I want to do the dual battery tray set up but Im having a problem deciding on what battery to get. I want to do an ultracap bank with a SLA battery hybrid with a small flexi solarpanel on the hood for the starting battery. Any reason Id need a bigger full size battery? My thinking is reduce the size of the starting battery and in turn get a much bigger secondary battery.
Why would I need a full size starting battery?
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Dieselchessy
New member
Are you splitting off the cabin air fans and headlights so they don’t pull from the starting battery?
gamefreakgc
Elite Member
I tried to check compression on a 5VZ-FE out of the engine bay (so no tranmission) with a battery with 375 CCA. It could not turn over the engine in 90 degree weather. I'd shoot for at least 500.
Have you thought about just using a deep cycle battery like the Optima Yellow Tops? I have one now and absolutely love it, I just use it for my stereo for when the car is off. Starts strong even after discharging. Just be sure to also own an AGM battery charger for when you get home or else it'll slowly lose capacity.
tx_shooter
New member
I know what you are chasing. I have a stock size starting battery and a trolling motor for my secondary battery. I get ~20 hours of fridge life with a large Dometic fridge and other accessories off and on. The trolling motor was an easy setup and is charged through a controller so when the motor is on the trolling motor gets charged.
Risking getting stuck in the back country with a battery that cannot start the rig is a real issue if you go too small. I would run the trolling motor secondary. They are purpose built for deep cycle and lots of amp hours.
Hopeless Diamond
New member
In the process of doing the same thing. Installed a simple solenoid, triggered by a key on power source. That will feed juice to a fuse block in the back. I'll also attach a deep cycle battery to that to supply power to overnight loads, i.e. a fridge, minor device charging, disco ball for the campfire party, etc.
Not looking to shift any existing "car" loads over so the stock size battery for starting etc will be kept.
Make sure to fuse any runs from either battery.
Not looking to shift any existing "car" loads over so the stock size battery for starting etc will be kept.
Make sure to fuse any runs from either battery.
The supercapacitor bank parallel with the small battery is what provides the cranking amps. I started and drove mine around on just the bank for a few days on a full load for a test. It passed wonderfully. Also ran it all on just the bank to see how long it would drain, did a constant crank test w/o starting, and it cranked for like 15 seconds, or longer, its been a while since ive done anything with my yota. Because I used a balance board, which was pointless on a 16v cap bank that doesnt charge past 13.8v, the bank would drain off way too quickly when the truck was sitting.
Once I remove that board the only drain will be from whatever in the yota when its off.
Once I remove that board the only drain will be from whatever in the yota when its off.
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TonyB66
New member
I also have a Dometic fridge, recently purchased. If you have details on your trolling motor set-up posted somewhere, can you direct me please? If in your build/fix thread, I'll read through it. Thanks.
tx_shooter
New member
Yes, my build thread has the basics. I will try to get some pics of my setup and specs to send over.
tx_shooter
New member
TonyB66
New member
Left-off on page 10, and will resume soon. Thanks much!
Dieselchessy
New member
Then the super caps explode!!! :roadkill:
Not the same situation, at all, but I've been using teeny tiny batteries on a couple of my other cars.
An Odyssey PC680 on my 1963 Volvo. The battery is about 7X7X3, weighs about 15 lbs. Alike any AGM battery, it could be installed in any position. No issues at all with how it works, engine cranks normally, and while the old car doesn't use as much electricity as a newer one would, no issues at all.
And on my goofy 1993 Volvo - I have a Braille 14115. About 6X6X3.5, weighs about 11 1/2 lbs. This car has an LS engine swap - the Braille has no problem cranking that over.
The Braille just costs a bit more than the Odyssey.
An Odyssey PC680 on my 1963 Volvo. The battery is about 7X7X3, weighs about 15 lbs. Alike any AGM battery, it could be installed in any position. No issues at all with how it works, engine cranks normally, and while the old car doesn't use as much electricity as a newer one would, no issues at all.
And on my goofy 1993 Volvo - I have a Braille 14115. About 6X6X3.5, weighs about 11 1/2 lbs. This car has an LS engine swap - the Braille has no problem cranking that over.
The Braille just costs a bit more than the Odyssey.
TonyB66
New member
John, a nice reminder as I have have an SLA in MINI Cooper S, and it sounds like the same one as in your Volvo at 11.5 lbs and those dimensions. I'm quite sure I can fab a platform and mount for such in the driver side rear behind that panel, here removed...
Find a way to dual charge it via engine and solar and I'd be all set... Since that battery should be dead, I'm going to remove it from the MINI and use it for mock-up purposes. Thanks for chiming-in....
I've pondered a dual battery setup on mine as well. After seeing the packaging issues with two full sized batteries in my wife's '96 (a red and a yellow Optima) I was pondering doing something similar for mine - a full sized deep cycle in the stock position for the house battery, and a cute little AGM stuck wherever it is easy for the start battery. And an automatic isolator to keep them from doing weird things like overcharging.
Kanoe
New member
Interesting thought there.
You could use an ignition switched relay to connect the second battery when the engine is running (standard procedure here). You could use a second relay wired as normally closed that would open with the same ignition source and disconnect your solar while the engine is running. Should be easy, although I am not positive that there would be any need to disconnect the solar at all...
TonyB66
New member
Appreciate the thoughts. I'll likely draw-up something, if the fitment is doable. That said, I crawled through the MINI to find the battery...
It's about 6x3x6 alright...
Registered .16 volts, dead alright. I'll remove that rear panel at some point soon and see what's possible...
EDIT/ADD: This battery, the ETX14 is less than 80 bucks:
Amazon.com: Deka Sports Power ETX14 Battery: Automotive
12 Ah, which looks to be fine for my application, a fridge that averages 1Ah on DC. It's job would be to get through the night, until I'm back on solar or driving...
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tx_shooter
New member
Those specs line up with a battery my motorcycle uses. I ran a motorcycle battery for a few years as my 2nd/ house battery without any issues. It did get my Dometic fridge through the night in cooler weather without any issues. Trips during the summer did not fare as well.
As for my 2nd battery; here is a quick pic for everyone. I came home from Death Valley right as the covid lockdown started so I have not had a chance to really go through my rig and get it back in proper shape. I need to get after that.
