Is 35 amps enough capacity for a charge controller?

[MCDenny]

I'm 6weeks late here, but having set up the same exact system ransom is considering I'd like to add that the proper converter (really just a battery charger) is about one-tenth the battery's C20 spec. Has nothing to do with DC loads.

A good energy meter is necessary to monitor your electric use when boondocking. Yes the battery life is extended by stopping discharge before it gets too low but it also lets you predict when it's going to get too low.

I use a 30 amp iota smart battery charger, a 10a PWM solar controller with a 100 amp solar panel, a Victron BVM700 meter and two 6v 220ah batteries.

Note on the BVM700, it uses a 500 amp shunt and resolves current to 10ma, that's 0.01 amps.


Denny Wolfe
Wanderingourway.wordpress.com

[Jon Vermilye]

Originally Posted by MCDenny

I'm 6weeks late here, but having set up the same exact system ransom is considering I'd like to add that the proper converter (really just a battery charger) is about one-tenth the battery's C20 spec. Has nothing to do with DC loads.

A good energy meter is necessary to monitor your electric use when boondocking. Yes the battery life is extended by stopping discharge before it gets too low but it also lets you predict when it's going to get too low.

I use a 30 amp iota smart battery charger, a 10a PWM solar controller with a 100 amp solar panel, a Victron BVM700 meter and two 6v 220ah batteries.

Note on the BVM700, it uses a 500 amp shunt and resolves current to 10ma, that's 0.01 amps.


Denny Wolfe
Wanderingourway.wordpress.com

Whether a 30 amp converter is large enough depends on a number of things. Do you plan to winter camp with a roof top solar panel (when the sun angles are low & the days are short? Depending on your amp hour usage, you may find you need more than a 100 watt panel (I think you have a typo of 100 amp solar panel - that would be great, but would cover the roof of most houses).

The solutions are more panels, portable panels that can be aimed at the sun, a generator, or hooking up to a pedestal for a couple of days every week or so.

If you are going to use a generator to recharge your batteries, a larger converter would be useful because the higher initial charge rate would cut down the generator run time. If you plug into a pedestal every couple of days, you will be able to deal with the longer time the smaller converter takes to charge the batteries, and possibly not need the generator.

Personally, I prefer to depend on solar alone. I have 195 watts (2 panels) on the roof & a portable 160 watt panel. I don't need the portable during the summers, but do during December & January, even in the Arizona desert. I use around 35 - 40 amp hours per day & also have a pair of 232 amp hour batteries. I don't carry a generator, and survived 93 days wintering in Quartzsite without hookups.

[gordon2]

Originally Posted by MCDenny

...
I use a 30 amp iota smart battery charger, a 10a PWM solar controller with a 100 amp solar panel, a Victron BVM700 meter and two 6v 220ah batteries...

Thats a typo.. he means 100 watt solar panel (or about 5.6 amps in actual use).

[Raz]

Note on the BVM700, it uses a 500 amp shunt and resolves current to 10ma, that's 0.01 amps.

From the BVM 700 spec sheet they list the shunt resolution as 50 mV for 500 amps.

So 50 mV/500 amps = 0.1 millivolts per amp shunt resolution. That's 100 microvolts for each amp of current flowing through the shunt.

So a 10mA current through the shunt will produce a voltage of 1 microvolt. That's one millionth of a volt.

Read 10 mA.? Sorry Denny, but this old engineer is skeptical. Raz

[MCDenny]

100 amp solar panel, I wish. Of course I meant 100 w, which only puts 65 watts into the battery.

Trojan battery charger specification is10% to 13% of battery C20 rating.

Re the BVM 700 meter, they say 10mA but I hear you Raz.


Denny Wolfe
Wanderingourway.wordpress.com