Advice required: <span class="highlight">Generator</span> for battery charging.

To add to Allan's post. I have noticed that a number of generators have a 12v output, but it is limited to exactly 12v and as such is designed to run appliances and NOT suitable for battery charging. You need more than 12v to charge a battery (unless its very flat), generally 13-15v.

Another vote to only use the charger from the generator.

Cheers,
Barry

Myles, I tried to keep my first response above concise, but there may be need to add a little more........

The 12v 5amp output from the gennie is intended for supplying portable camp lighting etc. It is not designed for charging batteries. If it were connected to a battery there is no guarantee that it will deliver 5 amps because, as Cravenhaven has said, you need more than 12v to charge the battery. With respect, Ross M's idea below of using both is not what I would want to do.

Allan, Cravenhaven & Barry,
Thanks for your reply.
My generator produces pure sine wave. It’s a Kipor Digital Inverter Series 2 GS2000. It states ‘The DC receptacle may be used for charging 12 volt automotive type batteries only. The zero load voltage is 15V-30V.’

Thank You Myles, for alerting the above posters as to the status of the 12v output.
My Honda Eu 20i even has battery clips on the end on the charge lead so you can connect it to a battery. Honda intended it that way. That's why they have that feature.
As mentioned previously it will charge the battery The Honda at 8amp supposedly, so will bring up the SOC of the battery but is not regulated to any respectable degree. It alone is too slow.
While the battery is "down" on charge the two can be used to quicken the charge rate while the Projecta should only be there for the finish for regulation and battery protection.

As suggested, the projecta will be a switch mode energy transfer device and may not like working on a generator which isn't full sine wave in it's 240vac output.

I was wrong, quite wrong, about the intended use of the nominal 12vdc output of the generators and my apologies to Ross. Whilst not owning one myself, I was relying on my memory of earlier thread comments of others. Now after reading the specs of the Kipor and Honda generators I see that they nominate the dc output for battery charging.

Nevertheless, I would suggest caution if using this output to charge batteries. It is not as controlled as a multistage battery charger and would need to be monitored to ensure that the battery was not overcharged. Ross' proposal to use both the direct output together with a multistage charger would certainly speed the charging but would need careful attention.

The other consideration is that because of its lack of regulation and limited output, the gennie dc output will take quite some time to fully charge a decent-sized battery, with the gennie running all that time. A much better way would be to use a 35 amp multistage charger from the generator's 240vac output which will both charge much quicker and without risk to the battery. But of course, if you already own the gennie and a smaller charger, then you may accept need to accept a compromise.

G’day Ross,
I hadn’t thought of implementing both. I usually keep the solar panels connected through the Anderson Plug from setup to packup. I guess there’s no reason to unplug them either. I would only run the generator late afternoon for top up if the need be and I could monitor the charge and unplug the dedicated DC charger on the generator when the batteries were approaching full charge.

My solar works on my battery in the vehicle and while connected the alternator also runs with the engine providing additional charge.
I have also used my switchmode power supply/battery charger off 240vac while the solar is connected. Usually off outback station generator plants.
No problems yet and batteries got charged ok. I do however, monitor the charge rates and voltage level often. I use a Jaycar $25 digital meter with the system for instant checking.

Bruce,
All right… but only half! We often spend Christmas at Fraser. Very few people are there before Christmas and we usually leave Boxing Day when everyone else is arriving. We have Christmas lunch at Eurong Beach Resort and there are very few people there either. Keep it to yourself though… we like it quiet.
Myles.

OK Myles, I won't tell a soul. LOL

Just another peice of advice re the genny charging batteries.
It is best to charge in two hour blocks about 2 or 3 times a day.

This way you get the most into your battery for the least amount of genny time. Easier on the ears and the neighbours that way. The bulk of the charge occurs in the first 2 hours.

Good to have a laugh with you mate.

Cheers, Bruce.

I made up a Honda 100cc2.2hp engine with a car alternator on a bracket to the crankcase. With suitable pulley sizes it outputs at least 50 amps and charges well. Good as a backup and half the price or less than a Christies.

Honky, the christies unit is very noisy and that presents some issues if you prefer to have harmony with any camping neighbours. The invertor generator is quiet and it surprised me that a C Tek 25 amp charger didnt take much longer to recharge to a 100 amp agm batterys. I had a 4 hp honda driving a 80amp alternator and iall things considered I thinlk the Yamaha Invertor Generator and the 25 amp C tek is a better choice. In practice the batterys wont accept a high current for long and I found the batterys were only accepting 25 to 30 amps from the alternator after about 15 mins run time.

I think the C tek with its multi stage charging catches up a bit on the alternator as the battery charge comes up, that is I think the c Tek must manage to get more current over a longer period to bridge the gap in the recharge times.