diy solar

diy solar

SOK upgrade in slide in Palomino Camper

Aquadoc

New Member
Joined
Jan 16, 2021
Messages
7
Location
PNW
I am upgrading the Battery in my ‘20 Palomino 1200. The SOK 100 came in yesterday, I plan on one more, I would have gone with the 200 but two 100’s will fit my Bat Box better. Camper is “Solar ready” I have used my 120w panel and it worked well, I now have two, and I’m sure this will be great also. Not worried about using the solar they both have charge controllers.

My question is do I have to put anything in between my truck alternator and the SOK? Will the SOK BMS figure everything out for me? I am concerned with short cycling the SOK and degrading it faster. I use the Camper as a work Cabin 3 nights/week as my work and home are quite far from each other. I am plugged into shore power most days.
Thank you for any advice
Pete
 
How is your truck alternator connected to the SOK battery in the first place?

Trailers generally have three electrical systems:
1. DC Automotive - 12V DC running/signal lights, e-brake. An extension of your truck's 12V system, connected via a 4-7 pin plug
2. DC Coach - 12V DC lights, fans, refrigerator (usually), Coach battery, etc.
3. AC Coach - 120V AC air conditioner, microwave, etc.

Systems #1 and #2 may or may not be connected. Some people use a Redarc or similar DC-DC charger to charge the trailer's 12V Coach battery from the truck's electrical system. It connects to the truck via a dedicated wire, not the 7 pin connector.

So it comes down to how your system is wired.
 
TY, DDW, I will replace my old battery and use the same cables. It’s basically the same 30a cable running from my truck into the camper as my tow behind but longer because it hooks up in the front Bulkhead.
 

Attachments

  • 79CB7C2A-CC59-416E-A73C-6FBB0986A423.jpeg
    79CB7C2A-CC59-416E-A73C-6FBB0986A423.jpeg
    122.9 KB · Views: 4
  • 89DDA414-9E6C-4589-BC54-455DA0FE167D.jpeg
    89DDA414-9E6C-4589-BC54-455DA0FE167D.jpeg
    163.9 KB · Views: 4
Hmm, I didn't realize your Palomino was a truck camper. Motorhomes also have three systems as I described, but the two 12V systems are usually connected via a DC-DC converter that works similar to the Redarc unit I linked.

I don't know how your Palomino is wired. It might be like a trailer, but it's possible the 12V power wire on the 7-pin plug feeds into your 12V Coach system. Not a problem if there's a DC-DC unit in the path, but you don't want 14.6V constantly feeding into your new LiFePO4 SOK batteries.

In fact, I'm a little suspicious if your Palo uses a 7 wire cable instead of 4. The extra wires are mostly for brakes, which obviously don't apply to you. Running lights don't need that 12V wire.

Do you have a wiring diagram for the Palomino that includes the connection to the truck? ,,,,,
 
Another question, is the Palomino's built-in converter/charger compatible with LiFePO4 or did you swap in a new one? This is only an issue when hooked up to shore power, but you mentioned you use shore power part of the time.
 
Another question, is the Palomino's built-in converter/charger compatible with LiFePO4 or did you swap in a new one? This is only an issue when hooked up to shore power, but you mentioned you use shore power part of the time.
TY again for the help. It is defiantly 7pin. I’ll look for the WD and get back. My fridge is 3way. I charge all three ways Shore, Truck, and Solar. Now that you mention it 7 pin does seem excessive since it’s in bed, no brakes needed LOL. I also have a BAT bypass in the front bulkhead to keep it from killing the truck.
 
TY again for the help. It is defiantly 7pin. I’ll look for the WD and get back. My fridge is 3way. I charge all three ways Shore, Truck, and Solar. Now that you mention it 7 pin does seem excessive since it’s in bed, no brakes needed LOL. I also have a BAT bypass in the front bulkhead to keep it from killing the truck.
I have the Arterra WF8735P converter in the spec sheet is says adaptability LA/AGM. So I guess that confirms it I will need something else in between or a replacement controller. I call TechSupportbut I am WEST so I will have to wait for their reply. Still welcome any advice as I am a noob. Thank you again for your help.
 
Yeah, sounds like you need a new converter. I came across this guide to switching from lead-acid to LiFePO4. It's written for travel trailers, but should apply. Scroll down about 3/4 of the page past all the fluff to:

How to Upgrade My RV System for Lithium Batteries?​

He lists a couple of converters. Some inverters also have built-in battery chargers that will handle LiFePO4. He mentions a couple other things to look at as well.
 
I would skip the converter altogether, and just get a lifepo4 battery charger. I just went all thru this with a winnebago motorhome. Meanwell, Victron, are good options for a 120VAC charger, in various amperage outputs, depending on what you really need. If you have enough solar gain then they'll generally keep your batteries topped up.

Converters never seem to have the right charge profile for LFP. And if you have solar input then you probably don't really need the load carrying that the original design intent of the converter was meant for.

240W of solar isn't going to produce much power, you might get 10 amps out of them, so you really need to do a load/usage calc over a day or night, and plan to replace what you use out of your batteries. 200Ah of LFP, discharged to 20%, or 180Ah used, could take 18 hours of sun to replace. If the panels are on your roof, flat mounted, getting more than 50% or so out of them can be a challenge - I know I have 430W on the roof of the motorhome and over summer at low latitudes (so-CAL) I might see 20A to the battery. MPPT controller does a good job of converting what it gets from the panels, to charge the battery.

Instead of two pwm solar controllers, consider one good mppt and put four panels up there in series, or 2s2p, depending on your SCC spec.

The problem with your truck alternator charging LFP, the batteries are such low resistance they will pull all your alternator will put out if they need charging. At idle or low speed there just isn't enough cooling to the alternator and they can and do regularly burn out. One poor guy with a boat engine had burned out three alternator, pulling his hair out in the process. So most will install some kind of dc-to-dc charger from the truck starting battery to your LFP house batteries. I got a Victron Orion and just love it, it's really a nice unit, and only turns on when the engine runs. It's just an 18A, but it's plenty for topping up the house battery while driving.
 
Last edited:
Thank You, Gentlemen. I appreciate the input. I did talk to tech support at Arrtera and they said the WF8735AD was the Lifepo model. I will also explore the direct dc/dc charge system aswell since my current battery is still functional.
 
The problems with the WFCO charge profile:
Bulk/boost is 14.6V. If the battery gets near full charge most DIY batteries will get an over-volt cell or two and bms will shut off charging.
Float is 13.2V, which is too low for lifepo4. It won't hurt it, but it won't keep it anywhere near charged up.
Re-bulk, or low-voltage to switch to bulk/boost is too low - your battery has to be near fully discharged before it will resume charging.

Most with these say it will charge their battery, but they never get full amps out of it due to the programming, and can take FOREVER to charge a depleted battery. All the same complaints about all these outdated charging units when trying to use on lifepo.

You can try it, see how it goes. Since I did my install, just about a year ago, we haven't needed charging from a 120V source - solar keeps it charged up, and if we drive at all it also charges it back up.

I have a whole thread on the 'new' Powermax converter/charger claimed to be 'for lithium batteries'. Uh, no. Just no. Finally sold it off and got a Meanwell charger, and it is fully dabomb. Works just perfectly in gel mode - charges the battery all the way up and then shuts off. In any case, I put a switch on the converter outlet so I can manually turn it on or off for if I do or don't want it running when plugged in or running the generator.

You can put lipstick on a pig... ?
 
The problems with the WFCO charge profile:
Bulk/boost is 14.6V. If the battery gets near full charge most DIY batteries will get an over-volt cell or two and bms will shut off charging.
Float is 13.2V, which is too low for lifepo4. It won't hurt it, but it won't keep it anywhere near charged up.
Re-bulk, or low-voltage to switch to bulk/boost is too low - your battery has to be near fully discharged before it will resume charging.

Most with these say it will charge their battery, but they never get full amps out of it due to the programming, and can take FOREVER to charge a depleted battery. All the same complaints about all these outdated charging units when trying to use on lifepo.

You can try it, see how it goes. Since I did my install, just about a year ago, we haven't needed charging from a 120V source - solar keeps it charged up, and if we drive at all it also charges it back up.

I have a whole thread on the 'new' Powermax converter/charger claimed to be 'for lithium batteries'. Uh, no. Just no. Finally sold it off and got a Meanwell charger, and it is fully dabomb. Works just perfectly in gel mode - charges the battery all the way up and then shuts off. In any case, I put a switch on the converter outlet so I can manually turn it on or off for if I do or don't want it running when plugged in or running the generator.

You can put lipstick on a pig... ?
TY Sir,
I would much rather listen to someone who's been there done that, than a sales man trying to sell a product. I have the drive and desire to learn, and I've found out early in my life some lessons do not need to be lived and or painful to be valuable. Even at the FT Benning school for wayward Lads, I tried to learn from others, tho I certainly learned many lessons there on my own LOL.
 
Back
Top