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I would like to put a battery in my van next mouth but know little about it. I what to add another battery or two and solar panels later. The picture is a diagram that I have worked up but I do not know if it is right. I would like to charge the battery mainly with my 180 amp alternator and sometimes with shore. I am pretty sure that I want the 1500 watt inverter but do not know how it will work with only the one 150 ah battery. I also am concerned about maybe damaging the alternator. Please tell me which parts and connections I have wrong here as I have never done anything with electricity like this before.
 

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Shunt

We agree with MsNomer, it is a beautiful diagram. But it would be helpful, in responding to your inquiry to know whose diagram it is.

Our first observation is more of a comment, in this power class of sine wave inverters (and we're going to avoid the pro/anti-sine debate here as it appears you've already made your decision with which we find no fault), there are now several combination inverter/chargers which not only offer automatic 'cut-over' in response to loss or acquisition of shore power but simplify the wiring and probably save space.

Our principal criticism with your design is your shunt. And this is why we asked "who drafted" this schematic - - it might help understand the curious wiring of the shunt. In our opinion, the purpose of a shunt is to measure the total current going to, or coming from, the house battery. In our system this information is used by our lithium battery controller and is displayed on that controller's monitor screen. We see no 'metering/monitoring' apparatus in your system. As some chargers/inverters use this information for limiting current, we again ponder whether one of your proposed vendors caused you to add the shunt to your drawing.

In our opinion the only correct way to wire a shunt is to tie absolutely all charging sources and loads to the negative, ground side of the shunt. The only connection to the top side of the shunt, other than small monitor/control wires (which must be there, otherwise there's no purpose in having a shunt) is the house battery itself. Any charging source or load that you tie to the high-side of the shunt will bypass the shunt and the shunt will not register it's current. Thus, if the purpose of your shunt is to monitor the total charge current and/or the total discharge current, then reconfigure as noted here. Incidentally, when wired as recommended here, the shunt is metering/monitoring the NET of all charge and discharge sources. Your frig may be on along with your led lighting and maybe the microwave . . . along with your shore and solar power charging sources . . . and this shunt will tell you at any instant whether your battery is being charged, or discharged and to what extent.

Now if your shunt is there because one of your charger/inverter vendors wants their own private current measurement - - that is, that piece of equipment needs to know only how much current it is providing or drawing - - then all bets off. If that's the case, we recommend re-evaluating the selection of that piece of equipment or its wiring. We think you'll be happier with something that tells you what's happening, overall, with your house battery.
 

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As for WHERE this stuff eventually goes. Each battery needs the large fuse at the battery terminal not beyond any appliance even the battery doctor. The line between the batteries can be fused well below the 150 amps you show. I would suggest 80 but in my experience 50 will never blow. This protects the wire and connections at a more reasonable level. Once you feed current through the main fuse from the positive side of the battery it should go to a load center in which each feed is fused at a level to protect that wire and appliance. I used a buss bar for the grounds and a 110V set of breakers for the shore power and a set of automative blade fuses in the load center. The wire to that inverter needs to be #4 or larger as it could carry 150 amps. For a very short run 8 would be marginally safe but Hey.
See: https://www.tessco.com/yts/industry/products/itm/automotive/get_wired.html
 

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" I what to add another battery or two and solar panels later."

OK to add the solar later, but don't make my mistake--run the lines now. It's no fun to take off finished panels.

As for the "another battery or two," batteries should age together.

I highly recommend the Trimetric meter by Bogart Engineering. It is crazy powerful. Check it out.
 

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" I what to add another battery or two and solar panels later."

OK to add the solar later, but don't make my mistake--run the lines now. It's no fun to take off finished panels.

As for the "another battery or two," batteries should age together.

I highly recommend the Trimetric meter by Bogart Engineering. It is crazy powerful. Check it out.
Great advice about running lines now, but you could also hold off on the paneling until you get the solar panels.

As for the batteries aging together, I could not agree more.

I have been using solar for a long time, and you always get the best performance from matched cells in a series.
 

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I would like to put a battery in my van next mouth but know little about it. I what to add another battery or two and solar panels later. The picture is a diagram that I have worked up but I do not know if it is right. I would like to charge the battery mainly with my 180 amp alternator and sometimes with shore. I am pretty sure that I want the 1500 watt inverter but do not know how it will work with only the one 150 ah battery. I also am concerned about maybe damaging the alternator. Please tell me which parts and connections I have wrong here as I have never done anything with electricity like this before.
Hi,

Please find the attached is a copy of my notes along with some other pictures. I was going to pretty up the wire diag, but I have not had a chance. For me the hardest part was determining wire size, so look for information on that especially the wires for shore power and connecting the batteries together and to/from the inverter. It has been a year and so far there has not been any sparks or fire--just kidding. For distribution panels I went with marine grade Bluesea stuff. The batteries are 100 AH each AGM, and these appear to be enough, but I left space in the battery box for a third battery.

Mike
 

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Hi,

Some thoughts on your wiring diagram:

- The wire from the starter battery through the isolator and to house battery is not properly fused and is too small for the fuse size shown.
This wire should have a fuse near the starter battery terminal and a 2nd fuse near the house battery terminal. Both ends of this wire have a large current source (the two batteries), and its not enough to put a fuse somewhere in the middle of it. Visualize what happens if the line is shorted to ground anywhere along its length. Both batteries will start to provide very high current to the short. One of the two batteries will be providing current through the fuse, and that will blow the fuse and stop the current from that battery, but the other battery is a dead short to ground and will provide LOTS of current -- enough to generate lots of sparks, smoke and maybe burn your van down.
Its important to have these fuses as close to their respecitive batteries as possible -- ideally right at the battery terminal -- google for Mega Fuse to see one solution.

I agree with RD that the 150 amp fuse in this line is much more than you need. If you actually were able get that kind of current to the house battery it would likely be well over what the battery manufacturer recommends and would damage the house battery. I'd find out what the maximum charging current the manufacturer of the battery recommends and pick a fuse or breaker that is a bit more than this. That way if the breaker does pop (unlikely) you will know that your house battery is being overcharged.
If you do decide to keep the 150 amp fuse, the #2 wire is not nearly large enough to handle 150 amps. You would need something like 1/0 wire, which is couple sizes larger than #2 . You can use this copper wire ampacity table to pick the miniumum gage for your wires: http://www.cerrowire.com/ampacity-charts It is never OK to have a wire protected by a fuse or breaker that is larger than the values shown in this table.

- I'd have a look at using an Inverter/Charger rather than the Power Converter and Inverter you show. Its easier to hook up an Inverter/Charger correctly and it handles the switchover from shore power to house battery power automatically and safely. As was pointed out, these can be had in either pure sine wave or modified sine wave depending on your AC loads sensitivity non-pure sinewave power.

- You don't show a distribution panel for you DC loads. It seems like you will need one of these. Each of your DC loads comes into the distribution panel and has its own fuse.


- The wires you show going to the inverter are too small and the fuse is too large. A #8 wire has an ampacity rating that is 40 to 50 amps depending on the insulation temperature rating, and this is way to small for the 150 amp fuse shown and will not provide the enough current to the inverter with enough current to run properlay when the AC load on the inverter is anywhere near 1500 watts. The way it is shown is not safe -- if anything like a 1500 watt load is put on the inverter, the #8 wires will overheat and the 150 amp fuse in the line is too large to properly protect the #8 wire.

- I'm not sure what you are trying to show on the output side of the inverter. You have a 100 amp fuse on the output line from the inverter -- this would be (115 volts) (100 amps) = 11500 watts -- about 8 times what the inverter can produce.
Normally on the output side of the inverter, there would be an AC loads distribution panel that would have a main breaker and then several smaller breakers for each of your AC circuits.

- I'm also not understanding the shunt. If you don't have a battery monitoring system that needs a shunt, I'd get rid of it.

- The #8 wire "future wire" shows a 60 amp fuse, which is a bit to large for #8 wire -- a 50 amp fuse would be OK.

You might want to start with an electrical system and wiring diagram that you know works -- this would give you a good starting point. There are probably lots of them out there, but this is what I used on my van: http://www.buildagreenrv.com/our-co...y-camper-van-conversion-electrical-and-solar/

Gary
 
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