BCI - 78 alternative

[chorty]

my truck seems to only have enough room/tray for a pair of group 78's.

I'd like to find a slightly larger batter for the 2nd/reserve (it's on an isolator with key on/off), but the corner bracket and radiator reservior are making things really tight.

I guess if i have no option, one dead battery that's undersized is better then two dead batteries undersized. I need to run a 12v winch back at the tailgate. Glad i wired up a relay, because i can't find any decent 78's rated for marine deep cycle. I measured everything the best i could ,and I don't think i can even make a 31M class battery work.

Suggestions? If i have no other options, i guess i'll just buy a $100 special 78 and see how long it lasts.

 

[eljefino]

How long are you running the winch, a few minutes at a time? That's almost starter motor type duty. I'd run a regular battery.

 

[chorty]

it's on a jib crane, and i use it to load truck and trailer. also use it to drag stuff closer to truck/trailer before picking up. Some stuff is quite large/heavy, so i use a snatch block, less amps/torque, but more run time/lead to spool back up.

I think a marine grade 24M might squeeze in there.

i hate this kids electric winch stuff. PTO or go home, but this truck isn't setup for it. it's got one of them garbage 4L60E's in it. Need a NV4500 and a pump.

 

[Timmastertech]

78 is a group size that at least in a Deka manufactured battery the longer warrantied batteries have more capacity and more CCA. 778MF is an 800 CCA battery. That should be plenty big for anything you need.

 

[chorty]

More interested in amp hours over CCA. And marine deep cycle. The aux battery is TP2 style.


I do have that battery on the other side already.

 

[chorty]

Well ,i went with a marine 24M. But i'm wondering if there's an issue with the choice of battery, or wire install.

I used some 4ga THHN from post (fused), back to the winch with some anderson's, and using the frame rail as a ground. I did the 'big 3', and 00 the 2nd battery to the alternator bracket, and also carried from alternator bracket down to the frame rail. I deleted the 6ga/12ga alternator wire going to the distribution post, and upped it to 4ga/8ga, just for peace of mind. Although i thought it was weird a 105 amp alternator is running 6ga to the distribution post.

after a fresh charge (1 hour drive), battery when isolated is a healthy 12.65v. I let it sit for easily a half a day. Since it's isolated, there's no PCM ******** to tease and trickle it, so it has an honest time to rest without any parasitic drains. I'm pulling around 80 -90amps, and at that ampacity, the voltage measured at the battery, and at the winch solenoid, lifting the same weight for the same amount of time, the average voltage is 12.14v @ battery posts, and it's 11.03v back at the winch solenoid. My understanding lead-acid's will drop like a rock when under a heavy amp drain, so maybe this isn't that big of an ordeal?

the 4ga run is around 12feet. I'd assume since the battery has 650 cca it shouldn't have a problem releasing amps, as it's a dual purpose marine/starter, so i'm leaning towards the wire being a whisker light, if that is plausible for my current situation?

It's not used heavily, or for very long times. The 2nd battery isolated was more for the fact of dropping 12v aux to the trailer hookup for keeping break-away kits charged or juicing the camper, and not killing the battery for starting out in the middle of BFE.

For the winch I pick up at most 1000#, and then set it in the truck box, So i don't think the voltage drop will cause any significant damage besides being a bit piggish on the amps, and the short run times shouldn't be an issue making excessive heat. Also, the 3500# winch capacity is based on 1st layer of rope, and at most i'm rolling out 10 feet of rope, So i guess that's a big variable. I notice as well the 6ga leads supplied with the winch going from solenoid to the electric motor posts get warm, the wire that runs for when doing lifting, and not my 4ga lead i ran through the frame.

Maybe i'm just trying to be nit-picky for no reason, and just need to relax now i can get rid of the 150 engine blocks and transmissions, and other odds and ends of junk laying around everywhere easily without destroying my lower back. At that point, a smoked winch is cheaper then a surgery.

Looking for other opinions. Should i tear something apart or just drink a beer and push buttons?

 

[chorty]

Oh, i debated on running a copper 4ga lead for the ground, but i decided to gamble and use the frame rail. Yes, i soft pad down to fresh iron, grease, and bolted copper lugs right to the fresh iron. I also stayed on the same rail to avoid cross-member and bolt 'jumping', but then i realized under the engine it's welded. /me shrugs

 

[meep]

Back in the day, the in car test for a good lead acid was to measure the post voltage while cranking. Anything above 9 was healthy. If it’s showing 11 under load, you’re probably doing just fine.

 

[JHZR2]

I'm pulling around 80 -90amps, and at that ampacity, the voltage measured at the battery, and at the winch solenoid, lifting the same weight for the same amount of time, the average voltage is 12.14v @ battery posts, and it's 11.03v back at the winch solenoid. My understanding lead-acid's will drop like a rock when under a heavy amp drain, so maybe this isn't that big of an ordeal?

That’s a decent IR drop on the conductors. Being at 12v under load isn’t concerning. Only getting 11v at the load is concerning to an extent, especially since a winch will run a while. Good job reporting both!

Go with a heavier conductor with the appropriate fuse.

 

[chorty]

well, winch runs for maybe 5 seconds at most. Maybe 30 seconds if i need to drag something to the truck before it begins to lift it.

It rolls the cable up quite quick since i'm only using 4 feet of cable, and the drum's diameter stays at max. Ive been thinking about changing the hot lead from battery to bumper, but i just don't think it's justified in the cost. I think it would still take 5 seconds to deadlift and it'll be fully wound up.

The only time i was able to make over 130 amps was when i wasn't paying attention and stalled it. Almost pulled the chain hook through the end of the lift boom. That was a chore to get pulled back out of the iron. Jacked up the square stock pretty good too. Nothing a wonder wheel and welder couldn't fix.

the fuse it came with are a pair of 50's wired in parallel. And i mis-read the battery, its 750ca/930cca It is overkill for winching, even with the truck off as far as capacity. But it'll be a huge gain when camping, as i tied in the 12v aux for the trailer hook up into it as well.

 

[chorty]

That’s a decent IR drop on the conductors. Being at 12v under load isn’t concerning. Only getting 11v at the load is concerning to an extent, especially since a winch will run a while. Good job reporting both!

Go with a heavier conductor with the appropriate fuse.

Good job?

I thought it was standard practice to measure voltage and amperage on designs and installs?

That's what I did when I got into the test department on engineered electrical jobs anyways.

I suppose such practice isn't common with the public.

If autozone sells the wire, it must be good enough.

 

[JHZR2]

Good job?

I thought it was standard practice to measure voltage and amperage on designs and installs?

That's what I did when I got into the test department on engineered electrical jobs anyways.

I suppose such practice isn't common with the public.

If autozone sells the wire, it must be good enough.

Being nice/friendly.

Not everyone on here would report it. Yes, it’s the correct practice, and you got the right info out there.

 

[chorty]

Being nice/friendly.

Not everyone on here would report it. Yes, it’s the correct practice, and you got the right info out there.

Oh, well, seems default in my eyes.. Otherwise advice would be a struggle.

So far its been acceptable. Its not getting hot. Warm. But not hot. I'm loading on average 4000# before I run out of room on the truck.

Seems its unlikely I'll ever burn it up from heat anyways. The Chinese o-rings will probably fail and let water in before that happens