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What maximum power inverter for 1G alternator

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BigBrother-84

Re: What maximum power inverter for 1G alternator

This post was updated on .

ArdWrknTrk wrote

The photo shows them on the battery positive lug of* the relay (as they should be!)

Jim, thanks for waking me up.
🤪

I was certainly not wide awake this morning, when I modified the inverter ground source.
Working from the side of the truck, I mistakenly thought that there were more than one wire attached to this pole.
It’s a simple washer…

Conclusion, my starter relay is for the starter only.

Gentlemen, I apologize for this confusion.

Jeff / 1984 F350 Crew Cab 4x4/5.8L w351 4V/ T18/ D50 4.10 front/ 8' bed.
Restored 2019-2022.
Nicknamed «Big Brother 1984», due to its soooo-looong shape & nod to George Orwell's 1984 famous novel.

ArdWrknTrk

Re: What maximum power inverter for 1G alternator

Administrator

It's cool

You had it right and didn't even know it! 💡

Gary often posts in the morning, saying he's ruminating on his second cup of coffee before going out to the garage.
You can't fault the wisdom of the elders....

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: What maximum power inverter for 1G alternator

Administrator

ArdWrknTrk wrote

Gary often posts in the morning, saying he's ruminating on his second cup of coffee before going out to the garage.
You can't fault the wisdom of the elders....

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

ArdWrknTrk

Re: What maximum power inverter for 1G alternator

Administrator

I certainly didn't mean that in any derogatory way, Gary.

Sharing these little pearls of wisdom is what you do best!

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: What maximum power inverter for 1G alternator

Administrator

I didn’t take it as derogatory, Jim.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: What maximum power inverter for 1G alternator

Administrator

Sometimes there's not the perfect smiley.... or I interpreted it the wrong way.

I suppose one can blush out of more than embarrassment. 💡

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: What maximum power inverter for 1G alternator

Administrator

Yep. All of the above.

Gary, AKA "Gary fellow": Profile

BigBrother-84

Re: What maximum power inverter for 1G alternator

In reply to this post by Gary Lewis

The inverter arrived!

Gary Lewis wrote

[…] is there a fuse?

There are two 40A fuses, plus ON/OFF switch.

Looks good for me, but should I add a fuse on the positive wire, just in case of accidental shorting?
If so, what AMP?

Jeff / 1984 F350 Crew Cab 4x4/5.8L w351 4V/ T18/ D50 4.10 front/ 8' bed.
Restored 2019-2022.
Nicknamed «Big Brother 1984», due to its soooo-looong shape & nod to George Orwell's 1984 famous novel.

Gary Lewis

Re: What maximum power inverter for 1G alternator

Administrator

Yes, you want a fuse on the wire close to the starter relay. And 40A should be enough since that's what the inverter is fused at. This is the fuse holder I bought, but it is overkill for your application.

What size of wire did you use? These fuse holders might be more appropriate if the wire is large enough.

Gary, AKA "Gary fellow": Profile

BigBrother-84

Re: What maximum power inverter for 1G alternator

Gary Lewis wrote

What size of wire did you use?

I used 6Ga wire (big pipeline to not loose current, long 14’ run).

I think the second model would fit nice.

Gary, why not install this fuse at the other end, in the cabin, instead of weather/dirt engine compartment?

Jeff / 1984 F350 Crew Cab 4x4/5.8L w351 4V/ T18/ D50 4.10 front/ 8' bed.
Restored 2019-2022.
Nicknamed «Big Brother 1984», due to its soooo-looong shape & nod to George Orwell's 1984 famous novel.

Gary Lewis

Re: What maximum power inverter for 1G alternator

Administrator

The fuse needs to be as close as is reasonable to the source of the power. It protects the wire downstream of it. So if you put it in the cab and have a short between there and the starter relay the fuse won't blow and the wire will burn - and maybe even catch the truck on fire.

The smaller fuse holders have #10 wire on them, and that's a lot smaller than your #6 wire. It would work if you keep the wires to it short, but it isn't ideal. The Wirebarn calculator says that your choice of #6 will give more than a 2% voltage drop with your 28' of wire run - you have to include supply and return. At 40A #6 is only good for 17' at a 2% drop, although at a 5% drop it is good for 44'. So interpolating it looks like each % gets 9', making a 3% drop good for 26', which is still a bit shy of your 28'. And the #10 wire in the fuse won't help that.

Personally I'd be more interested in the first stud-style holder and this 40A fuse to go in it. You should be able to use the existing ring-tongue terminal on the wire to connect to the stud of the fuse, and then make a short jumper from the other stud to the relay. That way you won't have to cut into your existing wire nor try to connect #6 to #10. And you can mount the fuse holder right by the relay to make it clean.

Gary, AKA "Gary fellow": Profile

BigBrother-84

Re: What maximum power inverter for 1G alternator

Ok, got it, thanks!

Will proceed in the engine compartment.

Jeff / 1984 F350 Crew Cab 4x4/5.8L w351 4V/ T18/ D50 4.10 front/ 8' bed.
Restored 2019-2022.
Nicknamed «Big Brother 1984», due to its soooo-looong shape & nod to George Orwell's 1984 famous novel.

ArdWrknTrk

Re: What maximum power inverter for 1G alternator

Administrator

There's still the option of a waterproof 40A circuit breaker like id originally mentioned.
These are intended for trolling motors popular with fishing kayaks and very robust from what I've seen.

Amazon, for $20 US (offshore) to $45 for top of the line Blue Seas brand.
Never worry about keeping a spare or having to unbolt a blown fuse on an always hot battery connection.
Just flip the lever back up

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: What maximum power inverter for 1G alternator

Administrator

I like that, Jim. Much better than a fuse.

Gary, AKA "Gary fellow": Profile

grumpin

Re: What maximum power inverter for 1G alternator

In reply to this post by ArdWrknTrk

Those are slick!

Dane
1986 F250HD SC XLT Lariat 4x4 460 C6-Sold
1992 Bronco XLT 4x4 351W E4OD
1998 GMC Sierra SLE K1500 350 4L60E
Arizona

BigBrother-84

Re: What maximum power inverter for 1G alternator

In reply to this post by ArdWrknTrk

Really interesting!
Thanks Jim!

Jeff / 1984 F350 Crew Cab 4x4/5.8L w351 4V/ T18/ D50 4.10 front/ 8' bed.
Restored 2019-2022.
Nicknamed «Big Brother 1984», due to its soooo-looong shape & nod to George Orwell's 1984 famous novel.

BigBrother-84

Re: What maximum power inverter for 1G alternator

This post was updated on .

In reply to this post by Gary Lewis

Gentlemen, I completed the inverter installation yesterday.

I installed a 40A fuse holder (6ga) at the battery end of the positive inverter line. The only solution available locally fast.
I hope this wire can feed a bigger inverter, in case I decide to upgrade Big Brother’s alternator in the future (not in my plans but who knows).

The inverter is located behind the rear bench seat, passenger side. I left about 3’ of free wire, to be able to move around the inverter, if needed.

Jeff / 1984 F350 Crew Cab 4x4/5.8L w351 4V/ T18/ D50 4.10 front/ 8' bed.
Restored 2019-2022.
Nicknamed «Big Brother 1984», due to its soooo-looong shape & nod to George Orwell's 1984 famous novel.

Gary Lewis

Re: What maximum power inverter for 1G alternator

Administrator

Jeff - That should work nicely. But are you going to secure the inverter some way so it doesn't slide around?

As for that wire powering a larger inverter, yes and no. Using the wirebarn calculator your #6 wire is good for up to 80A and 22' of wire with a 5% voltage drop. But if I remember correctly you said you have 14' of wire for both positive and negative sides, for a total of 28'. However, you also said you left an extra 3' of wire, presumably both hot and ground, so if you trimmed that off you'd be right down to 22'.

But, speaking of grounds, the way I wired my 3KW inverter was to use the frame as ground. In other words, I have maybe 18" of wire from the inverter to the frame, and the frame is grounded in many places to the engine and both batteries - as shown below.

I'm not suggesting you need to do that much grounding. Nor really change anything right now. But if you do want a larger inverter you can cut your wire run by about 50% by using the frame as ground and ensuring your battery is well connected to the frame.

Gary, AKA "Gary fellow": Profile

BigBrother-84

Re: What maximum power inverter for 1G alternator

This post was updated on .

Gary Lewis wrote

Jeff - That should work nicely. But are you going to secure the inverter some way so it doesn't slide around?

Yep, I bought commercial quality Velcro (with very strong sticky backing).
I’m confident that this inverter (it’s quite lightweight and doesn’t come hot) will stay in place.
And if needed, I can detach it and move it.

Gary Lewis wrote

But if you do want a larger inverter you can cut your wire run by about 50% by using the frame as ground and ensuring your battery is well connected to the frame.

Interesting strategy!
I take note of it!

Jeff / 1984 F350 Crew Cab 4x4/5.8L w351 4V/ T18/ D50 4.10 front/ 8' bed.
Restored 2019-2022.
Nicknamed «Big Brother 1984», due to its soooo-looong shape & nod to George Orwell's 1984 famous novel.

Gary Lewis

Re: What maximum power inverter for 1G alternator

Administrator

Gary, AKA "Gary fellow": Profile

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