This is a question for the electrical wizards out there...........SnowT?

This is the way my current set up is, could you tell me if there is a better way to hook it all up together, I think I got the inverter/converter names correct.

The switch is a HD red key type that was in the van already, the starter battery and working battery are the standard Transit set up under the drivers seat, the two AGM are directly behind them.

There is 330w of solar on the roof and hopefully later today or tomorrow a portable 160w folding panel which I will put 80mm2 cable on from the built in controller to the battery clamps (too difficult to connect to controller for now)

ALL cables are a minimum of 10mm diameter or 80 mm2 copper core (not thick plastic)

I leave the power switch on when driving so the alt can help the solar charge the AGM's but turn it off when camping unless the working battery starts to get a bit low - then I'll turn it back on to let the solar give it a boost.

I have just ordered a second 20a 3 way charger, if I'm camping and it's too cloudy is it ok to charge the two 130a battery's at 40a (2 chargers combined) off the generator or is this too high a charge? Only 600w off a 2kva genny.

If charging at 40a is it best to put the 2 chargers on different battery's or is it ok to just put the clamps on the same earth and positive terminals?

It seems to take about 7-8hrs to charge the battery's from around 11.8 - 12 volts which is why I bought the 2nd charger.

I think that's all.

Thanks

-- Edited by TizTom on Monday 21st of July 2014 03:04:37 AM

-- Edited by TizTom on Monday 21st of July 2014 03:20:26 AM

TizTom wrote:

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This is a question for the electrical wizards out there...........SnowT?

[1]This is the way my current set up is, could you tell me if there is a better way to hook it all up together, I think I got the inverter/converter names correct.

The switch is a HD red key type that was in the van already, the starter battery and working battery are the standard Transit set up under the drivers seat, the two AGM are directly behind them.

There is 330w of solar on the roof and hopefully later today or tomorrow a portable 160w folding panel which I will put 80mm2 cable on from the built in controller to the battery clamps (too difficult to connect to controller for now)

ALL cables are a minimum of 10mm diameter or 80 mm2 copper core (not thick plastic)

I leave the power switch on when driving so the alt can help the solar charge the AGM's but turn it off when camping unless the working battery starts to get a bit low - then I'll turn it back on to let the solar give it a boost.

[2]I have just ordered a second 20a 3 way charger, if I'm camping and it's too cloudy is it ok to charge the two 130a battery's at 40a (2 chargers combined) off the generator or is this too high a charge? Only 600w off a 2kva genny.

[3]If charging at 40a is it best to put the 2 chargers on different battery's or is it ok to just put the clamps on the same earth and positive terminals?

[4]It seems to take about 7-8hrs to charge the battery's from around 11.8 - 12 volts which is why I bought the 2nd charger.

I think that's all.

Thanks

 

 

 

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Hi Tom

[1] No, that is not the best setup fpr parallelling the batteries, especially with a large inverter load 

The idea is to have the same resistance path in both the charging & dischaghing path for EACH battery

A simple way of explaining it is to look on each battery as the rung of a ladder

All the cables connecting the batterries to the verticals should be the same sized cable & the same LENGTH

With say all the pos terminals connected to the left side & all the negs to the right side

Then connect both the charging & the load cables ,with the pos to pos at the bottom of the left side, &Negs  to the top of the right side

[2] No that would not be excessive

[3]simply connect the chargers to the same ends as the solar & load cables

[4]If those batterries have ben taken down below   11.8V frequently, they could be very sick

Suggest you have them load tested

PeterQ 

Howdy,

I am following this thread with interest as I always like to learn as much as I can about 12v power and Solar Power, you can never know too much, also I am about to hook up a duel battery system in the new Colorado but with the second battery in rear tub under a canopy.

TT, I am a bit confused but nothing new mate. In your diagram I can't see how the "Starter Battery" is connected to anything? Am I missing something?

Edit....I'm still computing what you have said Peter but think I understand. You explanation of a ladder is helping.

There is a battery box available and it sits on a wheel well inthe Colorado and Dmax

Howdy again Tom,

I was going to PM you but decided to sound even more stupid than I already am here in the open because there might be someone else sitting in the wings with the sam problem as me.

Sorry mate but I am still a little confused   when you say " When the ignition is turned on the starter battery kicks in" Wouldn't there still be a pos and neg cable connected to the "Starter Battery"?   The way understand it the "Starter Battery" is charged from the Alternator in the tug but see no cables connected to said battery in your diagram. Maybe I should be assuming it is connected and that is why it doesn't show up.

Maybe it's still too early in the day (7.20am) to compute yet 

Howdy PeterQ,

Am I correct in saying about your explanation that,

The "Starter Battery" connected to the tug alternator is fist in line at the bottom of "your" ladder with a isolation switch, then comes each other battery in turn with cables poss to poss and neg to neg as they go up "your" ladder. Using the same correct size cable all the way up the ladder?????

I allowed an extra ? incase of another battery in the future 

Bayonetmadness wrote:

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There is a battery box available and it sits on a wheel well inthe Colorado and Dmax

---

Thanks for the info. I have a link to a site for one of these when I am ready to purchase.

Isn't this a great forum to get info from!!

You have the batteries connected correctly, The charging and discharging must be connected to the same terminals. ie The input and output connected to the positive of one battery and the earths to the negative terminal of the second battery. If you connect the other way (input/output to one batter with the second batter then connected to the first battery) you will not charge /discharge both battery evenly. When a battery is being charged/discharge it draws current from the face of the plates of the battery until it is flat, say 12v. But the center of the plates will be still at a higher charge of around 12.5v, the voltage will level itself out to say 12.25v. This is why when you flatten the battery trying to start you car and you leave it for 10-15 minutes it has power to start the motor again. So if you connect -to- and +to+ the first batter will flatten while the second battery holds a higher charge, if left for some time the second battery will level it self with the first battery. If you have 2 buckets of water with a pipe connecting each bucket at the bottom if you drain/top up one bucket it will take time for the second bucket to balance with the first. If you drain/top up both at the same time the time to drain will be longer and the charging time will be shorter. Remember that your charger will be looking only at the first battery and will stop charging and go into float mode when it reaches full charge, in the mean time the second battery is not fully charged and it will take time for the first battery to discharge into the second battery, at this point both batteries will not be fully charged and the charger will cut back in and will go through the cycle again and again and again. (if charging is by solar you have most likely lost the sun for the day and do not have fully charged batteries) If you connect the the other way the charger thinks it is only charging 1 battery (all be it a large one) and will continue to charge until it is fully charged and the it will go into float mode. The sun has just gone down and you have 2 fully charged batteries to watch TV. I hope I haven't confused you.

Wassa

Dougwe, the battery set up is standard Transit 07-13, they are controlled by the remote/ignition switch, I've added lines to the original drawing to give you an idea, both battery's go to a control/isolator box that sits between them under the drivers seat, I didn't want to confuse things too much in the first drawing but this is pretty much what happens, hope you get it now.

Thanks WAssa41, I sort of think I get it but I'm putting power into one battery and drawing from the other, if I understand what you said shouldn't I swap either the 2 positive wires (or earths) from the controller over from one house battery to the other? that way I have the + going to one battery and the - going to the other, same with inverter power as that also comes from one battery atm?

Also as I have 2 X 20w chargers would I be better off putting one on each battery?

I bought a big inverter simply because they weren't that much dearer and in-case of an emergency and need to use the air-con or microwave but I could have got away with a much smaller one, the biggest draw would be the tv, computer, lights and fridge at the same time (probably 220w all up) unless I'm using my drill/4"grinder or my 600w Bullet food processor which I use most mornings for maybe 30sec.

I think I've confused myself drawing this!

-- Edited by TizTom on Wednesday 23rd of July 2014 12:43:37 AM

Your second drawing is right. The charging system now thinks its charging one battery.

Wassa