What do I need?

[bandaidqueen]

I am being gifted two 12v deep-cycle batteries this weekend (I think one is 100 a/h and the other is 60 or so?). I need to know the minimum I need to be able to use and charge these batteries. I've been using a small Jackery "Portable Power Station" as they call it, I bring it inside to work and plug it in every day to charge it. It has USB ports and everything built in - not much power but enough to run a USB fan and charge my cell phone, and it's very simple. Now I'll have REAL batteries to charge stuff, run the indirect swamp cooler AC I've been working on (2 fans, 2 water pumps, a car heater core, not done yet but I'm SO curious to see if it will actually work), run a 12v fridge and lights and security cameras sometime in the future. I want to charge the batteries when I'm driving (might add solar in the future but not sure). My co-worker who is giving me the batteries can help me a little with installing and wiring but I think I'll need some additional components. This electrical stuff mystifies me, although I've been reading here and there for almost 2 years, everyone says something a little bit different and it all sounds like a foreign language to me. Sooooo..... what is the most basic stuff I will need for the moment, to keep my batteries alive and happy and connect a few things to them? I can always add more later as I progress on the build. Thanks for all your help everyone!

 

[Weight]

Minimum? need to charge battery. So, a battery charger to plug into wall. A wall outlet to plug into. Alternative, solar panels and charge controller. Like a Renogy kit from Amazon. Next alternative; Not all that great unless you don't use much power, a device to connect the "house" battery and vehicle alternator. Generally called a battery combiner. I recommend an automatic to avoid mistakes. If you decide to try that, it does require a lot of driving. Then you need unused batteries as we have no idea if they are murdered or even abused. Last but should be first a firm anchor to keep battery from bashing in your head if crash landing. Then there are fuses, everyone forgets fuses.

 

[B and C]

Consider charging from the alternator as supplemental charging and not primary unless you are driving hours every day. Solar will charge all day while you are at work.

You have a mismatched battery bank. Ideally both batteries should be the same everything (chemistry, Ah capacity and age). Your bank wired in parallel is 160 Ah of which up to 80 is usable if these are lead acid batteries.

Knowing how much power your devices use and for how long is the real starting point. You jumped to step 2.

1. How many amps a day use.
2. Battery sized to load (or oversized for load is good too as batteries cycled less deeply will last longer).
3. Solar sized to battery.

I think you have seen this list posted on this site already.

You will need a continuous duty solenoid, probably 4 ga cable and a 150 amp fuse at the house battery and one at the alternator (best place to connect) if using 4 ga. A ground cable from your new battery bank to the frame for a return path (not sheet metal).

 

[desert_sailing]

Hey there Queen!

The link I have posted here I have found to be one of the best explanations ever on figuring  solar needs.  It is very clear and has a great sequence.

I highly recommend it. I have zero starting knowledge on this and wish I had found that site long long ago.

https://batterymanguide.com/how-many-watt-solar-panel-to-charge-deep-cycle-battery/

 

[bandaidqueen]

Thank you desert_sailing! It's going to be a while before I can put any solar on, but I do want to do that in the future. I'll be charging these bad boys with the alternator for a while, either with a solenoid, or smart isolator, or DC to DC charger which seems to be the best option to not put strain on the alternator (like this one https://www.amazon.com/Renogy-Battery-Batteries-Multi-stage-Charging/dp/B07Q5VYPCF/). Might even use a battery charger that I plug in during the day like I've done with the small Jackery. My power needs at the moment are very low, and my budget is very limited, I just got really lucky with the free batteries (my co-worker looked them up online and said they are over $500/each new, these are used but only slightly). I'm just trying to figure out what I'll have to buy to make them work for the next few months - wires, connectors, fuses, battery monitor, some kind of charger, etc. I'm NOT smart with electrical stuff but my needs are really basic for now. There's a lot of information online and on this forum but it's a bit overwhelming. I'm working on it though. Thanks again everyone!

 

[Qxxx]

First off, as Brian mentioned it's probably not a good idea to mix different types and/or size of batteries, eg 100 and 60 AH, in the same setup.

Everyone has their own opinions of course (YMMV), and I know you feel somewhat obligated now that you've been "gifted", but my feeling is you should get rid of those batteries, and go with a Portable Power Station. DIY electrics is just too difficult ... and also dangerous ... unless you get some professional help, despite all the hundreds and hundreds of advice prone posts on this forum. I just posted more on this on d-s' thread.
https://vanlivingforum.com/showthread.php?tid=40901

 

[barleyguy]

This is slightly expensive, but Renogy makes a DC to DC charger that"s also an MPPT solar charger. You connect your starter battery, your house battery, and a solar panel to it, and it handles everything. (Except fuses. I would definitely add fuses.)

www.renogy.com/dcc50s-12v-50a-dc-dc-on-board-battery-charger-with-mppt/?afmc=32

Personally, I would keep the 100 ah battery if it's in good condition, and pass the 60 ah on to someone else.

As far as DIY being too complicated, I don't actually see why connecting a solar panel to a charge controller and battery is much more difficult than connecting a solar panel to a Jackery. But I am an engineer, so maybe my perspective isn't reasonable.

 

[Qxxx]

As far as DIY being too complicated, I don't actually see why connecting a solar panel to a charge controller and battery is much more difficult than connecting a solar panel to a Jackery. But I am an engineer, so maybe my perspective isn't reasonable.

Yeah, "famous last words" as they say (BTW, I'm not really trying to be an asshole here). But here's what you have to do in general:

1. solar panel(s) plural to charge controller, how to wire more than one panel.
2. charge controller to batteries.
3. multiple batteries wired in some series or parallel combination.
3. batteries to inverter.
4. selection of proper size wires at each stage.
5. crimping proper size lugs to wires; having the proper crimping tool and knowing how to made a proper crimp.
5a. spending a lot of time just finding and buying the proper size wires, lugs, and plugs.
6. decision of where to put fuses, how to mount them, and what sizes to use.
7. decisions of where and how to mount charge controllers, inverter, and output sockets.
[font=Tahoma, Verdana, Arial, sans-serif]8. wi[/font][font=Tahoma, Verdana, Arial, sans-serif]ring of additional 12VDC and USB sockets.
9. maybe adding on additional power meters that are built into the solar generators.
10. properly dressing all wire bundles for driving on rutty BLM roads.
11. possible safety hazards for your vehicle if you do it wrong.
12. possibility of electrocuting yourself on the 120VAC if you don't know exactly what you're doing.

[/font]Now tell me, who in their right mind really wants to go to all this damn trouble. (just for reference, I did do all that myself 3 years ago, it took me a full week of time, and now I'm tearing it all out of my van and replacing with a Yeti 1000, and no DIY wiring).

 

[barleyguy]

Yeah, point taken. I did all of that also, except #8 and #9. And I paid someone to do the stuff on my roof, because my fifth wheel roof is about 12 feet up and I don't like being on high roofs. I think it took me about 2 days of about 4 hours each. But like I said, I'm an engineer, so my perspective might not be reasonable.

One point is that DIY is generally a lot cheaper, depending on the size of system. For small systems it might be more expensive.

I also own an Inergy Kodiak all in one. Used it before I built the DIY system, and still like having it as a backup, and for running an air compressor to fill up my tires and things like that. So I'm not against "solar generator" boxes at all.

 

[landyachtman]

If I were gifted those two batteries I would first thank my grantor,  and then quietly go somewhere and have them tested to see what condition that they are in.  (maybe two or three places that test them free just to make sure those shops are being honest and not just trying to sell you new batteries)  Just explain up front that you aren't ready to buy new batteries and only want to know about the ones you have.

 

[Qxxx]

Yeah, point taken. I did all of that also, except #8 and #9. And I paid someone to do the stuff on my roof, because my fifth wheel roof is about 12 feet up and I don't like being on high roofs. I think it took me about 2 days of about 4 hours each. But like I said, I'm an engineer, so my perspective might not be reasonable.

One point is that DIY is generally a lot cheaper, depending on the size of system. For small systems it might be more expensive.

I also own an Inergy Kodiak all in one. Used it before I built the DIY system, and still like having it as a backup, and for running an air compressor to fill up my tires and things like that. So I'm not against "solar generator" boxes at all.

For a 5th wheel you probably want a lot more power than just 1000W, so you need to go all out, but for someone like Queen, she needs to understand what DIY really entails. The Yeti has readouts of voltage, input-output power, amps, watts, time to charge, etc, but on my DIY, I added a simple voltmeter for easy battery voltage readout. I also did #8 on my DIY because I wanted USB jacks and also 12VDC jacks.

 

[jonyjoe303]

connecting two dissimilar capacity batteries together in parallel is no big deal as long as they are the same voltage when joined together. Once the voltage equalizes you have one big battery and they will both charge and discharge about the same. I used a dc wattmeter to measure any amp transfer from 2 batteries connected together and at most I would see 2 amps go from the strong to the weak when first connected, once equalized no amps are transfered between batteries.

The only problem I see is you probably at most only charge them to 80 percent with the alternator, unless you drive for 5 or 6 hours. The final 20 percent takes many hours. Don't use a dc to dc charger, it will charge too slow, you need full power from the alternator to get it to 80 percent as soon as possible. And you need to get the voltage reading directly from the battery terminals, you need 14.4 volts for lead acid. If your alternator cables are too small or too far from alternator, you might have voltage drop and not reach 14.4 volts. anything less then 14.4 volts and your not fully charging your battery.

I have a fridge, laptop, swampcooler, lights and couldn't figure how I would do it without solar. From the time the sun goes down 6 pm to 6 am, I use a total of around 34 amp hours, sometimes more if I run the swampcooler all night. If you only charge your battery to 80 percent it won't take long for it to be completely depleted.

 

[Qxxx]

Yeah, point taken. I did all of that also, except #8 and #9. And I paid someone to do the stuff on my roof, because my fifth wheel roof is about 12 feet up and I don't like being on high roofs. I think it took me about 2 days of about 4 hours each. But like I said, I'm an engineer, so my perspective might not be reasonable.

Plus, the first time around I forget to mention the last items.

13. running proper size AC wiring all through the rig.
14. mounting and wiring multiple 120VAC switches and plugs.
15. plus adding fuses in those AC lines, if one is meticulous.

Queen sure has her work cut out for herself, . Anyone ever hear of opening pandora's box, that's another name for electricity. I'm just trying to help people understand what they're getting into.

 

[bandaidqueen]

Thanks everyone! I ordered a NOCO Genius charger to charge them for now - I'm a city dweller and I have a full-time office job, so I can find an outlet somewhere and a long extension cord (probably at work). The indirect swamp cooler is the only thing I'll wire to my batteries at the moment. Also the friend who is giving me the batteries is helping me with wiring, he works for the fire alarm division in my company and knows a little about electric and has heat shrink and wire strippers and soldering tools at home.  So I'm not going into it alone, but I DO need help knowing what I need to purchase to put it all together. And if I am in a position where I can purchase the rest of the electrical system (solar panels, charge controller, etc - come on stimulus check!) I would most likely hire my mechanic to install it, or at least help. But I still have to buy the parts! I found this easy to understand diagram and parts list with the DC/DC and MPPT controller barleyguy recommended: https://www.mobile-solarpower.com/simplified-400-watt-fewer-wires-and-alternator-charging.html I'll probably have less panels but this is a great how-to and part list, much simpler than the other websites I've seen. Anyway time will tell. I'm REALLY curious to see if the indirect swamp cooler (it's almost done) will actually work in this humid area as others have claimed. There's almost no information about it online that I can find. It's going to be an adventure.

 

[B and C]

If this is a 2 amp battery charger, it won't do much for your battery unless you draw very little from it. 2 amps times 9 hours is 18 amp hours if it is putting this out the entire time.

 

[barleyguy]

If this is a 2 amp battery charger, it won't do much for your battery unless you draw very little from it. 2 amps times 9 hours is 18 amp hours if it is putting this out the entire time.

The Nono Genius charger is normally 5 amp or 10 amp (they sell both). I was considering buying one in case I ever need to charge from a generator, because my built in convertor is way too big. Not sure which one the post above was about.

Plus, the first time around I forget to mention the last items.

13. running proper size AC wiring all through the rig.
14. mounting and wiring multiple 120VAC switches and plugs.
15. plus adding fuses in those AC lines, if one is meticulous.

Queen sure has her work cut out for herself, . Anyone ever hear of opening pandora's box, that's another name for electricity. I'm just trying to help people understand what they're getting into.

I didn't do any of those things, because my fifth wheel already has both a 120 volt and 12 volt power system. My inverter goes to a transfer switch and then to the same input that shore power would go if I was at an RV park. So when I turn on the inverter it powers all of the 120 volt outlets.

If you were building out a van without an existing power system, you would definitely need to add those to the list. Though I'd use a breaker box for #15.

 

[B and C]

Here at the house I put the 30 amp car charger on the lawn mower battery will no ill effects. The battery will only accept so much. You can't overfeed it unless you have an unregulated charger.

 

[barleyguy]

In my case, I was actually more worried about overloading the generator. I'm thinking about getting a 900 watt propane generator that's more like 600 sustained, and think my converter draws way more than that.

I've never needed a generator a single time in the last 3 years, because I have 600 watts of solar and camp in sunny states. But one of these days I might wish I had one.

 

[B and C]

I guess you haven't tried it. I used to charge my 350 Ah battery bank with my 35 amp converter and a cheap harbor freight 600 watt generator. It pulled all 35 amps from the converter and the generator didn't complain at all. It was better than running my 2800 watt generator for such a light load.

 

[bullfrog]

We have a commercial cooler unit similar to your DIY one except it uses 4 computer fans. We power it from a Goal Zero. In our dry southwest climate it does cool but the ciggy plug with it’s seven amp fuse melted after running on high speed for about 5 hours. Ours drains the Goal Zero in about 4 hours from full charge. I would recommend you keep a close eye on wire and plug temperatures as well as discharging you new batteries too much. The colder the water in the sump to begin with the better ours seems to work. Only other disadvantage is ours takes up a lot of space.