Working with what I have, planning for the future (1 Viewer)

[dividedan]

Hey 12V gurus! Need some input and advice from y’all. I’m very new to automotive wiring so apologies for any poor explanations.

Here’s what I have, installed by PO in a 2003 100 series:
1. 100Ah deep cycle Group 31 AGM Dual Purpose battery by X2Power (this one). This is one and only battery.
2. What appears to be 10 gauge (though I don’t have a device to measure) wire off a Slee battery terminal wired to a accessory fuse block via the passenger gutter. It has a 15 amp inline fuse right at the battery. Ground wire runs back along the same pathway.
3. In the rear quarter panel the wire goes through a Blue sea on/off switch then into a 4 fuse block which then sends power to a volt meter, a USB port, and an Anderson PowerPole. The wiring of the switch panel is higher gauge (10 or 12 is my best guess), but the PowerPole itself is smaller gauge albeit a very short run from the fuse block.

4. Edgestar FP630 running off the PowerPole fixture. The manual for the fridge states it pulls 65W.

The problem I am currently having started during a cross country road trip through the south (hot) where we’d wake up to the fridge temp in the 40s and the compressor shut off even though the truck ran all day and battery reads 12.4-12.6V depending on how long it has been sitting. (Just learned about AGM batteries not fully charging by an alternator so “smart” battery charger will be arriving soon). With the key off as soon as the fridge compressor kicks on the voltage at the battery drops ~0.2-0.3V (~12.3V), but there is a drop of 0.8-1V from that reading to the voltage at the panel making it register 11.2-11.5V. Measuring the voltage at the back of the power cable as it plugs into the fridge can read as low as 10.4V causing it to shut itself off to save the battery.

I understand that there is voltage drop from the connectors and wiring, so my plan is to re-wire it to solve these issues. I am thinking of:
1. Removing the switch since it utilizes spade connectors that I am not a fan of and adds additional wiring that is probably not necessary.
2. Replacing the main power wire with a larger gauge (more on this later).
3. Attach the main power supply wire directly to the fuse panel with a quality ring terminal.
4. Purchase a 100-140W portable solar kit to be able to have the truck sit for more than 1-2 nights or even indefinitely in the right circumstances. Gotta love the cold nights in Colorado!

Should this solve my issues? Would just getting the battery charger and getting it good and topped off before heading out in the bush fix it all? This problem wasn’t present before, developed after owning the truck a few years, so does the battery need replaced? EDIT - Or maybe there’s an issue with the fridge causing it to pull more amps than it should?

At risk of packing too much into one thread, I also want to “future proof” any wiring that I place so want to think about the final goal for the 12V in the truck. Ultimately having a large Ah (100+) LiFePO4 battery in the rear to run the fridge and any scene lighting I might want to add with an isolator/charge controller to the starter and an easy way to hook up the solar would be ideal. So last question to that end: could an 8 awg wire serve to link the starter battery to a LiFePO4 house battery in the rear using a charge controller like those made by Redarc/Victron/etc? Or does that have to be the big honkin 1 or 0 battery cable? As in could I utilize the wire providing power to my switch panel as the connector in a future dual battery system?

Sorry for the novel! Appreciate any input even basics since I’m a newb.

 

[Mike6158]

That's a nice setup. You're on the right track. The longest run (battery to panel) needs to be pretty big wire. The web is full of calculators. I like the one from Blue Sea

Circuit Wizard - Blue Sea Systems

 

[dividedan]

That's a nice setup. You're on the right track. The longest run (battery to panel) needs to be pretty big wire. The web is full of calculators. I like the one from Blue Sea

Circuit Wizard - Blue Sea Systems

Thanks for reading my opus! This is part of what is confusing me which is the amount of voltage drop I get from what seems to be an appropriately sized wire. The fridge should pull around 5amps when operating (65W / 12V), but I just plugged in 7 amps at 12v over 20ft and it spits back 14 awg!? I traced the wire to the firewall with no issues, and plan to follow it the rest of the way to ensure there is no damage anywhere. Seems like most folks with this kind of set up use much higher gauge wire than those calculators recommend.

 

[e9999]

Presumably that would depend on what criterion you use. Typically so many % of voltage drop. That is subjective.
I think that very often the connectors do contribute to proportionally much higher voltage drops than "normal" size wires. You need to watch out for the former.
Also, it seems that some of those calculators out there fail to make clear whether or not you need to put in both wire directions or not in the figures, which may result in 100% off numbers.

 

[spressomon]

Generally, you will want 6AWG or 8AWG wire runs (yes, positive and negative...I prefer not to rely on the frame for the return path) from engine bay to rear compartment aux fuse panel for loads, all things larger inverter aside, most of us would see that allows ample capacity. And, a dual battery strategy, is a better strategy for supplying reliable electrical capacity for house and aux loads. If you are thinking of going with a DC-DC charger then you'll need to increase wire size accordingly.

For me, having the same battery chemistry for house and aux batteries has been a win-win strategy: Dual Odyssey AGM batteries has been getting me ~10-years out of house and aux batteries (engine bay mounted) since 2006. The key is to deploy a dual bank appropriately sized smart charger and/or solar system to properly charge and maintain the batteries when it is parked. A solar system would ideally need two controllers and two panels to properly charge and maintain two AGM batteries, although I typically carry one panel (170w Merlin folding) and primarily connect it to the aux battery when sitting for more than a day...but easy enough, with Anderson SB50 Powerpoles attached to each battery, to have flexibility to charge either when sitting/as necessary... For day-to-day charging & maintaining at home I use a dual bank Powermania charger system (10-years+).

An LFP might be OK as long as you work around the low temp charging restriction (LFP technology doesn't like receiving a charge below freezing...). A quality AGM will provide up to 80% useable discharge... Having said that, for our little Escape 15A, I do have a 400Ah/6500w LFP battery bank to supply all the electrical needs...but that's a different animal. And I have a 200Ah/3300w LFP mounted in the bed of the Silverado for running fridge when we take it as the pull vehicle and/or supplying current to a 2000w sine wave inverter I use for work...

 

[dividedan]

Generally, you will want 6AWG or 8AWG wire runs (yes, positive and negative...I prefer not to rely on the frame for the return path) from engine bay to rear compartment aux fuse panel for loads, all things larger inverter aside, most of us would see that allows ample capacity. And, a dual battery strategy, is a better strategy for supplying reliable electrical capacity for house and aux loads. If you are thinking of going with a DC-DC charger then you'll need to increase wire size accordingly.

For me, having the same battery chemistry for house and aux batteries has been a win-win strategy: Dual Odyssey AGM batteries has been getting me ~10-years out of house and aux batteries (engine bay mounted) since 2006. The key is to deploy a dual bank appropriately sized smart charger and/or solar system to properly charge and maintain the batteries when it is parked. A solar system would ideally need two controllers and two panels to properly charge and maintain two AGM batteries, although I typically carry one panel (170w Merlin folding) and primarily connect it to the aux battery when sitting for more than a day...but easy enough, with Anderson SB50 Powerpoles attached to each battery, to have flexibility to charge either when sitting/as necessary... For day-to-day charging & maintaining at home I use a dual bank Powermania charger system (10-years+).

An LFP might be OK as long as you work around the low temp charging restriction (LFP technology doesn't like receiving a charge below freezing...). A quality AGM will provide up to 80% useable discharge... Having said that, for our little Escape 15A, I do have a 400Ah/6500w LFP battery bank to supply all the electrical needs...but that's a different animal. And I have a 200Ah/3300w LFP mounted in the bed of the Silverado for running fridge when we take it as the pull vehicle and/or supplying current to a 2000w sine wave inverter I use for work...

Thanks for the reply @spressomon, if I’m hearing you right even downstream from a charge controller/BMS I would need much thicker gauge wire on the order of battery cable. Also sounds like you’re not sold on the Lithium craze yet which I get, though the integrated heaters and not using them under the hood or as a starter battery seems to help mitigate some of their pitfalls in my mind. What dual battery system do you use?

 

[dividedan]

Well I but the bullet and bought all the supplies to re-wire the accessory panel with 8AWG wire and jumped on the Overland Solar 130w folding panel with MPPT controller!

 

[spressomon]

@dividedan I have been successfully using two Odyssey AGM batteries since 2006/2007 I forget...anyway a Group 31 with steel shell in the starting slot and the former starting battery, a smaller size Odyssey now in the aux/2nd battery slot on my 100 (largest form factor for the passenger side location on UZJ100).

In the order of special charge profiles and generally requiring something additional to relying on the alternator (stock at least) to providing proper charge profiles...FLA (Flooded Lead Acid) which is generally the most alternator friendly, then AGM (also technically "lead acid") which generally requires a different charging scheme (as well as absorption & float) than FLA and then LFP (Lithium Iron Phosphate) that arguably requires the most from non-alternator charging, or at least a really well designed BMS (Battery Management System) that can make the most out of alternator charging. So, yeah you can buy a BattleBorn LFP with a built in heat pad...which of course cannibalizes the battery but hey, if you're going to need the battery to push a healthy dose of itself in below freezing temps on a consistent basis then it might be the ticket for you.

So, its kinda all about the application...just like everything...

So, start by figuring out just how many amps you need in a given period of time then work backwards from there to the type/chemistry of the battery, battery size, how you are going to properly charge and maintain the battery/batteries and then what size electrical cable to get the job done.

 

[dividedan]

Project completed! Ran 8 AWG power and ground off the battery to the rear panel, hooked up the fridge, and voila!! Voltage dropped from 12.5 to 12.3 when the fridge kicked on and held there, touching 12.2 occasionally. I hooked up my BugOut 130 from Overland Solar and left it to cool itself empty. Came back about an hour later and fridge is sitting at 33 degrees with the voltage reading 13.3 at the rear panel getting charged up by the panel. So happy with this set up! If I did my calculations correctly I should be able to sit indefinitely unless conditions are abysmal. Now I gonna mount the charge controller under the hood to keep thing tidy, guess it’s time to commit to the Anderson PowerPole crimper purchase.

 

[e9999]

Losing only 0.2V over that long run is great.
Powerwerx has a crimper (called TriCrimp if I recall correctly) that does Andersons PPs but there is also a kit for it that can do a bunch of other types of crimps by replacing dies. I like mine. There are others out there you may want to look as well. But altogether being able to do good crimps instead of improvised ones makes a big difference to the quality of the wiring IMO.
Since you mentioned solar you may also want to get a crimper that does the ubiquitous MC4 waterproof solar connectors for outside wiring. (Although I've used Anderson PPs outside with no problem for some years now.)

 

[dividedan]

Losing only 0.2V over that long run is great.
Powerwerx has a crimper (called TriCrimp if I recall correctly) that does Andersons PPs but there is also a kit for it that can do a bunch of other types of crimps by replacing dies. I like mine. There are others out there you may want to look as well. But altogether being able to do good crimps instead of improvised ones makes a big difference to the quality of the wiring IMO.
Since you mentioned solar you may also want to get a crimper that does the ubiquitous MC4 waterproof solar connectors for outside wiring. (Although I've used Anderson PPs outside with no problem for some years now.)

I just dropped $70 on a multi die crimper set that I really like. It’s this ratcheting one from S&G Tool:

S&G Tool Aid® 18960 - SAE 22 to 10 AWG RG-6/RG-59 Ratcheting Quick Change Terminal Crimping Kit

SAE 22 to 10 AWG RG-6/RG-59 Ratcheting Quick Change Terminal Crimping Kit - Part Number 18960 by S&G Tool Aid. Quickly and easily change Die Sets with the press of a lever.

www.toolsid.com

For now I’ll just pop the hood and connect the big Anderson plug to the controller and run the wire out the top. If that stops working would definitely consider an external weatherproofed SAE or Anderson plug though where to mount on the cruiser without cutting into body panels gets interesting. Have you ever tried to assemble PowerPoles without the “official” crimper? I’m tempted to buy some just to screw around with the crimp options on my S&G.

 

[e9999]

I imagine it's possible to crimp PPs with a DIY tool since I don't think the crimped barrel interferes with the plastic housing, and therefore also some other types of crimpers, but why take a chance. The dies I have for PPs are the little recurve types that fold the barrel wings back on itself. They look like a little heart, sort of. Pretty standard for any number of crimped connectors. They may even work for MC4s, I forgot. I would be more careful with MC4s, though because the barrel has to fit into the housing more precisely I think to be supported and latch on.

added: for bigger gauges, like ring connectors on 6 or 8 AWG, I prefer to use a hydraulic hand crimper with hex dies, it gives beautiful very tight crimps that I trust over the less secure ones one gets from repurposing other dies or just punching the barrel of the connector. Fun (?) fact: I got a bunch of 6 and 8 ga short wires with ring connectors that somebody had taken pliers to, it was pathetic, most you could pull the connector off by hand. Anyway, being the DIY (tightwad?) type, I reshaped the old connectors with a punch and crimped them back on with the hydraulic crimper and Lordy, just such pretty crimps, gave me the fizz (as a well know youtuber is fond of saying)...