d215yq
Senior Member
- Joined
- Mar 28, 2008
- Messages
- 2,664
- Reaction score
- 702
- Age
- 39
- Location
- Valencia, Spain
- Your Mercedes
- 1987 W124 300D 280k miles
Hi all,
Due to the lockdown I'm likely having to leave the city this week where i have no electricity and have built an electric off-grid system. The problem is I bought a inverter that incorporates a solar charger that needs 120V of panels minimum to work and i only have 40V of panels so I have normal electric power direct from inversor in daylight but no way to charge the batteries for a week until my extra panels arrive (they don't fit in the car!!)
So long story short I would like to keep two 12V AGM 75aH batteries topped up once everyday to allow for internet/phone charging and some basic light, etc at night. My calculations are based on 0,3kWh use/night that's 15aH or about 45 minutes.
Is 45 minutes an Ok time for the car to be idling if I check it doesn't overheat? It gets a lot of long journeys (600km just this weekend) so should have the carbon cleared out pretty soon.
I've measured the regulator voltage at 13.9 @ idle and my battery says charging from 13V to 15V so I assume that means it's compatible. I'd also charge them in parallel to ensure they are the least likely to be overcharged and ruined. As it's an old school diesel W124 no sensitive electronics to fry in the car either.
And yes, before the smart alecs come on with solutions like "buy a generator", it's a temporary solution I'm proposing which I'm likely to be forced into by extreme measures outside my control. Just wondering if there are any serious problems it will cause to either the batteries or the car, or if it's just an inefficient but safe way to charge stuff and allows me to keep workign and communicated after dark for a few days until my panels arrive!
Due to the lockdown I'm likely having to leave the city this week where i have no electricity and have built an electric off-grid system. The problem is I bought a inverter that incorporates a solar charger that needs 120V of panels minimum to work and i only have 40V of panels so I have normal electric power direct from inversor in daylight but no way to charge the batteries for a week until my extra panels arrive (they don't fit in the car!!)
So long story short I would like to keep two 12V AGM 75aH batteries topped up once everyday to allow for internet/phone charging and some basic light, etc at night. My calculations are based on 0,3kWh use/night that's 15aH or about 45 minutes.
Is 45 minutes an Ok time for the car to be idling if I check it doesn't overheat? It gets a lot of long journeys (600km just this weekend) so should have the carbon cleared out pretty soon.
I've measured the regulator voltage at 13.9 @ idle and my battery says charging from 13V to 15V so I assume that means it's compatible. I'd also charge them in parallel to ensure they are the least likely to be overcharged and ruined. As it's an old school diesel W124 no sensitive electronics to fry in the car either.
And yes, before the smart alecs come on with solutions like "buy a generator", it's a temporary solution I'm proposing which I'm likely to be forced into by extreme measures outside my control. Just wondering if there are any serious problems it will cause to either the batteries or the car, or if it's just an inefficient but safe way to charge stuff and allows me to keep workign and communicated after dark for a few days until my panels arrive!