Charging batteries without disconnecting batteries
Brodie Allen said
09:59 AM Oct 11, 2022
I often have the need to charge the batteries from the generator as well as
relying on the solar.
My manual says that the batteries should be disconnected before attaching them
to the generator. leaving them connected "will cause damage to the rest of the system".
Since batteries are under the seating that is a major hassle.
1. Can they be charged without disconnection in reality - I have an external Anderson that
I have been using for generator top-up purposes so far without problems - the solar is feeding
in at the same time.
2. If the car can charge at the same time as the solar why does this not cause problems?
Could the car Anderson plug be used for charging the batteries from a generator?
Brodie
rgren2 said
10:14 AM Oct 11, 2022
Why dont you plug your generator in the normal 240v inlet and let the system you (should) already installed do its job?
Mike Harding said
11:16 AM Oct 11, 2022
When charging from the generator do you use the generator's DC output or do you use a 240V battery charger?
Brodie Allen said
02:41 PM Oct 11, 2022
rgren2 wrote:
Why dont you plug your generator in the normal 240v inlet and let the system you (should) already installed do its job?
Thanks for your reply.
Often do but is very slow - most times I do that and run the charger
for mostly about 35A input.
Brodie Allen said
02:48 PM Oct 11, 2022
Mike Harding wrote:
When charging from the generator do you use the generator's DC output or do you use a 240V battery charger?
thanks for your reply.
Have never used the 12V. What would regulate the charge?
Mike Harding said
03:14 PM Oct 11, 2022
Brodie Allen wrote:
Have never used the 12V. What would regulate the charge?
From your reply I assume you have an independent 240V battery charger which you plug into the generator and connect to the batteries.
Your description of the system is not clear but what I understand is:
Batteries which are connected to a caravan charger
Solar panels which are, somehow, connected to the batteries
An Anderson connector which is connected directly to the batteries of, maybe, goes via the caravan charger
If my assumptions are correct then I see no reason why you should not connect a battery charger powered by the generator to the Anderson connector.
Brodie Allen said
11:34 AM Oct 12, 2022
Thanks Mike.
Is it ok to have 240 to system as well as to Anderson via charger?
Mike Harding said
11:46 AM Oct 12, 2022
Brodie Allen wrote:
Thanks Mike. Is it ok to have 240 to system as well as to Anderson via charger?
I understand you to mean, is it OK to have powered up and connected to the batteries the following:
Caravan OEM charger
Your generator powered charger
Solar panels
----
It's an unusual way to do things and suggests you either need a better caravan charger or more solar.
However the charging outputs of all three products should be designed such that they can tolerate connection to another 12V nominal power source - ie. they *must* tolerate the battery presence in the event of a power cut - so, yes, it should be fine to do the above.
Brodie Allen said
09:45 AM Oct 13, 2022
Sorry Mike to be vague.
You can see that a little bit of knowledge can be dangerous, so I
Have booked a session with the local lecco for his advice.
In the meantime it looks like my batteries are sulphated rather badly -
I put the charger on them because they were down a bit even with a bit
Of solar and the charger has been desulphating now for 2 sessions of about 6 hours
Per battery. Wont know how it has gone till I hook the loads back up and set
up a few hours draw.
Cant afford $6 to 8 big ones to go to Lithium - thats the estimation from the caravan mob.
And anyway I reckon that major expenditure at my end of the wick is likely
to become a waste.
Brodie.
Mike Harding said
11:00 AM Oct 13, 2022
Unfortunately if the batteries have sulphated there is not much which can be done with them; certainly it is worth trying the "de-sulpaters" and they may make a little difference but we are talking an improvement of 10% or 15% not 75%.
Assuming you are not running a microwave or AC from your batteries then most caravans can get away with 100Ah or, at most, 200Ah or AGM perfectly well. A 100Ah AGM will cost about $250.
Good luck.
Ivan 01 said
05:50 PM Oct 13, 2022
I am a mechanical fitter but my knowledge of modern electrics is under construction.
I was told some time ago that if I were using my generator (Honda) to charge directly from the charger, the batteries should be disconnected because remaining connected might damage any sensitive equipment.
Something to do with sine waves charging but I can not say any more as to why until I do further study.
Apparently just plugging the van into the generator GPO is ok as the charge is regulated by the van charger.
-- Edited by Ivan 01 on Thursday 13th of October 2022 05:52:58 PM
Mike Harding said
07:46 AM Oct 14, 2022
Most small generators have a DC output intended for lead acid battery charging, in the half a dozen generators I have checked this output is simply unsmoothed full wave rectified DC peaking at about 18V and I strongly suggest it is never used for battery charging except in an emergency.
If you are using a conventional 240V battery charger powered by the generator then the process I have outlined will be OK.
Aus-Kiwi said
10:03 AM Oct 18, 2022
It pays to use a proper battery charger . Most generators have 12v DC but hardly enough to charge a battery . Even my 5Kw Onan doesnt charge !! Best to get 20amp or so also so your not running generator all day . I leave the charger connected all the time . It has a built in diode . I would say your batteries are toast ? Plus do you really want the risk of unreliable batteries ? 5 years seems the limit ! Especially if theyve gone flat a few times . I bought two X 135 lithiums recently for $1500. All seems well !!!
Brodie Allen said
08:54 AM Oct 24, 2022
Aus-Kiwi
Did you need much mods to your system when you put the lithium in, or were they drop-ins?
I often have the need to charge the batteries from the generator as well as
relying on the solar.
My manual says that the batteries should be disconnected before attaching them
to the generator. leaving them connected "will cause damage to the rest of the system".
Since batteries are under the seating that is a major hassle.
1. Can they be charged without disconnection in reality - I have an external Anderson that
I have been using for generator top-up purposes so far without problems - the solar is feeding
in at the same time.
2. If the car can charge at the same time as the solar why does this not cause problems?
Could the car Anderson plug be used for charging the batteries from a generator?
Brodie
When charging from the generator do you use the generator's DC output or do you use a 240V battery charger?
Thanks for your reply.
Often do but is very slow - most times I do that and run the charger
for mostly about 35A input.
thanks for your reply.
Have never used the 12V. What would regulate the charge?
From your reply I assume you have an independent 240V battery charger which you plug into the generator and connect to the batteries.
Your description of the system is not clear but what I understand is:
Batteries which are connected to a caravan charger
Solar panels which are, somehow, connected to the batteries
An Anderson connector which is connected directly to the batteries of, maybe, goes via the caravan charger
If my assumptions are correct then I see no reason why you should not connect a battery charger powered by the generator to the Anderson connector.
I understand you to mean, is it OK to have powered up and connected to the batteries the following:
Caravan OEM charger
Your generator powered charger
Solar panels
----
It's an unusual way to do things and suggests you either need a better caravan charger or more solar.
However the charging outputs of all three products should be designed such that they can tolerate connection to another 12V nominal power source - ie. they *must* tolerate the battery presence in the event of a power cut - so, yes, it should be fine to do the above.
You can see that a little bit of knowledge can be dangerous, so I
Have booked a session with the local lecco for his advice.
In the meantime it looks like my batteries are sulphated rather badly -
I put the charger on them because they were down a bit even with a bit
Of solar and the charger has been desulphating now for 2 sessions of about 6 hours
Per battery. Wont know how it has gone till I hook the loads back up and set
up a few hours draw.
Cant afford $6 to 8 big ones to go to Lithium - thats the estimation from the caravan mob.
And anyway I reckon that major expenditure at my end of the wick is likely
to become a waste.
Brodie.
Unfortunately if the batteries have sulphated there is not much which can be done with them; certainly it is worth trying the "de-sulpaters" and they may make a little difference but we are talking an improvement of 10% or 15% not 75%.
Assuming you are not running a microwave or AC from your batteries then most caravans can get away with 100Ah or, at most, 200Ah or AGM perfectly well. A 100Ah AGM will cost about $250.
Good luck.
I am a mechanical fitter but my knowledge of modern electrics is under construction.
I was told some time ago that if I were using my generator (Honda) to charge directly from the charger, the batteries should be disconnected because remaining connected might damage any sensitive equipment.
Something to do with sine waves charging but I can not say any more as to why until I do further study.
Apparently just plugging the van into the generator GPO is ok as the charge is regulated by the van charger.
-- Edited by Ivan 01 on Thursday 13th of October 2022 05:52:58 PM
Most small generators have a DC output intended for lead acid battery charging, in the half a dozen generators I have checked this output is simply unsmoothed full wave rectified DC peaking at about 18V and I strongly suggest it is never used for battery charging except in an emergency.
If you are using a conventional 240V battery charger powered by the generator then the process I have outlined will be OK.
Did you need much mods to your system when you put the lithium in, or were they drop-ins?
Brodie