Amperage Draw for 10 dead batteries?

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decipha
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Amperage Draw for 10 dead batteries?

Unread post by decipha »

I'm thinking a 12v nominal car battery discharged down to 10.5 volts is going to take about 230-340ma minimum draw to charge if no load is placed on it. I have approx 10 batteries I'm going to be putting in a battery rack and tossing in the back of my work truck. I drive 2 hours each day so its plenty sufficient to maintain them. Using my worse case of 3.4 amps I'm assuming a 5 amp fuse should be more than sufficient.

I plan on using a spare trailer wiring connector I have so I can easily plug in the battery pack and let it trickle on my excursions. I figured a 5amp diode would be able to survive. Suppose we shall see.

Anyone have a more realistic number or done something like this before with any experiences?
decipha
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'19 F-150 3.3L

Re: Amperage Draw for 10 dead batteries?

Unread post by decipha »

well diode not needed my work truck - 2019 F-150 completely isolates the trailer circuit from the parking lamp circuit so it doesnt backfeed. I've had 9 batteries hooked for the past few days and all has been well.
wwhite
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Re: Amperage Draw for 10 dead batteries?

Unread post by wwhite »

When I first read this post, I thought "WTF?"
I am assuming you have the 9 batteries hooked in parallel.
I am assuming all batteries are identical, same amp hours, etc.
In a perfect world, each battery would have the exact same voltage, same electrolyte, same age, and take the exact same charge

When a battery with a higher voltage is connected to a battery with a lower voltage, one battery will charge the other.
This process will continue, while draining each battery.

This 'auto-equalization' of each battery is what is going to cause you issues.

The results are unpredictable.
You may have created a 9-cell electro-hydrogen bomb in the back of your truck!
PaulC-turbo5.0
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Re: Amperage Draw for 10 dead batteries?

Unread post by PaulC-turbo5.0 »

I am also curious as what the reason is behind wanting to do something like this, what is the need for 10 extra batteries? lol
decipha
Posts: 4956
Joined: 2021 Feb 15, 12:23
Location: Metairie, LA
Vehicle Information: Work Truck
'19 F-150 3.3L

Re: Amperage Draw for 10 dead batteries?

Unread post by decipha »

correct
no
these are all different

yes im aware of the nominal voltage

As long as they all get up over 12 volts when charged i.e. no dead batteries then I don't see any issues. Yeah a dead battery would kill the others no doubt.

lol nah no worries..

I have too many vehicles that I don't drive often enough so Instead of rotating charges every so often its easier to maintain them by having them get a little juice each day to keep them topped off. I calculated out 136 hrs of engine run time with the alternator giving them 13+ volts. I'm thinking that would be better than using a charger to charge them every other month or so.

These also act as my backup inverter power backup when the electricity goes out during hurricanes and such.
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