'46 Chevy Shorty - Page 159

Tango · 03-20-2018, 10:40 AM

It is an Interstate that I built my start battery box to fit. Based on what I've read online, good service and a lot of bang for the buck. But I also just read somewhere that all AGM's require a different battery charger than conventional batteries (?). I can only guess they were referring to something other than the vehicle alternator. Or do they need something upstream on the vehicle system to stay happy?

Mr4btTahoe · 03-20-2018, 10:47 AM

AGM batteries need a charge of roughly 2.25-2.3v per cell to be happy. You can get a regulator if need be to keep the alternator in check as most old school alternators put out around 2.4v per cell which can lead to overcharging on extended drives.

You want a float charge of around 13.6-13.8v when batteries are topped up.

Most smart chargers these days can handle AGMs.. old dumb chargers will cook them over time.

Tango · 03-20-2018, 10:54 AM

Thanks Tahoe. I definitely need to look into that when putting together the electrical. I need a power guru to help design the system I want.

Mr4btTahoe · 03-20-2018, 11:02 AM

Most HD alternators can be tweaked to produce the outputs you want/need.

Newer alternators such as the one on my Tahoe are controlled via the ECU which drops charging voltage as the batteries are topped off. On long trips, I can see voltage as low as 13.2v running down the highway. Just after startup, I can see 14+v.

14v and under is idea for an AGM when they are near topped off.

As far as sizing of your batteries is concerned.. depending on what battery case size you built your brackets for.. you should be able to run any brand of battery in that group size. Do you recall what group the batteries are you used for mock-up?

Tango · 03-20-2018, 11:11 AM

It is a Group 34 and one of the smallest I could find. Space on my rig is a major consideration. Looked at the batt you are using but it won't fit.

Interstate Part Number MT7-34
Group Size 34
Cold Cranking Amps 800
Cranking Amps 1000

Mr4btTahoe · 03-20-2018, 11:23 AM

Yeah.. the 3100 is a traditional group 31. You would need a 3400 if you went with XS Power.

Group 34 is a fairly common size.. So I would go with what is readily available. Are you using multiple or just 1?

Tango · 03-20-2018, 12:20 PM

I am going with a single group 34. According to the Cummins guys, 800-1000 cranking amps should be plenty to spin this 4 banger. Let's hope, cause I don't have room for another.

Mr4btTahoe · 03-20-2018, 01:00 PM

1k should be enough as long as the cables and such are up to snuff. A gear reduction style starter will go a long way to help as well.

During winter, you'll want to use a block heater and potentially a smart charger to top it off on a regular basis. When temps get to the single digits, my D3100 would struggle from time to time by itself.

Could always keep a booster pack on board. Cold weather strikes... hook it up and bump up the cranking juice a good bit.

cadillackid · 03-20-2018, 01:10 PM

I have 2 oklder group 31 standard batteries on my DEV bus.. at 0f. that DT-360 takes a lot of cranking to get it spun over... you've probably seen my cold start videos.. it huffs and puffs (no glow plugs or grid heater and wasnt plugged in). and I never got any signs it was going to run out of battery.. im thinking your single group 34 will spin that 4BT easily.. esp if you are running synthetic oil, and if you are in temps at 20 or above..

that DT360 at temps of 20 or above starts up just like a regular gas engine.. im thinking your 4BT will be similar..

of course plugged in with a block heater it doesnt care what the temp outsude is.. it starts right up.
-Christopher

Tango · 03-20-2018, 01:55 PM

The plan is to wire this thing up so the House batts can act as backup. There will be 2 more 150ah agms in back tied in with something like 4/0 cable. I am also looking into a doodad called a "Thermostart" that some of the 4BTSwaps guys have installed and are very pleased with. Takes a fraction of the juice that glowplugs, gridheaters or a blockheater pulls. The thermostart device burns a small amount of fuel in the intake manifold to preheat the intake air. Apparently something farmers have been using for a long time. And personally...I'll take a fix that farmers come up with over "engineers" most any day.

cadillackid · 03-20-2018, 02:01 PM

Sound like a great idea! Burn a little fuel to warm up the air stream coming in.
How about the Russian that lights a fire under his D80 dozer to get it started
Christopher

Tango · 03-20-2018, 02:05 PM

Da commrade! Just make no beeg Kaboomski.

sojourner · 03-21-2018, 09:03 AM

Quote:

Originally Posted by Tango

The plan is to wire this thing up so the House batts can act as backup. There will be 2 more 150ah agms in back tied in with something like 4/0 cable. I am also looking into a doodad called a "Thermostart" that some of the 4BTSwaps guys have installed and are very pleased with. Takes a fraction of the juice that glowplugs, gridheaters or a blockheater pulls. The thermostart device burns a small amount of fuel in the intake manifold to preheat the intake air. Apparently something farmers have been using for a long time. And personally...I'll take a fix that farmers come up with over "engineers" most any day.

I've even used a propane torch (into the intake while cranking) to heat the incoming air in a really cold situation. It seemed to help. Another thing you might look into is a heater coil in the intake. Having been in the marine repair business most my career, I've seen this on Onan generators, Perkins and Volvo diesels of yesteryear.
Google "Intake Air Heater". There's lots of stuff out there.

dan-fox · 03-21-2018, 09:10 AM

Quote:

Originally Posted by sojourner

<...>Another thing you might look into is a heater coil in the intake.<...>

Is this the same, or the same concept, as "grid heater"?

cadillackid · 03-21-2018, 09:24 AM

Quote:

Originally Posted by dan-fox

Is this the same, or the same concept, as "grid heater"?

I think so.. i like your idea.. Heat with a Fire not a Wire! ..

one reason living up north i'll NEVER live in a house that doesnt have Gas heat...

glowplugs do work but they pull a significant amount of current..

of course one of the other big issues with diesels in real cold weather is the oil.. you are trying to spin the engine faster to make more compression and heat. yet regular Dino oil is thick as molasses, which makes the starter require more power.. synthetics definitely help this issue and allow your engine to spin over faster...
-Christopher

sojourner · 03-21-2018, 11:44 AM

Quote:

Originally Posted by dan-fox

Is this the same, or the same concept, as "grid heater"?

Yea, that's one name for them:

https://www.ebay.com/itm/Diesel-Engi...JXUKWD&vxp=mtr

dan-fox · 03-22-2018, 08:46 AM

Quote:

Originally Posted by sojourner

Yea, that's one name for them:

https://www.ebay.com/itm/Diesel-Engi...JXUKWD&vxp=mtr

Wow, that thing looks like a lot of resistance to airflow! Is there ever any provision to bypass it when it's not in use?

cadillackid · 03-22-2018, 09:01 AM

if its on the forced induction side im guessing the resistance is less of an issue as you are pressurizing the air hitting it. (id think youd locate it as close to the engine as possible)..

-Christopher

dan-fox · 03-22-2018, 10:09 AM

If it's downstream of a turbo, yeah I can see that you could ignore that effect. Are they not used on NA engines?

Tango · 03-22-2018, 10:16 AM

"NA engines?" ????? Wazzat?

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