Battery charging

[tawoo]

Sorry for this redundant, asked a million times question...

My two, hooked in parallel, deep cycle batteries are down to one light ( probably 11 volts). How long will my Honda EU2000i take to charge them back up? The batteries are three years old.

Thanks!

[Big Sky]

What type of charging system do you have? Do you know if it is single stage or does it have the advanced charging capability?

[mike837go]

You'll see "Full Charge" on the panel in an hour or so.


In reality, 5-10 hours if you have a mult-stage charger. 24 if you have the old style 2A battery maintainer.

[tawoo]

My Jayco is a 2014 so the charger should be the new style.

[tnchuck100]

Seeing "full charge" on the panel is not a reliable indication while charging. That light is purely voltage sensitive. Shortly after the charging begins it will show full because the converter is in a bulk charge mode (14V). The panel light indicators should be determined only after 1 hour of no load and no charging.

[Big Sky]

X2 on the response from tnchuck100.


After I installed the Tri-Metric battery monitor I realized how little those indicator lights really mean.


Your charging system and actual state of discharge will be the biggest determining factors on your re-charge time. I'm not familiar if they are putting advanced converter/charging systems as standard equipment or not. Some will give you the option to use a plug in module to gain the advanced capabilities. Regardless, if you are at 11 volts now you are more than likely below 50%.

[Subaru297]

If you just plug your trailer into the generator it will take a very long time to charge back to 100% charge.

2-3 hours to get to ~80% but then another 10+ to get the rest of the way to 100% charge if your converter is even capable of reaching 100%. They usually drop out of bulk charge too early to get a complete charge.
Converters are designed primarily to maintain batteries (IMO) when they are plugged in for long periods of time (days) not to be efficient chargers.
Your batteries may need up to 15 volts to charge properly (varies with manufacturer) and most trailer converters will not provide this.

Cheers

[tawoo]

Subaru, is there any way to bypass the onboard charger to get a full charge?
Thanks!

[mike837go]

Originally Posted by tawoo

Subaru, is there any way to bypass the onboard charger to get a full charge?
Thanks!

I decided to build a 12VDC genset. A 79CC (~3hp) engine driving a 60A car alternator.

Haven't used it at the campsite yet. But it charges the battery directly from gasoline. An hour or two of that setup will recover from a full day of lights, radio, furnace, etc.

[Subaru297]

You don't need to bypass the onboard charger if you don't want to. You can hook multiple battery chargers to the same battery without issues. The stronger charger will dictate the charging parameters.
The one drawback from this is if your converter was bulk charging the battery already the new charger being hooked up would see that voltage and think the battery was already full so it would not go into bulk mode.

What scenario are you envisioning?

If you want to disconnect the onboard converter have a look for a circuit breaker labeled "Converter" and switch it off. If yours doesn't have a breaker associated with it then you would need to disconnect something internally and that is beyond my ability to describe on the internet.

[Subaru297]

Originally Posted by mike837go

I decided to build a 12VDC genset. A 79CC (~3hp) engine driving a 60A car alternator.

Haven't used it at the campsite yet. But it charges the battery directly from gasoline. An hour or two of that setup will recover from a full day of lights, radio, furnace, etc.

Is this still voltage regulated like a cars alternator would be? What is the charging voltage?

[mike837go]

Originally Posted by Subaru297

Is this still voltage regulated like a cars alternator would be? What is the charging voltage?

The regulator I had on the shelf has a cutoff at 14.2 volts. A bit high for my tastes.

But, if the rest of the cobbling holds, it'll beat the heck out of running a 2KW genset for hours on end. Or carrying enough battery for 5 days of camping.

Since I am keeping some old (1980's to 1960's) equipment running, I keep a Chinese copy of the Chrysler 2-wire electronic regulator on hand.

The GM 1-wire is all well and good, but has a 50ma drain when 'off' plus the regulators blow after about 100 operating hours. It takes a couple of hours to rip out the internal regulator and rewire the tractor (again) for the external regulator located much farther away from the exhaust pipe.

There are several web sites selling an adapter plate to run a GM 1-wire off a lawn mower engine. I just had to do it myself!