We are going to do a job - fly in, get rental car, buy car battery for GNSS base, go to site, survey ... fly out. It's likely that the battery isn't going to be recently charged up and we don't want to loose time going to a hotel to charge it from mains, so is it possible/viable to just make a cigarette lighter plug with some alligator clips and charge it from the car socket during the 1 hour drive to the site?
Most cigarette lighters are wired with 16 gauge wire which allows for 10 plus amps from a 12v dc circuit, some do have bigger wires though you can't count on that.?ÿ You will not get a lot of charging from this, but, it will be noticeable.?ÿ Of a bigger concern to me is that a lot of new cars do not have cigarette lighters in them.?ÿ USB with its limit of 2.4 amps is what I am seeing out there now.?ÿ You might want to make an alligator cable to go from the car battery to the GNSS battery and while you are at it a nice roll of Duck tape to finish the look, ... OK I am kidding.?ÿ Actually the cable I just described would work great once parked.
Thanks. We'll probably get the same rental as before, and that had about three 12v sockets in it - so we're ok there. We just want to top it up to get the charge up around 12.8v, to minimize the chance of the base shutting down due to low voltage.
I'm wondering whether the battery connected into a socket would draw more than 10 A, as presumably it is unregulated, and blow the fuse in the car?
Can you take a 18amh SLA battery with you in your base box?
Possibly add a small solar panel 10w to 20w to top it up while in use during the day?
18ah
Would the rental people supply a charged battery for you??ÿ Or the place you buy the battery charge it for you?
No I wouldn't use 12v socket to charge, could draw too much current and blow fuses, or worse.
In the past, we've done exactly that and I've got a couple of home brew solar "power-packs". However they caused a lot of problems (I think it was the pulsing of the base radio dipping below the low voltage cut out on the solar controller), so we gave up on them a long time ago and now just use exclusively the smallest car batteries that we can get - here they cost around US$50. Also I'm not sure how the airline would cope these days with an 18Ah SLA - I know they're sealed but to them it looks like a small car battery, like the one on their sign with a red line through it.
Yeah that's who we're getting the battery from. As this is a remote area they also deal in batteries. We were up there last month and had two, and when we got them I checked the voltage and they were 11.8 ish, but in that case we got them charged overnight off the mains as we didn't need to go to site straight away.
We are going to do a job - fly in, get rental car, buy car battery for GNSS base, go to site, survey ... fly out. It's likely that the battery isn't going to be recently charged up and we don't want to loose time going to a hotel to charge it from mains, so is it possible/viable to just make a cigarette lighter plug with some alligator clips and charge it from the car socket during the 1 hour drive to the site?
Take battery out of car.?ÿ Replace with other battery.?ÿ Drive to site switch.
Yeah that did flash through my mind but the issue would be that it would could cancel all the radio codes, etc and then the rental co might flare up. But thinking about it again, maybe we'll ask them to do the swap. Having said that, it looks like now we'll be getting one of these:
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The?ÿToyota Aqua?ÿis a full hybrid gasoline hatchback produced and marketed by the Japanese automobile maker?ÿToyota?ÿMotors. ... The?ÿToyota Aqua?ÿis equipped with the 1NZ-1LM 1.5 ?? liter engine which is mated to an electric motor that produces the output power of 73KW.
I must say, we've got a Toyota Fielder (Corolla station wagon) which has the same engine. It's a great wagon, it's got a 35L tank, and we get over 600km out of it, at around 5L per 100km (47 miles per US gallon).
There's no way they will let you fly in with your own?
When I did remote work on village airports, we had at least two motorcycle/ATV batteries for long static sessions, and one large marine deep cycle battery for external 35W radio broadcasting + logging static.
In the states, TSA will let each individual fly with two non-spillable ("maintenance-free") wet batteries as long as they do not exceed 12V and 100 Watt-hours.
Depending on who was working at the airports, they sometimes threw a fit and tried to claim we could not bring them, but all we had to do was show them the TSA rules and, if necessary, call the supervisor to give them a stern talking to.
one large marine deep cycle battery for external 35W radio broadcasting + logging static.
... as long as they do not exceed 12V and 100 Watt-hours.
Wouldn't that battery exceed 100 watt-hours? It would run a 35 watt radio for more than 3 hours, wouldn't it?
100 watt-hours = 100 volt-amp-hours / 12 v= 8.3 amp-hours
@richard-imrie?ÿ From my understanding that depends on the voltage difference
Cripes Richard, if there ain??t more than six of ya crammed into that beast of a Toyota you can surely squeeze a gasoline generator in there with you. ?????ÿ
That's what I thought too. One of our mains chargers is the "old" type and it a has needle ammeter on it and when we charge a battery that's had a full day's use, the needle goes up to 4A (the rating of the charger is 8A) so that could suggest a reasonably low battery will only draw 4A to charge, but I probably wont gamble on that being correct.
I have some spare voltage regulators which are typically rated for 5A, so I'll look into whether these also regulate or limit current on the draw side.
I think they'd probably pull us up for something that can be used as a heavy weapon.
@flga-2
Years ago I did a stint as a rodman and in that particular company, the staff we required to use their own vehicles which meant I got to go on jobs in other pilgrim's wagons. One guy had a Ford Anglia and the dimensions of it meant that the driver and passenger's shoulders would touch together and rub. So, to minimise the risk of romantic accusations, one or both of the occupants would need to sit at an angle. (Hence perhaps how Ford named it).
?ÿ
I installed a Grp31 AGM deep cycle battery in a trolling motor battery case in the back of my Jeep to power a compressor type refrigerator/freezer.?ÿ Initially?ÿ I kept it charged by running 18g wire to the dash cigarette lighter.?ÿ Two problems:?ÿ When the battery's near dead it draws 15+ amps and blows the cig' lighter fuse.?ÿ When it's above half charged the voltage drop in the wire run prevents the battery from charging further.?ÿ ?ÿSwitched to 8g wire connected directly to the car's battery with a 40amp circuit breaker and now it charges like a champ, 30+-amps when near dead (+- 3 hours drive time), and almost no voltage drop when near full charge.?ÿ
A high output alternator is a good idea and I disconnect the aux battery when the engine's not gonna run for more than a few hours (overnight, for example).?ÿ A bonus is if the car battery goes belly up, I can replace it with the aux battery (don't try to start the car through the aux wiring, it'll trip the breaker <g>) and be on my way.?ÿ When camped for more than a day I charge it with a military folding 100watt solar panel which only weighs 5 pounds.
When it's above half charged the voltage drop in the wire run prevents the battery from charging further.
The resistance of the wire will limit the rate of charge, especially if the run was long, but would not affect the ultimate charged voltage. When the battery approaches full charge the current is low so the voltage drop is negligible.
I'm digging on my really deep and sequestered EE torture i worked around, and ultimately remember this:?ÿ If you have a higher voltage, and amperage, you can charge the storage battery up to a point. Then you just create heat. Sometimes smoke.
We?ÿ used to build small solar ( 85W) panel arrays to charge our remote repeaters on tops of mountains to avoid the constant daily retrieval?ÿ and time wasted doing so.
Voltage regulator was the key component in the circuit, and zener diodes are important too.
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That being said, just search for an inverter/charger that can be clipped to the main battery cables(need long enough cables to reach wherever the battery is going to be and go to town.
my $0.02( American, not sure what the rate is on the ForEx at the moment.?ÿ 😉
