Generators, Batteries and Inverters

DMan

alid sinistra oliva
Ok, I presently in the van have a 110aH deep cycle battery in a battery box to run the fridge and 12V lights etc. I want to up the ante and fit a 2000w inverter. Now, I don't need more plugs just more capacity. Can I hook up a 200aH battery in parallel and still run everything off the 110aH battery in the box? And charge the system through the Anderson plug with solar like I'm presently doing? Or should hook the inverter to the larger battery and run everything else out of the battery box?
 

rockmoose

Likes Bikes and Dirt
If you want to run multiple batteries in series or parallel, you should always use the same capacity and the same age.

You're idea of running separate circuits is much better. Just make sure you are happy with the capacity of the bigger battery to perform its tasks. If you need more capacity for that circuit, now is the time to set up two batteries in parallel.

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DMan

alid sinistra oliva
If you want to run multiple batteries in series or parallel, you should always use the same capacity and the same age.

You're idea of running separate circuits is much better. Just make sure you are happy with the capacity of the bigger battery to perform its tasks. If you need more capacity for that circuit, now is the time to set up two batteries in parallel.

Sent from my SM-G780F using Tapatalk
It shouldn't matter if they are in parallel? I can understand if they were hooked up in series.
 

Minlak

would blow a manky old hobo for $20
It shouldn't matter if they are in parallel? I can understand if they were hooked up in series.
Simple answer you can run in parallel it will just be seen as 1 big battery - The idea of using two new batteries is that there is less chance of losing a cell. So its just a best practice not a requirement.
 

Dales Cannon

Deleted Banned Moderatuuur
Staff member
From what I have read you should keep capacities as close as possible to avoid preferential charging. Also you should balance the infeed and load. Say you have 3 110AH batteries in parallel then the positive of battery 1 is connected to the charging source and take off while the neg of battery 3 is. If that makes sense. If there is a big difference in capacity then internal resistance will differ and a bigger battery can take a much larger charging current which will affect the life of the smaller capacity battery.

Edit: if you just happen to have a 220AH battery then set it up as two independent circuits. Charge each separately from the input source through a changeover relay (manual switching or automatic) or dc dc charger from one to the other.
 

Lazmo

Old and hopeless
What do you want to run with the inverter? ... and how many watts does it draw, and how long do you intend to run it, per day.
 

DMan

alid sinistra oliva
From what I have read you should keep capacities as close as possible to avoid preferential charging. Also you should balance the infeed and load. Say you have 3 110AH batteries in parallel then the positive of battery 1 is connected to the charging source and take off while the neg of battery 3 is. If that makes sense. If there is a big difference in capacity then internal resistance will differ and a bigger battery can take a much larger charging current which will affect the life of the smaller capacity battery.

Edit: if you just happen to have a 220AH battery then set it up as two independent circuits. Charge each separately from the input source through a changeover relay (manual switching or automatic) or dc dc charger from one to the other.
Ok. that all makes sense. So as well as charging via pos on one and neg off the other should the inverter be hooked up the same way?

What do you want to run with the inverter? ... and how many watts does it draw, and how long do you intend to run it, per day.
Microwave and coffee machine of course... 700w and 1000w. Probably 3- 4 times a day each for upto 3 minutes at a time.

I mean really you know you should to run an inverter :)


View attachment 374143
I'd love to go lithium but don't have the budget for it. I can get a Kings inverter and 115aH battery for about half that price delivered...
 

fatboyonabike

Wheel size expert
to be more specific, if you have 2 different A/H rated batteries connected in parallel, as you discharge them through applied load the voltage will also decrease, the larger one more slowly than the smaller one.
So what will happen is that the smaller battery will have a lower voltage than the larger battery and the larger battery will try to recharge the smaller battery to try to achieve a balanced voltage across both.. this can be rectified with the use of diodes, but bear in mind that they have to be large enough to cope with the circuit current (so quite big!)
hope that makes sense, sorry, trying to less important stuff on the side ;)
 

Dales Cannon

Deleted Banned Moderatuuur
Staff member
Ok. that all makes sense. So as well as charging via pos on one and neg off the other should the inverter be hooked up the same way?



Microwave and coffee machine of course... 700w and 1000w. Probably 3- 4 times a day each for upto 3 minutes at a time.



I'd love to go lithium but don't have the budget for it. I can get a Kings inverter and 115aH battery for about half that price delivered...
Yes, you can even go the other way around in: batt 1 pos, batt 3 neg, out: batt 1 neg, batt 3 pos. I have only set up two batteries at time so pretty simple.
 

DMan

alid sinistra oliva
@DMan surely the missus isn't demanding more coffee or colder drinks after that effort .... I just checked - 2nd overall and won her category by a massive 10 laps!!! Congrats to the athlete and the support team (aka slave) !!
The coffee is for me to stay awake for 24hrs! She's a bit of a legend. I struggled to keep up with her on the first 2 laps at her 24hr pace....
 

creaky

XMAS Plumper
The coffee is for me to stay awake for 24hrs! She's a bit of a legend. I struggled to keep up with her on the first 2 laps at her 24hr pace....
Didn't realise you rode also .... should I expect a surprise if I check the results ??
 

DMan

alid sinistra oliva
Didn't realise you rode also .... should I expect a surprise if I check the results ??
Haha. No dude. It's not my thing. Credit is all hers. I did the 1st couple of laps to pace her and slow her down and then I ran the pits. It was hot though. 34c and 90% humidity. Caught riders by surprise with dehydration
 
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