Well Friends,
Since it was only 102 F (39C) in the garage, today, I decided to take some action on my battery situation that has never actually pleased me, since removing the car battery (885 CCA deep cycle Optima Bluetop Marine AGM) from the trunk and replacing it with a cheapo O'reilly's "Sure Start" 335 CCA AGM battery up in the hack body, under the seat.
This brain fart came up after I learned the hard way that having a 39 lb battery, in the trunk, behind the rear A arm was less than optimal.
I swapped in the smaller AGM battery, but never felt things cranked like they did with the big battery, and did have it fail on a ride, mentioned in a previous post, at only 6 months of age.
O'Reilly's gave me no hassle about replacing it under warranty, so that put a thought in my head (likely another brain fart.)
Why not put another one of the less than ideal batteries in parallel? Then set a calendar flag to test them every 5.5 months with a battery tester. If they are at all marginal, let O'Reillys give me another pair of them under warranty and reset the warranty clock for another 6 months? So...
Setup at the beginning of the afternoon, single 335 CCA agm battery, about 11 lbs:
Bend up some aluminum:
Custom mounting strap:
Didn't like the battery side end of the only red cable I could find quickly at O'Reillys, when picking up the 2nd battery. Opted to change the end, vs. just buying two black ground straps. @mikepa must be having at least a minor influence on my electrical thinking:
Second battery in place, using winch relay as the junction box to connect in parallel.
Incurs about 3 inches beyond the seat edge into passenger footwell. They can get over it.
Test started her a couple of times, seems more vigorous. 670 CCA to draw upon vs. 335 with the smaller single battery. 22 lbs vs 39 lbs, compared to the old car battery; weight is now centered between the two mounting points, so probably a better thing for handling and longevity of frame components.
All in all I think it is an ok compromise. Now to set the calendar reminder to test these batteries at the 5.5 month time lapse! Maybe another free set then?
They are pretty crappy batteries, but at $129 each, a semi-reasonable solution at a nation wide car parts place for warranty on the road. O'Reillys must be aware that they are shit batteries, hence the 6 month only warranty.
Caveat.... (please read first, before the flagellation begins.) because I know Dane, the OP, it is quite acceptable that I spank him publicly, as he asks for it periodically.
What an impossible wanker you are, doing the very typical electrical engineering malfunction....of jumping to steps D, E, and F.... without starting at steps A, B, and C This is an error that 93.14 percent of humans make, thinking they can outsmart the electrons flowing through the copper wiring.
Here's the point, you are attempting to build a nuclear fusion reactor, when all you need is a Zippo lighter.
# 1, what is the real alternator output of your bike? How many watts, or amps, can your bike produce at running speed, from the stator/alternator????
Example: the alternator on my '15 Wing produces 1,200 watts, or 100 amps of available electrical power, some of which are used by the bike, but leaving a lot of that available for use on accessories.
The alternator on my '19 Wing produces 1,560 watts, or 130 amps of available electrical power, and the bike uses less than my '15 Wing, because all lights are LED's, and it has the CanBUS system.
Now, it is not surprising that the motorcycle battery in each bike can handle everything I need it to handle, and ...not go dead. But then again, I buy the Shorai Lithium Iron batteries, and they last more than a decade. Not 6 months.....but more than a decade.
The battery in the '06 Wing I sold to Thane, is now 11 years old, still working great, and he agreed.... let's just see how many years that battery will in fact live.
In my opinion.... you are grossly overthinking (a problem you are all too familiar with) this electrical issue on your Africa Twin sidecar rig.
Question # 1..... what is the real world output of the bike's charging system ?
I could look it up, but you should have it memorized.
Two Million Mile Rider...All 7 Continents
Exploring the World in Comfort
Alternator is capable of putting out 490 watts, at 5,000 rpm...
Generally, no problem under normal circumstances.
However, if I want to use lights with the engine off, charge stuff with the engine off, or run a winch, I "feel better" having extra reserve capacity out in the middle of the desert, at night.
When the battery gets marginal, the engine might start, but the DCT won't shift out of neutral, if below about 13.5v.
I don't normally run a lot of accessories, but do like the heated grips, Baja lights, and the occasional heated jacket, pants and those lovely socks!
Again, just makes me feel better having reserve capacity if should I have to occasionally jumpstart a BMW/Harley! (or Chevy Pickup.)
First, I think you feel safe, knowing that I won't ride down, south of the 45th parallel, to the land where it's 102* in your garage, so....go ahead and act crazy.
What I would have done on day #1.....install the highest CCA battery that Shorai makes.....in the bike itself. One made by Shorai that can fit in the Africa Twin.
Then, I would also buy a second Shorai battery, like the one for the Goldwing 1800, that has a CCA of 540 amps, and put this second battery in the sidecar trunk.
Then, run a set of wires from the bike battery to the trunk battery, that keeps the trunk battery topped up.
But....when you want to actually use this trunk battery for your engine OFF accessories, then unplug the connection between the bike battery and the trunk battery, and connect the engine OFF accessories to the trunk battery, with a connector that is already sitting in the trunk, ready to be used.
And frankly, STOP worrying about jump starting everyone else on the road.
Two Million Mile Rider...All 7 Continents
Exploring the World in Comfort
Yeah, that's a thought.
Uncle Sochirio miffed it when he decided to make that behemoth of a dirt bike lighter.
In the 2020 model year change to crf1100, he stuck a HY110 lithium battery in the battery box that he shrank to fit the tiny little 6ah, 120cca darling into.
The OEM battery box makes a great junction box, but not good for much else. Didn't really want to keep buying $600 lithium batteries, so ended up where I'm at.
We'll see how it goes. Maybe a bigger lithium battery in the hack, if I really get to where I care about weight.
There may be a battery disconnect switch in my future.
Geeeez, I don't know where you are buying your Lithium Iron batteries, but I buy mine on Amazon, the biggest and meanest Shorai Lithium Iron battery they make, and get it delivered to my house for less than $ 375.00
Two Million Mile Rider...All 7 Continents
Exploring the World in Comfort
I like your idea to add a second battery in parallel.
Dual batteries have an advantage, in that you can hook them in series and do a small weld repair (best reason to carry jumper cables). Put a few 6011 1/8" rods, and a couple pieces of sanded coat hanger in a small welding rod tube with a bag of desiccant on a nice arid day, and you'll likely never break another metal part on your rig again. So maybe add a note in the tube for anthropologists to discovery in a few hundred years. I like a large #12 welding lens since a flashlight allows seeing well enough to get a weld started after dark. YMMV. Might even fit in that OEM battery box. You can tape it to a pair of goggles, wrench, pliers handle, screw driver etc., if you ever needed to use it (when someone else's rig breaks, because you know yours won't).
I carry a jump start pack to assist myself and others with a dead battery. No chance of damaging my rig, and it is lighter/easier to pack than cables.
Hold my keyboard and watch this! 🙃
I sort of agree with Ben's cost effective set up.. Essentially doubling his CCA's but not exceeding the weight limits of the rig.. Of course the advantage of the Lithium of the AGM Lead Acid is you can effectively draw them down further. Lead acids about 50 of reserve is about all they can deliver where as Lithiums can go to 80 to 90 percent before the voltage falls off a cliff.
We run two batteries in the LBS Overland. One as a bike/starter battery and one as a winch/accessary battery. But separated so one will not drain the other but charge together. Some of Mike Paull's magic. All I see is a little clean up of connections and Ben's set up might be perfect for what he does.
I sort of agree with Ben's cost effective set up.. Essentially doubling his CCA's but not exceeding the weight limits of the rig.. Of course the advantage of the Lithium of the AGM Lead Acid is you can effectively draw them down further. Lead acids about 50 of reserve is about all they can deliver where as Lithiums can go to 80 to 90 percent before the voltage falls off a cliff.
We run two batteries in the LBS Overland. One as a bike/starter battery and one as a winch/accessary battery. But separated so one will not drain the other but charge together. Some of Mike Paule's magic. All I see is a little clean up of connections and Ben's set up might be perfect for what he does.
Brian, I agree with you, and that is exactly what I proposed that Ben (really Dane, although he is not from Denmark) should have on his AT.
The highest CCA battery that Shorai makes, that can fit somewhere on his bike, and an even higher CCA battery that Shorai makes that fits inside the trunk of his sidecar, wired in series so that the bike's stator keeps them both topped up ....and it doesn't take much at all to keep a Shorai Lithium Iron battery topped up, but a disconnect so that when Dane (not from Denmark) wants to run his engine-off accessories, he can disconnect that trunk battery from the bike connection, and plug it into his winch, etc.
Brian, if you knew Dane (not from Denmark) like I know Dane (still, not from Denmark) 
, he is a very intelligent engineer, and therein lays the problem. They tend to overthink things, rather than just going with the basics. In some cases, Mike Paull is a bad influence on people like Dane, because they want to emulate Mike Paull, and his electrical genius. Mike Paull IS the Grand Wizard of motorcycle electrical wiring, and in some cases his wizardy is needed....but not in all cases.
Bottom line, doing this kind of stuff is what makes Dane (damn, I wish the guy was from Denmark) 
...this stuff makes Dane happy to mess with this kind of stuff. If HE is in his happy zone, that is all that matters.
BTW, I just checked (no kidding) it is going to be 108* outside Dane's house today, which means it will be over 110* inside his garage/shop, so.....yeah...a good day to mess with electrical wiring....on October 5th.
108* outside his house....in October....some people are just sick 
Two Million Mile Rider...All 7 Continents
Exploring the World in Comfort
OK, let's spend some of Ben's ( Dane's ) money. HA! A Shorai battery for his bike is 220.00 and the Biggest S x S battery is 350.00
https://shoraipower.com/battery?type=179&make=382341&model=382619&year=382619
Add in one of these
Hmmm won't let me add two links so more posts I supposed
Hmmm, My rebuttal to FM is proving to be work.
https://www.victronenergy.com/upload/documents/Manual-Cyrix-Battery-Combiner-Kit.pdf
Get Mike and Al to draw up a schematic of how it is wired
Fill the entire bottom of Ben's (Dane's) tub with exotic wires
Only lets me post one link per post 🤣
Using a bunch of stuff from these guys
https://www.bluesea.com/products/2104/PowerBar_600A_BusBar_-_Four_3_8in-16_Studs#
And Bob's your uncle.
OK, let's spend some of Ben's ( Dane's ) money. HA! A Shorai battery for his bike is 220.00 and the Biggest S x S battery is 350.00
https://shoraipower.com/battery?type=179&make=382341&model=382619&year=382619
Add in one of these
Hmmm won't let me add two links so more posts I supposed
Ha, Brian, that is basically the exact same Shorai battery that my Goldwing takes, and.....as per the one that is still in the Wing rig I sold to Thane, they last at least 11 years.
Two Million Mile Rider...All 7 Continents
Exploring the World in Comfort
@scott-h hmmm... now that is certainly something to think about! Would have been pretty handy a couple of subframe breaks ago!
@miles-ladue looks like it is the same form factor as the two I have installed. Maybe when O'Reilly finally quits giving me free replacements, that will be the next solution. I like the weight! Exactly 1/2 the weight of the AGM battery.
