stkshooter
Observer
sportsmobiles website talks about this info. too.
DIY A/C window unit in rear van door
- Thread starter stkshooter
- Start date
wrcsixeight
Adventurer
Thanks DWH for the links to the regulators.
Unfortunately my current voltage regulator is inside my engine computer, and If I bypass it, it will light my CEL, and I will not pass a smog test.
I've just learned to deal with the relatively poor output when within 20% of full charge. If I did not have a battery monitor I would be blissfully ignorant of the poor output.
But I did used to go through batteries much faster, and have them die when I needed them. Now I know an hour of driving is likely to not do very much, and surface charges will fool you every time when using a voltmeter on a recently charged battery.
Unfortunately my current voltage regulator is inside my engine computer, and If I bypass it, it will light my CEL, and I will not pass a smog test.
I've just learned to deal with the relatively poor output when within 20% of full charge. If I did not have a battery monitor I would be blissfully ignorant of the poor output.
But I did used to go through batteries much faster, and have them die when I needed them. Now I know an hour of driving is likely to not do very much, and surface charges will fool you every time when using a voltmeter on a recently charged battery.
stkshooter
Observer
dwh: thank you for the info. I was off on another project. always going in to many diff. directions.
Q: For my short term camping use why not keep it simple ? add a 12v batt. in parallel connection to my main batt. and hook up cheap 2/8/12 amp charger to run off 110v gen. or shore power.
I would be paying $40 for new blem 105Ah deep cycle batt. or $30 for highest rated interstate megatron. I could use 2 of the same reg. batt. I have now in parallel. along with $34 110v charger. (I own 2/10/50 amp charger that still work fine from 20+ yr. ago ) I have a hard time spending over $100 on charger to maintain $30-40 batt. when the less expensive ones would seem to work when not charging off van alt.
Is there a reason the $34 charger at wal mart wont work for this set up ?
http://www.walmart.com/ip/Schumacher-SpeedCharge-12-Amp-Battery-Charger/13005744
Also, if I wire 2 batt. in parallel without silonoid. What would be the diff. ? I would just be adding more amp hours right ? so why change wiring and add solinoid / breakers ?
I am trying to keep this simple and not add any more weight / expense then needed.
I read if your not charging at higher than 10 amps you can hook charger straight to main batt. It is only when you charge over 10 amps that you need to hook charger on + on one batt. and - on other to balance charge. With the smart chargers ability to regulate or be set to use say 8 amp or reduce down on its own from 12 to 8 amp, in prob. a pretty short time frame. I dont know that it would cause a problem or reduce batt. life. considering they prob. wont last longer than 4-5 yr. any way. And at $30-40 ea. would you really be better off spending $100+ on a charger to possibly get 1 more yr. out of a blem batt. if higher end chargers are in fact that much better or avg. out the over all cost and possibly buy 1 more batt. over the next 10-20 yr. then you might have with expensive charger. See where I'm going with this ? I may or may not spend more on batt. replacement in the end but if I spend 3-4 times as much on charger up front, that is a gauranteed expense.
Also the more connections, breakers, in line fuses you have the more items to go wrong, etc. If your just adding a batt. in parrellel you already have a fuse between van and batt. so what would be the worst that could happen ? You blow the main fuse ! A breaker would be better than buy fuses if you had a problem but you should not have a problem with this set up if your just adding more Ah.
The biggest expense this way is mounting hardware under van on frame rail. Anybody find mounting kits for ford van ?
Why I debate spending money on expensive chargers. I bought the top rated power supply unit for a computer I just built and spent months attempting to figure out little issues here and there. turned out it was the expensive power supply unit and I didnt know it until it went bad within 3 mo. of buying it. On top of that the 5 yr. warranty that is rated as best in the industry cost me another $20 to ship it back and since they take 3-4 wk. to send replacement I had to buy another PSU. I have many computers and in 20+ yr. this is the first PSU I have had fail and was the most expensive with the highest review rating. A cheap one has been going for over 10 yr. and still works fine in another computer. Just saying more is not always better and just because it cost more doesnt mean it works better. Some of this so called high tech stuff is no better. You charge a batt. at a lower amp rate and everything about that is better but we dont always have the time so we pump it up to 15 amp to get our quick fix but it doesnt last as long so we are back to charging again. fill it up drain it down. I could set a charger on 2 amp and let it go till it detected batt. was charged and a $300 charger would not perform that function any better. How about setting it on 8 amp and allowing the charger to determine when batt. is charged, then reduce to 2 amp setting off and on. Doesnt take a $300 charger to do that. Now if you want to charge many batt. seperate at the same time... but I wouldnt need that with 2 in parrellel. Any body using a vehicle for expedition wouldnt want 500 lb. of batt. loading it down so why would most use more than 2 in parrellel. Seems if you need more than that for expedition you may be better off with gen. because weight will always be the reason you cant justify more batt. for that type vehicle.
Thoughts ?
Q: For my short term camping use why not keep it simple ? add a 12v batt. in parallel connection to my main batt. and hook up cheap 2/8/12 amp charger to run off 110v gen. or shore power.
I would be paying $40 for new blem 105Ah deep cycle batt. or $30 for highest rated interstate megatron. I could use 2 of the same reg. batt. I have now in parallel. along with $34 110v charger. (I own 2/10/50 amp charger that still work fine from 20+ yr. ago ) I have a hard time spending over $100 on charger to maintain $30-40 batt. when the less expensive ones would seem to work when not charging off van alt.
Is there a reason the $34 charger at wal mart wont work for this set up ?
http://www.walmart.com/ip/Schumacher-SpeedCharge-12-Amp-Battery-Charger/13005744
Also, if I wire 2 batt. in parallel without silonoid. What would be the diff. ? I would just be adding more amp hours right ? so why change wiring and add solinoid / breakers ?
I am trying to keep this simple and not add any more weight / expense then needed.
I read if your not charging at higher than 10 amps you can hook charger straight to main batt. It is only when you charge over 10 amps that you need to hook charger on + on one batt. and - on other to balance charge. With the smart chargers ability to regulate or be set to use say 8 amp or reduce down on its own from 12 to 8 amp, in prob. a pretty short time frame. I dont know that it would cause a problem or reduce batt. life. considering they prob. wont last longer than 4-5 yr. any way. And at $30-40 ea. would you really be better off spending $100+ on a charger to possibly get 1 more yr. out of a blem batt. if higher end chargers are in fact that much better or avg. out the over all cost and possibly buy 1 more batt. over the next 10-20 yr. then you might have with expensive charger. See where I'm going with this ? I may or may not spend more on batt. replacement in the end but if I spend 3-4 times as much on charger up front, that is a gauranteed expense.
Also the more connections, breakers, in line fuses you have the more items to go wrong, etc. If your just adding a batt. in parrellel you already have a fuse between van and batt. so what would be the worst that could happen ? You blow the main fuse ! A breaker would be better than buy fuses if you had a problem but you should not have a problem with this set up if your just adding more Ah.
The biggest expense this way is mounting hardware under van on frame rail. Anybody find mounting kits for ford van ?
Why I debate spending money on expensive chargers. I bought the top rated power supply unit for a computer I just built and spent months attempting to figure out little issues here and there. turned out it was the expensive power supply unit and I didnt know it until it went bad within 3 mo. of buying it. On top of that the 5 yr. warranty that is rated as best in the industry cost me another $20 to ship it back and since they take 3-4 wk. to send replacement I had to buy another PSU. I have many computers and in 20+ yr. this is the first PSU I have had fail and was the most expensive with the highest review rating. A cheap one has been going for over 10 yr. and still works fine in another computer. Just saying more is not always better and just because it cost more doesnt mean it works better. Some of this so called high tech stuff is no better. You charge a batt. at a lower amp rate and everything about that is better but we dont always have the time so we pump it up to 15 amp to get our quick fix but it doesnt last as long so we are back to charging again. fill it up drain it down. I could set a charger on 2 amp and let it go till it detected batt. was charged and a $300 charger would not perform that function any better. How about setting it on 8 amp and allowing the charger to determine when batt. is charged, then reduce to 2 amp setting off and on. Doesnt take a $300 charger to do that. Now if you want to charge many batt. seperate at the same time... but I wouldnt need that with 2 in parrellel. Any body using a vehicle for expedition wouldnt want 500 lb. of batt. loading it down so why would most use more than 2 in parrellel. Seems if you need more than that for expedition you may be better off with gen. because weight will always be the reason you cant justify more batt. for that type vehicle.
Thoughts ?
dwh
Tail-End Charlie
No reason at all. I use a 10 Shumacher that is probably closer to 30 years old. Works fine. Just takes longer.
There are two problems with simply paralleling the batteries. Problem number one of course is if you run it down too far, then you can't start the truck.
The other problem has to do with how batteries are built. Basically, you have starter type batteries which are built with thin lead plates and designed to dump a lot of amps in a short time to start an engine - but only designed to be drained maybe 5% then recharged. Then you have deep cycle batteries which are made with thick plates, and are designed to push a steady amperage for a long time and can be regularly drained 50%. And then you have rv/marine/trolling batteries which are sort of in between.
The thinner plate engine start batteries will not survive very many deep discharges. You can drain a deep cycle to 50% maybe a thousand times - but a thin plate engine start battery might only do it 30 times. If you take an engine start battery to fully discharged, you might only do it a dozen times (or sometimes less) before the battery can no longer store enough power to start the engine (it's ruined).
There are two schools of thought on being able to run loads and still start the truck:
One is to put all loads on the secondary battery, and use an isolator to keep from discharging the engine battery, while still being able to charge the secondary battery with the engine running. In this scenario, you would normally have a thin plate starting battery for the engine, and a thick plate deep cycle for the loads.
The other is to tie all the batteries together into one big bank, and use a "low-voltage disconnect". All the loads are connected to the LVD and then when the battery is low, the LVD disconnects the loads, thereby leaving enough juice in the battery bank to still start the engine. In this scenario, you would use deep cycle for both.
Deep cycle batteries can be used as starting batteries, however due to the thick plates they won't dump amps as fast, so you need a bit bigger battery to get the same cranking amps. Of course, if you have two of them tied together, then you're gong to have enough cranking amps.
There are some definite advantages to the one big bank method. One of the main benefits, is that you actually get more amp*hours of real world use. Say you have a load that would drain a single battery in 20 hours. When you add a second identical battery, that same load would run for -more- than 40 hours. That has to do with the load being X% of the battery capacity. A lower percentage load can run longer, so by doubling the capacity, you halve the load percentage, which gets you more than double the run time.
Another benefit, is that by using AGM type deep cycle batteries, you can usually (but not always) recharge the batteries at a much higher rate so they can be recharged much faster.
However, to use the one big bank method, you have to replace the engine battery with a proper AGM deep cycle, and then add one or more additional identical batteries - AND you have to install the LVD.
Adding a second thin plate battery in parallel is going to end up with two ruined thin plate batteries. They are not designed to be drained much.
The best cheapest way would be a deep cycle battery for the loads, with a solenoid to charge it when the engine is running, and also isolate the engine battery so it doesn't get drained when the engine is off.
That's how my camper is setup, and I also use an old 10a charger and small generator to recharge the aux battery when parked.
Not really true. It depends on the wiring too. If the wiring is unbalanced, then you are going to get more charge into one battery than the other regardless of how many amps the charger puts out. That is also true for the loads. So if the wiring is unbalanced, one battery will end up putting out more amps, and taking in more amps than the other. It will do more work and wear out sooner.
I understand, and that's how I do it with the camper I have now. I use a cheap deep cycle battery and I abuse it. It won't last as long, but that's fine with me. Since I'm not using an expensive battery, I don't have to worry about taking good care of it, so I can use a cheap constant voltage charger and not worry about it.
As I've said before, if you have solar or generator auto-start or some automated method to insure that the battery is properly taken care of, then expensive batteries are worth the money. But if you know you are going to abuse the battery, it's not worth the money to buy a really good one.
I agree. Personally, I would not want to be without a generator. Many people feel that generators are smelly and noisy and so they want more battery and solar so they can be "generator free".
Not me. Even if I had solar and a ton of batteries I'd still carry the generator.
Anyway, you should forget this parallel idea unless you are going to parallel two deep cycles and wire in a LVD.
stkshooter
Observer
I will prob. go with 2 deep cycle 12v batt. in parellel. ( that is what I was thinking but offered options to get feedback ) One in engine compartment, other under van along frame rail. They will be connected using 2 gauge wire. ( already have it ) I plan to install 110v charger under hood connected to that battery with plug zip tied around grill/fender area for easy connection.
then use something like this to monitor voltage
[ame="http://www.amazon.com/Equus-3721-Battery-Charging-Monitor/dp/B000EVWDU0/ref=pd_sim_misc_1"]Amazon.com: Equus 3721 Battery and Charging System Monitor: Automotive[/ame]
Since the only time I would have to worry about voltage is during extended camping trips and only when not plugged in or running gen.
I feel the odds of a responsible person running voltage below 12v when a meter is available is unlikely. Considering the odds of this happening not being enough to justify the LVD cost vs batt. replacement of $80 brings me back to the possible expense vs guaranteed.
If I found a LVD at very low price ( not $75+ ) and had nothing else more important to spend money on then I would add one but priorities tell me I can still use jumper box as I have done in the past to start vehicle if I do run batt. dead and if they last 3 yr. vs 4 yr. I am still not spending as much as LVD would have cost and who is to say LVD would not go bad. this is also part of the problem when planning these projects, we have no way of knowing the life of products. Cant really claim if you do this the end result will be... or the total cost over 5-10 yr. will be...
All I can say for sure is 2 deep cycle batt. plus charger and connectors/cable along with frame mount battery box is going to cost me about.... ($200) with no way of knowing what the future life of those items are.
If I separate and add this and that it gets more expensive and what have I really gained ? My plan was to extend my batt. use ( Ah) and if I go with separate engine / house batt. and can only use 50% of house after spending all this time / money you start to ask yourself if that was the best decision or should I just use what I need and get out the jumper box if needed. Based on what it cost to do anything else like RV camp site fee or run gen. vs replace batt. 1-2 yr. sooner @ a cost of $80 because you shortened life from draining to many times.
If I were spending $150 per batt. vs $40 or were living out of van for months each yr. but the few times I might drain the batt. over their standard life makes it much harder to justify all the extra protection and that still doesnt guarantee to change the end results if you pay attention to your meter / use.
this could be compared to road service changing your tire or doing it yourself. I have never called road service to change a tire when I could do it myself.
In this case I will have to monitor a meter and save the service fee vs LVD doing it for me and sounding alarm.
Anybody know where I can buy batt. box frame mount kits.
then use something like this to monitor voltage
[ame="http://www.amazon.com/Equus-3721-Battery-Charging-Monitor/dp/B000EVWDU0/ref=pd_sim_misc_1"]Amazon.com: Equus 3721 Battery and Charging System Monitor: Automotive[/ame]
Since the only time I would have to worry about voltage is during extended camping trips and only when not plugged in or running gen.
I feel the odds of a responsible person running voltage below 12v when a meter is available is unlikely. Considering the odds of this happening not being enough to justify the LVD cost vs batt. replacement of $80 brings me back to the possible expense vs guaranteed.
If I found a LVD at very low price ( not $75+ ) and had nothing else more important to spend money on then I would add one but priorities tell me I can still use jumper box as I have done in the past to start vehicle if I do run batt. dead and if they last 3 yr. vs 4 yr. I am still not spending as much as LVD would have cost and who is to say LVD would not go bad. this is also part of the problem when planning these projects, we have no way of knowing the life of products. Cant really claim if you do this the end result will be... or the total cost over 5-10 yr. will be...
All I can say for sure is 2 deep cycle batt. plus charger and connectors/cable along with frame mount battery box is going to cost me about.... ($200) with no way of knowing what the future life of those items are.
If I separate and add this and that it gets more expensive and what have I really gained ? My plan was to extend my batt. use ( Ah) and if I go with separate engine / house batt. and can only use 50% of house after spending all this time / money you start to ask yourself if that was the best decision or should I just use what I need and get out the jumper box if needed. Based on what it cost to do anything else like RV camp site fee or run gen. vs replace batt. 1-2 yr. sooner @ a cost of $80 because you shortened life from draining to many times.
If I were spending $150 per batt. vs $40 or were living out of van for months each yr. but the few times I might drain the batt. over their standard life makes it much harder to justify all the extra protection and that still doesnt guarantee to change the end results if you pay attention to your meter / use.
this could be compared to road service changing your tire or doing it yourself. I have never called road service to change a tire when I could do it myself.
In this case I will have to monitor a meter and save the service fee vs LVD doing it for me and sounding alarm.
Anybody know where I can buy batt. box frame mount kits.
dwh
Tail-End Charlie
Looks good. Just remember that the battery voltage under load will be lower than the true charge state of the battery. I.e., the voltage monitor might show 12v, but if you turn off the load the gauge might show 12.5v or more.
If you turn off the load early then you only end up saving some power in the battery, which is a good thing anyway.
The monitor is a good piece of kit, though without the LVD, I think I'd prefer a monitor with an alarm:
http://www.samlexamerica.com/products/productdescription.asp?ProductsID=8144
stkshooter
Observer
I agree, an alarm would be ideal. The LVD sounds alarm and gives you the option to override. But they cost too much for me to justify.
I did find a cig. plug voltage reader with alarm for $30 Free S & H
http://www.voltminder.com/http://www.batterystuff.com/battery-products/UPGvoltminder.html
Just ordered it.
Looks like the largest interstate deep cycle blem I can fit under hood is SRM-24 with 550 CCA / 690 MCA and a RC @ 25A of 140. I will parallel this with a SRM-27B 675CCA / 845 MCA and RC @ 25A of 180 which will give me 475 CCA more than I have now. The van factory batt. specs rated 550 CCA.
Also gives me 110 more RC than largest single house batt. I can fit under body if I were considering 2 seperate batt. as you said was the benifit of parellel.
I can always add another 27B later if needed but cant imagine needing more unless spending a lot more time inside.
My current main batt. is Interstate Batteries Mega-Tron Plus 27 750CCA and it has been drained dead many times over the past 2 yr. first time I forgot key was on in acc position, then leaving fans on all night before gen / AC was available. Jump box saved me many times. I had this small motorcycle charger laying around so rather than carry the larger one along I zip tied this one right on top of batt. and that is where it has stayed connected the past 1+ yr.
When I plug in 1 amp charger while at campground over night I have run T.V. / DVD watching a couple movies (3-4 hr.) fans, laptop, lights, 12v AA batt. charger, everything without concern of using too much power and ran 12v fans all night. Wake up the next morning and engine starts right up. If 1 amp trickle charger can make up the diff. I cant imagine ever needing more than 2/8/12 amp charger for both these batt.
I might have been close to killing batt. before going to bed and didnt know it without meter but if so you would think 1 amp charger with fan running wouldnt leave much to charge batt. but I did this every night for a week or more.
The 1 hr. of driving I did per day was slow speeds around hunting area so alt. was not doing that much. I have drained the batt. approx 10 times over the past 2 yr. and when I just tested batt with load tester, it shows good.
http://shop.interstatebatteries.com...2147384803&Title=100+AMP+HANDHELD+LOAD+TESTER
I wont get to see how long it last if switching to deep cycles but at 2 yr. already I paid less then retail with 72 mo. warranty avg. This is another one of those factors which make it hard to break down cost, changing our minds on what is the best options.
I did find a cig. plug voltage reader with alarm for $30 Free S & H
http://www.voltminder.com/http://www.batterystuff.com/battery-products/UPGvoltminder.html
Just ordered it.
Looks like the largest interstate deep cycle blem I can fit under hood is SRM-24 with 550 CCA / 690 MCA and a RC @ 25A of 140. I will parallel this with a SRM-27B 675CCA / 845 MCA and RC @ 25A of 180 which will give me 475 CCA more than I have now. The van factory batt. specs rated 550 CCA.
Also gives me 110 more RC than largest single house batt. I can fit under body if I were considering 2 seperate batt. as you said was the benifit of parellel.
I can always add another 27B later if needed but cant imagine needing more unless spending a lot more time inside.
My current main batt. is Interstate Batteries Mega-Tron Plus 27 750CCA and it has been drained dead many times over the past 2 yr. first time I forgot key was on in acc position, then leaving fans on all night before gen / AC was available. Jump box saved me many times. I had this small motorcycle charger laying around so rather than carry the larger one along I zip tied this one right on top of batt. and that is where it has stayed connected the past 1+ yr.
When I plug in 1 amp charger while at campground over night I have run T.V. / DVD watching a couple movies (3-4 hr.) fans, laptop, lights, 12v AA batt. charger, everything without concern of using too much power and ran 12v fans all night. Wake up the next morning and engine starts right up. If 1 amp trickle charger can make up the diff. I cant imagine ever needing more than 2/8/12 amp charger for both these batt.
I might have been close to killing batt. before going to bed and didnt know it without meter but if so you would think 1 amp charger with fan running wouldnt leave much to charge batt. but I did this every night for a week or more.
The 1 hr. of driving I did per day was slow speeds around hunting area so alt. was not doing that much. I have drained the batt. approx 10 times over the past 2 yr. and when I just tested batt with load tester, it shows good.
http://shop.interstatebatteries.com...2147384803&Title=100+AMP+HANDHELD+LOAD+TESTER
I wont get to see how long it last if switching to deep cycles but at 2 yr. already I paid less then retail with 72 mo. warranty avg. This is another one of those factors which make it hard to break down cost, changing our minds on what is the best options.
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stkshooter
Observer
Hope this helps some considering propane heaters for van.
I tested big buddy heater in van with outside temp 39 and inside van at 39. Ran heater at 18000 btu and within 30-35 min. reached 100 degree. I then reduced btu to 4000 and watched temp fall to about 78 and level off. Stayed there for 15 min. and I stopped testing. Windows were open 1 1/2" on both front doors entire time. temp on floor vs middle of van was 10 degree lower.
I tested again with outside temps at 44 using 4000 btu. ( windows cracked the same 1 1/2" ) All was fine for the first couple hours until the van heated up and I couldnt turn btu down any lower. Inside temp was reading 83 and a little warm. I could have opened windows more but didnt see the point of wasting propane since I had a sleeping bag and since the temps were to be 40-45 I'm fine. I woke with inside temps around 45 and started heater, within a few min. at 9k btu it was nice and warm. ( no burning waste smell this time ) turned it down to 4k and got dressed. So most times you may not need the 18k btu but if temps do fall down around 15 with winds blowing 10-20 mph you will have more heat loss and need to make up for an additional 30-40 degree temp diff. The 9k may do this over time once the interior has warmed and if not you can always put on warmer clothes. You also want to use a fan for air circulation if possible. I noticed a lot of cold spots and my floor is not insulated well enough so I'm loosing a lot there. Since heater is in front of van ( see picture ) the rear area around doors is not as warm but I'm sitting / laying on bed in middle which is plenty warm. My van was not stripped and insulated so I have areas with less insulation and some bare metal areas around doors. You can touch your hand on metal and feel the cold sucking up heat but let us be real, you can only do so much and still have a nice looking interior. In my case I will turn up the btu for the limited amount of time I need to but if I were living out of van I would start with empty cargo van and insulate it very well to avoid these issues. Some of you may be looking for a way to heat van just the way it is without removing everything, you better count on using 18k and lots of propane because at 24 hr. per 20# bottle you will wish there was another way every time you pull out your wallet for more propane.
temps are to hit lower 20's this week with wind chill in the teens so maybe I will get a chance to test in some real cold weather. That will be the info. I need for my trip since the temps there have not been above 20's some days. If I use up one 20# tank per day in those temps it may be better to find a motel if available.
Doesnt appear humidity will be a problem since outside humidity was in the 50's and inside dropped to 26%. It was around 45% when I started if I remember right and dropped to 25% at the lowest point. Many have said if you keep windows cracked enough you wont have a problem with fresh air or humidity.
First test you could tell van had fuel burning waste smell in the air but only for the first 5-10 min. and then it was fine. prob. because it was started and running at 18000 btu real fast before it could warm up and burn off the extra fuel. I wanted to test at the max and see what happened in van with limited air flow/space. If I would have run heater outside first and then brought inside or started low and worked up to 18k that would prob. have eliminated smell but wasnt bad and was gone pretty quick.
Van is insulated and windows covered other than front windows which I didnt put covers on.
I used coleman 3000 btu in van last year before insulation and window covers and froze. It will be nice to have more btu then I need. Heat up quick if I want or ready for the worst temps. Glad I bought the Big Buddy vs smaller 4000/9000 because if temps were single digits and I returned to van with everything frozen, I would want things heated up pretty quick and with outside temps twice as cold it would take 30 min. using 9000 btu just to get above freezing. Down side is do you have enough propane to maintain running at those btu.
good luck!
I tested big buddy heater in van with outside temp 39 and inside van at 39. Ran heater at 18000 btu and within 30-35 min. reached 100 degree. I then reduced btu to 4000 and watched temp fall to about 78 and level off. Stayed there for 15 min. and I stopped testing. Windows were open 1 1/2" on both front doors entire time. temp on floor vs middle of van was 10 degree lower.
I tested again with outside temps at 44 using 4000 btu. ( windows cracked the same 1 1/2" ) All was fine for the first couple hours until the van heated up and I couldnt turn btu down any lower. Inside temp was reading 83 and a little warm. I could have opened windows more but didnt see the point of wasting propane since I had a sleeping bag and since the temps were to be 40-45 I'm fine. I woke with inside temps around 45 and started heater, within a few min. at 9k btu it was nice and warm. ( no burning waste smell this time ) turned it down to 4k and got dressed. So most times you may not need the 18k btu but if temps do fall down around 15 with winds blowing 10-20 mph you will have more heat loss and need to make up for an additional 30-40 degree temp diff. The 9k may do this over time once the interior has warmed and if not you can always put on warmer clothes. You also want to use a fan for air circulation if possible. I noticed a lot of cold spots and my floor is not insulated well enough so I'm loosing a lot there. Since heater is in front of van ( see picture ) the rear area around doors is not as warm but I'm sitting / laying on bed in middle which is plenty warm. My van was not stripped and insulated so I have areas with less insulation and some bare metal areas around doors. You can touch your hand on metal and feel the cold sucking up heat but let us be real, you can only do so much and still have a nice looking interior. In my case I will turn up the btu for the limited amount of time I need to but if I were living out of van I would start with empty cargo van and insulate it very well to avoid these issues. Some of you may be looking for a way to heat van just the way it is without removing everything, you better count on using 18k and lots of propane because at 24 hr. per 20# bottle you will wish there was another way every time you pull out your wallet for more propane.
temps are to hit lower 20's this week with wind chill in the teens so maybe I will get a chance to test in some real cold weather. That will be the info. I need for my trip since the temps there have not been above 20's some days. If I use up one 20# tank per day in those temps it may be better to find a motel if available.
Doesnt appear humidity will be a problem since outside humidity was in the 50's and inside dropped to 26%. It was around 45% when I started if I remember right and dropped to 25% at the lowest point. Many have said if you keep windows cracked enough you wont have a problem with fresh air or humidity.
First test you could tell van had fuel burning waste smell in the air but only for the first 5-10 min. and then it was fine. prob. because it was started and running at 18000 btu real fast before it could warm up and burn off the extra fuel. I wanted to test at the max and see what happened in van with limited air flow/space. If I would have run heater outside first and then brought inside or started low and worked up to 18k that would prob. have eliminated smell but wasnt bad and was gone pretty quick.
Van is insulated and windows covered other than front windows which I didnt put covers on.
I used coleman 3000 btu in van last year before insulation and window covers and froze. It will be nice to have more btu then I need. Heat up quick if I want or ready for the worst temps. Glad I bought the Big Buddy vs smaller 4000/9000 because if temps were single digits and I returned to van with everything frozen, I would want things heated up pretty quick and with outside temps twice as cold it would take 30 min. using 9000 btu just to get above freezing. Down side is do you have enough propane to maintain running at those btu.
good luck!
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dwh
Tail-End Charlie
I like it.
Couple of things.
Those ratings are at full charge.
Those aren't true deep cycle batteries. A battery with CCA and RC ratings, but not amp*hour ratings is usually not a true deep cycle. Those are rv/marine batteries with plates a little bit thicker than a regular starting battery, but not nearly as thick as a deep cycle. Still, they should be fine for what you are doing.
If using batteries of different sizes, and also depending on the wiring, resistance will be a factor. There is a good page here which explains the effect of battery resistance and/or wiring resistance and unbalanced resistance on the charge/discharge of each battery:
http://www.smartgauge.co.uk/batt_con.html
Electrically, it won't matter much, but for longest battery life the batteries should be same size and age, and the wiring should be rigged to balance resistance.
If not, one battery will simply do more work and wear out faster than the other.
It shows good at 100a load.
I have mixed feelings about load testers. They are bit like a go/no-go gauge in a machine shop. Great for a quick check, but I have also seen batteries that were used but still good, that were killed by those types of load testers. So I think it sometimes comes down to whether the battery survives or if the load tester kills it. I.e., the battery may not have actually been bad -until- the load tester killed it.
Damned useful of course if you are in the battery business. A customer brings in a battery that may be marginal but not actually bad, you put that load tester on it and bang, now that battery IS ruined. Sweet, sell the customer a new battery.
Jeffh555
Observer
Thanks! I was just pondering nearly the exact same setup.