Choosing a Battery

[Lane101]

Hi Bbergin, Responses to your questions below:

You were talking about needing to change out fuses on the quick disconnect. Can you explain that more? When its connected to the CPAP you use a 5A fuse but what do you use when its connected to charger? Or is that where you are talking about using a separate quick disconnect at 7.5A?

The Deltran chargers come with a separate quick disconnect (SAE connector) with its own 7.5amp fuse in the case of the 3 amp version at Costco. If you purchase the 1.25 amp charger you should confirm its fusing.

I just took a look at your DreamStation DC Shielded Cord guide and it includes a 8 amp fuse (versus 5 amps for my machines) so you may not need a separate fuse for your CPAP as is the case with my machines. The 7.5 amp fuse in the Deltran SAE O-ring battery connector will be fine for both charging and CPAP use. You can use the SAE cigarette lighter socket from your earlier post and be fine. If you decide to go with separate quick disconnects you should still drop the NOCO 15 amp fuse (pushing it for the adapter's 16 awg wiring) to 7.5 or 5 amps (either will be fine for the less than one amp per hour DreamStation current draw.

Is there a way to monitor my usage on the battery? There was a device mentioned by CapnLoki earlier in the thread but it looks to need to be spliced in. Is there any way to do it without splicing in?

Spliced in voltmeter is best. You can use a multimeter (set to DC voltage) to periodically check battery voltage for ad hoc measurement - not as good.

I'm starting to consider a smaller secondary battery (18AH? 20AH?) to support maintaining of the speaker and cellphones for music.



See my original May 17th post on this thread - I use seperate 20 ah batteries for a more modular approach. Note that you will need to purchase an extra set of quick disconnects for this.

Thanks again for the insight. Both you and have CapnLoki have been a big help and this is turning in to something that doesn't seem to be too difficult to pull off, just trying to figure out how to size it correctly.

[Goofproof]

The purpose of a Fuse in a device is to protect the device from damage in case of a overload of current, that's why to function correctly to disconnect the device from the power. If the fuse it too high a amp, it can destroy the device, or support a fire. This is why autos have fuse blocks, one fuse is needed for each circuit and one size doesn't fit all. Modern cars have many different fuse boxes mounted in different places, each with many different kinds of fuses. The wiring to each fuse must be able to carry more current than the Fuse is rated for, Jim

[bbergin76]

See my original May 17th post on this thread - I use seperate 20 ah batteries for a more modular approach. Note that you will need to purchase an extra set of quick disconnects for this.

Hi Lane,

I took a look at your original post and looked at the battery you had referenced. Looks like it has a different type of terminal post than the other battery I looked at and the other one you mentioned previous in my post. Does a ring connector still work with that type of terminal post or would I need to come up with something different? Simpler the better for me, since I'm not terribly mechanical (although I'd love to develop that skill).

From what I can tell U1 is just a size correct? I just need to make sure I stick with AGM batteries?

Thanks again, I really do appreciate the help you've been giving me.

[Lane101]

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.

[pdrhound]

HOW DOES THIS LOOK FOR CAR CAMPING SETUP?

72 bucks.png (109.38 KiB) Viewed 16086 times

[Midwest_non_sleeper]

I need to get in on this thread, the recent storms that came through the midwest this past weekend (we had two confirmed on the ground tornadoes) caused us to lose power for awhile. Thankfully, power was restored before bedtime, but it lit a fire under my posterior to get a power alternative in place for these circumstances.

[CapnLoki]

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?

[CapnLoki]

I need to get in on this thread, the recent storms that came through the midwest this past weekend (we had two confirmed on the ground tornadoes) caused us to lose power for awhile. Thankfully, power was restored before bedtime, but it lit a fire under my posterior to get a power alternative in place for these circumstances.

The system listed in about the 10th post, based on a U1 AGM battery (35 amp-hours) is a good starting point. The question you have to figure out is whether you need a larger battery - perhaps 50 to 100 amp-hours instead of 35. The U1 size is fine if you're preparing for a 1-2 night outage; if you're thinking 3-7 nights you'll want more juice. Beyond that a generator or solar is the way to go.

[Midwest_non_sleeper]

I need to get in on this thread, the recent storms that came through the midwest this past weekend (we had two confirmed on the ground tornadoes) caused us to lose power for awhile. Thankfully, power was restored before bedtime, but it lit a fire under my posterior to get a power alternative in place for these circumstances.

The system listed in about the 10th post, based on a U1 AGM battery (35 amp-hours) is a good starting point. The question you have to figure out is whether you need a larger battery - perhaps 50 to 100 amp-hours instead of 35. The U1 size is fine if you're preparing for a 1-2 night outage; if you're thinking 3-7 nights you'll want more juice. Beyond that a generator or solar is the way to go.

Thanks for the reply. I was thinking about that and found a deep cycle marine battery with over 100AH. That should last for a good while, without the use of humidifier of course. When the power goes out here, it could be a few days before it's back on, depending on the severity of the storms that passed through. Tornadoes came through on Saturday and there are some that are still without power right now.

I appreciate the still very helpful post regarding alternative power sources that you put together.

[CapnLoki]

... I was thinking about that and found a deep cycle marine battery with over 100AH.

Just two things: Although a "Deep Cycle Marine Battery" is the traditional advice, I strongly recommend an AGM battery (which should also be deep cycle, and may be sold as "marine") because they are essentially sealed and cannot spill acid. A traditional flooded battery, even if labeled "maintenance free" is really just a bucket of sulfuric acid, and not safe for indoor use. The other issue is to use a gentle trickle charger, like the BatteryTender because the common cause of battery problems is overcharging caused be cheap automotive quick chargers.

[Midwest_non_sleeper]

... I was thinking about that and found a deep cycle marine battery with over 100AH.

Just two things: Although a "Deep Cycle Marine Battery" is the traditional advice, I strongly recommend an AGM battery (which should also be deep cycle, and may be sold as "marine") because they are essentially sealed and cannot spill acid. A traditional flooded battery, even if labeled "maintenance free" is really just a bucket of sulfuric acid, and not safe for indoor use. The other issue is to use a gentle trickle charger, like the BatteryTender because the common cause of battery problems is overcharging caused be cheap automotive quick chargers.

Ah, noted, thank you. Would you recommend a very slow charger? 1 amp or lower?

[CapnLoki]

... I was thinking about that and found a deep cycle marine battery with over 100AH.

Just two things: Although a "Deep Cycle Marine Battery" is the traditional advice, I strongly recommend an AGM battery (which should also be deep cycle, and may be sold as "marine") because they are essentially sealed and cannot spill acid. A traditional flooded battery, even if labeled "maintenance free" is really just a bucket of sulfuric acid, and not safe for indoor use. The other issue is to use a gentle trickle charger, like the BatteryTender because the common cause of battery problems is overcharging caused be cheap automotive quick chargers.

Ah, noted, thank you. Would you recommend a very slow charger? 1 amp or lower?

There's no exact answer, and it depends on the size of the battery. I use a BatteryTender 1.25 amp charger for my U1 - it does fine keeping it topped off, but its a bit tedious replacing a big discharge. If I had a 80-100 amp-hour battery, I'd probably get the larger 5 amp charger. One key element is that the charger has enough intelligence and robust design to recognize that a battery is near full charge and taper of to a trickle, with no chance of running amuck if left unattended. This is why I like Batterytender, who's been playing this game for over 50 years.

BTW, on the low end, a trickle charger needs to replace 1-2% per day of "self discharge," so even the "baby" 0.75 amp charger can handle that for a large battery. In the high end, a battery can accept about 25% of its amp-hour rating, so a 35 ah U1 battery can accept about 9 amps from a larger charger; trying to charge faster would likely mean running the voltage too high. And even then, there's no way to top off a battery quickly - the last 15% takes time. So its a big balancing act - sometimes you want to be gentle and maximize the life of the battery, other times you're pushing to get the most into it in the least time. Two things help: an over sized battery, and quality electronics.

[Midwest_non_sleeper]

... I was thinking about that and found a deep cycle marine battery with over 100AH.

Just two things: Although a "Deep Cycle Marine Battery" is the traditional advice, I strongly recommend an AGM battery (which should also be deep cycle, and may be sold as "marine") because they are essentially sealed and cannot spill acid. A traditional flooded battery, even if labeled "maintenance free" is really just a bucket of sulfuric acid, and not safe for indoor use. The other issue is to use a gentle trickle charger, like the BatteryTender because the common cause of battery problems is overcharging caused be cheap automotive quick chargers.

Ah, noted, thank you. Would you recommend a very slow charger? 1 amp or lower?

There's no exact answer, and it depends on the size of the battery. I use a BatteryTender 1.25 amp charger for my U1 - it does fine keeping it topped off, but its a bit tedious replacing a big discharge. If I had a 80-100 amp-hour battery, I'd probably get the larger 5 amp charger. One key element is that the charger has enough intelligence and robust design to recognize that a battery is near full charge and taper of to a trickle, with no chance of running amuck if left unattended. This is why I like Batterytender, who's been playing this game for over 50 years.

BTW, on the low end, a trickle charger needs to replace 1-2% per day of "self discharge," so even the "baby" 0.75 amp charger can handle that for a large battery. In the high end, a battery can accept about 25% of its amp-hour rating, so a 35 ah U1 battery can accept about 9 amps from a larger charger; trying to charge faster would likely mean running the voltage too high. And even then, there's no way to top off a battery quickly - the last 15% takes time. So its a big balancing act - sometimes you want to be gentle and maximize the life of the battery, other time you're pushing to get the most into it in the least time. Two things help: an oversize sized battery, and quality electronics.

Very informative, I did not know all of that. I'll have to give this some more consideration before just springing for whatever comes up first on Amazon.

[Goofproof]

It's not that hard. If the U1 35 amp will cover 4 nights, and the Avg outage is 3 days or less max, the 1.25 amp would be back on to charge it up. If it lasts longer bigger would be better. This could be a second U1 35 amp or a bigger U1 battery to begin with. the two smaller would add better functionally, and be easier to move around, one could fail and you would still be good, or you could add a second battery later. Jim

[campervan]

Hi! I've read this whole thread and found it very helpful, though I'm sure there are things that I missed. I have a setup I'm hoping will work, plus a bunch of questions about the right decisions to make for my situation - I'm hoping you can help point me in the right direction.

My husband uses a Resmed Airsense 10 Elite CPAP, with a pressure of 10 and no humidifier/temperature control. According to ResMed, it would use about 1 ah per hour of use with a converter (they recommend rounding up 50% to 1.5 ah/hr, but I'm not sure if that's necessary.) I want to set us up with a cheap, safe, easy way to power his CPAP for 5 nights without recharging at 7 hrs/night. So I think I'm looking for a battery with 35 ah (+/-55 if Resmed's +50% cushion recommendation is a good one.) I'd like to have a little wiggle room to be able to charge phones and such, so I'd like to know if I should size up. Also, if we end up with a battery big enough to handle 7 nights camping with only minimal charging time, that would be amazing - but I'd have to balance it with whether I was carting something that weighs 30 lbs into the woods, or 75.

I don't mind charging the battery down heavily without recharging, because we'll only take one or two longer camping trips like this a year, and the rest of the time we'd use it would be for weekend use, and we can recharge before we get below 50%.

What I'm hoping for is a battery that:

- 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


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/

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

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

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.

- 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?

- 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?

- 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?

- 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?

- 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.

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!