Battery mix or not?

[Happy1]

No one has mentioned that doubling the battery bank size you will probably need a bigger charger.

16amp cbe charger and two 120w solar for 4x100 batteries enough?

 

[OS51EEE]

16amp cbe charger and two 120w solar for 4x100 batteries enough?

Yes just enough but all depends how many amps you going to use every day if u use a lot you may need a heavier charging system to be honest I have a similar set up and don’t have any problems but iam not a heavy user of 12 volt biggest use is the telly for me at night usually by 12 o’clock next day it’s charged back up by a 200 watt solar panel

 

[Lenny HB]

16amp cbe charger and two 120w solar for 4x100 batteries enough?

Charger needs to be at least 40 amps for a 400 a/h battery bank, really needs to be bigger to account for starter battery charging. Loads off Motorhome charges get blown up where people increase the battery bank but not the charger. 120 watts of solar won't do much with that size of battery bank.

From another point of view I have 234 a/h of batteries and 300 watts of solar with a good quality MPPT regulator. I didn't increase the 18 amps mains charger as the solar does 95% of my charging.

 

[Happy1]

2x120w
currently running 2x100 batteries
maybe extra 1 not 2?

on a slightly different note, wiring a 12v compressor fridge about 5m away from batteries but probably further when cable run finished, book says over 6m need 10mm cable to counter voltage drop, over 8 metres 12mm, over 10metres 14mm,
I can only find 10 and 16 on net reffered to as starter cables, do you recon 10mm enough?

 

[HandyAndy]

No one has mentioned that doubling the battery bank size you will probably need a bigger charger.

Not entirely true , it'll just take longer to charge.. Instead of 10 amps going to one battery, you get 5 amps going to each for example.
But for the most part those on hookup, 24 hrs plugged in would see a 120ah battery full charged at 5amps from flat

^{_{Subscribers  do not see these advertisements}}

 

[pappajohn]

So what you're saying is if you have a 100ah battery and a 50ah battery in parallel the 50ah will be dead flat when the 100ah is 50% discharged.

Your example of two cans of water doesn't hold water (see what I did there) as the two cans arent joined.
Take the same two cans and drill two holes in each, in one hole each put a hollow tube to link them (paralleled) then let the water out the other holes.... Both will empty at the same time.

I know I'm right so not wasting any more time arguing.

 

[Lenny HB]

Not entirely true , it'll just take longer to charge.. Instead of 10 amps going to one battery, you get 5 amps going to each for example.
But for the most part those on hookup, 24 hrs plugged in would see a 120ah battery full charged at 5amps from flat

If the batteries are fairly low it will overload the charger, a known problem with Elektroblocks and other Motorhome charger units, if you put a too bigger battery bank on them they blow up.

As I said in my post above I take risk as I know what I am doing and have reasonable solar bank that takes care of most of my charging and I have never charged my batteries from low state on mains.

If people are not that clued up on electrics it is best to play safe.

 

[HandyAndy]

If the batteries are fairly low it will overload the charger, a known problem with Elektroblocks and other Motorhome charger units, if you put a too bigger battery bank on them they blow up.

As I said in my post above I take risk as I know what I am doing and have reasonable solar bank that takes care of most of my charging and I have never charged my batteries from low state on mains.

If people are not that clued up on electrics it is best to play safe.

True, SOME of the early electroblocks (and others) didn't have very meaty connectors and high resistance at those connectors is what melted them because they weren't designed to take the full load from an alternators output.. which was crazy IMO.. but having said that, they realised the issues from Aabout 1999 onwards and "most" had redesigned their circuit boards and connectors to suit from that point on.

 

[Lenny HB]

True, SOME of the early electroblocks (and others) didn't have very meaty connectors and high resistance at those connectors is what melted them because they weren't designed to take the full load from an alternators output.. which was crazy IMO.. but having said that, they realised the issues from Aabout 1999 onwards and "most" had redesigned their circuit boards and connectors to suit from that point on.

They still recommend gitting the auxillary charging unit if fitting second battery.

 

[Happy1]

factory fit second battery so obviously with an uprated charger

^{_{Subscribers  do not see these advertisements}}

 

[OS51EEE]

factory fit second battery so obviously with an uprated charger

Listen boys do what u want it's just best practice to use same amp hour batteries for charging purposes mainly . Looking forward to next topic hopefully not so deep ehh!

 

[autorouter]

If 2 or more batteries are connected to same charger they must be same age ,same amp hour same type i.e. Lead,gel,what ever. That is because they need to be charged at same rate from charger as if there one battery. mix them up and they won't charge up to full capacity

So what you're saying is if you have a 100ah battery and a 50ah battery in parallel the 50ah will be dead flat when the 100ah is 50% discharged.

The amp-hour capacities need to be the same if the batteries are in SERIES, for example two 12V batteries making a 24V pair, or rechargable batteries in a torch etc. Or wiring four 12V batteries to make a 48V bank in an off-grid solar system. However in PARALLEL, amp-hour capacities can be mixed, provided the voltages are the same.

To play safe, it certainly does no harm to have the amp-hour capacities the same.