Electrical question

[tanukihimself]

Can someone tell me what kind of amps/hour I should be expecting to use with a small setup. I got a 2000w inverter charger but I need to decide on the battery. Ive been suggested getting a couple 6v gc2 batteries and Ive also been suggested get a vmax aeg battery. For the space, Id rather have 1 than 2. Could I work with 1 of those nice vmax batteries?

[Aguyfromohio]

Without a separate shunt, I believe there is no way for any charge source to know how much current the battery is accepting vs concurrent load consumption.

I guess that's why most use volt setpoints plus time settings.

Yup it's true.

Years ago we worked a project for the main battery on the F-16 fighter fleet.
We had a PhD electrochemist on the team. He assured me there is no way to "look" into the terminals of a battery and know how much energy is in it.

The equipment we designed used a microprocessor monitoring a shunt to measure current in and out of the battery to tally up net amp-hours remaining in the battery, with a bunch of little correction factors for stuff like temperature and rate of charge/discharge. One goal was to keep the battery from being discharged too deeply to often to keep the life good. The maintenance crews (the infamous 18-year-old on the flight line) would damage aircraft batteries by draining them dead flat running the canopy up and down or chatting sports on the high-powered radios. Our equipment would trip the battery off to warn them before they damaged the battery, and track the date and time of these events to encourage better behavior and deny battery warranty claims for abused batteries.

During battery charging those shunts monitored current flow to optimize and adjust the charge rate.

[John61CT]

Can someone tell me what kind of amps/hour I should be expecting to use with a small setup. I got a 2000w inverter charger but I need to decide on the battery. Ive been suggested getting a couple 6v gc2 batteries and Ive also been suggested get a vmax aeg battery. For the space, Id rather have 1 than 2. Could I work with 1 of those nice vmax batteries?

If you're actually using the 2000w inverter side for any length of time, that is not a small setup.

Try to calculate AH per day usage average, round up, 4x that, round up again will give you a conservative estimate.

Prepare for big hunks of lead.

Sam's Club GC2's can't be beat for low entry cost excellent value <$200.

Anything cheaper likely not true deep cycle, least likely 12V from big box in auto sizes with lying "marine" and "deep cycle" on the label.

[tanukihimself]

I won't be using even close to 2000w very much. Like I said, charging a couple phones, a laptop, 5 led puck lights, on Ac side. Thinking about getting a maxxair fantastic fan for the roof vent, but that will run off dc. Im thinking one vmax tank 155amps/hour battery might get the job done for now

[John61CT]

If it is the "solar power" version like Renology sell, probably OK, but Odyssey, Northstar & Lifeline are the top respected AGMs for true deep cycle.

All AGM should try to charge per mfg specs, high amps and to 100% as often as possible for longevity, takes 3-5 hours, best dino juice first then solar.

If you can't, FLA are more forgiving.

Do not add more batteries later, sell the old & get matching ones same mfg date.

[tanukihimself]

Ok, the vmax tank im looking at is on the renology site as well. Im not keen on running a genny or charging via alternator, so should I steer away from the agm batteries all together? Really like the idea of 1 vs 2 batteries but if running 30amp shore power occasionally and small solar setup want cut it then ill go with the gc2s

[John61CT]

Longevity requires getting up to 100% as often as possible. If you only free camp occasionally, have shore power overnight most nights, then fine.

Even "solar only" is fine, as long as most cycles your income is greater than your outgo.

Which has to be true in any case, a bigger bank just lets you average that equation over more days.

But if you aren't getting to true 100% most cycles, you're wasting money on expensive lead, other than Firefly Oasis at >$500 per 100 AH, specifically designed for PSOC and deeper discharges.

IMO Sam's GC2 at $180 for 200+ makes more sense than anything in between.

[tanukihimself]

wiring.png (29.73 KiB) Viewed 2117 times

so i am in the process of finishing up the trailer, and the last little bit of electrical stuff is causing me some grief. From whatever i can gather online and otherwise, i am about to get a 3' long 1/0awg wire made for connecting the inverter to battery, getting a spot cut in the red side for a 150amp inline fuse. Im fine with this so far. my questions are as follows:

1. Should the same size wire go from the battery to the PD5000 distribution panel for my dc wiring? How can that possibly fit into the input spots on the panel?

2. I am running 10/2 wire from my shore power plug to the inverter, and then from inverter to the distribution panel and this is strictly for the 120v correct? The dc goes thru the cable i asked about above correct?

im attaching a pic of what it looks like in my head. please correct it if its wrong

[John61CT]

Go to Blue Sea's calculator. The 12V DC cables (and fusing) should be sized for the max amps load they will carry plus say 30%, compensating for length, time and the voltage drop you're allowing given the sensitivity of the load devices.

A single distribution panel will have a max current rating, so that's your upper limit, likely a lot less than your total DC capacity.

Bigger loads maybe should bypass a lower-rated panel, put close to the battery, but after the fuse and cutoff switch.

[defjr333]

The pd5000 has a max of 60amps on ac side, and 60 amps on dc side. 4awg is the max that will fit the dc input terminal. I did read up on the aims pico2000w inverter charger today, and although it has a max fuse rating listed as a 200amps and 1/0 awg wire. Per installation manual. Think I may have told u 150. But that stated 200. Your schetch looks fine, but u prob don't need 10/2 for 120v outlets, prob 12/2 be fine unless u running a large ac or microwave....the INPUT ac wire needs to be larger due to it being able to pull in 60amps+ on shore power for charger.

[tanukihimself]

Ok, do I need a wire coming from both battery posts to go to the distribution panel? One to input and one to the ground? I can't find any diagrams for wiring up the panel online

[defjr333]

Due to my naval training, I do both. I run BOTH hot and ground from battery bank to hot and ground of inverter/ charger. Plus I run a ground from battery bank to metal, and inverter ground to metal. And a hot plus ground from battery bank to pd5000 and pd5000 to metal frame.You can just run a hot from each dc device to metal on trailer, or do a double ground again. I will be running hot and ground from each device back to panel. Just extra insurance I guess. If the ground to metal frame isn't perfect, or comes loose what a pain to tear everything apart to get to it.