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| Is there a way to safely charge a car battery with this equipment? If not, why? |
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| Marck:
Most of our DC systems are Eaton but we recently in the last few years used some Tristar gear for some solar installations. We found them quite good but with a slightly higher failure rate than the mains powered Eaton equipment but the cause of those failures could be put down to the duty cycle being much higher with daily discharge cycles. Don’t get me wrong we are only talking about 2 issues across 5 sites in 4 years. We just started trialing Victron inverter / chargers Thats because we also need inverters to run an air conditioner and one other piece of mains powered equipment along with the nice http based UI that we can access remotely to keep an eye on things and ease of gathering trends. This means that we only need to keep one spare device that replaces 3 seperate units a mains charger/inverter/solar charger. Set up in pretty much a plug and play setup. By no means am i suggesting that the Tristar gear is not as good as the Victron stuff its just ease of serviceability for us. Time is the only real judge of performance for most of these things. Most quality battery manufacturers will specify an ideal charge profile based on the battery and typical operating temps in sites that are not temperature controlled they quite often recommend a change in charge voltages for temps outside a specific range. Most of the better chargers will have a temp probe that can trigger a change in charge profile for excursions outside the optimum. Good luck with your service power is always a expensive and difficult thing to get spot on for long trouble free service. Just another bit of advice on the batteries that claim much more than 150 AH capacity in the standard long tall form factor used in these installations. Quite often these claimed capacity’s are at a lower discharge rate compared to the competition. A reasonable rule of thumb is if the battery dose not weigh more the capacity may not be as claimed. On average a good quality 150AH battery will weigh around 47 kilograms each if the claimed capacity dose not come with extra lead in the battery unless they have some design advantage its time to dig into the spec sheet and see whats going on. Its almost at the stage where Lithium is the correct choice for new installations. The increase in available discharge capacity the increased cycle count and the huge weight savings the lifecycle cost is almost at breakeven point. The only thing that is holding back the revolution is the cost of failures smudges the cost benefit line a bit. A out of warranty replacement of a battery is double that of lead acid. And at this point there is not quite enough long term data on any particular manufacturers lithium service life to adopt that risk. For any existing installations that wont allow constant voltage charging and will require upgrades of chargers and such its a little further away. But my personal opinion is that within 5-10 years we will not see many lead acid battery installations being used in telecommunications. Now we are way off topic. M |
| Tomorokoshi:
--- Quote from: Simon on October 20, 2019, 05:05:14 pm ---what vehicles use AGM batteries? --- End quote --- What cars use AGM batteries? Mine do! Just charged up some spare batteries using my HP 6114A power supply. Set to the recommended charging voltage of 14.4V and set the current limit to 1A. Then I slowly adjusted the voltage down to keep the trickle current to around 100mA. This all started because one of the batteries stopped taking a charge after being used for around a month. That was maybe 3 years ago. Took it to the store where they used the battery tester, declared it failed, and so I was able to submit a warranty claim for a free replacement. I never got around to getting rid of the failed battery, and before I got the coupon for the replacement I bought another one of a different brand and construction. Through a series of mishaps I now have all three batteries not installed in a car. Anyway, as part of topping off the two known-good batteries I connected the failed battery to the HP 6114A. No current. Well, that being the case, I instead used the HP 6186C 300V / 100mA Current Source to charge it. At 10mA it drove to something like 100V. Over the course of a few hours the voltage dropped to maybe 15V, so I charged with the HP 6114A instead. For the most part it topped off at the same voltage as the other two, and after 4 weeks the two good ones are 12.8V, and the "bad" one is 12.7V. I don't know what the failure process was and I don't know what may have fixed it. I have not signficantly load tested it yet. |
| tautech:
@ Marck The installation we did was purposely kept all DC and powers just a DC POE switch that in turn powers all the Ubiquity data transmission HW. NO freaking inverters ! Here's a link to some pics of the installation with a link to the docs of the DC POE switch we used: https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg2698096/#msg2698096 The 4 batteries are German SLA's and mighty heavy buggers @ some 55kg ea ! :scared: Yep and we used the Tristar solar controller battery temp sensor. ;) Anyways, IMHO it's over designed to hell as any one bit of HW draws under 30W max ea and there's 900W capability from the panels for a measly ~100W max load. |
| Marck:
That Ubiquiti gear is good value for money. We recently used a couple of the Air fibre 24hd links for temporary coms over about 2Km. A solid gigabit link and lets say very rough one eye closed alignment. That looks like a neat little switch. Here that would probably cost hundreds of $$. The US gets all the good cheep toys. M |
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