch on the positive side. That way if the 2nd battery if pancake flat, it can easily be removed from the circuit for starting the bike.
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Jameshambleton
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Re: 2 batteries

Post by Jameshambleton on Tue 28 Jun 2016, 1:57 pm

@Beresford wrote:I meant to ask earlier, what sort of memory does a GoPro use?
30 amp for that job, there should be a 30 in the positive lead from the reg/rec also.

It uses microsd cards, I personally use a 128GB sandisk card. 
The reg/rec cables doesn't have a fuse in it. 

I am going to be removing battery 2 completely from the bike and electrical circuit every evening and reconnecting it every morning. 

If I can find a 30amp fuse then I'll use that although would a 15 amp fuse suffice as I doubt I'll even be reaching 15amps coming from the reg/rec? 

I have thought about getting a connecter like the Anderson Powerpole although I'm thinking that be impractical and tricky to fit given the tools I have available. I've decided on fitting an oversized and longer plastic sheath over the top of the positive ring connector as this would then push back to its original length preventing the positive terminal from shorting against the frame, even though this will be in the plastic underseat storage, you can never be too careful.
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Re: 2 batteries

Post by Beresford on Tue 28 Jun 2016, 10:57 pm

SD card memory is quite cheap. Why all the faffing around with the batteries, is there a particular need to bring the computer camping ?
I'd just carry spare SD cards.
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Re: 2 batteries

Post by eternally_troubled on Tue 28 Jun 2016, 11:28 pm

@Jameshambleton wrote:

If I can find a 30amp fuse then I'll use that although would a 15 amp fuse suffice as I doubt I'll even be reaching 15amps coming from the reg/rec? 


You won't get 15 amps from the regulator rectifier but, given you are connecting the second battery directly across the battery terminals of the first battery, both batteries are going to be supplying current to the starter when you press the button, hence why I reckon the wires between batteries should be short-ish, large-ish area and have a similar fuse rating.

I think that the previous suggestion of a switch would be a good idea (option 1 from here).  

If you were feeling really flash you could use the big relay as per option 2 from the same place.  You could energise the relay from the side-light positive connection - that way it would only connect the second battery when the ignition was on *and* the side-light was switched on (I assume that you always ride with (at least) the side-light on).  In this way you could start the bike with the side-light switched off (thus only using the first battery for starting) but once you get going (and turn the side light on) it will start charging the second battery.

With either of these solutions (relay or switch between the batteries) you could fit some kind of connector that was permanently connected to the second battery and power your PC/inverter from a suitably dimentioned lead connected to the bike.  In this was you wouldn't have to remove the battery every time you wanted to use it.

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