I'm trying to ask a question that I know very little about. So in this posting I'm trying to find out what "ingredients" I need to include, so that I get the right answer. Couple days ago I posted about what type of generator I should buy to replace mine that was stolen from my carport. I've been looking at a lot of spec's and options etc and still have some questions. I've read on here more than once that a battery charger plugged into a generator and then connected to the batteries is better than using the charging system in RV. Is that correct or is it depending on what charger I have in RV? Or maybe what type of battery charger (running from generator) I'll be using? I don't even know if charging directly from charger is always better or sometimes or usually, or even better at all. What info do I need to provide.... so I get the best answer.

Depends on the converter and stand alone charger output ratings. Mist trailer's have at least a 45 Amp converter. Battery chargers more than 40 amps are rare.

path1 wrote:I've read on here more than once that a battery charger plugged into a generator and then connected to the batteries is better than using the charging system in RV. Is that correct or is it depending on what charger I have in RV? .That... Was the right question: Here is the answer.It depends on what charger you have in the RV.Most modern RV's have 3 or 4 stage smart chargers (4th stage is equalization) and if this is what you have, and if it is the right size (Amps = about 30$% of battery bank C/20 rate) then this is the best way to recharge.On the other hand if you have say 4 Pair of GC-2. (That is about 900 amp hours) and a 45 amp converter.. A big external may be better (That much battery can suck nearly 300 amps bulk mode)Some RVs though (oldr ones) may have a Magntek 6300.. If you do, please UPGRADE your batteries will thank you (Progressive Dynamics 4600 series works.. Replaces JUST the converter part. Lighter too) Some lower end newer units have the Parallex 7300.. this too is a single stage and an external may be faster.other models you need to read the spec sheet.

There's no inherent benefit to an external charger plugged directly into a generator. Electrically plugging a charger directly in is the same as plugging the RV in with it's internal charger connected.It all depends on which RV converter and which external charger we're talking about. Personally, if the one in the RV isn't multi-stage or doesn't have a high enough output I would just upgrade it instead of spending money on an external charger.

I carry an external charger with me even though I have a 3/4 stage converter. The converter is very good at keeping the RV battery charged.I tow a car and TTs have a tow vehicle. I have had to use my charger to recharge the car I tow several times. It's worth it to me to have the charger available.

Asking the right question about generator&battery charger

16 Replies

BFL13
Explorer II
Jun 20, 2015
You also have to match the converter or charger to the ability of the generator to supply the 120v to run the charger at its rated DC output. Big amp charger needs a big watt gen. With that, you can also choose a PF corrected charger to be able to run more DC amps from the same amount of 120v.

The first thing is to decide how long you want to run the gen for how often while camping.

Your daily AH usage from however big your battery bank tells how long before the batts are down to 50%. Then you will do a "50-90" recharge and we know how long that takes for various "charging rates" (DC charging amps wrt AH size of bank)

Now you pick a charging rate that fits your chosen recharge time for your size bank, and get a charger/gen combo that can do that.
tenbear
Explorer
Jun 20, 2015
I carry an external charger with me even though I have a 3/4 stage converter. The converter is very good at keeping the RV battery charged.

I tow a car and TTs have a tow vehicle. I have had to use my charger to recharge the car I tow several times. It's worth it to me to have the charger available.
KD4UPL
Explorer
Jun 20, 2015
There's no inherent benefit to an external charger plugged directly into a generator. Electrically plugging a charger directly in is the same as plugging the RV in with it's internal charger connected.
It all depends on which RV converter and which external charger we're talking about. Personally, if the one in the RV isn't multi-stage or doesn't have a high enough output I would just upgrade it instead of spending money on an external charger.
wa8yxm
Explorer III
Jun 20, 2015
path1 wrote:
I've read on here more than once that a battery charger plugged into a generator and then connected to the batteries is better than using the charging system in RV.

Is that correct or is it depending on what charger I have in RV? .

That... Was the right question: Here is the answer.
It depends on what charger you have in the RV.

Most modern RV's have 3 or 4 stage smart chargers (4th stage is equalization) and if this is what you have, and if it is the right size (Amps = about 30$% of battery bank C/20 rate) then this is the best way to recharge.

On the other hand if you have say 4 Pair of GC-2. (That is about 900 amp hours) and a 45 amp converter.. A big external may be better (That much battery can suck nearly 300 amps bulk mode)

Some RVs though (oldr ones) may have a Magntek 6300.. If you do, please UPGRADE your batteries will thank you (Progressive Dynamics 4600 series works.. Replaces JUST the converter part. Lighter too)

Some lower end newer units have the Parallex 7300.. this too is a single stage and an external may be faster.

other models you need to read the spec sheet.
westend
Explorer
Jun 20, 2015
Depends on the converter and stand alone charger output ratings. Mist trailer's have at least a 45 Amp converter. Battery chargers more than 40 amps are rare.
path1
Explorer
Jun 20, 2015
(sorry dup, please delete)

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Asking the right question about generator&battery charger

16 Replies

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