chuck3
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Re: Advice on Lithium Solar setup
2oldman wrote: You mentioned you could us an extension cord with AGM, but you had to take the Li in to a "wall charger"? Is that something permanently attached to a wall? No, but the extension cord would need to be in the neighborhood of 100ft. Plus, I was thinking it would be better to have it inside so I could watch the charge meter and feel the battery to see if it was getting warm. Not big issues, just preferences. landyacht318 wrote: One think I wonder about is the OP's Kill a watt readings. 80 watts for a laptop is fairly high. My laptop is an older dell that requires a 90 watt adapter, but if the battery is already full, it uses about 30 watts to type this. Turns out you're correct. The readings I took were when the laptop batteries had a nearly empty charge. As the laptop charged, it slowly tapered off on watt usage and once the battery was fully charged, the usage bounced between 32 and 20 watts...much better! As for your other suggestions, using the alternator is something I'll definitely want to do to supplement the solar. I've seen that the alternator alone can charge house batteries only up to 80%, give or take some, so solar and possibly another source will be needed. I plan on driving every other day for 1-2 hours, and at least 2 days a week it will be 4 hours. As for mounting the panels, I'll use some kind of rack because, as you noted, heat becomes an issue otherwise. Any van should be able to hold at least 400w of panels, and some will be able to hold more. I'm keeping an eye out for extended size. I'll need to build a frame for the flexible panels but that shouldn't be difficult.728Views0likes0CommentsRe: Advice on Lithium Solar setup
Well, that puts a big dent in my plans, but thank you for the calculations. I'd much rather find out now than after spending a lot of money! Since that many amp hours rules out lithium (> $4,000), and this topic is about a lithium setup, I'll start a new thread with other questions after I regroup and come up with a new plan. I appreciate everyone's help!377Views0likes0CommentsRe: Advice on Lithium Solar setup
Now I'm not sure if I calculated my battery needs correctly. I used an online estimator but as a result of comments here, I rechecked my numbers using several other online estimators and none of them are giving me the same results. Would you please help me determine what my battery needs are? All measurements are from a KillAWatt on 120v AC: 80 watts, 9 hours a day = Computer 1 80 watts, 6 hours a day = Computer 2 20 watts, 16 hours a day = Wifi hotspot 12 watts, 16 hours a day = LED lighting 50 watts, 18 hours a day = fans I can get DC-DC converters (12v DC to 19v DC) for the computers if needed for around $15, if that would make a big difference in power usage.377Views0likes0CommentsRe: Advice on Lithium Solar setup
Almot wrote: If your needs require nominal 200AH Li, it means nominal 300AH if you go AGM route. $600 for 300AH AGM is less than $1,900 for 200AH Li, but with (looks like) purchase of a new van, you're into big expenses anyway. Not really, but it looks that way from what I've written. Fortunately I'm blessed with a pretty good job and can work wherever I have internet access. I can go into the office but it's not necessary. My house is on the market now and I want to vandwell mainly for the freedom and sightseeing. The van and solar system will be large but necessary upfront costs. I'm actually fiscally conservative and spend way too much time obsessing about how to save money. Lithium offers many more charge cycles than AGM, plus less weight would mean better gas mileage, and those equal long-term savings, hence my interest. I'm an Army vet and am used to primitive camping (or worse) so a van will be luxurious, relatively speaking. I've previously done it for a month in a borrowed van and absolutely loved it. I'd still prefer Lithium because on paper it's a cost saver. It looks like I need to ensure that the float charge is set to null, and the solar charger can do that but the jury is out on if wall chargers will do it correctly. So, without certainty on the wall chargers I can't feel confident that it's a smart investment, and I'd also like for adoption to be more widespread so there is more feedback available before I make that plunge.321Views0likes0CommentsRe: Advice on Lithium Solar setup
2oldman wrote: Hmm.. what have I missed? Why would you have to take it inside? To charge it from a wall AC charger since my current solar setup (still in planning) would not produce enough power to cover my usage and would require wall charging from time to time.322Views0likes0CommentsRe: Advice on Lithium Solar setup
Thanks for all of the info. I have a better understanding of how lithium batteries work, but between my situation and also not being 100% certain that I won't overcharge or completely discharge the battery, I'm now leaning toward AGM even though that will have it's own challenges, but I consider them to be lesser challenges. For example, I can use an extension cord from my friends house to charge the batteries if needed instead of taking the battery inside. The LifeBlue in-battery monitoring looks promising but I'd rather wait until more people have used it and posted about it. Adapting, as always :)321Views0likes0CommentsRe: Advice on Lithium Solar setup
Thanks for all of your input! Please see my responses below. Almot wrote: You need AH meter, a.k.a. battery monitor, not cheap ~$170 and it won't help when you take the battery away for charging. Even with flooded/led battery you can't effectively estimate the remaining charge by looking at the voltage, other than early morning with loads off and before solar starts. Ebay had some $40 re-settable AH meters, maybe somebody will provide a link. If not a monitor, then get LifeBlue Battery, it comes with Bluetooth monitoring, i.e. the "monitor" chip is mounted in the battery case. 2 pounds lighter than Battleborn 100AH. Can't say anything good or bad about either brand. Thank you. I had not heard of LifeBlue and that's a handy feature. Supposedly the solar charge controller I referenced will stop charging when the battery reaches a certain voltage. Same situation with the AC wall charger (https://www.amazon.com/NOCO-G15000-UltraSafe-Battery-Charger/dp/B00PKIBVU0). At this point I'm not entirely clear on how either charger knows when to stop charging but from what I can tell from the manuals and to a lesser degree from user reviews, they seem like they'll work fine. I'm not comfortable with "they seem like," especially with the amount of money that would be involved. I'd rather be sure. So, I appreciate everyone's input here. pianotuna wrote: Back the envelope calculations suggest this... You're correct, and I appreciate you validating my estimates. The solar wattage needs to be increased. I'm waiting until I have the van before I buy additional solar panels since I want to plan the roof space (fan, solar panels, etc.). Unless the van is unusual, I should be able to put 4 x 100w panels on the roof but I'd rather wait until I have the van before buying anything else. If for whatever reason I can't get two additional 100w panels immediately, I can charge the battery from wall AC as needed until the two additional panels arrive. MrWizard wrote: where did you get that 200w to 400w per hour number forget any idea of solar powered electric heat or A/C... I'll need to run two computers for work, a fan, some LEDs, and a hotspot. The computers each use 75w as measured at the wall with a KillAWatt. That's for a fully charged state. If they're charging, it goes up to 85w. So, let's say 80w x 2 = 160w, and the rest brings it up to 200w or a little over. Only one computer would be used during non-work hours. The "400w" number is room to grow. I won't be running heat or A/C (other than a fan) from the lithium battery, nor a microwave or coffemaker. MEXICOWANDERER wrote: Where this runs-off-the-rails is where it goes "portable". I agree, more study is needed. Would you expand on how moving the battery could be harmful? The solar charge controller and the AC wall charger are made for lithium batteries. I am new to this so I may be missing something. If I took the battery out of the van and charged it with wall AC, would setting the monitor to "full" or its equivalent when I put the battery back in the van take care of the situation? 2oldman wrote: Either the Victron bmv700, or when the voltmeter shows float charge. Does that mean that if I use that monitor, or the app instead of the monitor, I'll know the amount of battery used? If so, I believe that would be what I'm looking for. If I charged the battery with wall AC, I'd reset the monitor to "full" when I put the battery back in the van.224Views0likes0CommentsAdvice on Lithium Solar setup
Hello, I'm about to move into a conversion van full-time, 80% boondocking, and would like your advice about what I'm planning. My electrical requirements won't be much. I don't expect to use more than 400 AC watts or it's DC equivalent at any one time, and normal usage will be less than 200 AC watts or it's DC equivalent for 9 hours a day. Currently I have 2 x 100w flexible solar panels and a 600w pure sine inverter. I'm planning on getting a 100ah lithium (LiFePO4) battery ( https://battlebornbatteries.com/shop/12v-lifepo4-deep-cycle-battery/) and a solar MPPT charge controller for it (probably https://www.amazon.com/Victron-SmartSolar-Charge-Controller-Bluetooth/dp/B073ZJ3L13). A big reason that I'd like a lithium battery is because I will occasionally want to bring it with me to a friend's house to charge it from the wall, and 30 pounds in a backpack allows that. Here are my biggest questions: how will I know when the lithium battery is fully charged, and how will I know how much capacity is used or remaining? With lead batteries it's fairly simple because the volts indicate remaining capacity, but from my understanding, lithium's voltage doesn't change much between it's full and empty states (I could be wrong here).11KViews0likes63CommentsRe: Anyone recommend PowerStar batteries?
Good points about the asian-made batteries. I'll stick to USA, and possibly Canada. As for the 6v golf cart batteries, sometimes I'll be in a camper shell on a pickup truck without much ventilation and the batteries would be in there with me. The longest I'd be in it would be 8-10 hours. I'm trying to avoid non-AGM because I hear the traditional flooded acid batteries can give off hydrogen and oxygen, potentially creating conditions ripe for an explosion. Should I worry about this or does that not apply to my situation?1.5KViews0likes0Comments
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