Choosing a Battery

CapnLoki · Post by **CapnLoki** » Wed Jun 19, 2019 3:16 pm

A lot of questions ... I'll try to get to them

campervan wrote: ↑
Wed Jun 19, 2019 11:13 am
...So I think I'm looking for a battery with 35 ah (+/-55 if Resmed's +50% cushion recommendation is a good one.)

For longest lifetime, we try to stay above 50% State Of Charge. Taking it down to 20% is still reasonable with the understanding that the number of cycles will be limited. Beyond that the battery will be damaged.

campervan wrote: ↑
Wed Jun 19, 2019 11:13 am
- can be set up and use safely, preferably inside a tent, around children and pets and uncoordinated adults
- can be stuck in the trunk of a small car with lots of other stuff, and possibly running a weatherproof DC extension cord from there, if they exist
- a relatively simple project for someone with no experience with batteries or wiring who does not want exposed wires hanging around
- cheap is best - $325 is my absolute max, $250 is a lot better, and $200 or less would be fantastic (but seems unlikely)
- would be great if it wasn't so heavy that it'd be terrible to lug from a car to a tent, or better, to carry maybe max 500 yards
- a DC port or two built in or easily/permanently installed would be fabulous

The AGM style battery fits the bill, with the understanding that they are made of lead, and weight = power.

campervan wrote: ↑
Wed Jun 19, 2019 11:13 am

I think that this setup qualifies? But I'd like your opinions! So here's my plan:

1. Deep cycle AGM lead acid battery, 100 ah ($170):
https://www.amazon.com/Universal-UB1210 ... 00S1RT58C/
alternate #1: two 35 AH batteries ($135):
https://www.amazon.com/12VOLT-DEEP-CYCL ... 0BUH0TAS/
alternate #2: one 55 AH battery ($120):
https://www.amazon.com/Mighty-Max-Batte ... 0K898AT6/
alternate #3: one 35 AH battery ($65):
https://www.amazon.com/Mighty-Max-Batte ... 0K8E0WAG/

I like the Universal brand because I thought they had better reviews, but its a tossup ...

campervan wrote: ↑
Wed Jun 19, 2019 11:13 am

2. Battery box with built-in DC ports ($50):
https://www.amazon.com/MinnKota-Trollin ... 01PTHKMG/

very spiffy, but possibly overkill. Its sized for a larger battery than the U1. Its easy to built the functionality with a 1 to 5 splitter and a few extra DC socket.

campervan wrote: ↑
Wed Jun 19, 2019 11:13 am

3. BatteryTender charger ($25):
https://www.amazon.com/Battery-Tender-0 ... 00CITK8S/

I would go with a larger model if possibly. I use the 1.25 amp "Plus" version; I notice the 3amp version is $40 at Costco.

campervan wrote: ↑
Wed Jun 19, 2019 11:13 am

4. ResMed DC to DC converter, product # 37297 ($65 - I got it cheap):
https://www.amazon.com/Resmed-37297-Air ... 721T72ML/
Total cost: 100/70/55/35 ah setup = $310/275/260/240

I have a bunch of questions if that's okay -

- What's my best bet in terms of size? I want to balance as many amp hours as possible with having something that is light enough that it won't kill an average person to carry it a couple hundred yards. If I can get a longer camping trip that's great, but I'm torn as I'd really love to keep costs down.

- If I wanted to buy one 35 AH battery for this trip, and pick up another when we'd be camping for longer next year, would that work without having to buy a different battery box? Would the box fit three if I added two later? Could I put a 35 AH battery in the same box with a 55 AH battery? Is the two-battery setup in any way less efficient than having only one? What happens if you have only half a night's charge on one of the batteries - can you set them up to run one after the other? This is where my electrical wiring ignorance comes through, sorry.

Normally the best advice is to join batteries together into the largest bank possible. However, since you're "carrying in" a ways, you're probably better served by two 35 AH batteries that are used separately. Batteries can be joined, but best practice is to only join similar sizes bought at the same time - my boat's house bank is four large batteries permanently joined. Otherwise, use them one at a time, - lug the depleted battery back to the car and get a fresh one.

Each battery should have a "ring to quick connector" tail bolted on (and taped) so it can be swapped in quickly. I use a simple box to make carrying easy, and a splitter to have multiple items connected.

campervan wrote: ↑
Wed Jun 19, 2019 11:13 am

- Is the fancy battery box worth it? Does any other solution exist that's cheaper but still doesn't have me dealing with exposed wires and fiddling?

Using the splitter keeps mostly controlled. If you don't have something to fiddle with, where's the fun? With the quick connectors its easy to swap batteries - to my mind the box adds work if you have more than one battery.

campervan wrote: ↑
Wed Jun 19, 2019 11:13 am

- The battery would travel in the small crowded trunk of our car, where it would be unsecured by anything except its own weight (I'm not sure there would be anywhere to tie it down to in the trunk of a sedan.) Is that safe? Will the vibration of the car mess it up? What if it gets tipped over? Bumped? Dropped?

AGM batteries were designed to be stuffed into fighter jets; they can handled harsh environments, including upside down.

campervan wrote: ↑
Wed Jun 19, 2019 11:13 am

- Can a battery setup like this be kept inside a tent, especially a crowded one with a kid? Does it become hot? Is it dangerous to have unvented? I'm assuming it's okay to run in a trunk, but is it okay for anything else to be in the trunk with it/crowding it/touching it?

If the terminals are protected its totally safe. If it heats up, something is very, very wrong. You want to make absolutely sure nothing can short out the two terminals - the wires are protected by fuses, but if you were to lay a screwdriver across the terminals you would have a melted screwdriver!! This is why the box is recommended - you can get away with tape, but the box is better. If you're swapping batteries, tape up the lug and ring connector - the lugs should never be exposed.

However, there is nothing wrong with having it the tent. These are the same batteries thousands of seniors have in their mobility scooters.

campervan wrote: ↑
Wed Jun 19, 2019 11:13 am

- The CPAP needs a DC converter, but I can't find any long waterproof DC extension cords that I could run from the CPAP in our tent to the battery box in the trunk of our car (50 feet would be ideal but this seems impossible.) Is thIs there a way I can have that DC port in use and protected from the elements, so that the converter could plug into the CPAP at one end, inside the tent, and then go through the tent door to plug into the battery box outside the tent at the other end? Or do I need to plan on using the battery in the tent?

You can certainly run an cord any reasonable distance, but the problem is that most such cords with SAE quick connectors are thin so once you go over 12 to 25 feet the voltage drop might hurt. If its only 50 feet then lug it into the tent - that way you can charge the phones overnight.

campervan wrote: ↑
Wed Jun 19, 2019 11:13 am

- Lastly, is there a way I can get a minimum of 40-50 amp hours with a lightweight lithium ion setup for under $300? I am assuming no. The closer I can get this to $200, the better, but if the difference between $200 and $300 was 70 pounds and a bunch of work, the more expensive option sounds pretty good. I can't go over $325 max (and I will have a lot more money for vacation if I can do this cheaper) so I'd love some advice on what the real options are in my situation.

Maybe in a few years - $600 might get you 45 amp-hours today. But Lithium is still evolving; lead/acid has been developed for 150 years. And its cheap to add another battery when your needs change.

campervan wrote: ↑
Wed Jun 19, 2019 11:13 am

Thanks! I really appreciate the help! I have read all the posts and just haven't quite wrapped my head around it all yet - I apologize for any questions whose answers I missed in what has already been written. I'll look forward to hearing what you have to say!

campervan · Post by **campervan** » Thu Jun 20, 2019 10:53 am

Thank you for this, Loki! This is extremely helpful.

So how is this revised setup?

- Two Universal 35ah AGM deep cycle batteries ($130):
https://www.amazon.com/Universal-Power- ... 007Q2CUD0/

- Two small battery boxes, no frills ($23):
https://www.amazon.com/attwood-9082-1-S ... 0000B12YQ/

- Two sets of quick disconnect cables ($10):
https://www.amazon.com/Battery-Tender-0 ... 000NCOKZQ/

- One quick disconnect SAE to DC female adapter (to connect the CPAP to the battery - is this the right thing?) ($10):
https://www.amazon.com/Battery-Tender-0 ... 0041CDPQO/

- One Battery Tender 3 amp charger ($40) (link is to Amazon but will pick this up at Costco - thanks for the suggestion!):
https://www.amazon.com/Battery-Tender-P ... 016S7NHWQ/

- Battery Tender cigarette lighter adapter (I realize this might not be all that helpful but maybe a long car drive would be enough to top us off for another few hours' worth of charge) ($8):
https://www.amazon.com/Battery-Tender-B ... 003CJ927I/

- ResMed DC converter ($65)

So that brings the total cost to $286 for 70 ah, down from $335 for the 100 ah single battery with the Minntonka box (adding the more expensive charger and the quick disconnect cables) - $50 less, but for 2/3 the capacity. The price is about $4 per amp hour capacity with this solution, as opposed to $3.35 per with the 100 ah battery - but it seems like lugging around a 25 lb battery will be a lot better than one that's 60 lbs.

I do want to double check about dealing with the quick disconnect cables to plug in the CPAP, or to swap out batteries. Once the terminal quick-disconnect cables are installed on the battery, there are no more wires, right? I just have to plug in an SAE-to-cigarette-lighter cable to the terminal cable on the battery, and we're good to go?

- Would it be a good idea to get a voltage tester, so we knew when a battery was getting low? Is there a cheap but effective option?

Thanks so much! This is seeming much more doable and I am really liking the drop in price

CapnLoki · Post by **CapnLoki** » Thu Jun 20, 2019 12:44 pm

campervan wrote: ↑
Thu Jun 20, 2019 10:53 am
Thank you for this, Loki! This is extremely helpful.

So how is this revised setup?

- Two Universal 35ah AGM deep cycle batteries ($130):
https://www.amazon.com/Universal-Power- ... 007Q2CUD0/

- Two small battery boxes, no frills ($23):
https://www.amazon.com/attwood-9082-1-S ... 0000B12YQ/

Batteries are good. They may or may not come with bolts. Get stainless, 5/16 ths, I think.
Two boxes are fine - some might say two is overkill but its cheap protection since one will always be in the trunk.

campervan wrote: ↑
Thu Jun 20, 2019 10:53 am
- Two sets of quick disconnect cables ($10):
https://www.amazon.com/Battery-Tender-0 ... 000NCOKZQ/

Actually, one should come with the charger.

campervan wrote: ↑
Thu Jun 20, 2019 10:53 am

- One quick disconnect SAE to DC female adapter (to connect the CPAP to the battery - is this the right thing?) ($10):
https://www.amazon.com/Battery-Tender-0 ... 0041CDPQO/

Yes, that's what I have. As I've mentioned you can add the splitter to have a second socket or USB charger.

campervan wrote: ↑
Thu Jun 20, 2019 10:53 am

- One Battery Tender 3 amp charger ($40) (link is to Amazon but will pick this up at Costco - thanks for the suggestion!):
https://www.amazon.com/Battery-Tender-P ... 016S7NHWQ/

Good. I'm now jealous.

campervan wrote: ↑
Thu Jun 20, 2019 10:53 am

- Battery Tender cigarette lighter adapter (I realize this might not be all that helpful but maybe a long car drive would be enough to top us off for another few hours' worth of charge) ($8):
https://www.amazon.com/Battery-Tender-B ... 003CJ927I/

I knew this one was going to come up - it has to be discussed every year or so. The "SAE to Cigarette Plug" adapter is for charging a car's battery with a BatteryTender, NOT for charging an outside battery from a car's charging circuit. Unfortunately its not obvious to tell by looking at it, and with the system we're putting together it sure looks like it would work. However, ITS WIRED BACKWARDS!!! and will instantly pop the fuse (either in the car or in the battery wire).

I know this is confusing - I have to work it out from scratch every time! The problem is the plug is a "hermaphrodite" meaning the male and female are symmetrical can be either hot or ground depending on the situation. The convention on cars is that the wire connected to the battery has to have the ground side exposed and the hot side is a protected socket. Thus, on the charger its the reverse. This means that the cigarette plug adapter has to look like a battery (i.e. ground exposed) and not a charger (hot exposed). If you connected the cigarette adapter to the battery adaptor you would have hot to ground and a literal meltdown - hopefully just fuses (You do have lots of spares of all the fuses. Of course you do.)

So how do you deal with this? The obvious solution is to cut the cable and reverse the SAE socket, or open the cigarette plug and do the same. Or get an SAE plug extension and reverse it. If playing with a soldering iron is fun for you, then go for it - just make sure you mark the cord as being non-standard. The other, sleezier way of handling it is to use a "1 to 5" splitter that I've mentioned on occasion, and connect the battery adapter and the cigarette adapter to 2 of the 5 side plugs. This will properly connect the two hots together, not hot to ground.

One more thing. I've mentioned that a depleted U1 can accept 9 amps. One a given day it might be 10 or 11, and traditionally the car fuse the cigarette socket is 10 amps. Newer SUVs have "power outlets" that are fused at 15 to 20 amps. If the battery is only at 50% it may only draw 6 amps, but if its dead it would be easy to pop a 10 amp fuse. Clearly, some experimenting is needed!

campervan wrote: ↑
Thu Jun 20, 2019 10:53 am

- ResMed DC converter ($65)

So that brings the total cost to $286 for 70 ah, down from $335 for the 100 ah single battery with the Minntonka box (adding the more expensive charger and the quick disconnect cables) - $50 less, but for 2/3 the capacity. The price is about $4 per amp hour capacity with this solution, as opposed to $3.35 per with the 100 ah battery - but it seems like lugging around a 25 lb battery will be a lot better than one that's 60 lbs.

I do want to double check about dealing with the quick disconnect cables to plug in the CPAP, or to swap out batteries. Once the terminal quick-disconnect cables are installed on the battery, there are no more wires, right? I just have to plug in an SAE-to-cigarette-lighter cable to the terminal cable on the battery, and we're good to go?

Yes, except for the quirk of trying to charge from the car, its pretty safe. If you use the "1 to 5" splitter make sure you always identify the "1 side" and the "5 side" and think about what you're doing because you'll have some extra sockets and they all look the same. And although this shouldn't be too hard for a sober adult, I don't think I'd let a toddler near it!

campervan wrote: ↑
Thu Jun 20, 2019 10:53 am
- Would it be a good idea to get a voltage tester, so we knew when a battery was getting low? Is there a cheap but effective option?

Yes, get two! Any lingering doubts about which is the hot side and which is the ground can be resolved with a digital volt meter, which shows + and -. Also, the only easy way tell the State of Charge is with a voltmeter, and remember its only an approximation. There are proper "amp-hour meters" but the're expensive; I actually have a small one wired with SAE connectors, but that's for another post.

If you really get into it, add the splitter and an extra socket, and then get a 12V meter to go in the socket. If you're like me, you'll wake up three times a night to check the voltage!

campervan wrote: ↑
Thu Jun 20, 2019 10:53 am

Thanks so much! This is seeming much more doable and I am really liking the drop in price

Hoot55 · Post by **Hoot55** » Thu Jun 20, 2019 3:51 pm

Any thoughts on using a Zopek battery (AC 54k)? 160 watt hrs, ~$250, no additional cords required.

I’m getting a Z2 for travel/camping and need multi-night battery capability.

CapnLoki · Post by **CapnLoki** » Fri Jun 21, 2019 4:23 am

Hoot55 wrote: ↑
Thu Jun 20, 2019 3:51 pm
Any thoughts on using a Zopek battery (AC 54k)? 160 watt hrs, ~$250, no additional cords required.

I’m getting a Z2 for travel/camping and need multi-night battery capability.

I'm not a fan of a battery pack that doesn't have a DC outlet and only uses an inefficient inverter. Also, I don't much care for the Z1/Z2. That said, it looks like it should work. If your primary need is use it on an airplane, this may be a reasonable choice. But for general travel a DreamStation is less than a pound heavier and runs off any 12V source and is a much superior cpap.

Hoot55 · Post by **Hoot55** » Fri Jun 21, 2019 8:25 am

CapnLoki wrote: ↑
Fri Jun 21, 2019 4:23 am

Hoot55 wrote: ↑
Thu Jun 20, 2019 3:51 pm
Any thoughts on using a Zopek battery (AC 54k)? 160 watt hrs, ~$250, no additional cords required.

I’m getting a Z2 for travel/camping and need multi-night battery capability.
I'm not a fan of a battery pack that doesn't have a DC outlet and only uses an inefficient inverter. Also, I don't much care for the Z1/Z2. That said, it looks like it should work. If your primary need is use it on an airplane, this may be a reasonable choice. But for general travel a DreamStation is less than a pound heavier and runs off any 12V source and is a much superior cpap.

Thx for the feedback; newbie here so I need all the advice I can get. I need multi-night (3+) off grid operation for backpacking. So, it seems my choices are the Zopek (3# & $250) or two Z2 powered pack batteries (3.2# & $790). I think both have solar capability so, that may also be an option. For clarity, the Z2 can also run on DC power, and the Zopek can be charged via DC power. Any other off grid setups being used or suggested?

CapnLoki · Post by **CapnLoki** » Fri Jun 21, 2019 9:15 am

Hoot55 wrote: ↑
Fri Jun 21, 2019 8:25 am
Thx for the feedback; newbie here so I need all the advice I can get. I need multi-night (3+) off grid operation for backpacking. So, it seems my choices are the Zopek (3# & $250) or two Z2 powered pack batteries (3.2# & $790). I think both have solar capability so, that may also be an option. For clarity, the Z2 can also run on DC power, and the Zopek can be charged via DC power. Any other off grid setups being used or suggested?

Since the Z2 can be used with a 12V cord, there are a large number of Lithium packs from 100 to 500 watt-hours. Some have a "cigarette socket," others have a small DC plug in (5.5 mm ??) that connects to a socket. The Z2 should use under 50 watt-hours, but a lot depends on settings. 100 might work for 3 nights - you'll have to experiment.

So what do you mean my "backpacking"? Are you completely gone for 3+ nights (and how many is "+"?), or do you return to a car? And solar is a lot easier to say than to do! A small panel, setup in the woods after a day's hike will gather very little juice even on a sunny day.

BTW, the is a thread about homemade battery packs used for an ascent of Kilimanjaro - that's the best minimalist setup I've seen.

Hoot55 · Post by **Hoot55** » Fri Jun 21, 2019 9:26 am

CapnLoki wrote: ↑
Fri Jun 21, 2019 9:15 am

Hoot55 wrote: ↑
Fri Jun 21, 2019 8:25 am
Thx for the feedback; newbie here so I need all the advice I can get. I need multi-night (3+) off grid operation for backpacking. So, it seems my choices are the Zopek (3# & $250) or two Z2 powered pack batteries (3.2# & $790). I think both have solar capability so, that may also be an option. For clarity, the Z2 can also run on DC power, and the Zopek can be charged via DC power. Any other off grid setups being used or suggested?
Since the Z2 can be used with a 12V cord, there are a large number of Lithium packs from 100 to 500 watt-hours. Some have a "cigarette socket," others have a small DC plug in (5.5 mm ??) that connects to a socket. The Z2 should use under 50 watt-hours, but a lot depends on settings. 100 might work for 3 nights - you'll have to experiment.

So what do you mean my "backpacking"? Are you completely gone for 3+ nights (and how many is "+"?), or do you return to a car? And solar is a lot easier to say than to do! A small panel, setup in the woods after a day's hike will gather very little juice even on a sunny day.

BTW, the is a thread about homemade battery packs used for an ascent of Kilimanjaro - that's the best minimalist setup I've seen.

3 nights to start, but would like the ability to extend that. Yes, completely gone for 3 nights, no car or power available. If you/anyone can recommend Lithium battery packs that will last that long, that would be great.

Hoot55 · Post by **Hoot55** » Sat Jun 22, 2019 8:07 am

Hoot55 wrote: ↑
Fri Jun 21, 2019 9:26 am

CapnLoki wrote: ↑
Fri Jun 21, 2019 9:15 am

Hoot55 wrote: ↑
Fri Jun 21, 2019 8:25 am
Thx for the feedback; newbie here so I need all the advice I can get. I need multi-night (3+) off grid operation for backpacking. So, it seems my choices are the Zopek (3# & $250) or two Z2 powered pack batteries (3.2# & $790). I think both have solar capability so, that may also be an option. For clarity, the Z2 can also run on DC power, and the Zopek can be charged via DC power. Any other off grid setups being used or suggested?
Since the Z2 can be used with a 12V cord, there are a large number of Lithium packs from 100 to 500 watt-hours. Some have a "cigarette socket," others have a small DC plug in (5.5 mm ??) that connects to a socket. The Z2 should use under 50 watt-hours, but a lot depends on settings. 100 might work for 3 nights - you'll have to experiment.

So what do you mean my "backpacking"? Are you completely gone for 3+ nights (and how many is "+"?), or do you return to a car? And solar is a lot easier to say than to do! A small panel, setup in the woods after a day's hike will gather very little juice even on a sunny day.

BTW, the is a thread about homemade battery packs used for an ascent of Kilimanjaro - that's the best minimalist setup I've seen.
3 nights to start, but would like the ability to extend that. Yes, completely gone for 3 nights, no car or power available. If you/anyone can recommend Lithium battery packs that will last that long, that would be great.

Found what seems a better choice; DC output & more capacity for ~same $$$ as the Zopek: MAXOAK CPAP battery, 297 Wh, 4#, $299. I could definitely pack that in for a multi day trip off grid. One downside is it’s not FAA compliant; I’m guessing it’s too much capacity. But, seems great for camping. My max pressure is 10 so, using your guideline from earlier posts, (~5aH/night) I could go for a couple weeks. I do need to experiment though. Just ordered Z2, which I’ll use at home for a bit, then will get battery for a trial.

Dog Slobber · Post by **Dog Slobber** » Sat Jun 22, 2019 8:28 am

Hoot55 wrote: ↑
Sat Jun 22, 2019 8:07 am

Found what seems a better choice; DC output & more capacity for ~same $$$ as the Zopek: MAXOAK CPAP battery, 297 Wh, 4#, $299. I could definitely pack that in for a multi day trip off grid. One downside is it’s not FAA compliant; I’m guessing it’s too much capacity. But, seems great for camping. My max pressure is 10 so, using your guideline from earlier posts, (~5aH/night) I could go for a couple weeks. I do need to experiment though. Just ordered Z2, which I’ll use at home for a bit, then will get battery for a trial.

Worth adding that with the MAXOAK you also save money by not having to buy the expensive ResMed DC-DC power brick, (about $75.00).

The MAXOAK has a 24v output and ResMed AirSense 10 cable.

pdrhound · Post by **pdrhound** » Sun Jun 23, 2019 10:37 am

CapnLoki wrote: ↑
Tue Jun 18, 2019 8:42 am

pdrhound wrote: ↑
Mon Jun 17, 2019 6:10 pm
HOW DOES THIS LOOK FOR CAR CAMPING SETUP?

72 bucks.png
It looks OK but the battery is a bit on the small side. For another $25 you could have double the juice and not worry about charging everyday. So I guess it really depends on how much the remstar uses and how long you're staying out. My guess is it will go 2 nights with a fair margin; a U1 battery might go 5 nights. And exactly how were you planning to charge every day?

Just wanted to follow up on my $71 battery set up for my airsense 10

1. 12v to 24 v DC cable can be had at Walmart online for $65. So the real total for me was $136.

2. I average 11.4 on my blow. I just used this $40 18AH battery for 2 nights with no humidity and I had a total if 15 hours of use. This is perfect for my 2 nights of camping.

3. my first night the pressure zoomed up the AUTO scale????? I did a mask fit and it slowed down. Did not happen since.

I want to thank capnloki for all his information. I do understand that Iam taking this battery below %50 in 2 nights and that may shorten battery life to 200 cycles. 200 cycles x 2 nights is 400 nights or 10 cents a night for the battery. 60% less weight the trade is simple for me. It will last probably ten years at 40 nights a year.

This is really just a test for me and the bonus is an emergency backup for a random power outage.

My main goal is to run a travel CPAP with a lithium Ion battery back that can charged with the 12 volt power on my motorcycle. I know it is done, i just wish someone would package up some reasonably priced compatible components

I'd really like to use this pack.

https://www.amazon.com/Poweradd-Pilot-P ... B00DN0KBXU

and the Z2 APAP for easy (small and light) 12 volt cord fro $26.

campervan · Post by **campervan** » Fri Jun 28, 2019 8:43 am

Thank you so much, Loki! Okay, so I've added a couple of the things you suggested: the final setup in my cart now is:

- Two Universal Power Group 35Ah AGM batteries ($134): (same as before)
https://www.amazon.com/gp/product/B007Q2CUD0/

- Two small battery boxes ($12x2 = $24):(same as before)
https://www.amazon.com/gp/product/B0000B12YQ/

- Battery Tender 12v 1.25 amp charger (the $40 3 amp was sold out) ($41):
https://www.amazon.com/gp/product/B00DJ5KEEA/

- One extra Battery Tender 6-ring terminal harness with quick disconnect plug (the second will come with the charger, right?) ($5):(same as before)
https://www.amazon.com/gp/product/B000NCOKZQ/

- One 5-way SAE adapter ($10):
https://www.amazon.com/gp/product/B003L643KS/

- One SAE to female cigarette lighter adapter (I found one cheaper than the Battery Tender model with equally great reviews) ($7):
https://www.amazon.com/gp/product/B01E04YWNC/

- One 5V 4.8A SAE to USB adapter, has a voltage meter? Is that sufficient? ($14):
https://www.amazon.com/gp/product/B07N1993MV/

Then, I don't know if I need a separate battery meter? I like the idea of this - both a battery level meter and a voltage meter - but (a) I'm not sure that this is the right thing for the job (b) I don't know if the volt meter attached to the USB adapter is adequate and (c) I don't know if this can be wired to the battery at the same time as everything else that needs to be connected to it (forgive my ignorance of the actual electrical details) or if I would need to do a significant amount of wiring (ie practically any) to make it work.

https://www.amazon.com/Capacity-Waterpr ... 07GQ4VGTB/

I'd also love to know what to do with those other two SAE terminals on the splitter! The USB port I listed has two sockets, which seems like plenty (I suppose we have three devices but still.)

I don't think I trust the charge-the-battery-using-the-car rigging you described - I'd rather just deal with the battery capacity we have left until we get back to an AC outlet. I would rather not take the chance.

So the total cost is $235, unless I've missed something - or about $4.50 per usable amp hour of capacity (assuming running each battery down to 25%.) If we run each battery down to 25% (which I don't mind because we'll only do it maybe 2-3x a year per battery), at 8 Ah/night, my husband should be able to get 3+ nights per battery (or more, since he doesn't usually get 8 hours camping), plus we should be able to charge our various electronic devices for the trip. That buys us 6 nights in the woods with this setup. If I want to get 9 nights for our trip to Yellowstone next year, I can spend another $120 and set up a third battery.

Thanks again! This has been supremely helpful.

CapnLoki · Post by **CapnLoki** » Fri Jun 28, 2019 5:45 pm

campervan wrote: ↑
Fri Jun 28, 2019 8:43 am
Thank you so much, Loki! Okay, so I've added a couple of the things you suggested: the final setup in my cart now is:
...

This all looks good. As for measuring the battery state, that's always a problem. Voltage roughly corresponds to State of Charge, but there are a lot of variables so you really have to watch for a while and build some experience. You can start by googling "agm voltage state of charge". Ultimately, you need an amp-hour meter, but they tend to be expensive and/or have to be wired up. I'm actually putting together a new one this weekend, so I may be doing a report on it soon.

bbergin76 · Post by **bbergin76** » Thu Jul 11, 2019 6:05 pm

Lane101 wrote: ↑
Fri Jun 14, 2019 11:45 am
Hi Bbergin 76,

The ExpertPower 12200 battery terminals work well with O-Ring adapter connectors; mine are hooked up that way. Just screw the connectors on. Note that my battery packs use o-ring connectors that are smaller than those on the Deltran (custom spliced 12 awg wire with Anderson Pole connectors on the other end) for both of my battery packs. The M5 bolts on the 1200 battery are 5mm across while the Deltran connectors are 3/8" (approx. 9.5 mm). You will need to check if a wider washer to hold the connectors securely. Once connected any exposed connections should be covered with electrical tape for added safety. Be careful when connecting wires to the battery terminal. A battery of this size can generate over 200 amps in a short circuit (even more for a full U1 size). I typically keep one terminal covered with electrical tape when making direct to battery connections. If you to the multiple battery route (one U1 and a second half-U1 size) you should by an extra Deltran SAE/O-ring connector so you don't have to deal with exposed terminals while camping.

Note, if you are referring the the Mighty Max U1 35ah battery the O-rings should also work. You may need to purchase connection hardware for this one (nuts, bolts and locknut washers). Again need to match hardware size to O-rings and battery terminals. One of my original half-U1 batteries had terminals like this.

U1 is a battery size. The Exp12200 and similar 18 - 22 amp hour batteries are often referred to as Half-U1 size. Note that while the Exp12200 specifications allow charging at up to 6 amps per hour it is more optimal to keep the charging rate below 4 amps/hour (referred to as .2 of Capacity or "C"). Would recommend the 3 amp charger as ideal if you also have a separate U1 battery.

Absolutely stick with AGM batteries for camping. They are the safest lead-acid type battery and the only type that does not vent gasses unless damaged or overcharged. Both Gel and flooded lead-acid require venting (source Battery University @ batteryuniversity.com). AGM is the only type I would use indoors or in a tent. Also, you can use 80% of an AGM battery's capacity versus a max of 50% of a flooded batter without damaging it.

P.S. Regarding Goofproof's comment. It is correct, we are seeking to protect both the device and the wiring from a current overload and one size often doesn't fit all. In your specific case, for charging with a Deltran Battery Tender (3 amp or less) and use of a Dreamstation, a 7.5 amp should protect both the CPAP, charger and wires given that it is the specified/provided fuse for the Deltran and below the 8 amps provided in the Dreamstation DC connector.

Good example of Goofproof's point is my set up (more complex with an inverter and solar power) where I use a 15 amp fuse on a 12 awg main battery connector with lower capacity fuses for the various items (bespoke Anderson pole connector for each that plugs into the main battery cable) in my modular system including:

- 5 amp fuse for my CPAP machines - 18 awg with barrel connector for CPAP with Anderson connectors for battery connection
- 7.5 amp fuse for the 3 amp Deltran charger - use the connector provided by Deltran, cut off the O-rings and spliced on the Anderson connectors
- 5 amp fuse for the solar panel wire (cable connects to solar charge controller)
- 7.5 amp fuse on my NOCO cigarette lighter socket (use to charge phones with a USB charger in the socket and to run our air mattress inflater)
- no additional fuse for the 400 watt inverter - 15 amp main cable fuse is more than sufficient as I want to cap the power draw to 180 watts given the size of my batteries. Also the inverter has its own fuses.

My system evolved over time. Started with just an 18 awg barrel connector cable for my CPAP with just a 5 amp fuse and one battery. Bought a second to camp more that 2 -3 nights. Later added an inverter that also had USB chargers that required the separate 12 awg cable to support it. Added the solar panel last year to support a week long camping trip to Assateague Island. Converted to Anderson pole connectors with the addition of the solar panel and also added the NOCO cigarette lighter adapter at the same time. Sounds like you don't require this level of complexity for your needs.

Hi Lane,

Sorry to resurrect on old post here. I've built my 35Ah battery for my wife's CPAP and its working well in testing, now I am looking to build a smaller 20Ah battery to be able to recharge electronics and blow up our air mattresses. This is what I am looking at and was wondering of your input.

Battery: https://www.amazon.com/ExpertPower-EXP1 ... way&sr=8-1
Connector: https://www.amazon.com/NOCO-GC018-Adapt ... ive&sr=1-1 Should I look to use a smaller fuse than the 15A that it comes with?
Inverter: https://www.amazon.com/Ampeak-400W-Powe ... way&sr=8-3 to be able to connect various electronics for charging.

Could it really be that simple, or am I missing something? I would of course get a box to be able to contain the battery.

CapnLoki · Post by **CapnLoki** » Thu Jul 11, 2019 7:10 pm

bbergin76 wrote: ↑
Thu Jul 11, 2019 6:05 pm

Hi Lane,

Sorry to resurrect on old post here. I've built my 35Ah battery for my wife's CPAP and its working well in testing, now I am looking to build a smaller 20Ah battery to be able to recharge electronics and blow up our air mattresses. This is what I am looking at and was wondering of your input.

Battery: https://www.amazon.com/ExpertPower-EXP1 ... way&sr=8-1
Connector: https://www.amazon.com/NOCO-GC018-Adapt ... ive&sr=1-1 Should I look to use a smaller fuse than the 15A that it comes with?
Inverter: https://www.amazon.com/Ampeak-400W-Powe ... way&sr=8-3 to be able to connect various electronics for charging.

Could it really be that simple, or am I missing something? I would of course get a box to be able to contain the battery.

Yup, its just that simple!

As for the fuse, its mainly to protect the wiring so its sized for the gauge of the wire, as it should be given that you don't know what your load will be. If you knew there was some other upper limit you could reduce the fuse appropriately. BTW, the 400 watt inverter could easily have a 40 to 50 amp load (or more) so bring extra fuses! Don't be tempted to increase the fuse size as it is close to maxed for the wire.

You don't mention charging - I like using the BatteryTender quick connects; you can also use the cigarette socket plug. I don't like alligator clips - they are an accident waiting to happen.

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